The URL can be used to link to this page

Ordinance 03-032 Adopts County Guidelines for Stormwater Management CITY OF SPOKANE VALLEY SPOKANE COUNTY,WASHINGTON ORDINANCE NO. 32 AN ORDINANCE OF THE CITY OF SPOKANE VALLEY, WASHINGTON, ADOPTING BY REFERENCE THE SPOKANE COUNTY GUIDELINES FOR STORMWATER MANAGEMENT AS THE INTERIM GUIDELINES FOR STORMWATER MANAGEMENT OF THE CiTY. WHEREAS, the City of Spokane Valley will incoiporate on March 31, 2003; and WHEREAS, the City of Spokane Valley desires to adopt Guidelines for Stormwater Management within the corporate limits of the City; WHEREAS, Spokane County adopted Guidelines for Stormwater Management dated January 1981, with subsequent amendments and addendums, which included the areas within the City of Spokane Valley; WHEREAS, after the date of incorporation, the City intends to review, revise and, as necessary, develop its own Guidelines for Stormwater Management. NOW, THEREFORE, the City Council of the City of Spokane Valley, Washington, do ordain as follows: Section 1. Guidelines for Stormwater Management. Pursuant to RCW 35A.1 1.020 and 35A.12.140, the City adopts by reference the Spokane County Guidelines for Stormwater Management dated January 1981, with subsequent amendments and addendums which is attached hereto as Exhibit "A" and incorporated herein by this reference as presently constituted or hereinafter amended as the interim Guidelines for Stormwater Management of the City of Spokane Valley. Unless the context requires otherwise, references to Spokane County shall be construed to mean the City of Spokane Valley and references to County staff shall refer to the City Manager or designee. Section 2. Adoption of Other Laws. To the extent that any provision of the Spokane County Code, or any other law, rule or regulation referenced in the attached Guidelines for Stormwater Management is necessary or convenient to establish the validity, enforceability or interpretation of the Guidelines for Stormwater Management, then such provision of the Spokane County Code, or other law, rule or regulation is hereby adopted by reference. Section 3. Reference to Hearing Bodies. When the attached Guidelines for Stonnwater Management refers to planning commissions, board of appeals, hearing examiner, or any other similar body, the City Council shall serve in all such roles, but retains the right to establish any one or more of such bodies, at any time and without regard to whether any quasi- judicial or other matter is then pending. Page I C:I,)ocuments and Settings\rmulIcr\Local SettingslTemporary Internet Files\OLKI l\Ordinancc I'Io.32.doc Section 4. Modification of Guidelines. The responsibility and authority for developing recommendations for modifying and monitoring the effectiveness of the Stormwater Management Guidelines of the City of Spokane Valley may be delegated to City Council Committee according to Council Rules. The Council Committee shall work with the City Manager, designated staff and others to provide for stormwater management and development of related facilities that promotes the orderly development of the City and serves the best interest of the residents. The Council shall periodically review the Guidelines for Stormwater Management and modify and amend the same from time to time, as necessary. Section 5. Uniform Code - Copies on File. The City Clerk is to maintain one copy on file of the Guidelines for Stormwater Management adopted by this ordinance. Section 6. Liability. The express intent of the City of Spokane Valley is that the responsibility for compliance with the provisions of this ordinance shall rest with the permit applicant and their agents. This ordinance and its provisions are adopted with the express intent to protect the health, safety, and welfare of the general public and are not intended to protect any particular class of individuals or organizations. Section 7. Severability. If any section, sentence, clause or phrase of this ordinance shall be held to be invalid or unconstitutional by a court of competent jurisdiction; such invalidity or unconstitutionality shall not affect the validity or constitutionality of any other section, sentence, clause or phrase of this ordinance. Section 8. Effective Date. This Ordinance shall be in full force and effect on the official date of incorporation provided publication of this Ordinance or a summary thereof occurs in the official newspaper of the City as provided by law. PASSED by the City Council this , 1 r-day of February, 2 03. Mayor, Michael DeVleming AT • interim City Clerk, Ruth i uller Approved As To Form: i eri rity A . ey Stanley . Schwartz Da .f Publication. /yAv=.c4. Z 11 Zmo3 Effective Date: Ki\a,,e,Z, 3I, X 03 Page 2 C:\Documcnts and Settutgslrn ullerlLoc.al SettingslTemporary Internet Files MOLKI llOrdinance No.32.dcc _ - w .,}1' r„�-. • .-h S--'17,.-:----r". ---.7 ,fj yi �t lr y r=-..-..-,-. e ti , 5. 1 ' + Yrt %.• v � 1 5` '-''''F",--9� t ac , --"'•".,-:'"',7 R! r ��ar t -+s2 t .1 ,,� t' • t t rt .x ' t ,•ci p i �f ' •? r ' I 3 ,e• t n t t 7 7 a� °-- t -0•• ', F✓d I• "" ..i „s:'L 7 ,1 y i✓ ? 3J,.�1 ',' f ;`P t'F7. 1 .1. / ✓' 7'��S ^<2 .. u 1 '- I f, r a 1 tr �•� 1, �, r r 4 '4 -i 1 'ar • N X"'-'4.-1 ? .� ;'''.:;,:',„;%-- � 3 -D `r ir. 1 --1%-------7,-,17,1.7 L "...Y..'"F- - - v C _� t .,,,-,r, .'J`.. I Y to t �• i''rx jC 4 y .� A a 7 A ,ds r< .A"r7t X <4,-..-::‘ e-r i�r �' '-,,,:::::5;,;-7±;:.-:';':,� p5. n5t1 _ + x � q � 7 "=-. *7 r �' 'III."' � � .1 "'t:' 1,7i'`,-:, •r ' � 't:• ‘,'._ �1..• -=`;-."r'S7 4,1 tip. Mr �� 7.y Y r�- ', ; '!`. - •7„,..%_ Cd ..`X14 l t,• . y '- 1. t Y ,- t_ f 4 :1� , t Si. ' e y t -, , ti• r- r11 !1 p . a , ` H r' t S -.i 'O _ 1 5 A t .� r-'? 4,--. S y ir- • 4.c.,i 3 y� '+ _` :r b 1, ,,,-, M ni ':-...:-..,c-. - 1y c e V l• J ' f-7-"-'' 1,-' .Q ^ a x r i � 7" r ' t rs> ' t I .'1 2 � f■ i s ra 1 S c \,... " -.t v e _ • r a i S q. F r ) t t 11 I'III ,• :� r `* I ^_F. r _. �' ,; �.; , h: t. ', k a• ,� .`%e4. n'"•4 ,.,' ,. y 1 } j .y'ti r - t tr t V U• ® 1 I �!T. 4® f � k^e J=1 i - _ ' P" tI .Y.ry c�.c t ,ter )v? a iF.. 1'1 r S• }I J t.,..--,f F.ad 4 'za; . K `_,e .i6 e f I . v -} 4' 1 L ? L 7.•••,`... ,ht 'I is r'�• s 1i to t1 •F >,..• 'i'4 3, K 3F -t' y l r 4 a • '"i- i it L? F I e,n 9,v i .n .t • r - ■ _. ,>_ r�.. �.;fir•. N 7'" v� � _J z r 4!. v1� F ,,i � b- x (f;'� ,.! f .f "AZ f L N_ } tom .." t,f G.'Y '1 .0�1' t --.+ 'a 1 �'$,.,T. _ eX" }- . .3 c 1.IS A 7; ..� > -'r71 i- _!: ; r ,r � jt &itëiT_r _ : . .�I€hii, àTinsiôt S.t®F r � i iN d' ' ' I � �- �••'a'v G �`' , .`� � x, � • � .J, � pp 'Fs w-c t � "" r A at ._.,_ , yLi *... P t lx �` -f f I 1-t � �r 1 : l i 1 ,=- 1T . r yv,�_ X� ,.t -. a =au '. rd?l -..M,. t.: a 41' X4 .`yr i p`'� 'y ` f "�z � ° ,,- r'4".e•F.. v `o tit . rt .✓ ht ,. .=)--,-;"-. .''''27'r i ; r-• ' r 1 t �" , 1. ,4, �• .t- t 7! , 147 ' ;44, �. S'',':, '•.• r ° -s * °94, 7 1 h S ,� ! 11' .j i. �y - c C �a .• t4.3 ai. .} Y ;`7,,;z'. .,;:,', P 1 ._l ,, < ' S . ,- mss• I ...h _.:! ..it:_ - M . s r. F 1< , • .%,-:‘ ,-,-.-;- --:-_ .� I . 'mod- T S _ (:- } �u� x•.a ?e !i t � � a � 'x i �.�' :t S_It 7~"LZ' ;rr tti 1�( 11 ,7 � C. - 3• , v. ° .,y `4 . -rr y_ 1 t1• to rc `•L1- IY l'• ; ,L - I 1.1 t •'. I L- S [`M' r' Cfti I'a:.1...r!'„ _ R r - 1 , . . ''.f ' C• -J-. k + t..� ''''I'''S `aY._7 -, +.� ` .x f ' N3.?-r '''x'.4 rt -1',.-.) e'1-,--;',.,-/ .c t - `,_ ', ' rr k .� " ._ _ .;.• is- .-,� ' .1.:'''',..•,1' ! lt?Y° Ij f r •X ',• �' . a :,�,' __ -' e-.. ' '._ 2 .f•7_ �r.' ",. - rt ate. ♦ 3,• _ 3 .y ,'..,r''._.% 71 { � c •1 y+ s .'--;-::',3r:. �>f ; HF-rte- X n'''.1 Y- '':.-•:rd_•_ a ^•; 1 ' I e .5: .41 r v ``i4-1.,,r i i `" r-2 rr e' Or z a .`r ':,;-t.--„+""-2 4 '• I.. • f t 1 .,.=,..'-- 1 :. n 1 ,_ � . 'i' ..:,1-.c.-,.--4:`";1:17 PL''"2-t.':'::- ,:-c:• 4.. ,, R 1 ,x ti,. - ,. ✓ h ,,,I,,-.1.1'.,'' : u ',4 a ."7.,- - .i d` -1 v;, T?-,,„..• r ; ;:,'...-.4:, .:. 1 ., s d I i a,s • .c t ty,�.Y, `... rl r J• ,c2 �:itic1V t�� _ c t c 1 t '.:4:',.- t`', -.. .7-s.;; 7 i '' n1 ,} - '* _ d .tT 4h J'' r ....-1,,,,,...,..t r ti.' , �`ti! I„ _ _+t d Y �, ` ' t.. �, LE', r _ r r fb f.'1'."''*:, .c,� .4,,,..',;:7.,' S�t - �+4 .. �y.7 L f �ws; D FJ ) ..? _ c t ? y 1 a^ i 1 't`�y a_�' 4 tit• ( Jd. rt 1•°'ir_7_,,,•,:?...-:--=.-R 'c• -fyS +._ = 1...3� .�; r.,:"fii+ ,., - �� • e Vlai 1' Oo O Et ��.P hhp 4.nrksVx :r< 7+• 7` Jy' .„V .c3,I'�,• �r;,c .'�-J' }t' -s. 'r el � ',,,,,Y+` `_ii � � " �•F,..-. Y 4. '.�cL-4 J_`a/ ';r:-.t •r-.. �'' �f,' S,. 4 Z FI,.. S s f t ... 4.tom.' �:' -r} 1F of-C.;-.,. p :i t� Divlj fr of Etjneer�ng & Raads ,Y �� ,� < i' 5 a r S.-r i`4 .: y' i ) F,t{ e o t? u .7-.."5;7','•,' V J '^ c o.. f- 1:I.-1''^t t o- < t V• �.=.1:'.!., al y-�21 ty �. r -', t C7 t'X �`2 7F4 • w a.�, ��,' �vr ,,--?-.1;1---`1`.P4 r.�y n ,g ot_.� ^ r -:��.. ,Lr } ..YYi1 .-I -rte 7 S 44 ,a i v x i� Inlues{Ad4denda ®ugh�Feb 111w998t �yyy • ; =A -.'-.:=7.'','t t� 1 4z, LPG` • n 3 : S Js' s � -.z 'ti Mt `' iyc a a + lfa zzy a� L z y. a Lc °- <j tom .a. • ';• i' t a-1 S I "‘"'•'4'1.- A- •''' '2�7t: i 1 '�. 'Y°+1•y:�35 r ..<, c- y.7 -i+ ., y` - 4,r'✓ t y 'L r Ct +). tiM1 •?}-d u - Y4- ,r'f k-.4, -'r ':6. x 6 ri5' v w 1,, n , r". r'a,- si }3 y ail' ? r -;'-:`7!, x T1 t 1� • , t .,,, °,[�y `' `#3'4c?,-';',.:!,,:.' 1,1,..",:;- :� S ,m rc fr r� ,I• L c ''-_-1'14. f. .,. 'k ha. � �� c � yr L '^ r� � v t _`' y '�*tl v .-.:t -�� ^ A,' r l ,y *4`. 4- :'"f'''; + z tr;• ; i -,,_,.r t -; ,:7:' .. R -14:,4's r k. z �K r+ 4:,- i• ` r )'t ,`' t ''' 'L r i 5 v s f `> ;9 7.,F'c ir. n t ' ) r.z 1 r{� e -'-4:-'7 Win, o 6-1 "rs J(:. -,:z4:1'. (,- v1. '--.-_4';'- ,, .- :?- icy ?'J ,f }cs a t t t 8, - Ev •rs-fr- tr 1 R iJ 7:: t :,.;3'.1."...`4:,..":' 'F� t �, r a p, t r-'...,11,); _ {. rj� K Y 2.•i L, _.t rl j` r 1 > $ 11 'n < '%_-'4\4-1:c.j ° •t.t E v t r0 ,:f s ti '2- ii•f_•c' rti " f,t :p i i.; R K+ C ~ ' J • --7,7 _.�;., t •� u° t , .'1i'1,;"' :'''''•• ',CST r . 41 t1 at1 ue' -,te C t i c x, a +,r -' .r` ^ k 7: • �"`� ,c'•.:+ is I �e. a-s '`mac � � ..... ...`1; =a.;'(,,°., � -,`^'r'__C .:1_,...7- ��'Y 3'ts' # 3jr :< + s ' v � -.E Z. 'r.' uc{ 1 F x r .) a Y:.`L''",',4,Z.,,:4",",{?t t - i t ::,,..7-1, - - `n- 4'''..r r s< ''.....r.' .�,;' .} . ,- -. Y +c.,).. s ,.Z a_. y 'c :c = K ' t _ �` - .} E ,`+°j r�Y "eI'6+ --c.:;:t.1..u.:._......y.,......�.:.sL..n�.c.� '' ;. t,:iLo.:.�l a '_ _ _,.., 1•', n ! Task Force on the Guidelines for Stormwater Management Spokane County Public Works County, Engineer Editors (Spokane County Staff Original Document (1980) Robert S. Turner,P.E. James S. Haines,P.E. Gary S.Nelson, P.E. Revisions& Addenda Robert S. Turner,P.E. Gary S.Nelson, P.E. (1981 - 1986) Addendum (1990) Ronald C. Hormann,P.E. Gary S.Nelson,P.E. Addendum (1998) • William A.Johns,P.E. R. Dean Franz, P.E. William H. Hemmings, P.E. James A. Radke,P.E. • Geotechnical Engineering Committee Provided Guidance for the 1998 Addendum Steve Burchett; P.E. - volunteer Jerry Peterson, P.E. -volunteer Alan Gifford, PE. - volunteer James Radke,P.E. -County staff Jim Harakas, P.E. -volunteer Gary Squires, P.E. -volunteer Bill Hemmings, P.E. - County staff Mark Storey, P.E. -volunteer , 1 . Guidelines for Stormwater Management iii Spokane County Public Works: February 1998 F O R E W O R D This manual has been prepared to provide • engineers and developers with informa- tion regarding drainage requirements for land development within Spokane County. It also contains design procedures and aids to be used in development of drain- age facilities. It is not intended to be. a. textbook of • hydraulic engineering. It is a refer- ence book of instructions. It is not presumed to cover all conceivable prob- lems that may arise, but it is believed • to be sufficiently comprehensive that its provisions along with good judgement will provide a safe guide for engin- eering practices. t iv �- Table of Contents Letter from County Engineer iii Task Force on Guidelines iv Forward Table of Contents Section Titles Section 1 General Requirements 1-1 Section 2 Drainage Submittal 2-1 Section 3 Hydrology 3-1 Section 4 Drainage Design - 4-1 Section 5 Control of Water Quality 5-1 Section 6 Tables and Charts 6-1 Section 7 Glossary of Drainage Terms 7-1 Appendices Appendix A: Hydrologic Soil Groups Appendix B: Standard Notes for Construction Plans Appendix C: Examples 0 Appendix D: Sediment Yield: Flaxman Method Appendix E: Seed Mixtures Appendix F: Easement Exhibit Requirements & Lot Plan Requirements Appendix G: Inspection Agreement Form Appendix H: Civil Site Plan Requirements, Checklist Appendix 1: Geotechnical Site Evaluation Requirements Appendix 3: Climatological Data: Monthly Averages Appendix K: Erosion and Sediment Control BMP Manual References Index Section 1 General Requirements Sub-Section Description 'me. General Requirements 1-1 Addendum (February 1998) Standard of Care 1-2 Applicability 1-2 Design Deviation Process 1-2 Maintenance of Drainage Facilities . .. 1-3 Drainage Easements and Tracts 1-4 Guidelines for Stormwater Management Spokane County: April 1998 Section 2 Drainage Submittal t( Sub-Section Description page Drainage Plan 2-1 Computations 2-1 Construction Plans 2-1 Drainage Review 2-1 As-Built Road and Drainage Plans 2-2 Addendum (February 1998) Construction Plans 2-3 Drainage Report 2-3 Downstream Analysis 2-4 Lot Plans • 2-4 Geotechnical Site Characterization Studies 2-5 Record Drawings 2-6 Concept Drainage Plans 2-6 Floodplain Requirements 2-8 Section 3 Hydrology Sub-Section Description page Design Storm (On-Site) 3-1 Rational Formula 3-1 Soil Conservation Service Method 3-2 Runoff Curve Number 3-3 Addendum (February 1998) Hydrologic Modeling 3-5 Drainage Ponds 3-5 Detention Systems 3-5 Infiltration Systems 3-6 Design Storm Events & Surface Discharge 3-6 Closed Depressions 3-7 Curve Numbers, SCS Method 3-8 Evaporative Systems 3-9 Section 4 Drainage Design Sub-Section Description page Inlets 4-1 Culverts and closed systems 4-3 Channels and Ditches _ 4 714 Guidelines for Stormwater Management vi Spokane County: April 1998 • . Sub-Section Description Section 4) ............ .... ...... Detention/Retention Systems. . 4-15 Drywells 4-15 Storage Facilities 4-15 Erosion Protection (DELETED - See Addendum below) 4-24 Addendum (February 1998) Standard and Non-Standard Subsurface Disposal Systems for Stormwater 4-26. Conveyance Systems: Closed Pipe Systems 4-26 Conveyance Systems: Culverts 4-27 Conveyance Systems: Gutters. Ditches& Natural Channels 4-27 Hydraulic Jumps 4-28 Riprap & Channel Stabilization 4-29 Hydraulic Structures, Energy Dissipaters& Outfalls 4-30 Detention Ponds - Berms& Maintenance Access 4-30 Addendum (April 1998) Erosion and Sediment Control 4-31 Section 5 Control of Water Quality �t � Sub-Section Description page • General Criteria 5-1 Addendum (February 1986) 5-5 Addendum. (1990) 5-6 Addendum (1986): Modified Rational Method Hydrographs 5-7 Addendum (February 1998) Grassed Percolation Areas 5-18 Large Grassed Percolation Areas 5-19 Curb Drops for Grassed Percolation Areas 5-19 Grassed Percolation Areas- Alleys 5-19 - Section 6 Section Tables and Charts Label_Chan or Figure Description __page -Table 1 Runoff Coefficients for Storm Sewers 6-2 Figure 2 Rainfall Intensity-Duration-Frequency Curves . 6-3 Figure 3 Time of Concentration Nomograph 6-5 Figure 4 isopluvial Map of Spokane County, 10-yr, 24 hr storm 6-6 50-yr, 24 hr storm 6-7 t Table 5 Runoff Curve Numbers for Selected Ground Cover 6-8 Figure 6 Acquifer Sensitive Area Map 6-9 • Guidelines for Stormwater Management vii Spokane County: April 1998 Figure 7 Hydraulic Length and Drainage Area Relationship 6-10 Figure 8 Peak Rates of Discharge for Small Watersheds 6-11 i f' Label Chart or Figure Description page Table 9 Slope Adjustment Factors by Drainage Areas 6-14 Figure 10 Isopluvial Map of Spokane County, 2-yr, 24 hr storm (1998) . . . 6-15 Figure 11 isopluvial Map of Spokane County, 100-yr, 24 hr storm (1998) . . 6-16 Table 12 Omitted, pages left blank 6-24 Table 13 Manning's Roughness Coefficients (n) 6-34 Figure 14 Capacity of Grate Inlet in Sump 6-35 Figure 15 Capacity of Grate on Continuous Grade 6-37 Figure 16 Capacity of Curb Opening Inlets on Continuous Grade 6-38 Figure 17 Nomograph for Capacity of Curb Opening Inlets at Low Points . . 6-40 Figure 18 Nomograph for flow in Triangular Channels 6-42 Figure 19 Pipe Flow Charts 6-44 Figure 20 Nomographs of Culvert Flow Characteristics 6-50 Table 21 Entrance Loss Coefficients 6-52 Figure 22 Culvert Design Worksheet 6-53 Table 23 Stage-Discharge Relationships for an Orifice 6-54 Table 24 Permissible Velocities for Channels 6-55 • Addendum (February 1998) Figure 25 Maintenance Access Requirements 6-57 , Figure 26 Hydraulic Elements of Culvert Design 6-58 Figure 27 Description of SCS Hydrologic Soil Groups 6-59 • Figure 28 Description of Antecedent Moisture Conditions (AMC) 6-60 Figure 29 Mean Annual Precipitation of Spokane County 6-61 Figure 30 Flow Regimes for Open-Channel Flow ' _ 6-62 Figure 31 Head Losses at Structures 6-63 Figure 32 Head Losses at Structures, Combined Flows 6-64 Figure 33 Types of Hydraulic Jumps . 6-65 Figure 34 Sizing of Riprap Revetment, Nomograph 6-66 Figure 35 Riprap Placement on Slopes 6-67 Figure 36 Channel Side Slope Velocity for Sizing of Riprap 6-68 Figure 37 Gutter Flow Widths in Roadways 6-70 Figure 38 Culvert Flow Characteristics with Inlet Control 6-71 Figure 39 Trash Rack Detail 6-75 Figure 40 Pipe Anchor Detail 6-76 Figure 41 Stilling Well Energy Dissipater 6-77 Figure 42 Gabion Energy Dissipater 6-78 Figure 43 Relative Energy Loss at Hydraulic Jumps 6-79 Figure 44 Oil-Water Separator - Details 6-80 Figure 45. Riser Inflow Hydraulic Characteristics, Nomograph 6-81 Figure 46 Riprap Revetment at Pipe Outfall 6-82 Figure 47 Pond Berm Minimum Criteria, Typical Cross-Section 6-83 l, Figure 48 Grassed Percolation Area, Typical Cross-Section 6-84 Guidelines for Stormwater Management viii Spokane County: April 1998 11 STORMWATER MANAGEMENT PROCEDURES AND METHODS 1. General Requirements All stormwater originating on any proposed land All storm water drainage systems including developments, roads, and all areas draining thereto collection, conveyance and restrictions,not located on shall be estimated as to rate of precipitation and the County property shall be so located in public percentage of runoff in accordance with criteria drainage easements approved by Spokane County. hereinafter stated. Said estimates of precipitation and All drainage easements shall be shown on the runoff shall be the basis of a drainage plan which Construction Plans and on the Final Plat. shall be prepared by a Professional Civil Engineer and which shall be submitted to the Spokane County Lands that lie within "flood hazard zones" as shown Engineer's Office for review and approval. on the appropriate maps prepared by the Federal Insurance Administration, shall comply with the Unless specifically approved otherwise by the County regulations of the National Flood Insurance Program. Engineer, the rate of stonnwater runoff from any proposed land development to any natural or All development within the aquifer sensitive area as manmade point of discharge 'downstream such as shown on Figure 1-1, where deemed feasible by the sewer or ditches, shall not exceed the peak rate of County Engineer, shall incorporate stormwater runoff for the design storm occurring prior to the treatment to mitigate the potential for groundwater proposed land development. In the event that waters degradation. Requirements and methods for from this development drain into a critical flood, complying with their are discussed in Section 5 of drainage, and/or erosion problem area, as determined these guidelines. Any system or method which can be by the County Engineer, the quantity of water from shown to the satisfaction of the County Engineer to this site shall be restricted to the existing quantity provide contaminant removals equal to or better than leaving this site prior to development. In the event the method discussed in Section 5 may be employed. that runoff from a proposed land development has in the past discharged directly into a relatively large body of water such as a lake, river or has or could discharge into such bodies of water to accommodate anticipated increased runoff from the proposed land development, then it shall be the sole decision of the County Engineer to permit or not permit such increased runoff to said bodies of water from the proposed land development. Restriction of stormwater runoff from any proposed land development shall be effected by stormwater holding facilities either open or closed or by introduction, on-site, of stormwaters into permeable soils via an infiltration system. Under no circumstances shall drainage be diverted in the proposed development and released to a downstream property at points not receiving drainage prior to the proposed development. Flow may not be concentrated onto downstream properties where sheet flow previously existed.' Guidelines for Stormwater Management 1 - 1 • Spokane County: February 1998 Addendum To Section 1 plans and calculations. The responsibility for (';'; (Effective: February 1998) adhering to these regulations for design and construction lies with the project sponsor and its agents. Standard of Care The sponsor is responsible for coordinating its These guidelines should be considered as minimum consultants, providing complete submittals, ensuring requirements to be used in design of stormwater adherence to the Hearing Examiner's Conditions and facilities. It may be very common for a design that County staff conditions, and general project utilizes good engineering practices, as required by fit. Spokane County Code, will need to exceed the requirements of the referenced guidelines due to The sponsor is required to obtain acceptance of the special site conditions, other applicable laws and construction plans from the County Engineers Office environmental constraints. Good engineering practice prior to final subdivision approval, final short plat is defined in these standards as being professional approval, issuance of a building permit, issuance of a. conduct that meets all applicable laws, rules, road approach permit for a private road, and other regulations and the "state of the art" for professional land use actions, as defined in the Spokane County practice in the.State of Washington. Code aid by County Resolution. It is incumbent upon the design engineer to be aware Drainage and road plans prepared for roads or road of, and to implement design practices and procedures approach construction, shall be done in accordance which reflect the current "stale of the art" in design with these Guidelines and the Spokane County practice, and to provide sufficient mrasures so that Standards for Road&Sewer Construction. the drainage facilities function as intended in the (`. design. The mad, approach, and drainage plans shall, upon recommendation of the County Engineer, be required •Where these standards may be found to be in Conflict for building permits involving new construction or with the"state of the art"of professional practice: substantial improvement(per Resolution Number 80- 1592, Section 11.07, and County Code 9.14.020). a) The design engineer shall notify the County Substantial improvement means any repair, Engineers Office, by providing a written reconstruction, or improvement•of a structure, the description of the section in COlIflict, and the cost of which equals or exceeds 50 percent of the "state of the art" of professional practice as it current appraised value as set by and found in the relates to that section. records of the Spokane County Assessor's Office, and is applicable for either: b) The more stringent standard, or the procedure resulting in the more conservative design shall 1) before the improvement or repair is started,or govern,unless specifically allowed by the County 2) if the stnuxure has been damaged and is being Engineer through the approval of a Design restored. Deviation application. Design Deviation Process Applicability Any nonstandard subsurface disposal system, (as Any person, including municipal corporations and defined in the addendum to Section 4), or any other political subdivisions, applying for permit and/or nonstandard drainage facility, or any request for a final approvals shall submit for acceptance, in deviation from these minimum Guidelines, shall be (t conformance with these standards, proper drainage evaluated by the Spokane County Engineer's Office Guidelines for Stormwater Management -Addendum I -2 Spokane County: February•1998 using the Design Deviation application process. For facilities applicable to the maintenance plan, which is consideration of a Design Deviation, the applicant to be a general site plan on a single sheet showing the shall submit a Design Deviation application, overall layout of the site and it's drainage facilities, supporting documentation, and an application fee. such as footprints of ponds, pipe systems, streets, Supporting documentation shall include all relevant etc.; and 5) recommendations for providing annual drainage information needed for the County Engineer set-aside funds for annual maintenance costs and to make a decision as to the adequacy of the proposed future replacement costs in the form of a sinking fund drainage facility or design. This normally will for the portions of the drainage system that will need include a drainage basin map, a plan view and typical replacement or major renovation in the future, as cross-section of the proposed facility;and supporting described below. As a preface to the maintenance drainage calculations. If infiltration is proposed,or if plan, the Sponsor's engineer shall wort out a negative impacts on down-gradient properties are of proposal with the project Sponsor and Spokane concern, or if seasonal high groundwater elevations County, describing who, or what entity will be are suspected, then a geotechnical report shall be responsible for the perpetual maintenance of the submitted along with the Design Deviation drainage facilities. application. Maintenance access drives shall be provided to all The applicant shall acquire approval of the Design drywells, flow control structures, storm manholes, Deviation prior to submittal of road and drainage catch basins, and drainage pond bottom areas for construction plans.Normally design or administrative detention ponds, evaporative ponds, or•infiltration conditions are attached to an• approved Design ponds. Maintenance access drives shall also be Deviation, which the sponsor shall be required to constructed along one side of a drainage ditch or as . adhere to as part of acceptance of the design or shown in Figure 25. Maintenance access drives are t. constructed facility. If any or all of the conditions to consist of an all-weather, driveable surface, 12 ft. are not met,then the Design Deviation approval will or greater in width, within a 20 R minimum width be null and void. tract or easement, extending from a public or private • road, and with a maximum grade of 20%:. The In the event that the Design Deviation application is driveable surface•shall be designed to carry the load not approved by the County Engineer, then the of a 48,400 lb. truck-with a 20-yr surfacing design Sponsor may submit a different proposal for life, assuming three trips/year:An acceptable design consideration in the form of a new Design.Deviation procedure for determining the thickness of a gravel application or adhere to these Guidelines for maintenance road is the USDA Forest Service Stormwater Management. computer program, version 2.00. Gravel maintenance roads shall be a minimum of 6 inch thickness of crushed• surfacing top course, in accordance with Maintenance of Drainage Facilities WSDOT Standard Specifications. For drainage ponds and other drainage facilities The horizontal alignment of the raaintmance access located outside of the public road rights-of-way, the drive, shall be designed and constructed to Sponsor shall provide for perpetual maintenance of accommodate the turning movements of a 40 R long the drainage facilities. For drainage facilities serving bus as defined by AASHTO. (See AASHTO Fig. II- single-family residential neighborhoods, or other 3, 1990 Edition_) A turn-around is recommended for land-use actions (as deemed necessary by the County all maintenance access drives. If the maintenance Engineer), the sponsor's engineer shall prepare a access drive is greater than 300 ft. in length, a turn- written maintenance plan. The maintenance plan around is required -at or near the terminus of said %l shall include, as a minimum: 1) a description of access. The maximum separation between a maintenance work to be performed; 2) frequency of maintenance access drive and drainage structure is as maintenance.activities; 3) expected design life of the shown in Table 1-1 and Fig. 25. various components; 4) an exhibit of the drainage Guidelines for Stormwater Management -Addendum 1 -3 Spokane County: February 1998 Type of Drainage Maximum Separation the drainage facilities will be sustained. See sample t 1 Facility or Proximity Requirements calculations in Appendix C.5 for determining annual Drywells, adjacent to 8 ft. separation from edge of Costs per lot. access drive• driveable surface Drywells, at terminus 3. ft. separation from edge of of access drive, driveable surface Drainage Easements and Tracts Storm manholes, 0 ft. separation catch basins, inlets(I) • A closed depression and a Grassed Percolation Area Drainage ditches Parallel and adjacent to ditch (GPA) with surface water storage encompassing an Note: (I) Maintenance access is not required for inlets area g r than 1,200 sq. ft., which is located on when they are used within a Grassed Percolation A . one parcel, and in a single-family residential and the inlet connects by pipe to a drywell which does neighborhood, shall be located in its own separate have maintenance access. tract, with ownership and maintenance arrangements as described herein. Maintenance Access Table 1-1 Detention ponds, infiltration ponds and evaporative ponds, which are located in single-family residential neighborhoods, or other areas (as deemed necessary Gates are to be provided where drainage facilities are by the County Engineer), shall be located in separate fenced. The gates shall provide a minimum of 12 ft. tracts. Storm pipes or drainage ditches are to be wide opening, with provisions for locks. To placed within 'a separate tract- when all of the minimize the unauthorized use of maintenance access following are applicable: drives, separate gates may need to be installed where • the maintenance access drive connects to a public or • the storm pipes or ditches are County maintained: (': - private roadway. • the storm pipes and ditches are located outside of County road right-of-way. Sinking Fund: For single-family residential neighborhoods, or other areas (as deemed necessary The minimum tract width shall be of sufficient width by the County Engineer), the sponsor shall normally to be able to have access to, maintain, repair or be required- to ,provide a sinking fund for future replace without risking damage to adjacent structures replacement costs of drainage facilities that he and immuring costs for shoring. outside of accepted public road rights-of-way. The sponsor's engineer shall provide to the County a list For privately maintained drainage facilities in of drainage structures and appurtenances listing the residential neighborhoods,a homeowners association, expected date of replacement and associated cost. or alternate entity acceptable to the County Engineer, The sponsor's engineer shall compute a fund'reserve shall by formed to maintain the tract(s)or casements. amount, also considering probable inflation over the Maintenance responsibilities are to be listed in the life of the materials or structures, which provides a maintenance plan prepared by the sponsor's engineer summary of the amount of money to be set aside and accepted by the County Engineer. The annually for said fund. The,sponsor shall prepare a homeowner's association and property owners financial plan to create a sinking fund account based association covenants shall include provisions for upon the its engineer's work, and submit a copy to adequate maintenance and replacement of drainage the County Engineer. Upon acceptance of the facilities it is responsible for. The sponsor shall financial plan by the County Engineer, the sponsor submit for acceptance copy of the covenants which shall be responsible for providing an• acceptable demonstrate that the maintenance requirements are mechanism for initiating and sustaining the account met. in accordance with the approved financial plan, which will be to ensure that perpetual maintenance of Guidelines for Stormwater Management -Addendum 1 -4 Spokane County: February 1498 For commercial developments with privately maintenance. All permanent easements which are maintained drainage facilities and multiple owners, a recorded separate from plat documents, shall be property owners association or similar entity shall be recorded with an exhibit as specified in Appendix F, formed to maintain said facilities. and in a format acceptable to the County Assessor's Office. Man-made, open drainage ditches proposed to be constructed through residential lots, are not permitted Easements for drainage ditches and natural drainage unless a Design Deviation is acquired. For open channels shall be wide enough to contain within the drainage ditches and natural channels located in easement the runoff from a SO year, 24 hour storm residential neighborhoods, the County Engineer may event, for the contributing stormwater basin, plus a require the limits of the easement or tract, (which the 30% freeboard. The easement shall also include an ditch is located within), to be delineated with a adequate maintenance access for the drainage course. permanent fence. The fence is to be shown in the road and drainage plans and constructed by the Easements for storm pipes shall be of sufficient width sponsor, at the same time the drainage facilities are to be able to have access to, and maintain, repair or constructed. All residential lots that have natural or replace the pipe without risking damage to adjacent man-made open drainage ways that cross any portion structures and incurring increased costs for shoring. of the lot, said lot shall be of sufficient size that the No storm pipe in a drainage easement shall have its following condition is satisfied: centerline closer than 5 feet to a private rear or side property lines. There is a minimum distance of 50 ft. between the building pad location and the edge of the drainage easement, delineated with a buffer easement. Fencing or other barriers may be required by the County Engineer to protect the health, welfare and safety of the public. If a GPA is less than 1,200 square feet, then it can be placed within an easement. Closed depressions less than 1,200 sq. ft area can be located within an easement granted to the entity responsible for maintaining the closed depression, and, Spokane County. See Section 5 which provides detailed information on GPA. Drainage casements shall be provided for any drainage facilities which arc located outside of County road rights-of-way, with the easements granted to Spokane County and the entity responsible for maintaining the drainage facility. The easement document shall include language prescribed by the County Engineer, and for public record be recorded at the Auditor's Office by the County Engineer's 1- Office following review and acceptance by Spokane - County. Said easements shall be granted to Spokane County for ingress and egress to the tract for purposes of routine or emergency inspection and Guidelines for Stormwater Management -Addendum 1 -5 Spokane County: February 1998 2. Drainage Submittal 2.1 Drainage Plan - When a drainage plan is called f. Invert elevations of the existing or other for as a condition of approval of land development proposed drainage system to which the proposal, said drainage submittal shall incorporate drainage plan proposes to connect. the best available topographical maps to clearly g. Stationing of all inlets, culverts and pipe define: (1) The proposed development; (2) All systems angle points areas, improved or unimproved, lying upstream and h. Invert elevations of pipes at all structures draining to and through the proposed development; such as catch basins or manholes and (3) Drainage courses, natural or otherwise, to i. Construction details for inlets, drywells, which the proposed development shall drain, detention facilities,etc. (notes referring to Standard plans may suffice where The drainage plan shall include all existing and applicable) proposed drainageways within a drainage easement. j. Drainage easements with all survey Whenever possible, an overflow drainage easement information shown shall be provided at all low spots. Drainage easement k. The location of existing underground and language will be supplied by the County Engineer. above ground utilities 1. Lot grading elevations where appropriate 2.2 Computations - The drainage submittal shall incorporate all calculations for the determination of 2.4 prainage Review - Two sets of prints of the the required size of the systems. Said calculations drainage and construction plans signed and stamped shall be based on the required criteria hereinafter by the design engineer and one set of computations stated and rigid analysis of estimated runoff from shall be submitted to the County Engineer's Office areas contributing runoff to those facilities. for review and approval. A print of the proposed Calculations that shall be submitted shall include but final plat map shall be submitted prior to plan not be limited to: approval where street layout and lot numbering have a. Hydrology computation been changed from the preliminary plat map. b. Inlet Capacities c. Detention/Retention storage capacities When plans are returned to the design engineer for d. Culvert and pipe system capacities and corrections, any changes by the design engineer must outlet velocities be marked on a revised print in color and returned. e. Ditch capacities and velocities The date of these changes must be indicated and f. Soil map with the project plotted then= colors red and yellow are reserved for County cocruneats. 2.3 .Construction Plans - Construction plans shall To help expedite the review of a development, the be prepared for all open and closed stormwater sponsor or his engineer may request a special meeting collection systems. Said plans shall call out all • with the County Engineer's Office following. his hydraulic and physical data such as, but not limited receipt of the initial review comments. However, to: before this meeting, the sponsor and his engineer a. A plan-profile of all systems should review all initial comments and be prepared to b. Invert elevations, slopes and lengths of discuss alternate solutions. ditches c. Cross sections of all open ditches Drainage plans, construction plans and calculations C d. Elevations of all inlet grates must be stamped and signed by a civil engineer, c. Size, types, invert elevations and lengths registered in the State of Washington, showing of all culverts and pipe systems responsibility for the drainage design. Guidelines for Stormwster Management 2- 1 Spokane County: February 1998 During construction if field conditions prove to be substantially different from the assumed conditions used by the designer , the approved plans will be deemed invalid. Revised plans then shall be submitted to the County Engineers Office for review and approval prior,to resuming construction work. Any deviation shall be approved in writing by the • County Engineer prior to construction. • • • • • • Date 4/4/84 Guidelines for Stormwater Management 2 -2 Spokane County: February 1998 Addendum To Section 2 2.2, and as listed herein. The computations are (Effective: February 1998) considered adequate for Spokane County acceptance when there is sufficient information for an unbiased third party to be able to review the record and Construction Plans determine that all applicable standards have been met. All assumptions and computer input and output The sponsor's engineer shall provide to the Spokane data, and variables listed in the computer printouts, County Engineer's Office a complete submittal of shall be clearly identified. Computer printouts are to construction plans, which is to normally include: road clearly show which subbasin(s) they are applicable and drainage plans (or civil site plans), a Drainage to, and the design storm event identified thereon if Report, geotechnical reports, a Submittal Checklist, multiple-storm events are addressed in the design. easement documents, and any other known relevant Copies of any design charts, nomographs or other information. The submittal and acceptance process design aids used in the analysis shall be included in shall be in accordance with the Spokane County the calculations. If the calculations are lengthy, than Standards for Road & Sewer Construction, and as the document is to include a table of contents with amended. For privately sponsored construction page numbering of the entire report. projects, original construction plan sheets shall be good quality reproducible, ink on inylar. Media size All relevant geotechnical information related to the 24" x 36". The designer may submit the original project, and all site specific soil logs and subsurface sheets on vellum paper if computer drawing files are testing information shall be included in the Drainage submitted. Computer files shall be in AutoCAD, Report or provided in a separate report prepared and 'r"-) ".DWG"or".DXF"format. Each plan sheet shall be stamped by the geatechnical engineer. signed and dated by the Sponsor, and stamped and signed by the Sponsor's Engineer. The cover sheet is The Drainage Report shall include a basin map. The to include the certification statement described in the basin map is to show: Spokane County Standards for Road & Sewer Construction. Road and drainage.plans shall include a. Site boundary the Standard Notes. See Appendix B. b. Basin limits, both on-site and off-site areas which contribute or receive stormwaler runoff When erosion control plans are needed,they are to be onto or from the project, field verified by the incorporated into the construction plan set; and if an fir. index of plans is included in the cover sheet, the c. Drainage sub-basins. All sub-basins are to be erosion control plans are to be included therein. clay labeled and correlated with the calculations. Civil site plans for commercial or muhi-family d. Topographic contours,. which shall extend developments can be provided on non-reproducible the project or drainage basin bond media, minimum of 24" x 36" plan size. The boundaries to the extent necessary to confirm civil site plans are to include the items listed in basin limits used in the calculations; or, in the Appendix H. absence of topographic mapping being available, the Engineer shall field verify the Drainage Report basin limits, including any contributing off- site areas, and shall describe how the basin The Drainage Report is to be inclusive, clear, legible, limits were determined. and reproducible, with a complete set of drainage e. Significant drainage features, natural or man- computations. The computations are to be presented made, such as creeks, seasonal drainage in a rational format with information included so as gels, culverts, closed depressions, • to allow a reviewer to be able to reproduce the same manholes,etc. results, and is to include the items listed in Section f. Time of concentration routes, clearly labeled and correlated with the calculations. Guidelines for Stormwater Management-Addendum 2-3 Spokane County:February 1998 • g. Footprint of proposed drainage features, such The Downstream Analysis is a visual inspection . as ponds, grassed percolation areas, conducted by the sponsor's engineer, reported with a infiltration facilities, pipe routes, ditches, etc. written summary and corresponding map drawn h. Indications of floodplain limits, as defined by approximately to scale, to be submitted with the FEMA or other studies. Drainage Report. The Downstream Analysis is to i. North arrow and scale bar. note the condition and approximate size of the j. Wetlands channel, evidence of erosion or flooding, the location k. Existing easements of hydraulic structures (such as culverts or inlets), any nearby buildings or roads, property limits, and Under most conditions both a pre-developed basin any other information which will convey the map and post-developed basin map shall be provided, condition and capacity of the conveyance route. unless deemed uruiecessary by the County Engineer. Locations where there are -constrictions or low conveyance capacity in the channel,areas where there The Drainage Report is to identify any existing is potential for flooding, or scouring,are to be clearly drainage facility which is clearly inadequate or needs identified. The Downstream Analysis shall extend a repair, such as collapsed or culverts with a minimum of % mile downstream of the project substantial amount of debris. For any existing boundary,or to where there is a large receiving water drainage facility located on-site, or downstriam to ''h such as a lake or river. At the discretion of the mile; and said facility is proposed to be utilized by County Engineer, the sponsor's engineer may be the development, the condition and capacity of said required to conduct an expanded downstream facility shall be evaluated and disclosed in the evaluation, and a detailed hydraulic analysis may be drainage report. required to determine if negative impacts on - downstream properties or structures are likely. Calculations for detention and infiltration ponds art to include: inflow and outflow bydrographs, level- For any existing/potential off-site drainage problems pool muting calculations, a listing of the maximum of concern,the design engineer shall demonstrate that water surface elevation, a pond volume rating table the "per project en&ineeling plan has .been (e.g. stage .-vs- storage), and discharge rating.table designed so that it neither aggravates an existing (e.g.stage -vs- discharge). For evaporative ponds, a drainage problem nor creates a new drainage stage versus surface area table, and pond volume problem. Aggravation of the problem can include rating table shall be provided. Each hydrograph and increasing the magnitude, frequency, or duration of level-pool routing calculation sheet is.to have clearly the problem. marked thereon: the design storm event, the applicable subbasin(s), and the paced identification name, which corresponds.-with the basin map and Lot Plans plans. If detention of stormwatrr is planned, then the . Drainage, Report shall include a Downstream For grassed percolation arras (GPA) and drainage Analysis. located in residential lots,the sponsor shall provide lot plans to the County Engineer's Office A copy of any applicable floodplain maps, or studies prepared by a civil engineer,showing the location and within the project area shall be included in the design of the GM, location of drainage easements, Drainage Report. and other proposed improvements. Lot plans are to be provided on 8 W' x 11" plan Downstream Analysis sheets. A separate lot plan shall be provided for each residential lot encumbered with a GPA and/or The Downstream Analysis is done to evaluate the drainage easement. Specific lot plan requirements i s_2'' surrounding drainage conditions, as described in are listed in Appendix F, and an example is shown in \, Section 1. Appendix C.2. Guidelines for Stormwater Management-Addendum 2-4 Spokane County:February 1998 Site Characterization Studies; In-Place Testing; impacted by the proposed subsurface disposal and Geotechnical Reports facilities, • • Exploratory borehole or test pit logs. When subsurface disposal of stormwater is proposed, • The results of any field and or laboratory testing a geotechnical site characterization study is required that was conducted including raw data, in order to demonstrate suitability. The required assumptions, and calculations used to arrive at scope of the investigation and requirements for in- permeability rates, infiltration rates, or outflow place testing will vary depending upon the site's razes. general location and setting, and whether there are • The existing, and expected seasonal high known or anticipated subsurface drainage problems groundwater table elevation within the local within the vicinity of the site. Please refer to the vicinity of the site. following appendices for further information: Appendix 1-1 provides a minimum set of standards The following additional information shall be for performance of the study. Appendix 1-2 provides provided when non-standard subsurface disposal a flow chart that graphically depicts a suggested site systems are proposed: investigation approach. Appendix 1-4 provides in- place test procedures and their applicability to • Recommended safety factors. subsurface disposal. Note that in those areas where • Recommended design values • including there has been a long standing record of satisfactory - performance of standard subsurface disposal . supporting calculations for parameters such as facilities, the minimum guidelines set forth in soil permeability, soil infiltration rate, hydraulic Appendix 1-1 may be reduced upon a formal request ��' 'outflow rates. fromtthe sponsor's engineer and approval of such a request by the County Engineer. a system P for use, as defined in the addendum to Section 4, the report It is important the sponsor's shall include an evaluation of the potential negative engineer field verify if impacts of the ro the in situ soil is as shown in the SCS soil map. P P°d0dY on properties located in the direction of down-gradient groundwater flow. The resulting site characterimtion report In general,a negative impact is when there is a threat summarizing the geotechnical investigation shall be to the health, safety and welfare of the ublic. A pan provided*.to the County Engineer as pa of the P drainage plan submittal. As a minimum the report � negative �� includes. but is not shall include: limited to, when the groundwater characteristics in • the area are significantly changed whereby • basements, foundations or surface arras have adequate description of the site, it's increased amount or increased frequency of subsurface setting, and it's suitability for on-site groundwater intrusion. A surface water negative disposal of storinwater. impact is when there is an increase in frequency of • A vicinity map including U.S. Soil conservation flooding,erosion, degradation of an existing drainage Service mapped soil units. • channel,etc. • Descriptions of the US-SCS mapped soil units within the vicinity of the site. . The geotechnical and civil engineer, if individual and • Site Layout Map •showing the approximate separate on a project, shall closely coordinate the site locations of: 1) Exploratory borings or test pits, characterization study and final design of the and in-place, field tests (if performed); 2)Project infiltration system. Demonstration of coordinating of boundaries & lot lines if applicable; 3) Proposed this work shall be included in the submittal of ( facilities including roadways and drainage construction plans and/or Drainage Report, by means featints such as ponds, drywells, etc. 4) of a written statement. It is the responsibility of the Significant structures or properties which may be civil engineer to inform the geotechnical engineer of Guidelines for Stormwater Management-Addendum 2 -5 Spokane County:February 1998 the possible locations being considered for placement needs to be provided by the sponsor in order for staff f of the infiltration system,and whenever practical, this to make a determination as to the adequacy of the information shall be given prior to conducting the site proposal. As it relates to drainage design, this characterization study. information is to be presented through a Concept Drainage Plan. If a seasonally high groundwater table is suspected at a proposed infiltration facility location, and the in- The purpose in providing a Concept Drainage Plan is situ soil matrix is highly granular in nature, the to demonstrate how the proposed stormwater design County Engineer may require monitoring of the can meet the minimum requirements of the Spokane groundwater depths through the late winter early County's Guidelines for Stormwater Management spring time of year. Monitoring work, if required, and the requirements of good engineering practice. shall be done before a Design Deviation is considered Each project site has varying design parameters, for approval of.a non-standard subsurface disposal design challenges and potential solutions. The system (as defined in the Addendum to Section 4), or proposed stormwater plan should demonstrate that a before acceptance of a standard surface disposal plan for stormwater management can be approved for facility. the project proposal. If a stormwater plan is proposed that does not meet Spokane County The sponsor's engineer is strongly encouraged to requirements for adequate infrastructure and the have a meeting with County engineering staff prior to approval of the. County Engineer, Spokane County conducting a site won study for a non- Engineers Office will recommend the proposal be standard subsurface disposal facility. The meeting denied. will be used to identify known stormwater or groundwater problems in the, project vicinity, if any, The general requirements for a Concept Drainage and discuss the scope of the work. Plan and Report are: ( • Record Drawings& Inspection I. Provide a• drainage basin map, showing. topography, basin limits; surface water Record Drawings of road and drainage plans shall be characteristics (i_e. creeks, intermittent channels, submitted by the sponsor, or its agent, in accordance . -wetl ands, closed depressions, known wet areas, with the Spokane County Standards for Road & springs,. etc.), and relevant man-made features. Sewer Construction, and as amended. The Record The basin map should cover both the developed Drawings are to leave the design elevations in the and pre-developed conditions. :In addition to on- plans, but shown as strike-through elevations; and the site topographic features, the basin map u to as-built, field measured elevations are to be listed include any contributing off-site areas with the adjacent to the strike through elevations. . overall basin limits clearly defined. If there are properties located dawn-gradient or downstream The County Engineer may require a separate of the site, the surface watery routes need to be inspection agreement between the sponsor, shown in an exhibit, and a discussion of the contractor, and sponsor's engineer for commercial ' probable impacts to.these properties. from the projects or non-standard subsurface disposal systems. stormwater proposal needs to be provided.. If The inspection agreement is to be in a form negative impacts to down-gradient or prescribed by the County Engineer. See Appendix G. downstream properties are likely or of concern, then the excess volume of stormwater from the Concept Drainage Plans proposed development must be held and disposed of on site. As an alternative, if downstream For certain l and-use applications, the sponsor is easements and mitigation are proposed for the required to demonstrate adequacy of existing or excess developed volume, the developer shall proposed infrastructure elements during the pre- , demonstrate that the necessary easements and or (. application process. A sufficient level of information agreements can be secured. Guidelines for Stormwater Management-Addendum 2-6 Spokane County:February 1998 , .1 2. The Concept Drainage Plan and report shall final plat. The expected locations of these describe what the proposed method of easements are to be shown in an exhibit or the stormwater disposal will be and include a basin map and included in the Concept Drainage schematic of the proposed system showing the Plan. Facilities located outside the Count). approximate size and location of all the rights-of-way will usually not be maintained by components that are anticipated to be built. Spokane County. Relevant information, supporting technical data, drainage calculations, and a written discussion 5. Off site easements will need to be obtained for describing how the proposed concept plan will areas where constructed stormwater conveyance meet minimum requirements. Detailed design is or disposal facilities are proposed and which will not being sought at this stage, but adequate be outside of the .project boundaries. The work must be done to demonstrate. that anticipated locations of these easements need to adequate infrastructure can be provided: If be provided in any exhibit or the Basin Map. the Spokane County Division of Building and (Note: These easements will need to be obtained Planning.decides that a critical arms evaluation prior to construction plan submittal) is required for the project proposal, any mitigating measures that are recommended 6. If a non-standard subsurface disposal system is should be incorporated into the preliminary plat proposed, as defined by the addendum to Section layout including the concept drainage plan. If 4, then a geotechnical analysis shall be done in phasing is anticipated, an explanation of how.the accordance with the sub-section labeled "Site system will be phased and built is to be included. Characterization Studies; In-Place Testing; and If non-standard systems are proposed that are not Geotechnical Reports." This geoterchnical report `, presently allowed or defined in the Spokane shall be submitted with the Concept Drainage '` County Guidelines for Stormwater Management, ' Plan. a Design Deviation application and approval will be required at time of final design and plan 7. If an evaporative pond concept is chosen, then a approval. Specific design criteria are developed water balance study will need to be performed. during the Design Deviation process. Concept Precipitation and evaporation amounts will need Drainage Plans that do not meet minimum to be obtained from NOAA. If this option is standards and recognized standards of good chosen, see the addendum to Section 3 which engineering practice, will not receive approval provides the design criteria for evaporative from the County Engineer. ponds. 3. If detention or any kind of surface discharge is 8. Provision for perpetual maintenance of the proposed, the facility will need to be designed to drainage facilities needs to be addressed in the attenuate multiple design storm events, as Concept Drainage plan. A written description of outlined in the addendum to Section 3. what is proposed is to be provided with the submittal. The applicant should be aware that 4. The proposed drainage facilities will generally .Spokane County does not accept drainage need to be located within drainage swale facilities for mai rum= which are located easements-and street right-of way for residential outside of County rights-of-way, unless its developments. Detention or retention ponds approved otherwise by the County Fngrn r and within single-family residential neighborhoods, or the County Commissioners. A homeowners other areas (as deemed necessary by the County association is normally the entity responsible for Engineer), must be located in separate tracts that maintenance. A final maintenance plan, in are dedicated to an entity responsible for accordance with the addendum to Section 1, will ., maintenance. If natural draws or channels be required at time of final design. i, convey stormwater and are located on-site, these will need to be placed within easements at time of Guidelines for Stormwater Management-Addendum 2 -7 Spokane County:February 1998 The Concept Drainage plan report needs to be Floodways are critical floodplain areas within certain {.. prepared and stamped by a Civil Engineer licensed in floodplains that must be reserved in order to the State of Washington. discharge the base flood. Floodways are extremely hazardous areas due to the velocity of floodwaters which carry debris, potential projectiles, and erosion Floodplain Requirements potential. These areas are identified on "Floodway, Flood Boundary and Floodway Maps" available for When any property is developed in and around review at Spokane County's Division of Engineering identified Areas of Special Flood Hazard (100 year and Roads. Residential development and floodplains) all work must conform to the redevelopment within Floodways are prohibited. requirements of the National Flood Insurance Encroachments and new non-residential construction Program and Chapter 3.20 of the Spokane County and other development is prohibited unless it can be Code. shown by the applicant's engineer that the • encroachments shall not cause erosion, obstruct flow, These requirements set forth in this document are for reduce the carrying capacity of the channel.or result guidance purposes. They are general in nature. More in any increase in the 100 year Base Flood Elevation restrictive requirements may be imposed to meet the (BFE). requirements of the National Flood- Insurance Program, Chapter 3.20 of the Spokane County Code, Residential. Commercial and Industrial- Building amendments thereto and other relevant local. state Requirements: and federal regulations. The general requirements for residential or commercial buildings proposed on property, all or a _ The Spokane County Flood Ordinance sets forth that portion of which is in a floodplain is that the lowest "No development, structure, manufactured home, floor including basement floor must be elevated to a - works or fill shall be undertaken, constructed, minimum of 1.0 foot above BFE.The FIRMS provide located, extended, connected or altered on any these elevations in Zones AH and Al A30. In property all or a portion of which is in any area of "Unnumbered A Zones" (where'the flood zone. is special flood hazard...without first obtaining a designated as simply "Zone A" without a letter or development .permit." Development •means "any number modifier associated with it) and B Zoaies man-made change to improved or unimproved real detailed information on BFEs has not been provided. estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, paving, For buildings proposed in arras.without established excavation or drilling. operations". Floodplain BFEs a site inspection by the Spokane County Development Permits can be obtained at Spokane Floodplain Administrator will be necessary. If it is County's Division of Engineering and Roads, Public not easily discernible that the proposed building will Works Building. be outside of the flood zone, a flood study will need to be completed by the sponsor's atgirmer to establish Regulated 100 year floodplains for unincorporated the 100 year BFE and delineate the 100 year Spokane County are delineated on Flood Insurance floodplain. Rate Maps (FIRMs). These maps are available for • review at Spokane County's Division of Engineering Commercial, industrial or other nonresidential and Roads. These maps outline 3 categories of zones; buildings within floodplains will also have the A Zones, B Zones and C Zones. Both A and B Zones opportunity to floodproof the building to 1 foot above are regulated flood zones which will require the BFE. Floodprooflng techniques shall be certified floodplain development permits prior to any by a licensed civil professional engineer or licensed development taking place on property associated with registered architect(registered as such by the State of _ these zones. C Zones are areas of minimal flooding Washington). and are not regulated. Guidelines for Stormwater Management-Addendum 2-8 Spokane County: February 1998 �I As built elevation certification shall be submitted by drawn to transfer ownership of any and all the applicant's surveyor to the County Engineer's property within this plat in the Area of Special Office upon completion of all buildings where BFEs Flood Hazard." have been provided or established. These Elevation Certificate forms will be provided to the applicant at Water-Dependent Works: the time a Floodplain Development Permit is issued. For water dependent installations, which by there Elevation Certificate forms shall be stamped and very nature must be in the floodplain (such uses as, signed by a surveyor licensed in the State of but not limited to, bridges, roads, dams, flood Washington. control, streambank stabilization structures and practices, etc.) the applicant shall provide convincing Subdivision and Other Proposed Developments: information showing that the location of the proposal Requirements for subdivisions, which include, but are in the floodplain is necessary. The applicant must not limited to: Subdivision approval, short plat also show that the proposal is consistent with other approval, planned unit developments, zone changes, relevant local, state and federal regulations. Shoreline Management Act developments, conditional use permits, variances, building permits, and When encroachments within floodplains are exemptions to the above shall be consistent with then necessary the applicant's engineer must show that the need to minimize flood damage. project will not cause a rise in the BFE beyond what is allowed by the flood ordinance. Subdivisions and other proposed developments shall have public utilities and facilities located and Floodplain Studies (Analysis) constructed to minimize flood damage. All new When a floodplain study is required prior to proposed building lots created on properties all or a portion of developments, the study must be completed by a which are in an identified 100 year floodplain shall registered professional civil engineer licensed in the have an adequate building site at least one foot above State of Washington. The engineer must use good the 100 year flood elevation. Drainage systems shall science and the state of engineering practice in be adequate to reduce exposure to flood damage. performing the analysis. The analysis and accompanying documentation shall be stamped and Where BFEs have not been provided, the applicant's signed by the engineer. engineer shall generate the information and studies necessary to determine the BFEs and delineate the The floodplain analysis shall include a determination floodplain. This shall be done using good science and of 100 year flood flows. Some floodplains may the state of engineering practice. All floodplain already have flows developed for them. These analysis and supporting documentation shall be sou= may include, but are not limited to FEMA stamped and signed by a registered professional studies, previous acceptable studies and watershed engineer licensed in the State of Washington. plans. If acceptable flows are not available from other sotucess they must be generated by the The plat dedication of all subdivision proposals applicant's engineer. associated with floodplains shall contain language prescribed by the County Engineer. Example The flood flow report must include all relevant floodplain language is provided below. calculations in determining 100 year flood flows. The "Development within this subdivision shall report must be presented in a rational format with all conform to the requirements of the National relevant information included so as to allow a Flood Insurance Program and Chapter 3.20 of reviewer to be able to reproduce the same results. All the Spokane County Code. Purchasers of assumptions and computer input and output data property in this subdivision are warned of shall be clearly identified. Computer printouts are to possible flooding or ponding and the potential be clearly labeled to show which arras or subbasin(s) requirement to purchase Flood Insurance. This they are applicable to. Copies of all design aids used warning shall be carried in each and every deed in the analysis shall be included in the report. Guidelines for Storrnwater Management-Addendum 2-9 Spokane County:February 1998 clearly delineate 100 year floodplain. Topographic _ The flood flow report shall include a basin map. The contours shall be clearly marked, a bench mark must basin map must show a site boundary and the limits be identified for the topographic work and the details of the watershed contributing to the floodplain for of the bench mark discussed. Maps must clearly that site. All subbasins must be clearly marked and show no violations to the requirements of the relate to the report. Topographic contours must be Spokane County Flood Ordinance. All lots and present on the map and extend beyond the development must be shown on the map, a north floodplain's watershed boundary to the extent arrow and a scale bar shall be included. The map necessary to confirm ,the basin limits used in the must be stamped and signed by the applicant's calculations. Time of concentration mutes must be engineer. clearly labeled and correlated to the calculations. The map must also include a north arrow and a scale bar. General conditions for complying with Floodplain Ordinance for encroachments into floodplains: The floodplain analysis to determine the BFE and to • BFEs must not increase at any point by more delineate the floodplain shall include a report and a than 1.0 foot within Unnumbered A Zones and B map. The floodplain analysis must include all Zones. relevant calculations in determining the BFE.. The • BFEs must not increase BFE in Numbered A report must be presented in an organized format.with Zones all relevant information included so as to allow_a • Floodwaters must enter and exit the property in reviewer to be able to reproduce the same results. All the same manner as it did under preproject assumptions and computer input and output data conditions. shall be clearly identified.. Computer printouts are to • No increase in volume may be disposed of in an be clearly labeled to show which areas or subbasin(s) identified 100 year floodplain. they are applicable to. Copies of all design aids used • functions (water storage, infiltration, in the analysis shall be included in the report. water quality, wetland functions, etc.) must be • preserved or restored to the highest degree The floodplain analysis shall use field surveyed cross possible due to project encroachment into the sections of the floodplain in the,area of the proposal. floodplain. The cross sections shall extend off site as necessary to accurately delineate floodplain in area of proposal. . FEMA generaned cross sections may be available for . use, however, these should .be supplemented with field surveyed cross sections for the specific site. • • Floodplain .analyses must include existing site - conditions to show BFE and d.lin,ate. floodplain prior to development. The floodplain analyses must also model future or developed site conditions to show the any change to the BFE and delineate • modifications to the floodplain. In areas where 1 foot of rise to the BFE is allowed the analysis must show pre and post BFEs to the nearest 10th of a foot. In areas where no rise in BFE is allowed, the pre and post BFEs must be shown to the nearest 1000th of a foot(as required by FEMA). The floodplain analysis maps must be prepared for pre and post project conditions. The maps must show BFEs within the project site to the tenth of a foot and Guidelines for Stormwater Management-Addendum 2 - 10 Spokane County:February 1998 3. Hydrology -1 A ten-year design frequency shall • s is the average slope of the prin- e used for on-site runoff except as cipal channel in feet per foot. oted in Section 4-4.2 "Storage facili- Ct = .40 for natural drainage ba- tes. " A fifty-year design frequency sins hall be used where off-site runoff Ct = .15 for overland flow ontributes to a drainage facility. Figure 3 on page 6-5 is a nomograph -2 Rational Formula - Runoff rates for for this equation •asins 10 acres or less shall be deter- iined by the rational formula: The time of concentration should be cal- . culated for each significantly different Q = C I A slope. Travel time for flow in pipes, ditches and gutters should be ccaiputed Q = Runoff in cfs as a function of the velocity as defined C = Runoff coefficient by Mannings formula. I = Rainfall intensity in inches per hour 3-2.1 EXAMPLE: A = Contributing area in acres Calculate the peak rate of runoff for a the runoff coefficients (C) should be plat with a density of 2.6 DU/GA (Dwel- )ased on Table 1 , page 6-2. The rain- ling units per gross acre) . The drain- \ ) Fall intensity (I) will be based on the age area being considered is shown below. rainfall Intensity-Duration Curves, pre- and comprises lots 1 through 12. A. 1C- )ared by the U.S. Weather Bureau for the year frequency storm must to useu. area (See Figure 2, page 6-3). An ex- ception to this is for areas in the vicinity of Mt. Spokane where consider- ably higher rates of precipitation are experienced. Data for this area shall r Grcy be submitted for review. 1 •The time of concentration for rainfall 60) I it S0 9 8 7 16 0 shall be computed for all overland flow, { O ditches, channels, gutters, culverts and pipe systems. When using the rational formula, the time of concentration for I 2 3 4 5 to I overland flow may be computed by the formula: _ ) Tc = Ct (Ln ).6 sf/2 l Figure 3-1 1 Where Tc is the time of concentra- Lawn: Street: t i on in minutes, S = .01 S = .G25 L is the length of the principal n = .4 n = .016 channel in feet, The area of drainage area ;11 is: n is the friction factor of the g ground surface (see Figure 3 , ea ; e 6-5) . 360 x 670, X 1 acre = 5.E acres 43560 sf - 3-1 The composite runoff factor for a devel- An alternate method to establish gutter - , opment with 2.6 DU/GA is shown on Table flow velocity is to use Figure 3-1, SCS( 1. C ■ 0. 25. The time of Concentration Technical Release 055. This velocit is the longest route in time that the must be checked against the velocity of flow will take. In this case, runoff the calculated runoff. from the Northeast corner of lot 7 must flow across grass to the street gutter Since the street creates a very high then in the gutter to the inlet. runoff and is close to the drainage outlet (drywell), it is possible that Overland: the street generates a greater rate of Tc ■ Ct Ln .6 Ct for overland runoff than the total combined area. lir flow is 0.15 Thus the Q from the street area must be checked alone. The area of street is The n Value for lawns is 0.4 2 (360'+670') x18' x 1 acre ■ .85 ac. Tc ■ 0.15 300 x 0.4 0.6 - 10.5 minutes 43.570 s.f. .U1 The runoff factor shown on Table 1 is Gutter flow: Assume a flow depth of 0.2' 0.9. The time of concentration is the gutter flow time from the northeast cor- A■1/2 a D2 ■ 1/2 x (0.2)2 • .8 sf ner of lot 7 down the north-south 0 025 street, around the corner onto the east- west street, and down to the inlet. S - inverse of cross slope Gutter flow: Assume a flow depth of 8 ■ 1 ■ 40, .2' , from before V ■ 3.1 f.p.s. .025 • Then travel time in the gutter is: n ■ .016, S ■ 2500 , n T ■ L ■ 970 ■ 312.9 sec. or 5.2 min. From Figure 18 V 3.1 Q ■ 2.5 cfs V - 2. - 2.5 cfs ■ 3. 1 fps T ■ Tc ■ Duration, therefore, from A .8 sf Figure 2, (page 6-3), I - .3.1 (10 yr.) Then travel time in the gutter is: Q10 • CIA • .9 x 3.1 x .85 • 2.4 cfs T - L • 610' ■ 196.8 secs or 3.3 min. 2.4 c.f.s. assumed 2.5 c.f.s. V 3. 1 fps In this case, the combined area controls Total Tc • Overland flow 6 gutter flow use 2.5 c.f.s. Tc • 10.5 min + 3.3 min ■ 13.8 min. Say 14 minutes 3-3 Soil Conservation Service Method - Tc ■ Duration, therefore, from figure 2, For drainage basins greater than 10 (page 6-3) acres, the SCS method shall be used. 1(10 yr) ■ 1.85 in/hr. The amount of runoff from a given water- shed is solved from the equations: Q10 - CIA ■ 0.25 x 1.85 in/hr. x 5.5 acres ■ 2.5 cfs S ■ 1000 - 10 Eq. (1) CN 2.5 ■ 2.5 cfs . . Assumption used to calculate Tc in street gutter is okay. Q ■ (P - 0.2S)2 Eq. (2) P + 0.8S Date: 4/4/84 3-2 Where S is the potential abstrac- having very slow infiltration rates tion in inches when thoroughly wetted and consis- P . is the total storm rainfall in ting chiefly of clay. soils with a inches high swelling potential, soils with CN is the runoff curve number a permanent high water table, soils Q is the actual direct runoff in with a claypan or clay layer at or inches near the surface, and. shallow soils over nearly impervious material . The design storm precipitation' is These soils have a very slow rate of shown on Figure 4 in Section 6. water transmission. 3-3.1 Runoff Curve Number - The CH in- See Appendix A which provides the SCS soil dicates the runoff potential of a water- classifications in Washington State. shed. The higher the CN the higher the potential. The CN is a combination of a hydrologic soil group, a land use and a Several factors should• be considered treatment class cover). when computing the anticipated future CN for urban areas. The combination of these factors is called the "soil-cover complex" and is In determining urban CN's, consideration the factor to which the curve numbers should be given to whether heavy equip- are keyed. There are four hydrologic ment compacted the soil significantly soil groups, classified according to more than natural conditions, whether their runoff characteristics: much of the pervious area is barren with • little sod established, and whether A. (Low runoff potential) . Soils grading has mixed the surface and sub- having high infiltration rates even surface soils causing a completely dif- when thoroughly wetted and con- ferent hydologic condition. Any one of sisting chiefly of deep, well to the above could cause a soil normally in excessively drained sands or gray- hydrologic group A or 8 to be classified els. These soils have a high rate in group B or C, respectively. In many of water transmission. areas .of the country, lawns are heavily irrigated. This may significantly in- 8. Soils having moderate infiltration crease the moisture content in the soil rates when thoroughly wetted and over that under natural rainfall condi- consisting chiefly of moderately Lion. fine to moderately coarse textures. These soils have a moderate rate of Table 5 (page 6-8) ,gives CN's for agri- water transmission. cultural, suburban, and urban land use classifications. The suburban and urban C. Soils having slow infiltration rates CN's are based on typical land use rela- when thoroughly wetted and consis- tionships that exist in some areas. ting chiefly of soils with a layer They should only be used when it ' has that impeded downward movement of been determined that the area under water, or soils with moderately fine study meets the criteria for which these to fine texture. These soils have a CN's were developed. slow rate of water transmission. One point should be emphasized. That D. (High runoff potential). Soils is, do NOT combine highly impervious _/ having very, slow infiltration rates 3-3 j (high CN) areas with low CN areas when the distribution of both is not uniform throughout the area. If high CN areas are very near..the outlet, there will be a rapid response to precipitation from the nearby area before .the upstream watershed contributes any runoff at all . Thus, the outlet would actually see two peaks, rather than one larger one which • as would result if the CN's were area- weighted. Alternatively, if the high CN areas are all upstream, then the runoff will take some time to travel to the outlet, by which time the low CN •areas downstream could a'lso. be responding. In this case a higher peak would result by adding the two separate flows together than would . occur if CN's were. area-weighted. • • • • • • • • • • • • • 3-4 • l \ ff Addendum (Effective: February 1998) with a 12 ft. minimum width gate for maintenance Addendum to Section 3 access. The construction plans are to define the location of the fence,and a detail of the fence shall be included or referenced in the plans. Hydrologic Modeling The construction plans for drainage ponds are to For drainage systems with basins greater than l0 include temporary erosion control and permanent acres, the hydrologic model which can be used is slope stabilization methods for the disturbed area in "Urban Hydrology for Small Watershed", more and around the drainage pond commonly known as Technical Release 55 (TR-55). The US Soil Conservation Service has produced a if a lined pond is required, such as for an evaporative computer program which automates the calculations system, the liner shall be constructed of compacted for TR-55. Additionally, Spokane County will clay, or other soil mix,or a impermeable fabric. The accept the results of Haestad Methods "Pondpack" liner is to have a permeability of no more than 1 x computer program. Other hydrologic models and 10'' cm/sec. At least six inches of top soil over the computer programs may be used, if the sponsor's liner shall be provided. • engineer acquires acceptance from the County Engineer. Said acceptance shall be obtained prior to submittal of plans and calculations. Detention Systems A detention system is defined herein as being a Drainage Ponds stormwater storage facility which has a surface discharge. The rate -of runoff under developed A grading plan for drainage ponds is to be included in conditions cannot exceed the rate of runoff prior to the construction plans. The grading plan is to development, as stated in Section 1. To fulfill this include, but not limited to: existing contours, criteria, it is necessary to take into account any proposed contours and catch points. A typical cross- runoff from the site which bypasses the detention section of the pond is to be provided in the plans, system. The release rate out of the detention facility showing.bottom of pond elevation, maximum water needs to be diminished in'an amount equal to the rate surface elevation for the, design storm(s), inlet and of runoff generated from the bypass area. This outlet elevations, berm elevation and slopes, and criteria is applicable to all design storms, and is as keyway location and dimensions. follows: Drainage ponds, pipe inlets and outlets, ditches, and %D.=Q1-Q. drainage structures,which are serving public roads or are in single-family residential neighborhoods, shall Where: - be horizontally defined with respect to property Q.uo. = allowable release rate out of a corners,street stationing, or a coordinate system. detention pond,cfs Drainage ditches are to have their longitudinal grades Q7, = Peak runoff rate under pre- defined with either a profile or elevation grades at 50 development conditions,cfs ft. intervals. Ditch centerlines and flow directions are to be shown in plan view in the construction plans. Qty. = peak runoff rate of bypass area, under developed conditions, cfs All drainage ponds in non-commercial areas which L. , have a design water depth greater than 1.0 ft., or The pre-developed condition is the ground-cover of E which take longer than 72 hours to completely drain the land prior to site disturbance. following a design storm event,shall be bounded by a 6 ft. high fence. The fence shall be visible-through, Guidelines for Stormwater Management-Addendum 3-5 Spokane County: February 1998 When runoff from a portion of the site does not flow Infiltration systems need to be designed to operate C through the detention facility, and. is not retained under frozen-ground conditions, otherwise additicuial anywhere else on site, that is defined as the bypass storage shall be provided for operation of the facility area Bypass areas are permissible only when said during the winter and early spring months. areas drain into the same chamiel as where the detention pond drains, and when Qbv„,„ does not exceed %'.. Any bypass areas associated with the Design Storm Events&Surface Discharge project site need to be clearly identified in the basin map. The drainage calculations need to demonstrate Detention facilities shall be designed to permit a that this criteria has been met. See example of how discharge rate which does not exceed the pre- to deal with bypass flowrates in Appendix C.3. developed discharge raze for multiple design storm events. The multiple-storm design criteria is needed to obtain greater control and attenuation of both low Infiltration Systems and high flow storm events. As a minimum, the allowable discharge rate shall not exceed the pie- An infiltration system may include, among others: developed rate of runoff for each of the following 24 drywells, and non-standard subsurface disposal hour storm events: 2-yr storm, 10-yr storm, and 50- systems. The criteria for the use of drywells and yr storm. The Drainage Report shall include a Don-standard subsurface disposal systems are hydrologic examination of each design storm event, provided in Section 4. where each of the three storm events listed above is considered a separate and distinct event from the Marginal soils (infiltration rates less than 10 other two. The criteria for each storm event is: inehesihr) will normally not be given any aulit for infiltration. Soils with higher infihration rates.may Qm1 be given Credit if adequate testing wad( is performed .perform and the County Engineer approves of the proposed Vp. (This volume criteria is applicable design infiltration rate. Normally a minimum of 4 ft. if the downstream analysis reveals vertical separation between the seasonal high ground negative impacts will result from watedlow,permeable soil strata, and the bottom of a increased volume of runoff, or if drYwell or bottom of pcmd elevation. When • the County Engineer*deans this a infiltration is proposed,. The *technical cogineer - aitical drainage area roet Sec. 1.) shall provide written recxrmriundations and the cavil where:Q runoff peak flcwrate,cubic ft/sec. engineer shall cum:lin= his/her design with the V= nmoff vol ft. geotechnical aiginecr. The seasonal variations, if total ume,cubic pre =pm-developed conditions' any are to be taken into account in the design, such co post=post-developed nditions as: seasonal high groundwater elevation, fru= ground conditions, and any other conditions which A detanian facility shall be provided with an may affoet the functional use of the drainage system. anerzency overflow stmenut, designed to accommodate the runoff resulting from a 104-yr, 24 The design of the infihration.facility shall consider hour stcma event gasemated under •developed the effect'that ground seepage from the facility will lbe overflow facility must be have on the groundwater elevations both on-site and conditices. anergatcy located to direct overflows safely towards the on nearby down-gradian properties. If negative downstream con system If the • impacts on neighboring properties arc identified, then ili veyance . overflow fac ty is located on an embankment, the mitigative measures shall be provided. If a pond liner embankment shall be annomd with itvetment which is proposed, that the effects that high, seasonal extends a minimum of 10 ft from the toe of the groundwater levels will have on the pond liner will also need to be considered in the design. anbankment Guidelines for Stozmwater Management-Addendum 3-6 Spokane County: February 1998 • Storm conveyance systems, such as pipes, gutters these closed areas are wetlands and the sponsor and open channels, shall be designed to convey runoff desires to fill these natural depressions, the sponsor's for the peak flowrate of the same storm event as the engineer who is evaluating the site and formulating a receiving drainage disposal facility is designed for. stormwater disposal concept shall consider these natural 'closed depressions and shall replace any Grassed Percolation Areas (GPA) shall be designed disturbed depressions with a concept that emulates to provide water quality treatment for the first %a inch the performance of these natural depressions. of runoff generated from road surfaces, parking lot Normally, the natural storage volume lost due to the surfaces, and asphalt roofs located in commercial proposed earthwork, shall be replaced using a 1:1 developments. ratio as a minimum. A higher ratio may be required The minimum storage volume of the GPA, for a if the new area infiltrates water at a lower rate than maximum of a one foot storage depth, shall be as was present in the natural depression. The road and follows: drainage plans shall'include a grading plan of the - closed depression area to be filled in. The grading Contributing Area ' Design Storm plan is to show both existing and finish grade . On-Site Contributing Area Only 10-yr Storm contours. Compaction and fill material requirements On-Site plus Off-Site Areas 50-yr Storm shall be shown in the plans. The time of concentration computed.for• the 10-yr For natural depressions that are capable of complete storm shall be muted through the on-site area, and disposal within 72 hours by infiltration of the runoff the time of concentration computed for the 50-yr generated from a 100 year, 24'hour storm event, an storm shall be routed through both the on-site and acceptable substitution for the depression could be a �., contributing off-site areas. For the two cases listed, a properly designed grassed percolation area or grassed comparison shall be made of the volume and rate of percolation area and drywell that is equal or greater .stormwater ' runoff generated, and the' 'grassed in volume that also'will infiltration completely the Percolation area, or' 'pond shall` be designed to runoff from a 100 year,24 hour storm event within a accommodate the greater of the two. See Example 72 hour time period. in Appendix C.1. For natural depressions that do not drain within 72 All storm water runoff from a proposed project shall hours, one acceptable method of handling this discharge at the natural, pre-developed location situation could be tei consolidate all the volumes of except.in the case of an approved Design Deviation. the depressions -frown the subject site that are A Design Deviation will be required for proposals pmlid for filling into Coco or more which do not discharge at the natural, pre-developed infiltrinicedevapmative ponds that will emulate the location. natural condition. If the site has a=disposal area that will allow increased percolation fixn the natural Closed Depressions condition on the site, a Design Deviation may be granted for increased infiltration if it can be A closed depression is a natural low area which holds demonstrated that the groundwater levels in the area a fixed volume of surface water. Depending upon will not be adversely affected and that there will not soil characteristics, a closed depression may or may be increased water quality problems. not accumulate surface water during wet periods of the year. Some closed depressions may be classified For sites that have natural depressions, the sponsor's as wetlands. The sponsor's engineer shall coordinate engimxr shall clearly identify the location of all -. its stormwater design with consideration of any depressions that could =lain more than 50'cubic ' wetland areas as defined by any applicable feet of stormwater. For these types of depressions, 1. regulations , laws, etc. with may govern wetland the eqgincer shall survey each depression and shall areas. If the proper authorities agree that none of determine the maximum volume that each depression could hold and shall show the maximum storage Guidelines for Stormwrater Management-Addendum 3-7 • . Spokane County February 1998 ■ • capacity-water elevation contour line on the pre- of these standards, if the development is a non ( developed condition basin map. The basin map commercial development. The easement shall be should show adequate survey data points to granted to Spokane County and any other entity that adequately demonstrate that accurate - volume is .responsible for maintenance of the closed calculations can be made from the data points. If the depression. site contains many small depressions that will hold . water but are smaller than 50 cubic feet in size, the engineer shall adjust the runoff.factors to allow.for Curve Numbers,SCS Method this retention of stormwater or shall.make other - adjusunents to the runoff model that are approved in When calculating curve numbers (CN) for residential writing by, the County Engineer. If,the site.had neighborhoods, care is required when using Table 5. natural depression storage in its historic natural state, The curve numbers for residential neighborhoods and grading and filling has been done of these natural listed in this Table are only applicable when: a) the features (which were made by the owner, previous impervious areas are directly connected to the owners or other unknown parties),.the engineer shall drainage system;and b) the percent impervious areas estimate in a reasonable way the depression storage are the same as those listed in.the Table. 5. If the that was on the site and shall comply with the percent impervious area is ,different, .or the provisions of this section. impervious areas are not'directly connected to the drainage system,then hydrographs shall be calculated If the total storage capacity,of a closed depression separately for pervious and impervious areas, and exceeds the .maximum-volume used, (as computed then the.hydroiraphs.can be added together to.obtain using the water budget method), then both volumes the resultant runoff Generally, if two areas within - , shall be clearly identified in the Drainage,Report and the same subbasin have CN „values which are both of these water surface elevation contour lines differing.. by more than 20 points, separate are to be shown in the basin map. hydrographs need to be generated'for the two areas • and the bydrogiaphs then added together to determine If a closed depression is to remain or be replaced,any the subbasin's runoff acs. For a building or road adjacent to a closed depression shall description of the hydrologic soil groups, See Figure have the lowest floor elevation or mad grade at.or 27. above the maximum water elevation, and outside of the limits of the closed depression. The maximum The Curve Number(CN) values listed in Table 5 are water elevation shall be computed using the water applicable under normal antecedent moisture budget method per the standards for.an evaporative conditions AMC II),. and are not applicable to systems design unless the pond can naturally drain snvwmelt or runoff on frozen ground conditions. within 72 hours following 41.100 year, 24 hour storm For residential areas, the lawns are assumed to be in event. If the depression can drain within the.72 hour good pasture condition. When dry or wet antecedent time period, the maximum water elevation shall be moisture conditions exist, then Fig. 28 should be computed as being the elevation containing the runoff used to adjust the CN. from..a 100 year, 24 hour storm event. The limits of the high-water-elevation, and corresponding contour Conditions where there is high groundwater, or lines shall be shown in the plans. When infiltration is shallow bedrock can cause a significant increase in considered in the design the engineer shall provide a runoff:- If these conditions exist, it needs to be .geotechnical -report that shows site _specific addressed by the design engineer. For a more infiltration testing results that verify that each complete discussion of .computing weighted CN depression being utilized will drain with the 72 hours values, see SCS publication 210-Vi TR-55, Second period unless waived by the County Engineer due to Ed,June 1986. knowledge of approved soils under the site. The closed depression• shall be placed in a drainage - easement or separate tract as described in other parts Guidelines for Stormwater Management-Addendum 3-8 Spokane County: February 1998 Evaporative Systems Where: Evaporative systems are stormwater drainage ponds V. = volume of water into .evaporative facility, or swales which dispose of stormwater through (usually cubic ft/month). V. is a evaporation, or with a combination of evaporation combination of stomrwater runoff, direct and infiltration. Due to the limited historical record rainfall onto pond surface, groundwater of the performance of evaporative systems, each seepage into evaporative facility, and any proposed system will be evaluated and approved on a other source of water into the facility. case-by-case basis, using the Design Deviation administrative process. V. = volume of water out of the evaporative facility(usually cubic ft/month). Va,is all The design of evaporative systems shall take into outflows, it can be a combination surface account applicable State and Federal regulations, the evaporation, plant evapotranspiration, minimum design standards listed below, and the most ground infiltraation, surface discharge, or current Best Management Practices (BMP's) for any other quantified outflow. facilities of this type. Site specific conditions may dictate the need for more stringent design criteria,and AVM = ' Net volume of storage increase (or it is the responsibility of the sponsor's engineer to decrease) into the evaporative facility determine if additional measures or more (usually cubic ft/month). conservative design parameters are to be used: Vito = Voluime of stormwater runoff resulting from a 100-yr,24 storm event. (cubic ft.) For the design' of evaporative facilities, a water budget is required. A cumulative, month-by-month AV, = Cumulative net volume of storage in • water budget is performed as follows: evaporative facility until storage equilrbrivm is obtained. A minimum of 1 Vm- = AVM year cycle. Equilibrium is obtained when the volume of water in the evaporative AVr.„ facility at the end of the cycle is less than the volume stored at the beginning of the The design criteria of evaporative systems is to cric• follow condition A or B: = Total storage volume needed for the evaporative facility, (cubic ft.) Condition A;If there is no surface discharge fur the drainage system, tarn the following = Total Volume of runoff from the basin, design criteria is to be used: • generated under pro-developed conditions for the design period (normally 1 year), AVM+Via)= V,m,i generated using mean monthly precipitation data. Condition B;If there is surface discharge of the V� = Total Volume of runoff from the basin drainage system,then the design criteria is: which discharges out of the evaporative facility and bypass areas, generated under Vv. ;and post-developed conditions for the •design penod (normally 1 year), generated using (AVn)(F.S.)= mean monthly precipitation data.. l • F.S. = Factor of Safety. The minimum factor of safety=1.2. Guidelines for Stormwater Management-Addendum 3-9 Spokane County: February 1998 A more detailed, written summary of the criteria for where the greatest net storage volume will be needed. ( evaporative systems is listed below. Example Contributing off-site areas are to be included in the calculations of a water budget is provided in analysis, considering existing conditions. The first Appendix C.4. month to begin the water budget will normally be in either September, October or November. The Design Condition A: When the evaporative system is sponsor's engineer will need to look at various designed with no surface discharge, then the water scenarios to determine which month will generate the • budget is to start with a 100-yr, 24 hr. storm event greatest amount of storage volume. (developed conditions). Equilibrium is considered to have been achieved when the water surface elevation The climatological data source for evaporation and is less than or equal to the beginning water surface precipitation rates used in the water budget shall be elevation, occurring prior to the inflow generated from published data, available from the National from a 100-yr storm event. in all cases the water Oceanic and Atmospheric Administration (NOAA), budget cycle shall be no less than a 1 year cycie. or other reliable sources. See Appendix 3. Average • monthly precipitation, rates and average monthly Design Condition B: If an evaporative system is used evaporation rates shall be used in the water budget in conjunction with surface discharge, the analysis,as a minimum. The monthly climatological calculations need to demonstrate that then is no net data from NOAA is taken from the Spokane increase in the volume of . runoff leaving the International Airport (GEG). To account for the developed site, over the water budget period, variation in precipitation in areas other than at the (normally an annual basis). An additional Spokane Airport, the U.S. Weather Bureau has evaporative storage volume. shall be provide to published isopluvial annual precipitation maps for the produce a factor of safety= 1.20,minimum. State . of Washington. The Mean Annual Precipitation Isopluvial Map for Spokane County is ( The evaporative system is to have a containment provided in Fig. 29. The average monthly volume separate from the detention volume, to precipitation is to be adjusted upward or downward provide attenuation of peak flows during design to account for this variation,and prorated based upon storm events. this isopluvial map. For example, if the project site has an average annual precipitation rate of 19.0 The surface discharge portion of the system, (i.e. inches, per the isopluvial map, then each published storage and ccratrol structure), shall be designed in average'monthly precipitation rate(from the Spokane accordance with the criteria for detention facilities, Airport arca) will need to be ,adjusted upward to described in the subsection labeled "Design Storm account for the difference between what is retarded Events&Surface Discharge"(pg. 3-6). at the airport, and the project site. Further, if the latest available climatOlogical data lists the airport to have an average annual precipitation rate of 16.18 Further Description of Design Criteria for inches, then each monthly precipitation rate for the ,Evaporative Systems site will have to be adjusted by a factor of(19.0)1 (16.18) = 1.17; or a 17%increase for each monthly A water budget of the proposed evaporative systems precipitation used in the water budget calculations. shall be performed by the sponsor's engineer. As When utilizing the isopluvial map, the engineer shall seaed above, the water budget cycle shall be round up to the nearest integer when deterinining the performed on a month-by-month basis,until a steady- annual precipitation rate at the project site. As stated state condition occurs (i.e. the volume at the end of previously, Spokane County will consider the use of the cycle is less than or equal to the Volume at the hydrologic values in exams of the minimum to be start of the cycle). The minimum duration of the good engineering practice and desirable when based water budget cycle is to be 1 year to account for upon proper engineering analysis of the factors which seasonal variations in precipitation rates and affect design. evaporation rates. The cycle is to start in the month Guidelines for Stormwater Management-Addendum 3-10 Spokane County: February 1998 f V f Runoff Volume Determinations: Runoff volume the absence of any site specific infiltration testing from the basin directing stormwater into the work being performed. evaporative system shall be included in the water budget analysis. Runoff volume can be determined Infiltration: When credit for infiltration is proposed, using the SCS hydrograph method. If this method is site characterization, in-place testing and reporting is used, then runoff from the impervious and pervious to be done in accordance with the addendum to areas shall be calculated separately, then added Section 2, and as described in the sub-section labeled together. Other methods may be permitted for use "Infiltration Systems." provided the engineer acquires acceptance of the method with the County Engineer prior to design. The design of the evaporative pond facility will need During the wet months and winter months of the to evaluate the potential of groundwater seeping into year, wet soil conditions and snowmelt conditions the pond from the surrounding area, under existing need to be taken into consideration_ conditions. A geotechnical evaluation shall be For the SCS b o �o evaluating this potential negative impact, ydr graph method, the following and if needed mitigative measures provided. As a parameters are to be used to determine minimum minimum, soil borings/test pits will need to be runoff volumes and flow rates: performed at each pond site. The subsurface investigation is to extend to a minimum of 4 ft. below MONTH ANTECEDENT RUNOFF CURVE" the anticipated bottom of pond elevation, or 12 ft OF THE MOISTURE NUMBER(CN) below the ground surface, whichever is of greater YEAR CONDITION MINIMUM depth. All soil logs' are to be included in the (AMC) geotechnical report and provided to the County. ,/ ' April - Normal (AMC Per Table 5 `` j October II) ` Nov., Wet (AMC CN Modified Sources of imported water need to be considered in March III) Fig. 3.3") the water, budget design and calculations.• Other Dec., — sour may include: irrigation, sewer septic Sa� tank/drainfreld systems, natural springs, foundation Jan., 9 Feb. drains, de-watering 'wens, etc. The gootechnicaJ (I)See Fig.28 shall address this issue in his/her report and (2) CN to be used to approximate runoff from pervious the Civil Engineer shall include any imported water in sulfa= ing snowpack buildup and snow melt season. the water budget analysis. ces The *rater budget analysis and geotechnid work shall be performed by an engineer, licensed ®'the Water loss through evaporation from overland Stott of Washington. All reports submitted to the surface areas is normally not to be considered in the County shall be stamped and signed by the engineer. water budget, for the areas contributing runoff to the evaporative pond(s), due to the wide variation in Credit in the water budges for pleat upi ake and evaporation rates which occur over these types of negation facilities cannot normally be eonsderrd in surfaces. The only reduction which can be the analysis; exce t in certain'conditions where the considered in the analysis is runoff interxption and County Engin= may permit it, such as when the surface infiltration, which is normally accounted for won system is a single-owner controlled in the SCS curve numbers. facility,and it is commercially operated. �� Disposal is primarily through evaporation from the The maximum water surface elevation permissible in ! pond surface. Credit for infiltration through the soils the water budget is to be below the finish floor will not be considered in the water budget analysis in elevations of the surrounding buildings (existing or pmp )• Parking lot arias, privately owned, can be used for temporary storage of stormwater and Guidelines for Stormwater Management-Addendum 3-11 • Spokane County: February 1998 • considered in the water budget analysis. If pending is drainage facilities at time of construction, and shall proposed in parking lot areas, the maximum water submit to the County: inspection reports, lab reports, depth shall normally not exceed 8 inches. If water and certified Record Drawings. The sponsor shall depths greater than 8 inches are proposed, it will agree to coordinate and pay for the construction and require specific approval by the County Enginixr, inspection services. The three party agreement shall and it may require title notices placed on the affected be in a formal acceptable to the County Engineer, properties. Public roadways and rights-of-way are and shall be signed by all three parties prior to not to be used for storage of stormwater. If it is beginning of construction of the drainage facilities. determined that adjacent properties will be used for storage,then the Sponsor will be required to obtain a drainage easement from the affected property owner(s). The easement .document shall be in a • format acceptable to the County Engineer. If snow removal operations deposit snow into an evaporative systern, this added factor must be considered in the water budget,.especially if snow from,another basin is put into the system. ' Temporary sediment.traps or sediment ponds are to be included in the design, to,prevent sediment-laden . • • runoff from entering the pond and storm disposal system during construction. The sediment traps/ponds are to be sized to contain sediment for a minimum of.a three month period, using the Flaxman Method. (See Appendix . D.). The sediment traps/ponds are to be installed prior to•c:onducting other earthwork on the project site. A'written maintenance plan for the drainage facilities shall be prepared by the sponsor's engineer.. In addition to the items listed in the addendum to Section 1 of these Guidelines, the maintenance plan shall provide written procedures-that will prevent over-irrigating of lawns,which could impact the local groundwater elevation. As - a preface to the maintenance plan, the sponsor's engineer shall work out a proposal with:the project sponsor, desenling - who, or what entity will be responsible for the perpetual mainturance of the drainage facilities. Construction Monitoring and Inspection: If deemed necessary by the County Engineer, the sponsor, the sponsor's engineer, and the contractor shall enter into a three party agreement to insure that the drainage facilities are constructed in accordance with the plans and specificaticms. The contractor shall inform the engineer of construction schedules. The sponsor's • engineer shall provide inspection and testing of the Guidelines for Stain:water Management-Addendum 3-12 Spokane County: February 1998 4. Drainage Design 4-1 - Inlets - The locating and sizing against clogging. For depths of water of drainage interception facilities above 1.4 ft. use orifice formula: shall be done proving by computations, that they will hydraulically perform Q = CA 145ff their intended function. Where A = total area of clear opening Depths of flow and velocities shall be H depth of water calculated for open channels including C may be taken as 0.67 street gutters (see figure 18, page 6-42). The quantity of water inter- When no curb opening is provided, divide cepted by a drainage structure, such as the area of clear opening. by 2 to pro- a grate inlet or curb opening, shall be vide a.safety factor against clogging. shown along with the quantity that by- passes to a lower inlet. For depths between 0.4 and 1.4 ft., operation• is indefinite due to vortices Grates must be depressed to insure sat- and other disturbances. Capacity will isfactory operation. Use a 2" maximum be somewhere between that given by the depression. Gutter depressions shall above formulas. conform to the standard plan. All grate • installations constructed at low points Problems involving the above criteria with types A or B curb shall be a com- may be solved graphically by use of Fig- , bination structure with a grate and a ure 14 (page 6-36). curb opening. Inlets shall not be lo- cated on the curved portion of a curb b. The capacity of a curb opening in- return. let (no grate) in a sump condition . may be calculated as follows: 4-1.1 Sump Condition - The capacity of a grate inlet in a sump or low point For heads (depths of water) up to (water ponded) may be estimated as fol- a height of the opening, (11 < 1 ) , lows: the inlet is assumed to act as a a. For depths of water up to 0.4 ft. weir with the flow passing through use the weir formula critical depth at the entrance and following the formula: Q = CPH3/2 Q = 3.087 X3/2 Where P = perimeter of the grate opening ignoring the bars For heads equal to or greater than H = depth of water twice the height of opening L >/2), C = may be taken as 3.0 h the inlet is assumed to act as an Where one side of grate is against a orifice following the formula: curb, this side must be omitted in com- puting the perimeter. When no curb • 3/2 opening is provided, divide the peri- meter by 2 to provide a safety factor 4-1 • f where h = Total height of opening in T = 0.5 cfs/ft. feet. 2 L = Total length of opening in feet. From Figure 17 H/h = 1.25 H = Depth of water at the en- Head = 1.25 x 0.25' = 0.31 trance in feet. Q = Total peak rate of flow to Since 0.31 ' < 0.67' then curb opening is the inlet in cfs. sufficient. H' = H - h This is a rearrangement of the standard orifice formula -- Q=CA 14r7 with C = Normally, Q, L, and h will be known, and 0.7' and H' equal to the head on the mid- the formulas can be used to determine dle of the inlet opening (H' = H - h) the depth of .water H at the inlet. 2 Problems involving the above criteria For heads with H/h between 1 and 2, may be solved graphically by use of Fig- a transition was used as the opera- ure 17 (page 6-41). tion of the inlet is indefinite. Example 1 : Given a proposed paved If the inlet is a combination type with street with 6" curbs. It''s proposed to grate and curb opening, the recommended place a catch basin with a rectangular procedure is the same as with a grate grate at a low point on the road profile alone except the perimeter and area are to dispose of a flow of 1 cfs. The not divided by 2. - The ' reason for this grate measures 1.7' x 1.5' (measured to is that the curb opening will serve as the end of the slots). • If we depress relief in event the grate becomes the grate 2" from the gutter flowline, ged. �". then the maximum allowable head is the height of the curb plus 2". 4-1.2 Continuous grades - On continuous grades the water entrapped by a grate Max. H = 0.67' will be' equal to the amount flowing dir- ectly over the grating plus the amount From Figure 14, if H = 0.67' the 2 = 1.6 that flows. in over the side of the grate (page 6-36) P according to the weir formula. The perimeter of the standard grate is Figure 15 (page 6-37) 'may be used to de- 6.4'. we must subtract the length next termine the percentage of flow entrapped to the curb: P = 6.4 - 1.7 a 4.7'. The by a grate. rate of flow passing through the grate at maximum head is Q = 1.6 x 4.7' = 7.5 The minimum length of clear opening, cfs. Max Q = 7.5 > 1 cfs parallel to the direction of flow, re- , quired to allow the jet of water falling The grate is sufficient, however a coon- through the opening to clear the down- bination structure with a grate and curb stream end of the slot depends upon the opening shall be provided for a safety depth and velocity of flow in the ap- factor against clogging of the grate. proach gutter and the thickness of the grate at the end of the slot. The mini- Example 2: Given the same problem as in mum length may be estimated by the fol- Example 1 except that a curb opening ling formula. However, the formula structure is used with no grate. The shall not be used with street gutter , ., opening length is 2 feet. The height of velocities greater than 6 feet perk, the opening is 3". The Q per foot of second. length would be: 4-2 L = V (y+d)1/2 2: The same problem as in Example 1 ex- -\ cept the facility considered is a curb opening with no grate. The opening is Where L = minimum length of slot in 4' long and 3" in height. The opening feet is depressed 2' from the gutter grade. V = mean velocity of flow in the From Figure 16 using the depression (a) approach gutter of 2" y z depth of water at curb in ap- a 0.08 cfs/ft proach gutter Q d = thickness of grate at down- La stream end of the slot Q = 0.08 cfs/ft _x 4 ft . 0.32 cfs Figure 16 (page 6-37) may be used to de- termine the capacity of a .curb or side The amount bypassing equals 1.5 cfs - opening on a continuous grade. 0.32 cfs = 1.18 cfs. A curb opening on this grade would not 'be economical nor 4-1.3 Examples - 1: A proposed paved desirable.. street is to be constructed with. 6" curbs. The cross slope is 2.5%. The 4-2' Culverts and, closed systems - Cul- street grade is 4% and flow of 1.5 cfs verts shall be sized for the design will flow in the gutter and must be storm, by determining the maximum allow- intercepted by a grate. A grate 1.5' x able headwater elevation at the entrance 1.7' is being considered. First calcu- to which water may rise without damage late the depth and width of flow in the to private property or the public road. gutter. From Figure 18, depth = 0.12' , Headwater elevations shall be shown in width 4.8'. the computation. Pipes in closed sys- tems similarly will be sized by calcu- j -We can check the length of the grate by lating the headwater in each catch basin 1/2 or manhole. A minimum of 0.75' free- . the formula L = V (y + d) d = 0.145' board will be allowed between the water surface in a catch basin or manhole and the top of grate or cover. Except as The velocity = = 1.5 cfs = 5.2 fps hereinafter allowed, the minimum dia- 4.8' x 0.12' meter culvert under a public road shall 2 be 18": Culverts shall be designed to 1/2 carry the design runoff with a headwater L =(1/2)(5.2 fps) (0.145'+.12' ) = 1.34' depth not than 2.0 times the required -- 1.34' < 1.7' The grate is 'culvert diameter for culverts 18 inches long enough. . . and under., or 1.5 times the culvert • diameter for culverts greater than 18 The percentage of width covered by the inches. grate is 1.5' = 0.31 From Figure 15 4.8' Minimum velocities in pipe systems and the percentage of Q intercepted is 64%. culverts shall be 4 feet per second at Q intercepted = 0.64 x 1.5 cfs 0.96 design flows to prevent silting unless cfs. Say 1' cfs otherwise permitted by the County Engin- eer. • The amount bypassing the grate is 1.5 cfs - 1.0 cfs' = 0.5 cfs. An additional Minimum cover over culverts and . pipes facility will be required downstream to � within a oublic roadbed shall be 1 foot. intercept the remainder. 4-3 Minimum culvert and pipe slopes shall be critical slope to less than critical 0.5%. slope causing a loss of energy and re- sulting in a possible deposit of silt Horizontal angle points shall not be al- just downstream from the jump. Angle,` lowed in a storm system unless a manhole points in ditch profiles shall be place( or other suitable access is provided for so as to prevent a jump from occurring cleaning. at the entrance to culverts. When two different sizes of pipes are joined at the same manhole or catch ba- 4-2.1 Types of flow. Flow in open sins, place the 0.8 diameter point of channels is classified as uniform or each pipe at the same elevation. The nonuniform. The flow is said to be uni- exception to this rule would be at drop form when the rate of discharge is not manholes. varying with time. In these guidelines, the flow will be assumed to be, uniform Downsizing;.of culverts within . a closed at the discharge- rate for . which- the system with culverts less than 18 inches channel is to be designed. Uniform flow in diameter, is not permitted. Culverts occurs when the channel cross section, larger than 18 inches in diameter may be roughness, and slope are constant; and downsized 3 inches, if the- culvert capa- as nonuniform or varied when the channel city i's' adequate and a minimum 100 foot properties vary from section to sec- run of pipe is proposed to be down- Lion. sized. Depth of flow and the mean velocity will Except as hereinafter allowed,' no pipe be constant for uniform flow in a uni- within a storm sewer system shall be form channel. • smaller. than 12 inch diameter. Storm sewer systems shall conform to the. fol- lowing manhole spacing: 0 4-2:2'-Uniform flow. With a given' depth See Note #1 of flow d in a uniform channel, the meat Pi • Size velocity V may be, computed by the Maxi tanceBet ' manholes Manning equation: • 12"-15" -4 ove 42" V =' 1 .49 R2/3S1/2 300' A 10-inch pipe with a minimum velocity in which: of '4 fps May be used to connect a ton- :R Hydraulic radius = A/WP = area of crete inlet to a catch basin or drywell cross section of flow divided by if the design flows are accommodated and wetted perimeter. if the length of the pipe does not ex- S = Slope of total head line. teed 44 feet. n = Manning roughness coefficient. No storm sewer pipe-in a drainage ease- • The discharge. Q is then:shall. have its centerline closer ': than 5 feet to a private rear or" side Q = AV property lines. The Manning equation will give a rel i- A. hydraulic jump occurs when the slope able estimate of. velocity only if the of the channel changes from greater than discharge, channel cross section, rough- 4-4 Note #1: Please refer to pages 4-4A through 4-4C re: Drainage Design of Storm Sewer Pipe Systems. -;�� S P C) K A I■T E � ' i „f '• ��± C O U N T Y --- DIVISION OP ENGINEERING AND ROADS A DIVISION OP THE PUBLIC WORKS DEPARTMENT May 15, 2003 Attn: All Spokane County Standards Holders Re: Drainage Design of Storm Sewer Pipe Systems • Dear Standards holders, For minimum pipe velocities in storm sewer pipe systems, Spokane County will now accept the design standard set forth by the Urban Drainage Design Manual • Hydraulic Engineering Circular No. 22. The manual is available from the U.S. Department of Transportations Federal•Highway Administration. Seethe attached sheets. - .In section 4-2 of the Spokane County Guidelines for Stormwater Management, the "Pipe Size Maximum Distance Between Manholes"table is deleted and replaced with - the following: The maximum distance between storm sewer-manholes for'all pipe sizes shall be 300 feet.. • This change does not include culverts. Very truly yours, • Ross E. Kelley, °.E. County Engineer • • 1026 W.Broadway Ave. • Spokane,WA 99260-0170 • (509)477-3600 FAX: (509)477-7655(2nd Floor)477-7478(3rd Floor) • TDD:(509)477-713; 4-4A 7.2.4 Minimum Velocity and Grades ' It is desirable to maintain a self-cleaning velocity in the storm drain to prevent deposition of sediments and subsequent loss of capacity. For this reason, storm drains should be designed to maintain full-Flow pipe velocities of 0.9 meter per second (3 feet per second)or greater. A review of the hydraulic elements in chart 26 indicates that this criteria results in a minimum ( ' Flow velocity of 0.6 meters per second.(2 feet per second)at a Flow depth equal to twenty-five (25)percent of the pipe diameter. Minimum slopes required for a velocity of 0.9 meters per second(3 feet per second)can be computed using the form of the Manning's formula given in equation 7-28. Alternately, values in table 7-7 can be used. Table 7-7. Minimum Pipe Slopes to Ensure 0.9 m/s(3.0 ft/s)Velocity In Storm Drains Flowing Full. Minimum Slopes, m/rn Pipe Size Full Pipe Flow . mm (in) • m3/s (cfs) n • n n 0.012 0.013 0.024 200(8) 0.03(1.1) 0.0064 0.0075 0.0256 250 (10) 0.05 (1.6) 0.0048 0.0056 0.0190 • 300(12) • 0.07 (2.4) 0.0037 0.0044 • 0.0.149 380(15) 0.10(3.7) 0.0028 0.0032 - 0.0111 460(18) 0.15(5.3) 0.0022 0.0026 0.0087 • • 530(21) 0.20 (7.2) 0.0018 0.0021 0.0071 610(24) 0.27(9.4) 0.0015 0.0017 0.0059 • • 680(27) 0.34'(11.9) 0.0013 . ' 0.0015 0.0051 766(30). 0.42(14.7) .0.0011 . 0.0013 0.0044 840(33) 0.50(17.8) 0.0010 . 0.0011 0.0039 910(36) 0.60 (21.2) 0.0009 0.0010 0.0034 1070(42) 0.82 (28.9) ' • 0.0007 • 0.0008 ' 0.0028 1220(48) . 1.07(37.7) 0.0006 . 0.0007 • 0.0023 1370(54) 1.35(47.7) .0.0005 0.0006 .0.0020 • 1520(60) 1.67(58.9) • 0.0004 0.0005 . ' 0.0017 1680(66) 2.02(71.3) 0.0004 0.0005 0.0015 . 1820(72) 2.40 (84.8) • 0.0003 • 0.0004 0.0014 s S a ici D(-ozy (7-28) where: • K, = 6.35(2.87 in English units) ' D is to be in m or ft when using equation 7-28 • FHWA • Hydraulic Engineering Circular No. 22, Second Edition . ,__- 4-4B CHART 26 100 ,.... 90 A A 1\ tf 4 . .r ., .main • -m n. V' -. Izt.*- 7° 0 o 111111p11,11, a m O 40 0"1/ eoo# . e 00'111 ' . . . 2° ; , . 10 4. ,,,,..., 0 0 10 20 30 40 60 60 70 93 90 100 110 120 130 Percent Of Value For Full Section (approx.) Hydraulic Elements Chart • A-44 FHWA Hydraulic Engineering Circular No. 22, Second Edition . i 4-4C ness, and slope are constant over a suf- tally for the average velocity V in ficient distance to establish uniform given channel if the normal depth flow conditions. Strictly speaking, is known, because the various factors uniform flow conditions seldom, if ever, the equation are known or can be det4 occur in nature because channel sections mined (the hydraulic radius can be ci change from point to point. For practi- puted from the normal depth in the gi' cal purposes in road engineering, channel ). Discharge Q is then the pn however, the Manning equation can be duct of the velocity V and the area applied to most streamflow problems by flow A. More commonly, however, • making judicious assumptions. depth is the unknown quantity, and wi• out channel charts, the solution • When the requirements for uniform flow quires repeated trials. are met, the depth d and the velocity V are said to be normal and the The charts (Figure 19) in these gui• slopes of the water surface and the lines provide a direct solution of • channel are parallel. For practical Manning equation for many channels purposes, in road drainage design, minor circular cross section. A pipe flow undulations in streambed or minor devi- less than full operates as an open ch ations from the mean (average) cross nel. section can be ignored as .long as the • mean (average) slope of the channel can 4-2.3 Energy of flow. Flowing wa be represented as a straight line. contains energy in two forms, potent and kinetic. The potential energy a• / The Manning equation can readily be particular point is represented by ', ,,/ solved either graphically or mathe;nati- depth of the water plus the elevation the channel bottom above a conveni Specific Head Head (Depth . Velocity Head) V2 `•Line / 2Q Total Head Line 10 Yji SpeClfic 2 — �ti` Head V 8 _ ` `Wo'er Surtooe w°ter S 20 5 +�e /` — 2 7r 1 do do Total 'r I —'I i Head Culvert Total l 2 4 6 8 t0 • II_ I - - _, , Head Depth-ft. z z Datum Plane A. Supercritical Flaw B. Specific Head Curve C. Subcritical Flow 1 FIGURE 4-I - Definition sketch of specific head. 4-5 datum plane. The kinetic energy, in tion. The total head loss in length L feet, iS represented by the velocity is equal to• S x L. Under uniform flow, head, Y /2g. In channel-flow prob- the energy line is parallel to the water lams, it- is often desirable to consider surface and to the streambed. For flow the energy content with respect to the to occur in a channel , the total head or channel bottom. This is called the energy line must slope negatively (down- specific energy or specific head and is ward) in the direction of flow. equal to the depth ,pf water plus the velocity head, d+V /2g. At other 4-2.4 Critical flow. The relative val- times, it is desirable to use the total ues of the potentia energy (depth) and energy content (total head) , .which is kinetic energy (velocity head) are fin- the specific head plus the elevation of portant in the analysis of open-channel the channel bottom above a selected da- flow. Consider, for example, the ela- tum. For example, total head may be tion of the specific head, d + 114/2g, used in applying the energy equation, and the depth d:.of a given discharge in which states that the total head (ener- a given channel that can be placed on gy) at one point in a channel carrying a various slopes. Plotting values of flow of water is equal to the total head specific head as ordinates and of the (energy) at. any point downstream plus corresponding depth as abscissa, will the energy (head) losses occurring be- result in a specific-head curve such as tween the two points. The energy (Ber- that shown in figure 4-1B. The noulli) equation is usually written: straight, diagonal line' is drawn through • points where depth and specific head are dI , V 2 . Z1 d2+ V. • Z2 • h equal. The 1 i ne thus represents the 2g 2g loss potential energy, and the ordinate interval between this line and the spe- In the equation, cross section 2 (sub- - cific head curve is the velocity head - script 2) is downstream from cross sec- for the particular depth. A change in tion 1 (subscript 1), Z is the elevation the discharge Q or in the channel size of channel bottom, and h loss represents or shape will change the position of the loss of head between cross sections 1 curve, but its general shape and loca- and 2. A convenient way of showing spe- tion above and to the left of the diag- cific head is to plot the water surface oral Tine will remain the same. Note and the specific head lines above a pro- that the ordinate at any point on the file of the channel bottom (See Figure specific head curve represents the total 4-1 , sketches A and C). specific energy, d + V /2g, at that point. The lowest point on the curve Note in figure 4-1 that the line ob- represents flow with the .minimum energy- tained by plotting velocity head above content. The depth at this point is the water surface is the same line as known as critical depth de. and the that obtained by plotting specific head corresponding velocity is the critical above the channel bottom. This line velocity Vc. With uniform . flow, the represents the total energy, potential channel slope at which critical depth and kinetic, of the flow in the channel occurs is-known as the critical slope and is called the "total head line' or Sc. "total energy Line". Points on the left of the low point of The slope (gradient) of the energy line the specific head curve (fig. 4-1B) are is a measure of the friction slope or for channel slopes steeper than critical rate of energy head loss due to fric- (supercritical or steep slopes) , and • 4-6 • • indicate relatively shallow depths and five channel , such as a culvert or high velocities (fig. 4-1A). Such flow flume, on a steep slope; (2) at the is called supercritical flow. It is crest of an overflow dam or weir; and difficult to handle because violent wave (3) at the outlet of a culvert or flume action occurs when either the direction discharging with a free fall or into a of flow or the cross section is changed. relatively wide channel or a pond in Flow of this type is common in steep which the depth is not enough to sub- flumes and mountain streams. In super- merge critical depth in a culvert or critical flow, the depth of flow at any flume. point is influenced by a control up- stream, usually critical depth. Critical slope is that channel slope, for a particular channel and discharge, Points on the right of the low point of at which the normal depth for uniform the specific head curve (fig. 4-18) are flow will be the same as the critical for slopes flatter than critical (sub- depth. Critical slope varies with both critical or mild slopes) and indicate the roughness and geometric shape of the relatively large depths with low veloci- channel and with the discharge. ties (fig. 4-iC). Such flow is called subcritical flow. It is relatively easy The open-channel flow charts for circu- to •handle through transitions because l.ar channels presented in this guideline the wave actions' are tranquil. Flow of Figure 19) have a heavy broken line from this type is most common in streams in which critical depth and critical velo- the plains' and broad valley regions. In city may be read directly for different subcritical flow, the depth at' any point values of Q, regardless of channel is influenced by a downstream control, roughness. Critical slope, however, which may be either critical depth or varies with roughness and must be deter- the water surface elevation in a pond or mined as provided in the instructions. larger downstream channel. .Figures'4-1A and 4-iC indicate the relationship of 4-2.5 With supercritical flow, a change ' supercritical and subcritical flows, in . channel shape, slope or roughness respectively, to ' the specific head cannot be reflected upstream except for curve. very short distances. However, the change may .affect the depth .of flow at Critical depth de is the' depth of flow downstream points; thus, the flow is at minimum specific energy content (fig. said to be under upstream control or in 4-1B), and it can readily be determined the case of culverts, inlet control. In for the commonly used channel sections. this case critical depth, dc, is The magnitude of critical depth depends greater than normal depth, dn, and the only on the discharge and the shape of flow is supercritical. The total head- the channel, and is independent of the water (HW) in this case is• shown in Fig- slope or channel roughness. Thus, in ure 4-2A, and is calculated as follows: any .given size and shape of channel, there is only one critical depth for a particular discharge. Critical depth is HW = do + V�2 + Ke .VV22 (1) an important value in hydraulic analyses Zg Zg because it is a control in reaches of - nonuniform flow whenever the flow changes from subcritical to supercriti- cal. Typical occurrences of critical depth are: (1) Entrance to a restric- i • 4-7 Entrance Loss • Velocity Head Entrance Loss • Velocity ►teas CI • KeIy2 (I • Ke)29 • 20. - HW `\\•t�� `� Wotei ,�_ g water Surf= Sur. g Free Outlet • • • • Fig. 4-2A. Flow through .a culvert with Fig. 4-2B. Flow through culvert with free. discharge: Normal depth do is free discharge - and normal depth do ' less than critical depth dc: -.slope is greater than critical depth d when greater than critical. Discharge de- entrance is unsubmerged or slightly sub- pends on' type of inlet and headwater. merged: Open-channel flow occurs and discharge. depends on headwater loss at entrance, and 'slope Of culvert. With subcritical flow, a change in chan- nel shape, slope or roughness affects the flow for•a considerable distance up- If the Headwater is greater than 2 times stream, and thus the flow is said to be the .culvert diameter for culverts 18 under downstream control , or in the case inches and under, or 1.5 times the of "culverts, outlet control. In this culvert diameter for culverts greater case normal depth, dn, is -greater than than 18 inches, the entrance will be critical depth, dc, and the flow is . submerged, and the culvert will flow subcritical. The total headwater (HW) full. . This will no longer be an open in' this case is shown in Figure 4-2B, flow condition. Therefore, equations 1 and is calculated as follows: and 2 do not- apply in this case. HW = do + 112: * g 2 K V '(2) Also when .both the entrance and exit are 2 fully submerged, the culvert flows full , and the discharge is independent of Equations 1 and 2 assume open flow con- slope.. (See Figure 4-2C.) These two ditions and a free exit. If as in a cases are called pressure flow, and the pipe system, the Headwater from the Headwater is calculated as follows:- downstream pipe submerges the exit of the pipe immediately upstream, a back- HW = H - S01 + ho (3) water curve computation may be neces- sary. The computation of backwater where curves is explained in textbooks and HW = vertical distance in feet from handbooks on hydraulics, and will not be culvert invert (flow line) at covered here. entrance to the pool surface. L 4-8 H = head loss in feet as determined Equations. 1 and 2 can be solved using from the appropriate nomograph Figure 19, Sheets 1 - 6 for inlet and (Figure 20). outlet conditions and Equation 3 can be solved using Figure 20 , Sheets •1-2 , for ho = vertical distance in feet the pressure flow conditions. from culvert invert at outlet to the hydraulic grade line. (In this case, ho equals TW, 4-2.6 Procedure for Selection of Cul- measured in feet above the cul- vert Size vert invert. ) • So = slope of barrel in ft./ft. Step 1 : List design data. (See sug- L culvert length in ft. gested tabulation form, Figure 22. ) a. Design discharge Q, in cfs., with average return period. (i.e. Q10 or Q50 etc.) HW = 1 g HYDRAULIC b. Approximate length L of culvert, in � -GRADE LINE feet.pp g c. Slope of culvert. (If grade is given in percent, convert to slope in ft. per ft. ) Oluarr.-1 . ( ' . d. Allowable headwater depth, in feet, which is the vertical distance from the Fig. 4-2C. With entrance and exit sub- culvert invert (flow line) at the en- . merged, normal pipe flow occurs in a trance to the water surface elevation culvert, and discharge is independent of permissible in the headwater pool or slope. The fluid flows under pressure. approach channel upstream from the Discharge may be determined from Ber- culvert. noulli and Manning equations. e. Type of culvert for first trial sel- ection, including barrel material , bar- rel cross-sectional shape and entrance For tailwater Tw elevations less than type. the top of the culvert at tI�a outlet find headwater HW by equation 3 above Step 2: Instructions for use of Figure except that 19 Sheets 1-6, for pipes 12 to 36 inches in diameter. It will be noted that each ho II d + D or TW, whichever is slope line has a hook at its right ter- the greater. minus. If do is greater than 0.82 diameter, two values of do will be where shown by the slope line hook for a par- ticular value of Q. In these cases, do ° critical depth in ft. (Figure 19) flow will be full flow or be pressure Note: do cannot exceed D flow, and these charts cannot be used. D - height of culvert opening in ft. 4-9 Interpolated slope lines follow the same pattern as those drawn on the charts. Find: Depth, velocity, type of flow{ and Headwater. For a given discharge, slope and pipe size, the depth and velocity of uniform 1 . Select the Figure for a 30-inch flow may be read directly from the chart pipe, Figure 19, Sheet 5 of 6 (page for that size pipe. The initial step is 6-48). to locate the intersection of a vertical line through the discharge (on the ap- 2. From 25 on the Q scale for n=0.015, propriate n scale)' and the appropriate move vertically to intersect the slope slope line. At this intersection, the line S=0.005; at the intersection, from depth of flow is read or interpolated the depth lines read do=2.05 ft. from the depth lines; and the mean vela city is read opposite the intersection 3. Move horizontally from the intersec- on the velocity scale for the n value of tion and read the normal velocity, Vn the pipe (see 'examples 1 and 2). This =5.8 f.p.s. , on the ordinate scale. depth• is normal depth, and the velocity is normal velocity. The procedure is 4. The intersection lies below the reversed to determine the discharge at a critical curve, and the flow in there- given depth of flow. If the discharge fore subcritical. At the intersection line passes to the right of the appro- of the Q=25 c.f.s. (on the scale n= priate slope line, the pipe will flow 0.015) line with the critical curve, the full (in which case, see example 3). chart shows critical depth do=1.7 ft. and critical velocity Vc=6.9 f.p.s. Critical depth and critical velocity are independent of the value of n. They are 5. As dc<dn, flow is subcritical. read at the point where a vertical line From Equation 2, ' ' - through Q. on the scale n=0.015, inter- sects the critical curve. Critical HW=2.05+5.82+5.82+(.9)(5.8)2=3.04' slope for-n=0.015 is also read or inter- 2g 2g polated from.the slope line at the same - intersection. For n values of 0.012 and 2: Given: A long 18" - c.m.p. with 0.024, critical slope is determined by Ke=.9, n=0.24, on a 4% -slope (S=.04) , first finding critical depth, using Q on discharging 10 c.f.s. Length = 60' the -scale n=0.015. Critical slope is then read or interpolated from the slope Find: Depth, velocity, type of flow, lines at the intersection of critical and Headwater. depth and the vertical line through Q on the appropriate - n scale. Critical 1. Select the figure for an 18-inch depths falling between the last two pipe, Figure 19 Sheet 3 of 6 (page normal depth lines have little signifi- 6-46). cance, since wave action may intermit- tently fill the pipe. 2. From 10 on the Q scale for n=0.24, move vertically to intersect the slope 4-2.6 . Examples - line S=.04; at the intersection, from the depth lines read dn=1.08. 1 : Given: A long 30-inch concrete pipe with Ke=.9, n■0.015, on a 0.5 percent 3. Move horizontally from the intersec- slope (5=0.005) , discharging 25 cfs. tion and read the normal velocity, V, = 7.5 on the .024 Ordinate Scale. 4-10 + o Z C 4.■IC n 1 ' 111 rg'" C O U n u •8 o w 0v v ^41 U O v O no PIO z A :`°$:::: to a •C~ m i J C t o v e 0" A A Q w C 3 J u c O /1/ st cE H , N 0 Cr p 2 N C am _ Q a IN 40 S 1� t . H C d u • 2 W • 4 . - -cS o N Z fu U = C Al W co N• e*) • C M � « CC 0 ..r C H N a -•N 0. c 4 >le" en a r ..- 3 - . la 3 C '6 L J I J Q Ti 4.1 0 W a W W d10L ..O-. ac• = 3 _ LIiJ 0 Pa 0 0 . L — J 0- nu_, eL �.. U CO N 2 .>C .-.en > N its a. - 4 1 N ■ O •• w e c C n e • _ tL, 0% 3 0 0 tD = ~ >u ID 0 N Q 415) . Q• g f� 41 c e Z • GJ 0 : to a J 0 H CO .> • W v . 2 .- t d Q C ii s _ O i i 0 o Q N Q = W i p p — V Q W t 0 O - a u 0 p d W I.I. G H W • (,) J X V — > d W V < ONE el y) 0 z U /- ]G C 3 W W 0 U J J W u L O c o - .4 11C Le)-\ W tL .. - 11 0 C 4 3 N A ■ I O > zY u 2 IA s 1 O W D > - Cr V •" =C3 Cl) I" - - - 4-11 1 - - ' . L i en en O IU w r d ai �' S. 0 4:n.47..., V � Q C � NCI 44 R »= a en N !t N O.V CA 1 O. 100 • 3 L4p0t�/� �i V I ~� ��14110 /� _ - If O ^ c n S' w w vg iir W Aig Li w Pf J e o AA #I 0 o e I� J I CO W c° H gut:. . . 0 W W H ; d J N W • •t O IZ G z cL H " o Z W W a a _ I Z - C9 C U 10 Pi • to r" LO W Al O awl n C O► A fq W Q W 'Q ILI i 1i O • - = • r ; QI L r O = a- � �,- In _ id d N I I. C W W N C m CL - e •• 0 e • 0 w • Z 4•10 IR 0 m Z p Q O >4P CI .4.1).4.1) a CC i3 0 0 u N - 0 oO ""I 41 Z ea O _ J w a wWi • m - as W — Z 0. . Z H >~ I K d W• II Qof 0 0 O . C • o V c Z T 0 A • O O = v Z a O Z t Q Q v1 O .� 0 In W a. to t. c d d W = o CI v1 Z ¢ Q0• Cr t n m dts J Q 0 J J Q 0 W U O O Z ac >- t.) i 0 O W O .. I- Q.. I . C • w D } C Iz Q ; N 0 = O W U Y N d ` J W = / • • 4-12 I . 0 y N ? w cu 2 =cm O H C u . w en 3 CL M t 00 p 0 dypo�,A ^ V.I J~� NI��O to % ; M O I 3 C1 5 1 H III _ • Mt ci o " rr CI N W N J C ! Y o N e 10 0 3 r•1 A A ~' 0 :: = N V 0 fh V .-� W Y W ey , H O ..J VI 2 W 1 Q a Qlre en . s s < .-i = e► = N a s z C 0 ° �+ t o W ..-+ COI er1 u Q' N r p ° W = .1 N N Q 1 o O.....i P] a N�1 �~ .r ; cu co -i I J Q ?? • W Q ea W O N O L • X r3N� 0 JL O L'� V • . J .e r N W >` y >� a C. , d • 0 1 • e N v a 0 0 ' A _ Q 0 >160 O W 2 eA r 0 0 u N O LL 0 - 2 N — 0 .r T ..J a 0 H • N 2 a- a. .-. O a s QZ c�i1 0 O W s ■ 2 a as 0 VI A It o 2- . L. w ° ° . 2 4It 0 c _ n a = 0 0 C H W �. T J 1f. Y. ac V r W an W 5 v • Q t •�f In OJ W W al. m O at /111 tJ U 0 0 ° O Z *' - 0 0 O W C P• Q• CI, Q w a Ji ' Q = > 2'IC s2 d i a es— _ J W s E _N t v i'>' ... [D N 4-13 4. The intersection lies above the cri- All road ditches shall be as shown qf tical curve, and the flow is therefore Spokane County Standard Plan S-4. A( supercritical. At the intersection of other ditches or channels shall have the Q=10 c.f.s. (on the n=.015 scale) side slopes no steeper than 1-1/2 hori- line with the critical curve, the chart zontal to 1 vertical unless approved by shows do=1.2 and the critical velo- the County Engineer's Office. Ditches city, Vc=6.8 f.p.s. (on the n=.015 may be "V" shaped or trapezoidal. scale). Channel protection shall be provided 5. As do>dn, flow is supercritical. when velocities exceed permissible velo- From Equation 1. cities for the soil in question. Refer to Section 4.5 of these Guidelines. HW = 1.2 + 6.82 + .9(6.82y 2.56 ft. 2.g `64.3 Normal depth in open channels may be calculated by means of Manning's formula 3: Given: Same as Example 2, but S=.02 V = 1.486 R2/3 S1/2 Find: Same as Example- 2. n . 1. Select the figure for ' an 18-inch Critical depth may be computed by the pipe, Figure 19, Sheet 3 of 6 (page . following formulas: 6-46). Triangular: Dc =" 2 22 2. From 10 on the Q scale for n=.024, ` g move vertically to intersect the slope 3/2 line S=.02. The line passes to the Trapezoidal : Q =-lg bb + Z Dc Dc 3 Dc right of the .02 slope line, therefore ry b + 2 { ud r the pipe is flowing full at pressure • flow, dn=D. Where Q = rate of flow, cfs .g = acceleration due to gravity, 3. From Figure 20, Figure 2 of. 2, H .= 32.2 ft/sec 2.8 ft. = slope of sides expressed as a ratio, i.e. 2:1 or 2 4. From Figure 19, d = 1.2 ft. Dc= critical depth ho =: d,. + D = 1.2 + 1.5 = 1.35 ft. b = channel bottom width 2 The formula for a trapezoidal section 5. From Equation 3 must be solved by a trial and error HW = 2.8 + 1.35 - 60(.02) = 2.95 ft. method. . Most hydraulics handbooks con- tain tables that simplify this calcula- 6. Q=VA or VcQ/A=10/IT(l.5� - 5.7 fps- ti on considerably. 2 • Exam le: A channel is to be designed to 4-3 Channels and Ditches' - Open channels carry 30 cfs at a slope of 2%.. An un- shall be sized according to Mannings lined ditch is planned. The soil can formula. Velocities shall be shown for resist a flow of 4 fps. all proposed ditches. Minimum grade for unpaved ditches shall be .005. Minimum Solution: Try a 2' wide trapezoidal grade for Portland cement concrete or eta h with 2:1 side slopes. asphalt ,concrete lined ditches shall be From Table 13 n = .03 .0025. 4-14 • Try a depth of 1.2' • 4-4.1 Drywells - Precast concrete dry- wells, as shown on County standard 2/3 1/2 drawings, may be used to retain storm V•1.486 R S R ■ Area drainage in soils with a very rapid per- Wetted perimeter meability. Types A and B Drywells in 2'x1.2'+(2x1.2x1.2) 5.28 s.f. the following soils may be designed to • infiltrate a rate of flow of 0.3 cfs and 2 +2(1.22+2.42) 7.36 ft. 1.0 cfs respectively: Bong Marble R • •717 Bonner Phoebe • Garrison Springdale V ■ 1.486 (.717)2/3(.02)1/2. 5.61 fps Hagan .03 The locations of these soil types are • - shown in the Soil Conservation Service •Q ■ VA - 5.61 fps 2 5.28 sf - 29.6 cfs Soil Survey for Spokane County. The drainage report shall include a copy of • ■ 30 cfs d 1.2' the SCS map with the subdivision plotted thereon. The County Engineer shall re- Solve Dc: Try 1.3' quire the developer to provide a sieve analysis and soil type test from a soils laboratory acceptable to the County En- Q • g (b + a Dc)3 Dc 3/2 gineer if there is a question regarding b + 2A Dc the above soil types. 3/2 In rural areas, as defined in Spokane Q .432.2 (2+2x1.3)3 x 1.3 ■ 30.9 cfs County Road Standards, open gravel dry- (2+2X2X1.3) wells may be q permitted in lieu of the es precast concrete drywalls. 30.9 cfs ■ 30 cfs do Dc > De flow is supercritical. Precast concrete drywells proposed for use in other soils than those shown Since the flow is supercritical, care above and all open gravel drywalls shall should be taken to provide a proper de- be designed according to percolation sign at points where horizontal and/or rates determined by a field test con- vertical alignment change. forming to the Manual of Septic tank practice. A County inspector shall be A free board of .30d should be applied present during all percolation teats. A percolation test calculation sheet D - .30 X 1.2 ■ 1.56' signed and sealed by a,,registered civil engineer shall be submitted. The per- V • 5.6 fps > maximum- allowable. colation rate shall be equal to or greater than 72 inches per hour to be Provide rip ra acceptable for drywall construction. p p (Refer to Section • 4.5.) 4-4.2 Storage Facilities - Detention • 4-4 Detention/Retention Systems - The storage facilities may be used to peak rate of run-off from an existing regulate flow rates. An overflow site shall not be increased due to the tape storage system which regulates the proposed development for a given design rate of outflow shall be used. See Figures 4-3, 4-4, 4-5, and 4-6 for storm. Therefore, a retention/deters- suggested details. Landscaped facil- tion facility on-site will be required. ities such as parks, playfields, tennis • Date: 4/4/84 courts, etc. are recommended for• t J 4-15 • Cast Grate In Top Slob Per Unit P WSH.D. Type 2 Compact To 95% Catch Basin Dry Density I Minimum Freeboard 61-0 sc Dike 15' •0 six ( Sod Or Seed Dike aximum Water Surface 0 2 Min. 3 Min IDetention Pond 1 r— Inflow PipeOverftow Pipe Outlet Pipe 3 MirL s r---- Clean Out Gote Sump Capacity of outlet pipe '`'�'� 6, must be equal to or greater I Control Orifice than discharge during emergency overflow Hydroseed All Disturbed Surfaces condition. • • * 6' Minimum when "H" less than 3' ** 15' Minimum when 'H" greater than 3' • PROFILE VIEW /Dike • . a SUMP ` Overflow Pipe O — Outlet Pipe I • Bottom of Pond— PLAN VIEW . No Scale • SPOKANE COUNTY TYPICAL STORAGE FACILITY PLAN a PROFILE FIGURE 4- 3 a-16 .m.---- a `a Er _ o aI O a, 1- E a a o O „ O W to .c _ m to N +TS CO a d N O O O .� C V a1 a O. H v Or CO 7 r a Cr) CO o c i` H C 0 p .....:,:vo4 07 .;- Oeal U C.) - O .� cn' a` c T—FTTTTrmi • 2_ °ii To 2' 2' p < 0 P' Min. Min. a cu .. .. a e"./3 (I) o : c, E c I g a °V L l o v O 0 FE b- E o cn ° O G Ka N o ' .i .M3 c rn �� rd P v S _ J ; J i i r- \1 E t fr.1 m O • to �.. I 0= U a o cr a `c N 0 CU o .0 a c C 0 0 a .0 O C-C 1 SPOKANE COUNTY TYPICAL DETENTION CHAMBER FIGURE. 4-4 ■ ...NW...NW N C O CO lit i c VN Ti 1 N p O ° t E P� .. ..e..-o.,l etrti •—',IN �j�' O r T c a • iii . . roc v o a i- v) O c O J Q O a E .0 C E W J o ID . o, I 13 it' xv � is v 72 c ° -' 2N m W c 'int J N N N \i, Z N d -- L_______= :Iiirit. O = m n to .0.3 v --'1 Z > a SPOKANE COUNTY Ow TYPICAL CLOSED DETENTION PIPE FIGURE 4-5 Offset Frame Grate So That • - Restrictor/Pollution Device —' Is Visible At Edge Of Opening * '\'\ - And Directly Over The Ladder. Grote Elevation --,-- • u js� +� — — - Overfl ow Pipe And Outlet Pipe Two Rows Riser • .•" Must Have Capacity Equal To Brick Maximum fir.'= • . . . Or Greater Than Combined • inlet System • .. ' . / -.: ' , Standard Galvanized .4.• u? Catch Basin Ladder Steps • ;i • •v I -Overflow Elevation-Set To Provide Chain-2004-Capacity - Required Detention And Adequate Slack When Gate is Down Oil Separation Protection ii Weld To Catch Basin Frame ii e:' 2� Min: 0 SWrcp To Basin Wall Overflow Pipe Outlet Pipe Min. Slope 0.5%' Min.Slope.0.5% IIII II 5:1' Invert Elevation ;• C l s _-- Watertight Clean Out Y. N Grate With Minimum 8 Gauge Slide _ c 1: N Type II Catch Basin Or Large Restrictor Plate Appropriately If Required. Note: Traffic Sized Orifice Cut In Plate Safe Structure With Minimum ID. (eg. Utility For Ty) Note: All Metal Parts And Surfaces Must Be Mode Of May Be 8t Substituted For Type II Corrosion Resistant Material Or Galvanized. Complete Catch Basin p Corrosion Protection Must Be Assured. *Grate Not Allowed On Restrictor Manhole. - Must Be Round, Self-locking Lid. No Scale SPOKANE COUNTY FLOW RESTRICTOR FIGURE 4-6 use as a stormwater storage area. Fa- Where cilities with side slopes steeper than 11 and I2 - inflow rates at times 5:1 shall be fenced as approved by the 1 and 2; County Engineer. All storage facilities 01 and 02 ■ outflow rates at times ( '- shall be planted with a type of grass 1 and 2; approved by the County Engineer. Access S1 and S2 ■ storage volumes at for maintenance vehicles shall be pro- times 1 and 2; vided in. design. Further information on t ■ elapsed time between 1 and 2; actual facility construction details are known at the routing time increment. available from the County Engineer's Of- fice. ' The equation can be rewritten in the form of a "routing equation" and expres- The reservoir routing method is one of sed as: the most straight forward ways to design a detention facility. This involves I1 + I2 + 2S1 - 01 ■ 2S2 + 02 plotting an inflow hydrograph for the —2—t future condition in the basin, then, superimposing an outflow hydrograph over The routing equation is solved by a com- the inflow graph. The area inscribed bination of analytical and graphical between the two graphs represents the methods to yield a series of outflow volume to be stored..• The inflow hydro- rates, thus generating an Outflow hydro- graph may be developed as shown in graph. To simplify the presentation of Section 3-3. The facility -shall be de- the following solution procedure, Al signed using a 50 year storm, however, and R2 ' are substituted for the brac- . the emergency overflow shall bel designed keted elements and the foregoing equa- for the 100 year storm. tion becomes: • The outflow hydrograph is dependent upon Il + 12 + Al ■ R2 the particular control structure se- lected as well as the depth -of water and R2 is known as the . routing equa- stored in the detention basin. The tion element. • actual shape of the outflow hydrograph can be developed by an application of a SOLUTION PROCEDURE technique known as reservoir routing. The step-by-step procedure used to check Referring to the set of typical inflow- the size and discharge rate from a given outflow hydrographs shown in Figure detention basin is summarized as fol- lows: • 4-10, the change in storage volume from - time 1 to time 2 is indicated by the 1. Compute the storage volumes in cubic shaded area between the two curves. feet for various selected incremental This quantity can be expressed by the depths of impoundment: To accomplish equation shown below: this, a specific trial size basin * * * must be selected with known contour. Pram such information, the designer Inflow - • Outflow ■ Change in Storage - I1 + I2 x.Qt - 01 + 02 2. dt - S2 - S1 2 2 Date 4/4/84 4-20 . t will be able to compute total storage The equation at the time zero has the volumes for different depths of im- form: 0 + I2 + 0 - R2. The R2 poundment. value at the end of the first time in- crement will always equal the inflow 2. Select a specific outlet control rate at this time. Knowing this R2 structure, such as an orifice, and value, one can read a corresponding dis- compute outflow discharge rates, or charge rate from the graph prepared in values of Q, for each incremental Step 5. storage depth selected in Step 1. (Figure 23 is used for the orifice Inflow values at the beginning and end STAGE-DISCHARGE RELATIONSHIP.) Of each time increment, I1 and I2, are determined from the inflow hydro- 3. Select a routing time increment, graph. Determination of Al and R2 t. It should be noted that .the presents a complication because each units of routing time must be ex- contains a storage value and outflow pressed as seconds for computation . value. Two factors, however, alleviate purposes. the situation of attempting to solve for • four unknowns with a single equation. 4. For each incremental depth selected First, is the significance of the sub- in Step 1, compute a corresponding script notation. Subscripts 1 and 2 value for the routing equation ele- refer to parameters at the beginning and ment, R. From the basic routing end of each routing time increment. equation, this element is defined as: Hence storage, inflow and outflow dis- charge at the end of one time increment R - 2xStorage Volume, cf + outflow, cfs automatically become the beginning Routing time, sec. values for the next time increment. l Second, and most important, is the fact r-- Steps 1, 2 and 3 provide the information that all equation elements must equal for calculating the series of R values: zero at the beginning of the rainfall event. 5. Prepare a graph, plotting the values of discharge, 0, from Step 2 versus Since the end of the first time incre- the R values from Step 4. ment and the start of the second time increment occur simultaneously, the be- 6. Solve the routing equation for values ginning discharge rate for the second of R2 at the end of each routing time increment can only be equal to the time increment. At this point, one discharge rate at the end of the first must keep in mind the objective of increment. This fact enables the de- the entire process - to determine the signer to compute the Al term of the outflow rate from the detention basin routing equation for the next time in- at the end of a series of selected crement because its value must equal the time increments equal to the time of R2 value from the previous increment concentration. Now, if an R2 value less twice the discharge rate at the end could be computed for the end of each of the first time increment. Proof of time increment, corresponding dis- this can be derived from a study of the charge value could be obtained from routing equation in its basic form. It the graph prepared in Step 5. The must be remembered that discharge at the problem then becomes one of devel- end of a one-time increment must equal oping a method for solving the the beginning discharge rate for the routing equation. next time increment. Date: 4/4/84 4-21 The process can now be treated in a Example: A plat is to use a detention (,; step-by-step manner throughout the en- pond at its downstream end to limit ( tire rainfall event, producing a series discharge to the undeveloped rate of of discharge rates with respect to time, flow which is 32 cubic feet per second. enabling the development of data for the The inflow hydrograph is shown on Figure construction of an outflow hydrograph. 4-10. . 7. Superimpose the outflow hydrograph on Solution: Try a pond 120' X 120' with the inflow hydrograph and determine side slopes. Try a 22" orifice as the area between the two plots. This the outlet control structure. (See Fig- area represents the required storage ure 4-3.) Pipe invert is set 1 ' above volume to contain the rainfall event bottom of the sump. described by the inflow hydrograph. The solution is shown on the following To illustrate the design process, the table. following problem and its solution are offered. TABLE 4-7 - Tabulation of Storage-Discharge Data . . , NOTES: . Depth Basin above Storage Discharge. Computed ._ 1. Basin storage volumes shown in column invert ft. =s 0 in cfs R cfs 2 are computed from the detention 0.5 - 7,566 .9.4 26.1 design geometry for the various in- 1.0 15,650 13.4 48.2 cremental .depths shown in column 1. 1.5 24,469 16.4 70.8 2. Discharge values shown in column 3 !n - 2.0 34,000 18.9 94.5 are determined by using Figure 23. 2.5 44,281 21.1 119.5 • 3. Values of R are computed by substitu- 3.0 55,350 23.1 146.1 tion in the equation: 3.5 67,244 24.5 173.9 R = 2S + 0 4.0 80,000 26.7 204.5 At . 4.5 93,656 28.4 236.5 • At= routing time = 15 minutes or 900 5.0 108,250 29.8 270.4 seconds 4. Plot 0 vs. R, Figure 4-8. FIGURE 4-8 DISCHARGE VS. RZ. 30 U. . 20 . o M. 10 C 0 20 •o i0 io 100 Ito 140 Iso lip zoo 220 2:0 !" cis R = GS . 0 `) n. 11 • TABLE 4-9 - Solution of Routing Equation • NOTES: Inflow Computed Computed Value of Time Rate Value Value 0 from 1. Inflow in column 2 was obtained (min. ) I(cfs) of A of R Figures . ' from the inflow hydrograph, 0 0 0 0 0 Figure 4-10. 15 2.5 2.5 2.5 0.9 ere 2. Tabular values of A, R 6 0 are 30 6.0 2.0 11.0 3.3 474 obtained by solving the routing 45 26.0 12.0 34.0 11.0 equation I1+I2±A1=R2. 60 77.0 73.0 115.0 21.0 For the first time increment, 0 75 36.0 135.0 186.0 25.5 to 15 min. , I1-0, I2=2.5 90 18.0 137.0 189.0 26.0 A1=0. R2 therefore must 105 11.0 117.0 166.0 24.5 equal 2.5 and from Figure 4-8, 120 8.0 , 91.0 136.0 22.5 the discharge at the end of the initial time increment equals U. Al at the beginning of the second time increment, which is also the end of the first increment, equals the first increment R2 value less twice the discharge at the end of the first incre- ment or 2.5-0-0-2.5. R2 for the second increment = 6+2.5+2.5=11; from Figure 4-8, 0-4.5 cfs; and Al for the third increment = 11-4.5-4.5-2. The process continues until the desired number of points on the-outflow hydrograph have been achieved. * * * * . EXAMPLE PROBLEM : PEAK .0 = 77 cfs ,. 20 z 20 a 60 r 3.1 0 74,400 •o. • I I 1 • 70 3.I SO IN. so. _ c .. so INFLOW HYDROGRAPH . -"--..,..,....,_ 4. OUTFLOW HYDROGRAPH soy SO. lO • ` O 10 20 20 00 00 00 le 00 00 100 110 1s0 Suet lanai Figure 4-10 The outflow hydrograph, Table 4-9, Column 5, is then plotted on the inflow hydro- graph. The area inscribed is the required storage volume which is found to be 74,400 cf. The maximum discharge from the control orifice is 26 cfs which is less than the previous flow of 32 cfs. A head of 3.8' produces 26 cfs and also pro- vides a storage volume of 74,800 cf which is greater than the required 74,400 cf. The design is satisfactory. Date: 4/4/84 4-23 • • 5 EROSION PROTECTION - Erosion protec- ti • is required when the design flow vel . sties of constructed channels exceed the -Commended velocities as shown on Table (page 6-55). Ditches sh•ll have rock-lined bottoms and side slopes at the discharge point of storm sewers • culverts. Said rock lining hall extend for a dis- tance of 10 feet ,inimum from the point of culvert or sto sewer discharge and shall have a width feet in excess of the diameter of the ulvert or storm sewer. A special • let ' structure serving as an energy di .ipator may be required. - For normal rock-lined ditches • ith design velocities less than 8 feet pe second, quarry spalls should be used as .efined in Section 9.13.1 of Washington tate Highway Standard Specifications. The minimum rock lining thickness shall be 12 DELETED inches. For velocities of 8 feet p second or greater, rip rap shall be de- , See Addendum to Section 4.5 signed as specified in the Washingto• Pages 4-31 to 4-38 State Hydraulics Manual. Where velocity of flow in road di ches ' exceeds the allowable velocity, the ditch shall be lined with rock as •ecified .. above to a minimum depth of 12" Top of rock lining shall extend to t bottom-of the shoulder crushed rock. 4.5-1 T- .orar Erosio Protection- - Where extensive i in• or gra• ing. dis- turbs the natural g • nd surface, mea- - sures shall be-taken •uring and after. the construction period o reduce erosion and silting. Propos d measures to .reduce temporary erosi• and silting shall be ' shown on the • •nstruction plans. This may include • •roseeding or other land- scaping tec• iques. Figure 4-11 is of- fered as • desirable measure to protect against -mporary silting and may be re- quired •t all swales and natural drainage chann: s. ( STRAW BALES AS REQUIRED TAKE BALES TO MAINTAIN POSITION REQUIRED /. • • '� " �' � i ie i � Ir=Vim S I' MIN. FREER WARD • • Temporary Erosion/Sedimentation Co rol Plan No es: 1. Where possible, maintain Halos veg bait DELETED See Addendum to Section 4.5 2. Temporary siltation and detention • •nds to Pages 4-31 to 4-38 straw bales across swales. • • 3. All temporary siltation and . .tention p. ..ds shall be maintained in a satisfactory condition. un . 1 such time at clearing and/or con- - struction is completed d the permanent •rainage facilities are operational. 4. Return siltation co. rol areas to original groun. conditions. 5. Rip-rap base (. .th sides) of bales for erosion • .ntrol , as re- quired. .6. Approval o . this plan does not constitute an approval •f design, - size nor location of pipes, restrictors, channels or -tention facilit' .s; but is an approval of temporary sedimentation ontrol plan . ly. • Figure 4-11 4-25 r . Addendum to Section 4 • The anticipated rise in the elevation of the local I (Effective: February 1998) groimdwater table resulting from the disposal facility will not significantly impact adjacent properties or structures. Standard and Non-Standard Subsurface Disposal • The cbywells are adequately Framed during and Systems For Stormwater after installation from siltation & clogging arising as the result of erosion and sedimentation. Standard subsurface disposal facilities are defined as Spokane County Standard Type "A" and Type "B" Standerd drywells discharging at the above rates may drywells operating under the provisions set forth be sited within other USDA-SCS soil groups below for "Standard Drywell Practice." Any form provided the remaining conditions are met, and the of subsurface disposal facility other than Type "A" permeability of the soil surrounding the drywells and "B" drywells or which does not operate under meets or CX1XidiS the minimum required permeability Standard Drywell Practice conditions is classified as • We given in Appendix I when tested in accordance a"non-standard"subsurface disposal system. * with the methods outlined in Appendix I. . . Standard Drywell Practice: Erosion control and protection from sedimentation are critical to performance of subsurface disposal The use of Spokane County Standard drywells systems. Therefore, it is important that provision is discharging to the subsurface at an assumed made for pre-trunimat of runoff prior to discharging maximum outflow rate of 0.3 CFS for Type ."A" into an infiltration disposal system which receives drywells and 1.0 CFS for Type "B" drywells is runoff from non-paved surfito0s. Pre-tnatment - permitted as "Standard Drywell Practice" provided normally consists of a settling sump, prior to the following conditions am met: discharging into the infiltration facility. The settling (. - sump volume can be determined using the Flaxman • The drywells are sited within the followin,g Method (See Appendix D), amsidnin,g a 3-month Natural Resources Conservation District pain& (formerly USDA Soil Conservation Service) soil . ,• . ,. ginuPings: . .. . .... . . Conveyance Systems:Closed Pipe Systems Springdale Bonner Bong• Garrison Hagen Phoebe• A closed pipe system is a network of storm pipes, Marble catch basins, manholes, inlets and outlets which are designed to convey stonnwater. To analyze the Of capacity af a dosed pipe system which • Note that in some locations, these. soil groups has-gradually varied flow, the following steps can be require in-place permeability testing at the discretion usal when steady flow auditions exist,or a:Editions of the County Enginea. It is Elmo=the sponsor's am bc accunuely appuncinsted assuming, sus* engineer field way if the in-situ soil is as shown in flow=Edifices: the SCS soil map. . 1)Estimate the size of the pipes assuming a uniform • There is nrinimal variation in the subsurface flow condition, using Manning equation listed on profile within the vicinity of the drywells. Page 4-4. • There is a minimum clearance of 4 feet between the bottom of the drywell to any =die= that 2) For the trial pipe sizes chosen, determine uniform mould inhibit downward flow such as berdnxic, flow depth and creaml flow depth; - -- impermeable soil layer, or seasonally adjusted high grtendwater table Guidelines for Swrmwaier Management-Addendum 4-26 Spokane County: February 1998 \ J 3) Determine if upstream (accelerated flow) or trash rack detail is shown in Fig. 39. A trash rack is downstream (retarded flow) conditions exist. required under conditions listed in Table 4-12. This Subcritical flow occurs when downstream conditions criteria for trash racks is not required for culverts control, supercritical flow occurs when upstream crossing roadways. conditions control. Then by comparing uniform flow depth, critical flow depth, and initial flow depth, Nominal Pipe Density Conditions When a determine what flow regime will occur. See Fig. 30 Size,Dry) Designation Trash Rack is Required These curves provide a check while performing (inches) profile computations. Identify hydraulic jump D 18" Urban All exposed pipe, Inlets locations, and where any other discontinuity of flow and thi ' depth will occur. D 12" Wooded or Inlets Only Rural• 4)Conduct a more detailed analysis by computing the Notes: (1) D=Nominal Pipe Diameter •hydraulic grade line. The direct step method or Outfalls standard step method is often used to calculate the (2) which are in an enclosed fenced hydraulic grade line. For supercritical flow, begin at area do not need trash racks. the upstream end and compute flow. sections in consecutive order heading downstream. For Trash ble Criteria subcritical flow, begin at the downstream end and Table 4-12 compute flow sections in consecutive order heading upstream. Energy losses at bends and catch basins Conveyance Systems: Culverts can be determined using Figures 31 and 32. Entrance The nomographs shown in Figure 38 can be used for head losses can be computed by IC.V Rg, where K. culvert.sizing with inlet =nil conditions. The values are listed in Table 21. Example calculations are shown in several technical public ons'an open Homographs in Figure 20 can be used- for culvert channel s�8 with .outlet control conditions. For a hydraulics, such as: "Handbook of description of the appropriate use of these Hydraulics",' by Bracer' and King; and "Opca- Chanoel Hydraulics"by French. namogaphs• see fixtraulic Charts for Selection of Highway Culverts, published by the Federal When required by the County Engineer,the hydraulic Highway Administration. HEC 5, Dec. 1965 and reprinted April 1977. grade line(HGL)shall be included in the pipe pinfile . • or in the Drainage Report. The design flowrate and " design storm event shall be clearly marked on the drainage calculations shall include calculations determining the maximum headwater elevation for the HGL profile. design storm emu. • When the grade of a storm pipe is greater than or Beveled axis at ailvens shall be provided for road equal to 20%, than pipe anchors are required un less the engineer demonstrates through the submittal and and driveway aPP � acceptance of calculations that the pipe anchors are Pipe anchors for culverts are required when the not needed. The pipe anchors are to be placed at 25 culvert slope is greater than or equal to 20%, as 8. intervals along the pipe. See Fig. 40 showing a described in the previous paragraphs. typical pipe anchor detail. Pipe anchors locations are to be defined in the plans, and a pipe anchor detail Conveyance Systems: Gutters, Ditches & Natural referenced or provided. Channels Trash racks at pipe system inlets and outfalls are The centerline of all man-made drainage ditches or needed under certain circumstances to protect the altered natural channels located within the project systan from debris and from unauthorized limits, art to be clearly shown in the construction individuals entering the closed pipe system. A typical Guidelines for Stormwater Management•Addendum 4-27 Spokane County: February 1998 plans and basin map. The centerline of all natural Gutter flows in roadways shall allow for the passing (,, drainage channels within the project limits, are to be of vehicular traffic during the design storm event, by clearly shown in the basin map. The direction of providing non-flooding zones. For paved roadways flow is to also be shown thereon. the minimum width of pavement non-flooding zones is shown in Figure 37. Rolled curb (Type R curb) shall not be used where . ,grade, curvature, and joint displacement of curbs may create a situation where stonnwater=aft-flows Hydraulic Jumps over the au*, which may cause erosion and other possible hazards. . Hydraulic jumps are to be evaluated using the design storm event, and the peak flow= for the design If required by the County Engineer, the hydraulic storm. All hydraulic jump locations are to be grade line shall be computed for drainage ditches,and identified . in the drainage calculations. The included in the drainage calculations. evaluation of the hydraulic jump needs to consider . - - the high energy_loss and erosive forces that occur. The sponsor's engineer shall check for channel wall Unless erosive forces are controlled,,serious damage stability, and provide appropriate measures to ensure to the...chamiel can result. Control of the jump adequate stability for the design°storm event. Table location is usually obtained by check dams or 24 lists the maximum, permissible mean channel structures that. confine-the erosive forces to a velocities for various types of soil and ground cover, protected area. Riprap revetment is often used to If mean channel velocities exceed.these values, then provide channel pratecticm. riprap lined, fabric lined or some other form of „ channel stabilization method will be ruined. For For ditch_design at a location where a hydraulic jump-. grais-lined channels, the plans are to specify the seed occurs, the size.and extent of riprap revetment, and mixture and when-the seed mix is to be plated. An the, energy kiSt..,.needs to be determined by the ( ‘ allowable dryland seed mixture is listed in A‘ppenchic designer. . The riprap revetmem length needs to be of \ E. Other seed mixtures may be permitted subject to sufficient length to adequately armor the hydraulic• acceptance by the County Engineer.. jump area. For non-submerged hydraulic jumps in trapezoidal diannels which are nearly fiat at the . , Because Spokane County has a semi-arid climate, hydraulic jump location, the hydraulic jump length, temporary or permanent irrigation facilities may be 1.4,•can be estimated using the following equation : required to ensure plant growth, depending upon seed . mix and when the seed is applied. If grass-lined . LitY1 = 01F1 ditches, are not used or are-inappropriate for the • • situation, then other means shall be given to provide where y1 =upstream water depth,ft. for channel stability. a =channel shape factor,, See Table 4-13 . r =channel shape factor, See Table 4-13 If riprap revetment is' .chosen; • the drainage. F1=Fantle number of upstnam flow conveyance calculations shall include calculations for I =,length of hydraulic jump,Ft. sizing of riprap and it's filter blanket. . - . . Side Slope of Channel a .. r . Calculations for channel stability are to be included if El Ft., other means of channel stabilization is chosen, such • 2 . 17.6 0.905 as geotextile fabrics or bio-engineered channels. - 1 210 0.885 0.5 35.0 0.836 Minimum freeboard in feet (F) for open Him s Hydraulic Jump-Length Factors shall be as follows: . Table 4-13 ' • 1 min. F=.0.33(flow depth) Guidelines for Stormwater Management-Addendum 4-28 Spokane County: February 1998 • r`1 Various types of hydraulic jumps may occur. These V.,= RV.,,a ' are summarized in Figure 33. Oscillating jumps in the Froude number range of 2.5 to 4.5 should be Various values of R are listed in Table 4-14. A avoided; or if used in this range, more extensive more detailed approach for the design of riprap analysis and revetment installation is needed . around channel bends can be used as shown in Figure 36. Maximum channel side slopes with riprap is The energy lost at a hydraulic jump can be shown in Figure 35. determined using Figure 43, for the channel shapes shown in the figure. Channel Type e For jumps within pipes, the primary concern is Trapezoidal-straight run 0.8 whether the pipe can withstand the forces, which may Natural-straight run 0.9 separate the joint or damage the pipe wall, and Channel Bends 1.5 whether the height will exceed the clearance of the Outfalls,without a drop 1.25 catch basin or structure. Therefore, hydraulic jumps occuring within pipes need to be carefully evaluated Conversion to Characteristic Velocity by the engineer. Table 4-14 Riprap & Channel Stabilization Stone size is often defined by 13%, where % denotes the percentage of the total weight of the graded Whenever riprap revetment is proposed, the engineer material that contains stones of less weight. For shall submit design calculations included in the example D,o = 2.5 inches, denotes that 30% of the Drainage Report.'which justifies the riprap area, stone by weight will pass through a sieve size of 2.5 1 - thickness, riprap size and gradation,and filter blanket inches. Similarly,W,equals the weight of individual reinforcement. stone having diameter of D,,.. The mean stone size, The ability of riprap revetment to resist ertision is Wso,can be determined using Figure 34. If the riprap �' PmP is to be used for a stilling basin or other highly related to size, shape and weight of the stones. Most turbulent area, then the size of the riprap shall be riprap lined channels required either a gravel filter increased by at least 2 times W,o determined from the blanket or filter fabric under the riprap. Where very chart. The riprap should be reasonably well graded, large riprap is Used it is sometime naxssary to use within the following gradation parameters: two gravel filter layers between the subgrade and the riprap. When riPrap is used, the drainage Plans shall 125 s DI„/D,o s 1.50; D15/D30 =030 specify material gradation, thielmess and area to be covered. Dei,/Dso=0.25 Riprap material needs to be blocky in shape rather The minimum thickness of the riprap layer shall be than elongated. The riprap stone needs to have 12 inches,DIG,or 1.5D,o,whichever is greener. sharp, angular, clean edges at the intersections of relatively flat faces. Riprap stone should be A filter blanket under the riprap is normally needed. reasonably well graded throughout. If a gravel or sand filter blanket is used,then it needs to conform to the gradation parameters listed in Design guidance is primarily related to channel Table 4-15. The size of the filter blanket material is velocity and stone size. The velocity used must be designated d„,the size of the riprip is designated D70. representative of flow conditions at the riprap face, and the size of the subgrade is designated d'„. The termed the characteristic velocity- (V..). The thickness of each filter blanket should be one-half characteristic velocity can relate to mean channel that of the riprap layer. If it is found that Dis/d' Is<2 t velocity(V.,$)by the following equation: Guidelines for Stormwater Management-Addendum 4-29 Spokane County: February 1998 then no filter blanket is needed. Where very large oil/water separator can be elbows at the orifices and riprap is used, it is sometime necessary to use two with a sump, See Figure 44 showing an example. filter blanket layers between the subgrade and the riprap. A flow control structure utilizing a riser arrangement, shall conform to Fig. 4-6. It is to include, as a Gradation requirements,area, and thickness of riprap minimum: a watertight cleanout, 200# chain, and filter blankets shall be specified in the plans. The overflow riser, maintenance access, 12" diameter or size of the riprap revetment pad for pipe outfalls can larger riser, and sump. At least three riser straps be done in accordance with Figure 46. spaced no more than 2 ft. on-center shall be provided. The flow characteristics of an overflow riser pipe are provided in Figure 45. Primary Criteria D s<5das Recommended Secondary Sd,s<D,s<40d,s A weir used as a flow control structure shall be made Criteria Dso/dso<50 of a non-erosive material, and resistant to alteration or vandalism, such as reinforced concrete or metal Criteria for with a non-corrosive surface. An overflow weir can Gravel or Sand Filter Blanket Gradation be made of soil with revetment Table 4-15 Detention Ponds-Berms&Maintenance Access When geotextile fabrics are used for channel stabilization, the engineer shall submit calculations Detention pond berms greater than 4 ft. in height and/or manufacturer's recommendations to the shall include a keyway, clay or geotextile liner, and County Engineer, which demoastrares adequacy of minimum top of berm widths, in accordance with the proposed fabric. The plans shall clearly specify Figure 47. The liner and keyway may be waived if r fabric type, placement,and anchoring requirements.• recommended by the sponsor's geotechnical engineer - and accepted by the County F.ngtneer. All detention pond berms are to have material and lift compaction Hydraulic Structures, Energy Diuipaters & 1eq shown in the plans. • Outfalls • Berm heights greater than 12 ft. in height shall Catch basins, inlets and storm manholes shall require a geotecbnical report and subsurface conform to the details shown in the Spokane County investigation to determine adequacy of the proposed Standards for Road & Sewer Construction, or the pond site to suppart this large of a berm, and to Standard Plans jointly published by the Wash. State provide sped& genechnical re00mmendations for Dept. of Transportation and APWA (M21-01), or as the design and construction of the berm. Depending approved by the County Engineer. upon the site,a BODtechnical report may be necessary when berm heights are less than 12 ft. The berm An Energy dissipater is often useful in reducing height,as defined herein, is measured from the top of excess velocity, as a means of preventing erosion the berm to the catch point of the native soil at the below an outfall or spillway. Common types of lowest elevation. Provisions are to be made for energy dissipaters for small hydraulic worts are: stabilization of the berm,and its overflow. hydraulic jumps, stilling wells, and gabion weirs. Typical details for these types of structures arc If the control manhole is placed within the pond shown in Figures 41 and 42. bem, the top of the manhole lid shall be placed 3 inches above the finish grade of the top of berm. . Flow control structures which discharge to a pipe Maintenance access shall be provided to the control system shall include an oil/water separator. The structure and bottom of pond. No fence shall be placed over the control structure. ( ' Guidelines for Stormwater Management-Addendum 4-30 Spokane County: February 1998 public roads and rights-of-way. and water bodies > Addendum to Section 4.5 caused by land-disturbing activities: and EROSION AND SEDIMENT CONTROL 3) Protect the health, safety and welfare of the (Effective April. 1998) general public and shall not be construed to establish any duties to protect or benefit any particular person or class of persons. 4.5.200 GENERAL PROVISIONS 4.5.100 PURPOSE AND INTENT 4.5.200 GENERAL PROVISIONS 4.5.210 Administration • 210 Administration The Public Works Director/designee is responsible .220 Applicability for interpretation, administration and enforcement of .230 Exemptions the requirements of this chapter. .240 Erosion and Sediment Control Best 4.5.220 Applicability Management Practices This chapter applies to all major land-disturbing .250 Interpretation activities, and all minor land-disturbing activities for .260 Abrogation and Greater Restrictions which .a permit is required by County Ordinances, .270 Severability 0 within the unincorporated areas of Spokane County, 4.5.300 DEFINITIONS unless exempted in this chapter. 4.5.400 EROSION AND SEDIMENT CONTROL PLANS 410 Submittal of Plans All major land-disturbing activities which do not 420 Content of Plans require a permit or approval by Spokane County, .430' ESC Requirements for Minor Land- remain subject to the. performance standards and Disturbing Activities enforcement provisions of this chapter. Although a .440 ESC Plan Requirements for Major land-disturbing y not require a permit Land-Disturbing Activities from Spokane County,a permit may be required from .450 Modifications To Plans stare and/or federal agencies. 4.5.500 MAINTENANCE. PERFORMANCE The performance standards and other requirements of • STANDARDS AND ENFORCEMENT this chapter apply.to other activities allowed by .510-. Maintenance Responsibility County ordinances relating to land-disturbing .520 Performance Standards activities. .530 Enforcement 4.5.230 Exemptions 4.5.100 PURPOSE AND INTENT The provisions of this'chapter do not apply to the The requirements and performance standards of this following: chapter are intended to control soil erosion and' 1) Commercial agriculture regulated under sedimentation through the use of temporary and permanent erosion and sediment control practices. Revised Code of Washington (RCW) chapter 84.34.020. The purpose of the requirements is to allow 2) Forest practices regulated under Washington flexibility in choice of erosion and sediment control Administrative Code (WAC) Title 222, except methods through the requirement of applirarnts to for Class IV General Forest Practices that are prepare an Erosion and Sediment Control (ESC) plan conversions from timber land to other uses. that meets the specific needs of each site and employs 3) Actions by a public. utility or env other appropriate measures to meet the performance governmental agency to remove or alleviate an standards for erosion and sediment control. emergency condition, restore utility service, or The purpose of this chapter is to: reopen a public thoroughfare to traffic. provided 1) Protect and prevent damage to Spokane County's the public utility or governmental agency cleans stormwater management infrastructure: and/or removes any erosion and sedimentation ) Minimize erosion and sedimentation, and the after the emergency condition is alleviated, utility impact of increased runoff, onto private property, service restored or the thoroughfare is reopened. Guidelines for Stormwater Management- Addendum 4-3 I Spokane County: April 1998 pursuant to the performance standards in section the remainder of this chapter or the application of the _ 4.5.520. provision to other persons. entities. or circumstances (' 4) Issuance of permits and/or approvals for land shall not be affected. divisions, interior improvements to an existing 43300 DEFINITIONS structure, or other approvals for which there is no physical disturbance to the surface of the "Best Management Practices (BMPs)" means land. physical. structural. and/or managerial practices that. 5) Minor land-disturbing'activities which do not when used singularly or in combination, have been require a permit under County Ordinances. shown to prevent or reduce erosion and sediment transport. 4.5.240.ESC Best Management Practices (BMPs) - ESC BMPs •should be used to comply with the "Class IV Forest Practices" are defined as Forest requirements in this chapter. Examples of BMPs are Practices other than those contained in Class I or I1: outlined in the Spokane County Erosion and (a) On lands planed after January 1, 1960; (b) on Sediment Control BMP Manual available at the lands being converted to another use: (c) on lands Spokane County Public Works Building. The intent which, pursuant to RCW 76.09.070 as now or of the BMP' Manual is to provide an example of hereafter amended,are not to be reforested because of available BMPs which propeiry owners can choose the likelihood of future conversion to urban from, to help meet the requirements contained in this development: and/or, (d)which have a potential for a chapter. Use of BMP's from the'Manual is at the substantial impact on the environment and therefore discretion of the property owner, permit applicant, or require an evaluation by the Department as to their agent. . whether or not a detailed statement must be prepared It is not the intent of the BMP Manual to limit any pursuant to the State Environmental Policy Act, innovative or creative effort to effectively control chapter 43.21.0 RCW (RCW 76.09.050), as erosion and sedimentation. In those instances where amended. appropriate BMPs are not in the BMP Manual, "Commercial Agriculture" means those activities experimental management practices. can be conducted on lands defined in RCW 84.34.020(2), considered. Experimental management practices'are and activities involved.in the production of crops or encouraged as a means of.solving-problems in a livestock for wholesale trade. An activity ceases to manner not addressed by. the BMP Manual, in an be considered commercial agriculture when the area effort to improve erosion control technology and meet on which it is conducted is proposed for conversion to the purpose and intent of this ,chapter. All a nonagricultural use or has lain idle for more than experimental management practices are required to five (5) years, unless the idle land is registered in a meet the performance standards identified in section Federal or-State soils conservation program, or unless 4.5.520 of this chapter. the activity..is maintenance of irrigation ditches, laterals, canals, or drainage ditches related to an 4.5.250 Interpretation The provisions of this chapter will be held to be stung and ongoing agricultural activity. • minimum requirements in their interpretation and "Earthen Material" means any rock, natural soil or application. fill and/or any combination thereof. 4.5.260 Abrogation and Greater Restrictions "Erosion" is the wearing away of the land surface by This chapter is not intended to repeal, abrogate, or running water, wind,.ice, or other geological agents, impair any existing regulations, easements, including such processes as gravitational creep. covenants. or deed restrictions."However, where this Detachment and movement of soil or rock fragments chapter imposes greater restrictions for erosion and by water, wind. ice,or gravity. sediment control, the provisions of this chapter will "Lend-Disturbing Activities" means any activity Pal. that results in a change in the existing soil cover (both 4.5.270 Severability vegetative and non-vegetative)and/or the existing soil If any provision of this chapter or its application to topography. Land disturbing activities include, but any person, entity, or circumstance is held invalid, Guidelines for Stormwater Management- Addendum 4-32 Spokane County: April 1998 • arc not limited to: demolition, construction, clearing, "Water Body" shall include those water bodies that 1 grading, filling, logging. and.excavation, are defined as surface waters of the state or waters �� Minor Land-Disturbing Activity" is a land- defined as waters of the state under Revised Code of disturbing activity of less than one acre of disturbed Washington (RCW)chapter 90.48.020, as amended. area; an individual, detached, single family residence "Wetland or Wetlands" means those areas in or duplex; or the creation or addition of impervious Spokane County that are inundated or saturated by surface areas less than 5.000 square feet. surface or ground water at a frequency and a duration "Major Land-Disturbing Activity" is a land- sufficient to support, and that under normal disturbing activity greater than or equal to one acre conditions do support, a prevalence of vegetation of disturbed area or the creation or addition of typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs. impervious surface area greater than or equal to and similar areas. Wetlands may include those 5.000 square feet. artificial wetlands intentionally created from "Permanent Erosion and Sediment Control nonwetland areas created to mitigate conversion of Measures" are erosion and sediment control devices wetlands, if permitted by the county or city (RCW that replace any temporary devices and provide for 36.70A.030), as amended. For identifying and long-term, permanent stabilization of a site. delineating a wetland, Spokane County will rely on "Permitted Activity" any activity for which a permit the methodology contained in the Wetland Delineation is required under County ordinances. Manual. "Public Works Director" That person, or his/her 45.400 EROSION AND SEDIMENT CONTROL designee, who has been appointed by the Board of PLANS County Commissioners to direct the activities of the 4.5.410 Submittal of Plans Spokane County Public Works Department An.ESC plan is required for major land-disturbing �1 :ediment" is earthen material moved by wind, activities that require a permit or plan acceptance by .rater, ice and tracking. Spokane County. An ESC plan is not required for minor land-disturbing activities. "Sedimentation" is the .gravitational deposit of Air ESC plan, when required, shall be submitted with transported material in flowing or standing water. a permit application prior to any land-disturbing "Site" means the piece of property which is directly activity. ESC plans are only required to address the subject to land-disturbing activities. area of'land that is subject to the land-disturbing acti "Soil" means the unconsolidated mineral and organic "nY for which a permit is being requested. material on the immediate surface of the earth that Although others may prepare the ESC plan the serves as a natural medium for the growth of land permit applicant is responsible for ensuring that all plants requirements are addressed in the ESC plan. The ESC plan is required to be on file at the County, "Stormwater" means that portion of precipitation or although it will not be reviewed or approved by the snow melt that has not naturally percolated into the County. ground or evaporated. but is flowing via overland flow. interflow. channels or pipes into a defined 45.420 Content of Plans surface water channel. or a constructed detention At a minimum, all ESC plans must be legible, and/or infiltration facility. reproducible, and contain the following information: 1) Title Block "Temporary Erosion and Sediment Control . 2) Name of property owner Measures" are erosion and sediment control devices 3) Name of permit applicant used to provide temporary stabilization of a site, 4) Name of contact person at project site usually during construction or land disturbing 5) Project address hctivities, before permanent devices are installed. 6) Legal Description ,'racking" is the deposit of sediment on to paved 7) Name of person preparing plan surfaces from the wheels of vehicles. Guidelines for Stormwater Management-Addendum 4-33 Spokane County: April 1998 8) Professional seal (required for major land- comply with stated performance standards contained disturbing ESC plans) in section 4.5.520. Special site conditions may(� 9) Description of project include, but are not limited to, steep slopes. slope 10) Description of ESC measures length, soil type, or vegetative cover. 11) Description of existing vegetation on the site 12) Location of any existing water bodies 1) Construction Access Route 13) Date plan was prepared Access for construction vehicles should be 14) Scale of drawing limited to one route whenever possible. The 15) North arrow access route must be stabilized to minimize the 16) Property boundary and dimensions tracking of sediment onto public roads. 17) Vicinity Map 2) Stabilization of Denuded Areas 18) List of soils on-site (information may be Stabilization of all exposed soils to prevent soils obtained at the County Soil Conservation from eroding and depositing sediment District) downstream. 19) Certification statement by the person 3) Protection of Adjacent Pronerties/Water Bodies/Public and Private Roads preparing the plan that the plan meets the Protection of adjacent properties, water bodies. ESC plan requirements as listed in chapter public and private .roads from erosion and 4.5 of the Guidelines for Stormwater Management. sediment deposition. The intent is to keep sediment on the project site and not allow it to 4.5.430'ESC Requirements for Minor Land- reach adjacent' properties, water bodies, and Disturbing Activities public and private roads. Though an ESC plan is not required to be submitted 4) Protection of Inlets for minor land-disturbing activities for which a Protection of downstream inlets to drywells. permit is required- by Spokane .County, •the catch basins.and other stormwater management Performance Standards and other provisions of this facilities. • Ordinance shall remain in affect. The-provisions of 5) Increased Runoff from Construction Sites this Ordinance shall not govern minor land-disturbing 0 Consideration and mitigation of the effects and activities for"which no permit is required. However, iMpacts of increased and concentrated runoff individuals/property owners undertaking minor land- from land disturbing activities on downstream disturbing activities for which a permit is not properties, water.bodies, and public and private required may desire to ensure that such activity roads. protects adjacent and surrounding private properties. 6) Washout Site for Concrete Trucks and Equipment Desi 43.440 ESC Plan Requirements for Major Laad- gnate the location of a slurry pit where Disturbing Activities concrete trucks and equipment can be washed All ESC plans for major land-disturbing activities out. Shiny pits shall not be located in a swale.area shall be prepared and have a seal axed by either a stormwater facility, or water body affixed licensed professional engineer (PE) or a licensed nor in an area where a stormwater facility is landscape architect (LA). Both the professional PmP - enginttr and the landscape architect must be licensed 7) Material Storatte/Stocknile • in the State of Washington and be knowledgeable in Identify location for storage/stockpile areas, both hydrology and ESC practices. within the proposed ESC Plan boundaries, for any soil, earthen and landscape material which is The following fifteen (15) items shall be addressed in used or will be used on-site. ESC plans for major land-disturbing activities. As 8) Maintenance and Permanent BMPs site conditions dictate, additional measures relating to Maintenance of all erosion and sediment control ESC. as determined by the licensed professional BMPs is required during the land-disturbing engineer (PE) or licensed Landscape architect (LA) activity. Regular inspection and maintenance of (cOO preparing the plan, shall be addressed in order to all erosion and sediment control BMPs is meet the intent and purpose of this chapter and to required to ensure successful performance of the Guidelines for Stormwater Management - Addendum 4-34 Spokane County: April 1998 BMPs. Permanent BMPs shall be included in the 4.5.500 MAINTENANCE, PERFORMANCE plan to ensure that successful transition from STANDARDS, AND ENFORCEMENT temporary BMPs to permanent BMPs occurs. 4.5.510 Maintenance Responsibility 9) Clearing Limits Delineation Field identification and delineation of all clearing During any land-disturbing activity subject to this limits, sensitive/critical areas, buffers, trees to be ordinance.the property owners) or permit applicant. preserved. and drainage courses. if different from the property owner(s), ended in the 10) Sediment Trapoine Measures land-disturbing activity is responsible for preventing • Design and construction of sediment ponds and erosion and sedimentation through-the use of BMPs. traps. perimeter dikes. sediment bathers, and The property owners)_ or permit applicant, if other onsitc sediment trapping BMPs different from the property owner(s), is subject to the necessary prior to the start of other land enforcement and penalty provisions provided herein. - disturbing activities. and it is their responsibility to ensure BMPs are used II) Cut and Fill Slopes and the performance standards are met. After any Design and construction of cut and fill slopes in land-disturbing activity is complete and the site has a manner that will minimize erosion. been permanently stabilized maintenance and the 12) Stabilization of Temporary Conveyance prevention of erosion and sedimentation is the Channels and Outlets responsibility of the property owner. Design, construction. and stabilization of all 4.5.520 Performance Standards temporary on-site conveyance channels to The performance standards set forth below are prevent erosion from the velocity of runoff from intended to provide a minimum threshold for storms under developed conditions. Design. controlling soil erosion and sedimentation caused by construction, and stabilization of all temporary land disturbing activities and will be• used to f� conveyance system outlets to prevent erosion of: determine if the requirements of this chapter have stormwater facilities. adjacent stream banks. • been met: _ slopes and downstream reaches. i 3)Removal of Temporary BMPs 1) Minimize Tracking onto Public. Private. and Removal of all temporary sediment control Future Public Roads BMPs within 30 days after.final site stabilization 2) Protection of Public Roads and Stormwater or after the temporary BMPs are no longer Facilities needed. Trapped sediment shall be removed 3) Proper Washout of Concrete Trucks and from the project site or stabilized on-site. Equipment Stabilization. of disturbed soil areas resulting 4) Protection of Private Properties from removal of the temporary BMPs. 5) Protection of Water Bodies and Wetlands 14) Dewaterina Construction Site The following criteria will be used to determine if the Discharge of dewatering devices to appropriately performance standards listed above have not been designed sediment traps or sediment ponds. tact 15) Control of Pollutants Other Than Sediment on 1) Minimize Tracking. onto Public. Private, and Construction Sites Future Public Roads Control of all on-site pollutants other than The performance standard for minimizing sediment in a manner that does not cause tracking onto public, private, or future public contamination of stormwater or groundwater. roads has not been met if soil. dirt. mud or debris 4.5.450 Modifications to Plans is tracked onto a public, private. or future public ESC plans may be modified after submittal to the road and there is no evidence of reasonably trying County. An amended plan should be submitted to to control it through the use of ESC BMPs or `'-Jlustrate any modifications to the techniques and experimental BMPs (i.e. sweeping), both as nethods used to prevent and control erosion and defined in section 4.05.240. 'dimentation. • Guidelines for Siormwater Management- Addendum 4-35 Spokane County: April 1998 • 2) Protection of Public Roads and Stormwater 2) Notice of Non-Compliance Facilities The Public Works Director/designee will have the ( The performance standard for protecting public authority to issue a Notice of Non-Compliance roads and stormwater facilities has not been met and penalty to the property owner(s), or permit if there is deposition,other than'cracking,of more applicant if different than the property owner(s). than two (2) gallons (0.27cubic feet) per day of engaged in the land-disturbing activity, if an soil, dirt. mud or debris from the project site onto action is being undertaken that does not comply adjacent public roads and/or a stormwater with all performance standards)of this chapter. system within a public right-of--Kay. A) Content of Notice of Non-Compliance 3) Proper Washout of Concrete Trucks and A Notice of Non-Compliance will contain: pment • Equi i) The name and'address of the proper The performance standard for ensuring the awner(s) or permit applicant to whom the proper washout of concrete trucks and equipment Notice of Non-Compliance is. directed: has not been met if there is observation or and evidence of concrete washout material within a ii) The street address, when available. or a drainage any stormwater facility, or water general description of the building, lot. or body, nor in an area where a stormwater facility land upon which the non-compliance is is proposed. 4) Protection of Private Pronertiee occu rn$'and • iii) A description of the specific nature. Spokane County does not presently have and date of non-Compliance:and sufficient resources to enforce the provisions of iv) A notice that the non-compliant activity this Ordinance for violations that affect private cease and desist, and corrective action be properties. Therefore, no performance standards- undertaken to correct the activity within have been established with respect to the deposit twenty-four(24)hours;and of soil, dirt, mud or debris from a project site v) A statement that a cumulative civil {. onto adjacent private property. Private property, in the amount of two hundred- owners, however, may have the ability to seek judicial redress for such actions. fifty ($250) dollars per day for minor 5) protection of Waxer Bodies an. Wetlan ' • �'� rbing activities or one-thousand ($1,000) dollars per day for major land- The performance standard for protection of water disturbing activities: will be assessed for bodies has not been met if there is each and every day following the date'set deposition of soil. dirt_ mud, or debris from the for correction on which the non- project site into adjacent water bodies. .. compliant activity continues. 45530 Enforcement vi) A statement regarding the appeal 1) General • process. Enforcement and penalties will be in accordance B) Notification with this section whenever there is a violation of The Notice of Non-Compliance will be issued the projects Erosion and Sediment Control plan in writing, either by certified mail with return or any performance standard(s) contained herein, receipt requested, or by personal service, to as they relate to public facilities. Failure to the property owner(s) or permit applicant. If submit an Erosion and Sediment Control plan the Notice of Non-Compliance is not issued will result in non-issuance of underlying permit. to the property owner(s), the property owner The Public Works Director/designee has the will be given a copy of the Notice of Non- authority to assess penalties only related to Compliance so that the property owner(s) is public. facilities including but not limited to, informed that a Notice of Non-Compliance swales, drainage areas. or stormwater facilities. has been issued to the permit applicant. A /' Violations related to private property are a civil copy of the Notice of Non-Compliance may `-.. /` matter and are not enforceable by Spokane also be given to the contact person at the Count... project site. Guidelines for Stormwater Management- Addendum 4-36 Spokane County: April 1998 C) Effective Date vii) A statement that the penalty is due within The Notice of Non-Compliance issued under thirty (30) days. A statement of the this section will become effective Appeal process will also be included. immediately upon receipt. C) Penalties Due D) Compliance Penalties imposed under this section will Failure to comply with the terms of a Notice become due and payable within thirty (30) of Non-Compliance will result in the calendar days of receipt of the Notice of issuance of a civil penalty. Penalty. If the amount of a penalty owed to 3) Civil Penalty the County is not paid within the time A person who fails to meet the performance specified, the County may take appropriate standards of this chapter and who fails to comply action necessary to recover such penalty. with a Notice of Non-Compliance issued under If an appeal of a Notice of Non-Compliance this chapter will be subject to a civil penalty. is filed, the thirty (30) day time frame does A) Amount of Penalty not apply. A penalty will.not be assessed if The penalty will be two hundred-fifty dollars the decision of an appeal is that a violation of ($250) per day for each violation associated the performance standards did not occur. with a minor land-disturbing activity and D) Penalty Recovered one-thousand dollars ($1,000) per day for All penalties will be deposited in a fund each violation associated with a major land- created with the Spokane County Treasurer's disturbing activity. Each day of continued Office and may be appropriated for violation or repeated violation will constitute education, administration, and enforcement a separate violation. Any costs associated of this chapter. with clean-up or other corrective actions 4) Appals shall be the sole responsibility of the A Notice of Non-Compliance may be appealed in violator. writing to the Public Works Director/designee B) Notice and Assessment of Penalty within fourteen (14) calendar days of receipt of A civil penalty will be imposed by a written the Notice. The Public Works Director/designee Notice of Penalty either by certified mail shall have the authority to approve or deny the with return receipt requested or by personal appeal. A reduction or waiver of a penalty may service. A Notice of Penalty will contain: be granted if the Public Works Director/designee i) The name and address of the property determines that there is substantial evidence that owner(s) or permit applicant to whom reasonable ESC BMP's, or experimental BMP's, the Notice of Penalty is directed; and were used prior to the Notice of Non- ii) The street address, when available, or a Compliance, and that damage to public facilities general description of the building, lot, did not occur. or land upon which the violation is The decision of the Public Works occurring. and Director/designee may be appealed to the Board iii) A description of the specific nature, of County Commissioners. This appeal must be extent, and date of violation:and filed within fourteen (14) calendar days of the iv) A statement that the corrective action decision of the Public Works Director. The ordered in the Notice of Non- Board of County Commissioners will hear the Compliance was not undertaken: and appeal and make a final decision on the Notice of v) The amount of the penalty; and Non-Compliance and penalties due. vi) A statement that the penalty shall be assessed for each and every day the violation continues. Guidelines for Stormwater Management - Addendum 4-37 Spokane County: April 1998 - This Page intentionally Left Blank • - . , . . • 5. Control of Runoff Quality All land developed within the Aquifer they shall be designed to store the Sensitive Area (See Figure 6 ), where first 1/2 inch of runoff from a storm deemed feasible by the County Engineer, event. Infiltration Of the stored run- shall incorporate storm water runoff off through the grassed area then af- treatment facilities to mitigate the fects the desired contaminant removal. potential for groundwater degradation. The preferred treatment mechanism is the Using the concept of storage volume as infiltration of storm water runoff• the basis for grassed percolation area through a grassed area. Alternative design yields the following general de- systems which meet or exceed the contam- sign equation: • inant removal levels contained in Table 5-1 may be used subject to approval of Vgpa ■ 1/2 in x 1 ft/12 in x Aimp (5. 1) the County Engineer. Where the grassed area infiltration concept (grassed per- Where • colation area) is employed infiltration Vgpa ■ volume of grassed percolation of the required runoff volume shall be area (ft.3) assured by designing the system to re- Aimp ■ area of •impervious area (ft.2) tain the pre'Scribed volume. This is necessary to insure that 'various physi- The volume of= a flat uniform width re- cal, chemical and biological processes tention basin can be determined' by active within the root zone •act on the multiplying the basin cross-section area required volume of runoff. by the length of the basin. In this case, equation 5. 1 can be written: Considerable research has shown that approximately 902 of the contaminant As x La ■ 1/2 in x 1 ft/12 •in x Aimp from any runoff event is carried by the (5.2) first one-half inch of runoff. As ■ basin cross-section area (ft.2) TABLE 5-1 Figures 5-1 and 5-2 illustrate this con- cept for two typical grassed percolation Expected Contaminant Removals; area configurations. In Figure 5-1, a Using Grassed Percolation Areas roadside Swale is used to , dispose of storm runoff water. Here the impervious Total Suspended Solids ' 95% surface and grassed Swale are rectangu- Total Dissolved 'Solids 50% lar in plan view. Assuming ' that the Nutrients:. swale has a triangular cross section, Nitrate 20-50Z the• relationship in Equation 5.2 can be Total Nitrogen 802 expressed as: Phosphorus 902 Metals • 80x+ 1/2D x Ws x La • 1/2 in x 1 ft/12 in x Organic Chemicals 602+ Wr x Lr (5.3) Bacteria 992 Where • D ■ depth of deepest part of swale Therefore, where treatment of storm (feet) water runoff is required, the system We - width of swale (feet) shall be designed to treat the first Ls ■ Length of' swale (feet) one-half inch- of runoff from the imperv- Wr ■ width of roadway draining to ious surface draining to the treatment swale (feet) facility. If grassed percolation areas Ls ■ length of roadway draining to rr are used to treat storm water runoff, swale (feet) i Date: 4/4/84 5-1 Similarly, if we assume the swale to 1/2 4 ia. x 300 ft x Wx = have a trapazoidal cross-section, equa- 12 in/ft tion 5.2 becomes: 1/2 in x 1 ft x 18 ft x 300 ft % ' . - . . 12 in 1/2D x (Wst + Wsb) x Ls = 1/2 in x 1 ft/12 .in x Wr x Lr (5.4) 50 ft2 x Ws ■ 225ft3 Ws ■ 4.5 ft In this case A total wale width of 4.5 feet is Wst ■ distance across the top of the . required. If we allow 3 inches for head swale (feet) required to get a flow of 1 cfs through Wsb ■ distance across the bottom of the drywell inlet, the cross-section the Swale (feet) shown in Figure 5-3 is applicable. In this installation. a total of 6 feet of For swales with triangular or trapazoid- . _ al cross-sections, side slopes of 4:1 . are desirable to prevent erosion and facilitate maintenance. In most cases &,, where swales are used along roadsides . r- r a 3, I the slope limitation will be the con- trolling factor in determining wale 14' . width. . ® . 4.° Figure 5-2 illustrates the : grassed percolation area in a somewhat less specific case. Here the grassed area FIGURE 5-3 • configuration -is a regular shape, ..while ' the impervious area may be regular or width is needed to provide .4.5 feet of irregular. In this case, a rectangular infiltration area. The drywall in this ( ' -/ cross-section is employed. The fol- installation is shown only to establish loving equation may be applied swale depth and is not included in the slope designation. D x Ws. x Ls ■ 1/2 in. x l ft./12 .in. . • x Aimp (5.5) To illustrate an alternative design, • consider a parking area of 15,000 square where. all variables are as previously feet with a Swale designed following the defined.. concept shown in Figure 5-2. If we wish to locate the wale along an edge of the Using equations 5.2 - 5..5 for designing parking area that is 90 feet long, how grassed percolation areas, several sets wide must the swale be if the depth is 4 of characteristics for acceptable inches (0.33 ft.)? The swale considered grassed areas can be generated for here is rectangular, so equation 5.5 is swales that are applicable to a given used. Substituting the known informa- impervious surface. These can in. turn tion yields be evaluated in terms of the available site. .. 0.33 ft x 90 ft x Ws - 1/2 in x 1 ft/12 in x 15,000 ft2 As an example, consider the., design of a_ 30 ft x Ws ■ 625 ft3 roadside Swale for a street segment 300 Ws -_20.8. ft feet long and 18 feet wide. If we take the length of the swale to be 300 feet The total width of the grassed area re- also and assume a triangular cross-sec- quired is about 21 feet. Note that if tion with a maximum depth of 4 inches, this had been designed with a triangular equation 5.3 becomes: cross-section, i.e. a swale with sloped r,, Date: 4/4/84 5-3 • ` ��—_. \ . - /"ma `-r� • VP � ---,c- Ct29 moo. ` e_ • C +vim.�ca�_ --' • • 0`. ..4i . v.'s pr.:;-...-.... ..::. . . . .. . • . - . .......mb„,4 ... .„ r, ....„0, t _ ;,,,,-..„ - -.-. -,.. ..*--...,--, ..- ...7..„..... ..._„„ _....._ . s,,..,�. , oaS° GURFS... ,...f.„. ... ............ :,. r •w0,2 SWALE ....F..!2, i FIGURE 5-1. Roadside drainage swale �Q _AIL. rlG IfT1 with drywell detail. DQYWELL • 7.-1= -111111144 ----- . • . : `./®QUUOFF FLOW ,(7---( tfe-S. - ---'. • • . &UIJOPF Fj. •• O . - • • . • . -•-.-fi . ' "'" . FIGURE 5-2. Drainage swale in parking lot. I 5-3 sides , the total width required would for a storm with a 1U-year recurrence have been 42 feet. interval, each grassed area must be c equipped to handle runoff volumes corn ' The preceeding examples all assume that siderably greater than can be stored in- swales are flat. In situations where the grassed area. This shall be accom- the swale slopes toward the overflow plashed by allowing the excess volume to drywell, compensation must be made for overflow to a drywell or structural sys- the slope. For purposes of this regula- tem designed in conformance with the Lion where a sloping swale is less than standards outlined in this manual. 10U feet long, slopes of 12 or less will be considered as flat. In other situa- At the present time, contaminant removal tions, the storage volume of the swale data is available only for grassed must be corrected using the following areas. Alternative cover material may relationship be -allowed if additional data indicating 100D removal capacity comparable to grass is Vgpa (corrected) ■ As x 35 (5.6) provided for a specific alternative. Where Spill Control Requirements: Section Vgpa - grassed area volume corrected 4. 16A.050(5) of the Spokane County for slope (ft3) Zoning Code (part of the Aquifer Sensi- As - cross-section' area of svale tive Area Overlay Zone) requires that (feet) • special consideration be given to storm D - depth of swale (feet) water runoff from areas within commer- 5 ■ slope of svale. (Z) • cial and industrial developments where chemical spills might occur. Specific It is important to note that the surface problem areas include outdoor loading area required for grassed percolation docks and outdoor chemical storag,_" area installation is dependent on the facilities. Further information on th ' __ ./ flooded depth. The first edition of design of facilities for these situa- this manual specified an 8: 1 ratio of • tions is contained in • the Critical impervious area to grassed area for Materials Handbook. systems with .an average storage depth of four (4) inches. Equations 5. 1-5.3 described above are consistent with the earlier specification but allows more flexibility in_ design. Though flexibil- ity in depth is desirable, there are certain limits that must be observed. An average flooded depth on the order of four (4) inches' is desirable for three • • reasons. At this flooded depth, the time the grassed area is under water allows the use of 'traditional turf grass rather than water tolerant varieties; shallow grassed areas have the desired aesthetic appearance; and the amount of • surface area involved should provide. 20-30 years of effective contaminant removal. Based on Spokane area precipitation data, the storm event producing one-half inch of runoff has a recurrence interval of about 120 days. Since storm runoff systems must be designed, at a minimum. Date: 4/4/84 5-4 RUNOFF TREATMENT GUIDELINES ADDENDUM 5-2 General Design Considerations. The following general guidelines shall be applied during the design, operation and maintenance of grassed percolation areas: .1 Grassed percolation areas (GPA) in shall be a maximum of 8 inches deep (calculated as the difference between the low point of the GPA and the inlet of the overflow system.) Standard design of CPA's allows a flat bottomed, round or triangular cross-section having a permissible average depth of 6 inches (see figure S-2b). Consideration should be given to integrating the GPA into the overall landscape design in an aesthetically pleasing manner. .2 Runoff from the roofs of Commercial and Industrial buildings shall be discharged to grassed-percolation areas rather than directly to drywells. The roof area will be added to that of other impervious surfaces for calculating GPA size. .3 In situations where average Swale depths of greater than 6 inches are allowed, the County Engineer shall require soil tests to insure that the soil is capable of assimilating the contaminants in runoff and will percolate the runoff at an acceptable rate. • When soil tests are required, one (1) test each. for cation exchange capacity and soil organic matter shall be performed for each grassed percolation area 1500 ft.2 or less. An additional set of tests may be required for each additional 2000 ft.2 or fraction thereof. Tests shall be performed on a well-mixed compos- ite sample consisting of the top six (6) inches of, soil from at least four (4) cores uniformly distributed over the percolation area. If the average cation exchange capacity is 15 milliequivalents/100 g. or more or the soil is 22 organic carbon or more, the soil will be considered suitable for stormwater treatment. ' J Where existing data is sufficient to assure that the soil type on the site meets the requirements for contaminant removal, the County Engineer may waive the testing requirement. Soils which meet the requirements of Section 4-4. 1 of this drainage manual as being suitable for drywall installation will be considered to have an infiltra- tion/percolation rate acceptable for grassed percolation area installation. • .4 When the grassed percolation area has reached the end of its useful life, it shall be renovated. The useful life will be considered to have ended when water remains standing in the CPA more than 72 hours following the end of a runoff event or when the CPA cover material dies, whether due to the buildup of toxic materials in the soil or any other cause. In the situation where infiltration fails, renovation may be accomplished by any needed action from standard soil aeration to removal of the sod layer, scarifying the underlying soil and sod replacement. When the cover material dies, the sod and at least six inches of soil shall be removed from the affected area and disposed of at an approved site. The soil shall be replaced, graded and a new cover material installed. .5 The inlet to the CPA overflow structure should be located away from the point or points where runoff flows into the CPA. When the overflow structure is located within the GPA, slopes around the inlet shall be no greater than 1:4. .6 If, on final inspection, it is found that the constructed GPA does not conform to the approved design, the system shall be reconstructed so that it does comply. 12/2/85 5 - 5 i RUNOFF TREATMENT GUIDELINES ADDENDUM iE 5-2 . 2 _ Runoff from the roofs of Commercial and Industrial buildings shall be discharged to grass percolation areas rather than directly into drywells, unless one of the following shall apply: when the total roof area of the building is less than 3000 square feet and no electrical or mechanical equipment is located on the roof , roof runoff may be disposed directly to drywells, ' or when the roof is predominately of sloped design and is covered with a non-asphalt based material and no electrical or mechanical equipment is present, roof runoff may be disposed of directly into drywells, or when' a sloped non-asphalt roof has electrical or mechanical equipment that can be hydraulically isolated from the remainder of the roof, only runoff from that part of the roof on which the equipment is located need be drained to the swale. The remainder of the roof runoff may be disposed directly into drywells. 6/1/90 • • • • (I 5 - 6 RUNOFF TREATMENT GUIDELINES ADDENDUM 02 1 When drywells are used in combination with grassed percolation areas (CPA) storage, a simplified routing technique can sometimes be used to reduce the number of drywells required. Modified Rational Method Hydrographs Depending on the relative magnitudes of the time of concentration and the storm duration, triangular or trapezoidal hydrographs can be drawn for various storm durations, with the recession period (TR)•of hydrographs being equal to 1.67 time to peak (TO. The peak runoff, Qp. is computed as in the "regular" rational method outlined in Section 3-2 of the Spokane County Stormwater Guidelines. When these hydrographs are used, different time values .must ,be. selected, a "family" of volumes calculated, and the time value which produces the largest volume is used. Using small t as the time value under consideration, the time to peak (Tp) is taken as the time of concentration (Tc) whenever t > TC, and taken as t whenever t < T . Again depending on the values of t and Tc, , - the hydrograph can be sketched as a triangle or trapezoid. When the recession period is taken as 1.67 Sp, the time base of the triangular. hydrograph will be 2.67 t, and for the trapezoid it is taken as t + .1.67 T . The top width of the trapezoid will be t — Tc. With this information the hydrographs can be constructed as shown below. Recession Period ■ 1.67 TC . V(t) 1.34 Opt for t < TC OR V(t) ■(Qp(t))+(0.34 Qp Tc) for t > TC t<TC t■TC t>TC • t 1 • -1 t +1.6,7 t-{ tTc -. I4o7 Tc. + Tc.—} {.1.b rrc,.�- RECESSION PERIOD ■ 1.67 Tc These equations can be used for the volume of hydrographs in the Bowstring Method for Detention Basin Design. These hydrographs can be used when the total drainage basin is completely contained within the project boundary and is less than 10 acres in size. 1 5 - 7 Bowstring Method - For Detention Basin Design r ` The Bowstring Method for detention basin design is a procedure in which the modified rational method is used to design the detention basins without performing routing. An allowable release rate (ARR) and volume are calculated for the undeveloped condition using the modified rational method. Similarly the developed rates and volumes are calculated for various time periods and the storage requirement of the basin is calculated as the maximum difference between the volumes for,the developed and undeveloped conditions. This method should be limited to basin areas less than 10 acres in size. The procedure is: 1. Select a storm frequency (such as 10 year) and compute the peak discharges • for •the developed and undeveloped conditions for .various time.._periods (t): t = at time t Qdt ° CditA d - developed where the subscript d refers to the developed condition, Q is the peak • discharge (cfs), C is the runoff coefficient, I is .the' intensity of rainfall (in/hr) and A is the drainage area (acres). • • 2. For different t, calculate volumes: Inflow volume = 1.34 * Qdt * t for t < TC or • �Qp * t')+10.34 * Qp * TC)for t > TC Outflow volume = Qdt x t 3. The required storage is obtained as the maximum difference between inflow and outflow volumes by either graphical or tabular method. Example 1: The following sheets are suggested forms to use in calculating a detention basin using the Bowstring Method. The given information is shown on page fl 4. Step 1 Using the given information we first must compute the peak discharge. t(L * n '6 . TC - C nar- • 700 * .016 •6 - .1 1/.715U- = 2.83 minutes use 5 minutes I is for 5 minutes - 3.18 5 - 8 • (.9 * 5.65 + . 1 * 1.63) Weighted "C" factor = (5.65 + 1.63) • _ .72 • Q developed = C * I * A _ .72 * 3. 18 * 7.28 ■ 16.7 C.F.S. • Select a desired outflow, such as 2 c.f.s. Q undeveloped ■ 2 c.f.s. Step 2 Select a time increment less than the time of concentration for calculating,. or 5 minutes (Tc is never less than 5 minutes). The solution is shown on page 0 5. Column 01 is the time increment selected. .Column 02 is Column 01 in seconds. Column_ 03 is the 10 year intensity from Figure 2 (page 6-3 of the Stormwater Guidelines) at each time increment. - Column 04 is the area X "C" factor X Column 03. Column 05 is the volume in using the equations for volume used in the Modified Rational Method Hydrographs. Column 06 is the desired outflow X Column 02. Column 07 is Column 05 minus Column 06. • Step 3 The required storage is the maximum difference between the inflow and outflow volumes, or 7495 cubic feet. This is less than the 10,255 cubic feet required for the 208 ponding volume and the 2 c.f.s. can be disposed of in 2 County standard type B drywells, rather than the 17 drywalls required under Step 1. • • • • • 5 - 9 RAT WNAL FORMULA PROGRAM • INPUT FORM ( ' DATE DESICN Q • NAME PROJECT • BASIN. NAME C of Sub Areas SUB AREA • 1 2 3 4 5 6 . 7 8 9 10 (max) • Area in • Acres Runoff Coefficient OVERLAND FLOW CHANNEL FLOW • Ct 7 L . • L • • Z1 • N ■ Z2 • S • N • 8 • S • • TD A. Impervious Area B. Required '208' Ponding Volume A x 1/2" - 12 5 - 10 RA r ZONAL FORMULA PRoORAM • INPUT. FORM DATE 1/6/86 UESICN 10 yr• NAME C. Nelson PROJECT 8-Plex Cinema BASIN NAME 1 • Q of Sub Areas 2 SUB AREA 1 2 ' 3 4 S 6 7 8 9 10 (max) . Area In 5.65 1.63 • Arses Runoff Coefficient OVERLAND FLOW C1(ANNEL FLOW 0 >' . 15 L ■ L ■ 700 21 - .016 N ZZ ■ . .007 N •S - B ■ S ■ • ?D A. Impervious Area 246,114 8. Required '208' Ponding Volume 10,255 A x l/2" _ 12 5 - ll 306/6 . BUWSTRINC METHOD • DETENTION BASIN DESIGN Time Increment (min) (4 Time of Concentration (min) , Outflow (c.t .s.) Design year (low (yr.) Area (acres) Developed "C" factor Area x "C" Si 02 t 03 • 04 05 - lb p7... Time Inc. Time Inc. Intensity Q dev. , V in V out Sturage (min.) (sec.) - (in./hr.) (c.f.s.) (cu. ft.) (cu. ft.) (cu. ft.) (ft • 6U) (A*C*03) (see below) (outflowfU2) (95-06) I • I - 1 I 1. - 1 1 I I l l I 1 I 1 1 1 I I I - I 1 I I 1 1 1 I I I I I I 1 1 ! 1 I . -1 I 1 I I I 1 I � • 1 I f L_________1 1____:_:____I 1_______.1 . . 1 I . , I • I . I 1 - 1 ,1 I I: • I 1 I I I 1 ! I 1 . 1 1 I I I I 1 1 1 1 I I I I 1- 1 1 1 1 1 - 1 -I I I I I 1 1 1 1 1 -1 1 I - I Vin •• 1.34 • Q dev " t for t t Tc Vin ••(Q dev • t)+(.34 • Q dev • Tc) for t > Tc 306/6 ( i 5 - 12 BOWSTRING NETILOD DETENTION BASIN DESIGN • --' :rime Increment (min) S I:lme of Concentration (min) Outflow (c.f.s.) Design-Year floe (yr.) Area (acres) Developed "C' factor Area x -C- F1 12 t I3 14 f5 06 07- Time Inc. Time Inc. Intensity Q dev. V in V out Storage (min.) • . (sec.) (in./hr.) (c.f.s.) (cu. ft.) (cu. ft.) (cu. ft.) ' • (il a 60) (A*C•03) (see below) (outflovC2) (05-96) 5 , JU6 3.18 I j10 • 600 I 2.24 I I I 4 1 15 - . . 900 1 : 1.77 1 • - L....21. I. '. ' M_ .00 ( I J ' 25 1500 . 1 1 .21 1 . _ - i 1 30 • 1800 1 1.04 1 •. 1 .1 • 35 2100 ..I .91 I .J _ l 40 . 2400 1 .82. . 1 • . . . I ' ' F . 45 . 2700 .74 .I -! I ] 50 • • . 3000: .68 I j • 1 J 55 3300 . . .64 1 1 1 • I J • 6n • 3600 .61 I. .. I . J 65 .. 3900 .60 1 1 01 . . 1 I . J 70 4200 .58 I_ • I. l . ! 75 4500 .56 1 ( • ( 1 I 80 1 4800 .53 I • I I I I 85 1 5100 1 .52 1 • 1 1. . - • -I • I 1 90 1 5400 1' .50 I -01 I I I 1 95 • 1 5100 1 .49 i 1 I 1 I J 100 I 60ci0 1 .48 1 - 1_ _____I.- .1-L.----1 Lin - 1.34 • Q dev • t for t ( Tc - yin -(9 dev • c) •(34 • Q dev • Tc, for t > Tc 306/6 1 1 , . 5- 13 BOWSTRING METHOD DETENTION BASIN DESIGN 0 Time Increment (min) 5 Time of Concentration (min) 5 - Outflow (c.f.s.) 2 Design year flow (yr.) 10 Area (acres) 7.28 Developed "C" factor .72 Area x "C" 5.24 01 f2 t 03 04 iS 16 .07 Time Inc. Time Inc. Intensity • Q dev. V in V out - Storage (min.) (sec.) . (in./hr.) (c.f.s.) (cu. ft.) (cu. ft.) -(cu. ft.) (01 * 60) ' (A*C*03) (see below) (outflow*02) (95-06)' 5 1 300 1 3.18 1 16.66 I 6,697 [ 600 1 6,097 10 1 600 1 2.24 1 11 .74 ' I 8,241 ( ' • 1 ,200 I 7,041 15 1 900 I 1.77 9.27 - 9,289 1 ,800 I. 7,489 1 1_22_I_12 . 7.60 1,895 I 2,400 1 7,495 25 I 1500 1 1.21 1 6.34 10;157 1 3,000 1. 7,157 j 30 I 1800 1 1.04 I 5.45 j . 10;366 1 3,600 1 6,766 1 35 i 2100 1' .91 1 4.77 I 10,504 I 4,200 I 6,304 • I 40 I 2400 I .82 1 4.30 10,759 I 4,800 1 5,959 . 45 2700 .74 3.88 . 10' 872 5 400 5 472.. . ', 1 50 3000 - .68 1 3.56 I 11 ,043 1 6,000 j .5.,043 55 3300 .64 1 3.35 11 ,397 J • 6,600 1 4,797 ' j 60 3600 .61 1 3.20 ' 1 11 ,846 j 7,200' j 4,646 I 65 3900 .60 1 3.14 12,566 1 .7',800 • 1 4,766 1 70 4200 . .58 3.04 ' 13,078 1 8,400 1 .4,678 1 75 4500 .56 2.93 1 13,484 1 9,000 j 4,484 1 80 . 4800 .53 2.78 1 13,628 I 9,600 1 4,028 j 85 5100 .52 2.72 . 14,149 10,200• 1 3,949 j 90 5400 1 .50 2.62 1 ' 14,415 I 10,800. • 1 3,615 95 1 5700 1 .49 2.57 1 14,911 11 ,400 1 • .3,511 1 100 - 6000 1 .48 ! 2.52. 1 15,377 1 12,0b0 1 • 3,377 . Vin ■ 1.34 * Q dev * t for t < Tc Vin -(Q dev * t)4-(34 * Q dev* Tc' for t ) Tc 306/6 5 - 14 .�; Example 2: Using the information given for Example 3-2. 1 in the Spokane County Guidelines for Stormwater Management (page 3-2). Step 1 The Time of Concentration is calculated as 13.8 minutes and the peak runoff is 2.5 c.f.s.' This calculation is shown on page 3-2 of the Stormwater Guidelines. We select 2 c.f.s. as -our desired outflow. • • Step 2 • • Select a- time •increment which is less than the time of concentration for calculating, such as 5 minutes. The solution is shown on page D 8. • Step3 • The required volume is the maximum difference between the inflow and the outflow. or 1276 cubic feet.- This is less than the 1455 cubic feet required for the 208 ponding volume, and the 2,c.f.s. can be disposed of in 2 County standard Type B drywells, rather than the 3 Type B drywells required to dispose of the 2.5 c.f.s. calculated under Step 1. • 5 - 15 RATIONAL FORMULA. PROGRAM INPUT FORM DATE March 18, 1986 OLS lGN 4 10 ( , . NAMF. C. Nelson PRUJgCT • Example 3-2.1 • BASIN NAME A d of Sub Areas I • • SUB AREA 1 2 3 4 5 6 7 8 9 1�) ._ \ (coax) ' - Aria in . Acres _ 5.5 - - Runoff _ Coefficient -25 OVERI.At1O "FLUU CHANNEL FLAW Cc - .15 L ■ 610 L - 300 Z1 - .172 f... ., U ■ .4 Z2 - . 40 S .01 N - .016 ' B ■ 0 s - .025 TO ■ .2 • A. impervious Area 34920 360 X 36 + 610 X 36 B. Required '208' Pending Volume 1,455 . Ar. 1/2" - 12 ( 5 - 16 306/6 BOWSTRING METHOD I DETENTION BASIN DESIGN Time Increment (min) 5 Time of Concentration (min) 13.8 Outflow (c.f.s.) 2 Design year flow (yr.) , 10 . Area (acres) 5.5 Developed "C" factor .25 Area x "C" 1.375 01 02 t 03 • 94 05 06 07 Time Inc. Time.Inc. Intensity Q dev. V in' . V out. Storage (min.) (sec.) - (in./hr.) (c.f.s.) (cu. ft.) (cu. ft.) (cu. ft.) (01 * 60) (A*C*83) (see below) (outflow*02) (05-06) . 5 1 300 I 3.18 t 4.37 1757 i 600 . 1157 10 I 600 3.08 I 2476 1200 I 1276 I 13.8 828 1.86 2.56 2840 1656 1184 ' • 15 • 1 I 1.77 I 2.43 I 2879 1800 I 1079 I 20 . I 1200 - - 1.45 I 1.99 1 2955. • 2400 I 555 I _ . 25 I 1500 I 1.21 1 1.66 I 2963 I 30 1 00 . -37 I ,\ I 30 - I 1800 1 1.04 � 1.43 1 2981.4 . . - • 3600 I -619 I 4 h 35 2100 .91 . 1.25 2981.2 4200 1 -1219 . 40 1 2400 I . .82 . I 1.13 1 3034 4800 1 -1766 I '45 1 7 2700 I - 1.74 - 1.02 3045 5400 -2355 I 50 • ' 3000 . I .68 . I. :94 ! 3088 ( 6000 1 -2912 1 ' • 55 3300 .64' • .88 I 3155 I 6600 • -3445 60 I 3600 - ' .61 • . .84 1 •3263 I' 7200 1 -3937 I . .65 1 3900 .60 .83 I 3473 1 7800 I -4327 I 70 1 4200 - .58 .80 1 . 3588 I 8400 1 -4812 I • 75 1. 4500 .56 .77 , 3684 I 9000 --1-----121.6--1 80 I 4800 .53 .73 1 3712 • I .9600 1 ' -5888 I -85 1 5100 .52 .72 1 3877 10200 1 -6323 I 90 1 5400 . .50 .69 I • 3923 * I 10800 -6877 95 5700 .49 .67 I • 4010 11400 I -7390 I 100 6000 .48 .66 1 4148' 12000 1 -7852 I Vin - 1.34 * Q dev * t for t < Tc • Vin 4.0 dev * t)+�.34 * Q dev-* Tc') for 't > Tc k t306/6 5 - 17 Addendum to Section 5 . Topsoil Infiltration 0.50 inehesllar,minimum (Effective:February 1998) Rate,to be noted in ( plans. Sod Infiltration Rate 0.33 inches/hr,minimum .. Grassed Percolation Areas Bottom of Swale Elev. 6 inches(0.50 ft.)below for swales without gutter elev.of adjacent A typical "Grassed Percolation Area" (GPA) is drywells curb-to top of lawn sod shown in Fig. 5-1, 5-2, and Figure 48. A GPA is - 8 inches(0.67 ft.)below used for treatment for stormwatcr prior to disposal gutter elevation of adjacent into the ground. It is for protection of the Spokane curb-to subgrade Aquifer,and the limits of the protected area is defined as the Aquifer Sensitive Area,shown in Figure 6. Bottom of swale elev. a)9 in. (0.75 ft.)below for swales with gutter elev.of adjacent The total sumrroratcr storage depth for the required drywells curb-to top of lawn sod design storm event is to.be no greater than 1.0 -ft. • b) 11 inches(0.92 ft.) depth for GPA which have chyv:ells, and no greater below gutter dev.of than- 0.5 ft. depth for GPA without drywells. adjacent curb-to subgrade Following the design storm event, the GPA is to Drywell•Grate Elev. At water quality design completely drain within 72 hours.. A standard . depth drywell is normally placed in the bottom of the GPA Grass Seed Mix Sec Appendix E .. for major storm events and overflow. Runoff is •Note (1): The side slope can be increased to a permitted to flow frtim One GPA to'another,normally maximum of 2:1 grade if the Maximum .surroimding along the curb and gutter of a street_ The basin map grade creates a cut with no greater than 1.0 It depth. is to-show the limits of the land area which=tribute • , runoff to a •GPA or combination of Grassed Percolation Ansas. For GPA's,the canstructicm plans arc to specify as a ".-• mina= bottom_ of await elevation for both The.Supplemental criteria for Grassed Perinlation subgrade and the top of sod, top of swale or berm Areas art: . .' elevation, drywell grate . elevation, horizontally pond location and chywell location, and •Water Quality depth a) 6 inches(0.50 ft),MX. easeriont limits. The -easement shall extend a (depth to top of lawn . without cation exchange minim of 5 ft. horizontally from the bottom of • 'Sod) testing ' , await,or to the area bounded by the maximum water b) 8 inches(0.67 ft.)max. elevation for the design storm,whichever is greater. with cation exchange =MA For GPA lerving public or private roads, the Water Quality depth. a)8 inches(0.67 ft.),max. horizontal location and vertical elevations of the (depth to sub,gmde) without canon exchange • GPA, drywdls and inlets axe to be clearly defined in testing&passing of test the plans. Normally by station and drum, or b) 10 inches(0.83 ft.) dimensioning from property, lines. The plans•art to • max.with cation exchange clearly define.the inaimum berm elevation around a testing&passing of test pond or grassed percolation area ((WA). No GM Elevation See Fig.48 shall be placed in back yards of residential lots unless • Ran/ire:marts tuect • the GPA is adjacent to a public or private road , to roadside curbs A concrete inlet can be placed in the bottom of the Total Storage depth 12 in. (1.0 ft.)maximum Side Slope 3:1 -maximum GPA, with a pipe connecting to a drywell,to provide,' ' the messalY maint=anee a000ss to the dlYwellf\ - • 'See Note(1) C — t Guidelines for Stonnwater Management - Addendum 5-18 Spokane County. February 1998 • Maintenance access to the concrete inlet is not curb drop shall be 6 ft. Some designs may require required, but is macro nendod. more than one curb drop at the low point. Large Grassed Percolation Areas Grassed Percolation Areas-Alleys A GPA which has a treatment area gaiter than For 16 ft wide, crowned private alleys constructed 1,200 square feet and which drains within 72 hours is within the Aquifer Sensitive Area,a GPA can consist defined as a "Large Grassed Percolation Arta." of a Standard Border Swale on both sides of the (Large GPA). The supplemental criteria for Large paved alley when the following conditions are met: GPA is listed herein, with the exception that the total storrnwater storage depth can exceed 1:0 R. for the • The GPA will be located in well-draining soils, mquired design storm event and are within one of the following SCS Soil Groups: Springdale, Garrison, Bonner, Hagen, Mai • re access shall be provided to the bottom Bong, Phoebe,or Marble. of a Large GPA in non-commercial areas, in accordance with the criteria specified in the • The maximum grade of the alley dos not exceed addendum to Section 1 of these Guidelines. 3.0%longitudinal. The easement containing a Large GPA shall comprise • The Swale is lined with grass lawn turf, installed the area bounded by the high-water elevation for the with sod or hydnoseeding. design storm, plus a 1.0 ft. freeboard, and the maintenance access. The Standard Border Swale is a swale with a If large GM are within residential neighborhoods, minimum storage depth of 0.75 R. (9 inches)across a and outside of the ��bottom width of 4 ft..,with no drywell. It is County�-ofd', they shall be continuous along the edge of a paved alley, except placed within a separate tract,and encumbered with a where driveways art located. To make use of a easement granted to the catty responsible SAM Border Swale, the driveways can constitute for maintaining the drainage facility, normally a no more than 25% of the homeowners association. Where runoff from the 5'0 along the private public right-of-way drains to the tract, an easax it for conveyance, discharge and disposal shall be The Standard Border Swale is to be maintained by granted to Spokane County,with adequate casemeats the owner of the property when✓the Swale is located for ingress and egress to the tract for purposes of tberaaa. routine or emergency inspection and maintenance. If the inside slope of the pond is greater than 5:1, then the limits of the tract is to bounded by a 6 R. high, visible through fence, and a 12 ft. minimum width gate for mainusance access into the pond area. Curb Drops for Grassed Percolation Areas When curb inlets are used with GPA and ponds, the curb inlet shall have a 2 inch drop at the nub lint, and the subgade elevation is to be placed 2 inches ",below the adjacent edge of concrete to allow for sod growth. See Figure 48. The maximum length of a Guidr i •s for Stormwater Management - AdA ndnm 5-19 Spokane County: February 1998 6. TABLES AND CHARTS 6-1 TABLE 1 RUNOFF COEFFICIENTS FOR STORM SEWERS ROLLING HILLY FLAT 22 - 102 OVER 102 Pavement and Roofs 0 90 U.9U 0.90 Earth Shoulders U 50 0.50 0.50 Drives and Walks 0 75 0.80 0.85 Gravel Pavement 0.50 0.55 0.60 City Business Areas U 80 0.85 0.85 Lawns, Sandy Soil 0 10 0.15 0.20 Lawn, Heavy Soil U 17 0.22 U.35 Grass 'Shoulders 0 25 0.25 U.25 Side Slopes, Earth 0.60 0.60 U.6U Side Slopes, Turf 0 30 0.30 0.30 Median Areas, Turf 0 25 0.30 U.30 Cultivated Land, Clay and Loam U 50 0.55 0.60 Cultivated Land, Sand and Gravel 0 25 U.30 0.35 Industrial Areas, Light 0 50 0.70 0.80 Industrial Areas, Heavy U 60 0.80 0.90 Parks and Cemetaries - U 10 0.15 0.25 Playgrounds' • 0 20 0.25 U.30 Woodland and Forests . . . . . . . . . . . . . . 0.10 0.15 0.'20 Meadows and Pasture Land 0.25 0.30 0.35. * * * * • *SINGLE FAMILY RESIDENTIAL • (Dwelling Unit/Gross Acre) (Sandy and Gravelly Soil) 0-1.0 DU/GA 0.15 • 1.0-1.5 DU/GA . . . . . . . . . . 0.20 1.5-3.0 • DU/GA 0.25 3.0-3.5 DU/GA 0.30 3.5-4.0 DU/GA 0.35 4.0-6.0 DU/GA 0.40 6.0-9.0 DU/GA 0.60 9.0-15.0 DU/GA 0.70 ' * Assumes flat lot plus one-half width of abutting street. Other configurations should be checked by combining individual runoff factors for each various surface. Date 4/4/84 TABLE 1 6-2 . . ti . - ' Mae. C I�t■■ ■Qt■■1aa ■■a WIZ .•_• .■a... ■wallas■ .■1111/0..•u 11 • Mgiggg r w aa•■u■■■aa.■a■aa■aa■m • ••••s• • 1 I • { • u/•■■aa,a un • : ■/, ■ •••••••• rRE 4 • ■••■•••••• ■ai • • . l atn■• I . ▪ ••••••••/ ■■■/■ • ■■■••••••• ■au■ • N•=■ l• t!� ■■■wa■■ s■o■ _� •■ ■ ■■■wa■■ i■E!■sE::N.=Ns■IEZNEK_ I - '• oiiis ■:awa••u�■� , ■w■aa■a •■a�tlaa•/wu ■■■-iiw■■■■■uar■w■■aw■�■ if • ■■■■•i■uu�i�■aa■1 au s�ru■■wu=ww■ w/■u■as/■/■■aa■■ ■ ■ ■uat■■■■•nami ■ ■■Iw.aaa■■w ■■■Ni■•■■asuw■■uaaw■■ i •i INSTRUCTIONS FOR FIGURE 3 Step 1. Find the approriate points on the vertical lines labeled "L" (hy- draulic length) and "s" (slope) and connect these two points with a straight line. Step 2. Find the correct point on the line labeled "n" (roughness coeffi- cient) and connect that point with the point where your line from Step 1 intersected vertical line (1). Step 3. Find the point on the vertical line labeled Ct (See values on Fig- ure 3) and connect with the point on vertical line (2) where your line from Step 2 intersected. Step 4. Read the value of Tc (Time of Concentration) on the vertical line labeled Tc. These values are in minutes. • • • 6-4 TYPE OF AREA "n" TIME OF CONCENTRATION AVERAGE GRASS COVER .4 Tc = C 1 (Ln /-) 0.6 POOR GRASS COVER .3 Example VALUES OF Ct L = I,000 s = 0.01 n = 0.5 C t = 0.3 NATURAL DRAINAGE AREA .4 OVERLAND FLOW .I5 ; = 49.7 minutes 10,000 0.0001 -- 100 5,000 - — 0.01 50 0.0005 — • / / .0 / 1,000 0.001 ~ ,- / • (3)// 30 \ —0.05 / 500 • _ _ / 1.0 / — ",----= a_ / • (2) 20 / • \1 / — 0. \ - / `\ 0.009 • • ` —0.5 CO 0.01 ...I►- t0 ± 0.1 - —1.0 0.05 50 (C,) _ - e 0.05 - CL 01 (n) (2) 10 0.1 — 5 - (1) - fU L- t- S _ (2) t -2 -. - ( (3) C,- 2 - ' 1 1 (L) (5) (re) FIGURE 3 5-5 . R42E R43E R44E R-15 E Spokane County Isopluvial Map T -WM • - T -, 10—yr,24 hr Storm 2 9 • - q At(tenths of inches) N 1Mi •e\, I • I ;V. t _1 T =Mkt . '. •ii - T - r, I . . J T I �'1�1 T ?7 2: T , rg � i T _MIN� �� i 26 A' A' - T eir. `� T—A Mill I r 1 25 I I=IM M -11 -41A"u211111..Mini M I IV opPg., mac: � T , T I, 24 o, �4 i R42E R43E R44E R45E Spokane County 1 - Isopluvial Map T '— T ( - 50-yr,24 hr Storm 2 9 2 (tenths of inches) ?�' :�'9 T '. g T 28 28 k 0. AI Iv ?MI-=OAF ail mffill . • i T I -- ' \ �.d.. T '% Ro'! z � On& Ar T ---: - 1 CD IliF • NO T TT • i T 2 5 f + . r� _mg�' /i 71,5 ;d © .-iF.S ■ : I 1 - _liar� -- •-• `� lip '.-- .\ ,• 24 •,dliag% . 1 ir: .: • 24 • C ' MAW T 22 • - _ t 33 N - ' . Etc . . tiM A' ' . t. IIII la: . — �' _ - 1� . ' t ( I 22 F1t 21 - - ------`-, :1 ! 21 N . . - = - . M. . i N R4OE R4IE R42E RJ3E R44E R45E 50-Yr, 24 Hour Rainfall for Spokane County , ^ Guidelines for Stormwater Management ' I Figure 4 Addendum,February 1998 ini Sheet 2 of 2 Pg. 6-7 %r \ • Table 5 --Runoff curve numbers for selected agricultural, suburban, and urban land use. (Antecedent moisture condition II, and Ia = 0.2S) HYDROLOGIC SOIL GROUP LARD USE DESCRIPTION A B C D Cultivated land!/: without conservation treatment 72 81 88 91• : with conservation treatment 62 Ti 78 81 Pasture or range land: poor condition 68 79 86 89 good condition 39 61 74 80 Meadow: good condition 30 51 71 78 Wood or forest land: thin stand, poor cover, no mulch 45 66 . 7T 83 good cover!/ 25 55 TO TT Open Spaces,.lavus.-park.. golf courses, cemeteries, etc. good condition: grass cover on 75% or more of the area 39 61 74 80 • fair condition: grass cover on 50% to 75% of the area 49 69 79 84 Commercial and business areas (85% impervious) 89 92 94 95 Industrial districts (72% impervious). 81 88 91 93 Residentia1:2/ • Average lot size Average f Impervious=l 1/8 acre or leis 65 • T7 85 90 92 1/4 acre 38. 61 T5 83 87 1/3 acre 30 5T 72 81 '86 .1/2 acre 25 54 TO 80 85 1 acre 20 51 68 79 84 Paved parking lots, roofs, driveways. etc.!' • 98 98 98 98 Streets and roads: paved with curbs and storm sewers-1/ ev 98 98 98 98 gravel 76 85 89 91 dirt • 72 82 87 89 for • more detailed description of agricultural land use curve numbers refer to National tnglneering Handbook. Section 4, Hydrology, Chapter 9, Aug. 1972. _/ Good is protected from grazing and litter and brush cover coil. 1/ Curve numbers are computed assuming the runoff from the house and driveway 1s directed towards the street with a minim= of roof water directed to lawns where additional infiltration could occur. ._% =l The remaining pervious areas (lawn) are considered to be in good pasture condition for the3e curve numbers. 1V In some warmer climates of the country a curve number of 95 awl be used. 6-8 TABLE 5 R42E R43E R44E R45E Spokane County Aquifer Sensitive Area T , ( ' 29 9 • I T " � hi I 28 i A 1■1 IMOMMIi l J T Eli rim T 2i < �4�.�■1110!EM ws�� sr Ir�lmm -.�s AEI TIMMINS ErE6 T 1 Wahl lir m�llE��II T 26 ,.(15111111 0131FEE111 MENEM fularaelEt 26 -- - ' 11Mal IN EIS-1:1211 RPM iii WS trawar El N T moms Ed 4 !ER s a . T 2: 1�1_ 1l! __ s a I l Eli IIi 5 T A `� T 24 � ' MU i 24 1 ' L� �� N.. 1.42:2 MIINIMINI=EWE IINENNILli a•T T A' _ 1111 N T --- -. I T N N T _. 1 T- NM • 21 _ _ - -- _ • 1 2/ R4OE R:IE R42E R43E R44E R4SE Spokane County Aquifer Sensitive Area Guidelines for Storm k water Management ( - Addendum,February 1998 1100 Figure 6 Pg. 6-9 SNE COUNTY- 0. . .....u.`- -i--�--∎. - oQO INIML■11111•M la NMI MEMO=MEI MI 1=1114MIM 116•1==.11011! v...s.___as--assn-ate a • • Imm sass am emu mum asImssmar a��.f•■■t�•M as.•••sa�liQ! S E ilminalmiwaraassmrra owrrru■nmrrrrrrs • rswnssommown==rra■r1E111rrrr1O iz F.ui ..r !■ssrmanluass■sommssmurlrraln .c 111111111111111111•1111111■111111111111111MINIMIM=111111 .4 el co • ° n u•■iu111•IMMI n i•• 111mi��■e�� mn _ m1 i 8 -• - 1111■iiliU■•11111 _ m : , I ' 11111,1iw•ui111111®mu : r Cil 111111 eiII•I■ �,,El : 2 iiaEls E>QNoas _ co ii�� 0 r�a��No�� 1■ •NN'm. d 0 00 i. .^_�rra�r •■.r�as�.o� o�.otr�o.ra II!111IO11iii51i ! 1 .. : i = EIIIIM1111!!/■••111111Iili► ii 8 , x .••• _. �s�smaI1iIIII 1 a, ........._,.. . 0 CP o • II -1 : 1 , , M Z 11 1E ! , . 4 Iti 1 -•MM I I rs e. o -. W 11 lim mime su .0 1 E --E., . - '. :- II s ..-111111- :I I. ■ I1aN� - H 1$nn lr M : 7--- :. 11111IIIIIIIM F ! : : , iJiIIii§ [I- 0 § §R o M a MIL a yn to acorn •mil; 6-10 Figure 7 2000 ih I 1000 soo US p W ,ao N CC •oo W Z kki 300 Q J J 11 m 1k 0 , 1 111111 -0,‘ too =100 to J EO C'N SO 4■1 440 w. N cr.O M LLJ CC 30 Z � 4J a N a0 � o G f- N 0 o 14 er CC � � e Y 111 A'Al W y 3 4. W 2 a ,-I- 000000 0 0 0 000002 0 0, 0 0 • a '� • as 00000 0 0 0 0 0.0"• ■ "' • KKR OISCN•11Gt (CIS/oNCN Or NVNOIr( 6-11 1�. FIGURE 8 Sheet I of 3 - , - - 2000 1000 • GOO N • _ O • ' GOO • W boo CO) ..-. C • •00 Cr Z ,D . w O 13, J r , . 200 m _. J J t- • Q N 100 . N O G0 Q: M O et . , .i0 4 O Iii 30 ,T, W N , , _ .a0 u Q N SO = = W o N 4 zo i- • w .p . CI O 0 L • G ta 1 "' H N 2 , , *mg \k '5 G Q ... O : `;' • • Y i- ` Q CL ~ \ 0 00 0 0 0 0 0 0 0 00 0 0 g 0 2 0 ' 0 . • • . . « - 0 00 0 0 0 0 0 0 Off•�-• • « -. o••• • e • ^ « Ka* O/SC•••GC CC'S/INCH Or Humor,) • FIGURE 8 6-12 Sheet 2 of 3 T ■4 , - moo 0■ - GOO W S •500 N . ,00 W 2 . 300 a o 3 f- M ' .:oo J m \\:f�7 Q_ 2 to s J 0 u) . ' .t00 a O oc i Q W •S0 = = W J 20 N ;N , • • 0 O . \ .. 10 W = 2 N4 O` � �.. , .. e a Cr er O ` `5. Y � - • Q to w CL W • a 00000 0 0 0 0 00000 g 0 R' 0 0 • • • ^ « 000000 0 0 0 000~• . N O•O P • n • n N PEAK DISCHARGE (CFS/INCH OF RUNOFF) ( . FIGURE 8 Sheet 3 of 3 6-13 i Table 9. -- Slope Adjustment Factors by Drainage Areas . . FLAT SLOPES Slope 10 20 50 100 200 500 1 ,000 2,000 (percent) acres acres acres acres acres acres acres acres 0.1 0.49 0.47 0.44 0.43 0.42 0.41 0.41 0.40 0.2 .61 .59 .56 .55 .54 .53 .53 .52 0.3 .69 .67 .65 .64 .63 .62 .62 .61 0.4 .76 .74 .72 .71 .70 .69 .69 .69 0.5 .82 .80 .78 .77 .77 .76 .76 .76 0.7 .90 .89 .88 .87 .87 .87 .87 .87 1.0 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.5 1.13 1.14 • 1.14 1.15. ' . 1.16 1.17 • 1.17 1.17 2.0 1.21 1.24 1.26 1.28 1.29 1.30 1.31 1.31 . MODERATE SLOPES 3 .93 .92 .91 .90 .90 .90 .89 .89 4 1 .00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 5 1.04 1.05 1.07 1.08 1.08 1.08 1.09 1.09 6 1.07 1.10 1.12 1.14 1.15 1.16 1.17 1.17 7 1 .09 1.13 1.18 1.21 1.22 1 .23 1.23 1.24 STEEP SLOPES 8 .92 .88 .84 .81 .80 .78 .78 .77 9 .94 .90 .86 .84 - .83 .82 .81 .81 10 .96 .92 .88 .87 .86 .85 .84 .84 11 .96 .94 .91 .90 .89 .88 .87 .87 12 .97 .95 .93 .92 .91 .90 .90 .90 13 .97 ' .97 .95 .94 .94 .93 .93 .92 14 .98 .98 .97 .96 .96 .96 .95 .95 15 .99 .99 .99 .98 .98 .98 .98 .98 16 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 20 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 25 1.06 1.08 1.12 1.14 1.15 1.16 1 .17 1.19 30 1.09 1.11 1.14 1.17 1.20 1.22 1.23 1.24 40 1.12 1.16 1.20 1.24 1.29 1.31 1.33 1.35 50 1.17 1.21 1.25 1.29 1.34 1.37 1.40 1.43 TABLE 9 6-14 x , - R42E R43E R44E R45E . Spokane County Isopluvial Map ; 2-yr,24 hr Storm T T (tenths of niches) 2 9 ■ MEW 7Vi ARM 11 _ . .. A ��2rll �1 27-8 a 28 I 11IR MITA M A T 27; _ A7 IMMINIIIIIM P1111111% '411 AT �k __s�/%s a®IN�T IMIRIMPI ._ . T ! ..1 ABM —,"4111Mili k!i.e.r • -. . N � � S mit VIM. �11K 41 1� - Will) IPPAl WNW WIMP T _ T 4 arM� Tramp_ I 24 ir -.... - d .I' _ � T - - ' T• __ . Mg arriem., . : __. i . • .- . MIES . R1114 . : -: T - • - 9 - kb.- ' ' L.__ . T `? N . . im . ,.. . .y- 1 T — --= -; ' • 21. ... �� ' 1 I I 21 L: II N R4OE R41E R42E R43E R44E • R45E 2-Yr, 24 Hour Rainfall • .' for Spokane County ' � +, Guidelines for Stormwater Management Addendum, February 1998 i100 Figure 10 S Pg. 6-15 �C TY R42E R43E R44E- R4SE Spokane County Lsopluvial Map 7 , : T { 100—yr,24 he Storm 2 9 NM , l 2 9 (tenths of inches) N - r .111M I A \e__ - 7. frc `® T 28 � �� e` 2s N =MI .0 I. i,!L N.i. a AI._ . rL,. 7 , Llam Aa L ..i 77 . miLva..T r E 111.M° _ T 2,6, Ce ... I IV .1_ T . ir�� m �sr�i Aufalifirivil T t nNE=v �� _�" °i' ' LSI�_1•�� T 2 `�$ C I 24 (. . . 1507i Mit& . MIA..o �� ..s low Amisomm...mmt um Nibb-msoll , . r Kamm . : . . IT= T NM _W=MIME Mr SI - 1....i. v ' ME T �O�� r�) T 21 �1 1 21 N i I N R4OE R41E R42E R43E R44E • R45E 100-Yr, 2A Hour Rainfall for Spokane County Guidelines for Stormwater Management (:\ Addendum, February 1998 ail Figure 11 SICKANEUNTY Pg. 6-16 CO , ‘;- Table 12 Omitted pages 6-17 through 6-33 omitted • \ r�1 TABLE 13 MANNING'S ROUGHNESS COEFFICIENTS (n) 1. Open Channels, lined: A. Concrete 0.014 B. Gravel 0.030 C. Asphalt 0.016 2. Open Channels, excavated: A. Earth, fairly uniform section: 1. No vegetation 0.025 2. Grass, some weeds 0.030 B. Rock 0.035 Street Gutters A. Concrete gutter, trowled -0.014 B. Asphalt pavement 0.016 C. Concrete pavement 0.016 3. Closed conduits A. Concrete pipe 0.012 B. Vetrified clay pipe 0.013 C. Plastic pipe 0.010 D. Steel pipe 0.011 E. CMP (annular) or helical, part full 0.024 F. CMP (helical, 243" x 1/2", flowing full: diameter n diameter n 12 0.011 42 0.019 15 0.013 48 0.020 18 0.014 54 0.021 21 0.015 60 0.022 24 0.016 66 0.022 30 0.017 72 0.023 36 0.018 78 and over 0.024 6-34 TABLE 13 INSTRUCTIONS FOR FIGURE 14 For Heads Less than 0.4' : 1 . Calculate the perimeter of the grate. If one side is against a curb, do not include that side. 2. Find the intersection point of the Q/P curve and the horizontal line for the maximum allowable head. Read the proper value for Q/P that lines up verti- cally with the intersection point on the Q/P curve. 3. Multiply the value for Q/P by the perimeter calculated in Step 1. The result is the maximum rate of flow accepted by the grate. For Heads Greater than 1.4' : 1 . Calculate the area of the openings in the grate. 2. Find the intersection point of the Q/A curve and the horizontal line cor- responding to the maximum allowable head. Read the proper value for Q/A that lines up vertically with the intersection point on the Q/A curve. 3. Multiply the value for Q/A by the area of the openings calculated in Step 1 . The result is the maximum rate of flow accepted by the grate. NOTE: The operation of the grate between heads of 0.4' and 1.4' is indefinite due to vortices and other disturbances. Capacity will be somewhere between the two methods shown above. (� • { 6-35 P = 2(o ' b) 1073.02 A : 6ow 10 f 6 I J b - . w I I r - 1 11 I I. a HEADS UP TO 0.4: CURVE (a) APPLIES. 2 b HEADS ABOVE 1.4 : CURVE (b) APPLIES. HEADS BETWEEN 0.4 AND 1.4 : TRANSITION SECTOR AND OPERATION IS INDEFINITE. - 1.0--I . r7 -,-.TT- -n.j-Jill n ,rr,rfl ,,,-„ ,,,,,t I - F. A Ad ii — 0 0/A '5.37 H1/2 sr t 14.- ..f. • 4,, , I J _ n F ' Ik D/P= 3.OH3itj ' Ia. — . X ”— o.1 . 0 W 4 � - - r i E. F • I. w - s - u ,� c = I J 11 1 1 1 1 11 II L 01 . 1 1 1_ — 1 1 l l W 1 1 1 1 1 1 1 VIII I I I`t111 114 l I I i 0.1 2 .3 .• .5 ./ I .1 .9 LO 2 3 • 5 B 7 0 9 10 20 DISCHARGE PER FOOT OF PERIMETER (0/P) DISCHARGE PER FOOT OF AREA (0/A) CAPACITY OF GRATE INLET IN SUMP BUREAU OF PUBLIC ROADS WATER PONDED ON GRATE DIVISION TWO WASH., D.C. 6—36 FIGURE 14 ( GRATING IN PLANE OF PAVEMENT) WATER SURFACE d ATING L�Wg � I W.. WIDTH OF FLOW 0 10 20 30 40 50 60 70 80 90 100 100' - r Wg ;AV o % WIDTH OF FLOW 90, . 80. 704 — - 60 NOTE: The curve Is based on pavement with ° 50 uniform role of rise from curb to crown. 40• AI I • 30• 20 A 10. • 0- EXAMPLE: Given: Q= 10 cfs d = 0.5 5x = 5% W = 0.5' • 0.05 = 10 With Wg - W = = 20%, Grating 2' wide takes 44.5 % 0= 4.45cfs And Grating 4' wide takes 75 % 0= 7.50 cfs GRATE ON A CONTINUOUS GRADE FIGURE 15 6-37 INSTRUCTIONS FOR USE OF FIGURE 16 (a) and (b) "CAPACITY OF CURB OPENING INLETS ON CONTINUOUS GRADE" Figure 16 applies only to curb or side opening inlets on continuous grades. The capacity of the inlet depends upon the length of opening and the depth of flow at the opening. This depth in turn depends upon the amount of depression of the flow line at the inlet and the cross slope, longitudinal slope, and the roughness of the gutter. To use the figure, the following information must be known. 1. Length (L) and height of inlet. 2. Depth (a) of.flow line depression, if any, at the inlet. 3. Design discharge (Qa) in the gutter or information ,as to drainage area rainfal intensity, and runoff coefficients from which a design dis- charge can be estimated. Any carryover from a previous inlet must be included. 4. Depth of flow in normal gutter for the particular longitudinal and 'cross slopes at the inlet ih question. This may be determined from Figure 18. • Procedure: • 1: Enter Figure 16 (a) with depth of flow, y, and gutter depression at the inlet, a, and determine Qa/L,, the interception per foot of inlet opening if the inlet were intercepting 100% of-the gutter flow. 2. Determine length of inlet L.1 required to intercept 100% of the gutter flow. La = total gutter flow Qa divided by the factor ga/La 3. Compute ratio L/LL where L E actual length of inlet in question: .4. Enter Figure 16 (b) with L/L and a/y and determine ratio Wok, the pro- - portion of the total gutter flow intercepted by the inlet in question. 5. Flow intercepted, Q, is this ratio Q/Qa times the total gutter flow Qa. 6. Flow carried over, to next inlet is Qa - Q 6-38 DEPTH OF FLOW - y- FEET .01 .02 .03 .04 .05 .06 .oe .10 .2 .3 .4 .5 .6 .t .e .9 1.0 I I I l ( ( I I I I �.o i 1 1 1 I I !/. 1 i t I i I I I I i I I i I I I V e -- I I I !�I i11i 1 I I I _ 1 1 . ( 1 I I1:// 6 i �- T 1 1 11-r-r-I-I.t± -I-T -4-T�-T 1 1 .5 --r I I 1 1 1 I l I I 4T;" -I I I t 1 1 ' .3 -...� I _i. i I ' III 1 4_I I / ;' 1I L � 1 1 -r-1�-i--r i I I I I j- I I j 1 ..: I � I l I � III I I jI j I III 1 1 Qa - I 1 -17-1-1-1- 11... L._��,� 1 I ' 11 I I I La . 1 I 1 1 1 1 1 1 1 1 1 1 1 1 ° I I. I I I j 1 I I I .10 o i5 !V/ 0. ,>� 1 I I 11 1 1 1 i 1`� ,� V/ 1 o I I i I I 1 i i 1 1 oe - -1-.f.J_ 1.l- I 'ti� ,1 1 � 1 I 114-1-J---4.06 I I I 1 1 1 /fir l II 1 � II I ' II .o. .- - ---r I I I 1 1 1 j 1 1 1 I I .03 - I I ) t om/�I 1 t l I I I 1 1, ,I 1 I IIlIt I I I . I. 1111 III 02 (, . I 1 1 .111 ..1 I ' I I I I . I 1 1 .1. 111 I II - ---+- ---�-�-1-}--T�-1-t-rt- I II± III I I L . I I I I I 11 I I I I 1 1 1 I. I I I ., : I I I. I -1 ..I I I I I .1 // / l I I I I I I i , I I I I' I ' 1 I I I I I I ! 't ! 01 - - - I I I 1 I / l.0 I 1 I I - 1 . f I I e (a) DISCHARGE PER FOOT OF i O/y 4 1 - `+' 1 I ..6•LENGTH OF CURB OPENING _ --- INLETS WHEN INTERCEPTING -1 _�- �� 9. I I I .5 100% OF GUTTER FLOW ._r'- ��--2-- % _, ♦-1 --1-* 1 S i 1 1 ..4 1-4 I I I I I (b) PARTIAL INTERCEPTION ��_ T� _ I obi ' , I -4.-r I I 1 ' 00 RATIO FOR INLETS OF I Jr 1 -4.-1-I LENGTH LESS THAN La I /,°/ I 1 1 I I : . I I ✓ I I 1 I 1 1 / o I I I I I I I ✓;/yi i- - I I i I I _ 1 _ i . i . 1 _ 1 . I -.Io 05 .06 .0S .10 .2 a .4 .5 .6 .e 1.0 L/La I CAPACITY OF CURB OPENING INLETS ON CONTINUOUS GRADE 6-39 FIGURE 16 INSTRUCTIONS FOR USE OF FIGURE 17 CAPACITY OF CURB OPENING INLETS IN A LOW POINT OR SUMP This nomograph is based on the following conditions: 1. The curb opening inlet (no grate) is located at a low point in the grade. 2. All flow coming to the inlet must eventually enter the inlet and will pond until sufficient head is built up so the outflow through the in- let will equal the peak inflow from the gutters. Enter the nomograph with any two of the three values h, Q/L, H/h, and read the third. Where h = Total height of opening in feet. L = Total length of opening in feet. H = Depth of water at the entrance in feet. Q = Total peak rate of flow to the inlet in cfs. Normally, Q, L, and h will be know, and the nomograph can be used to determine the depth of water H at the inlet. The spread of the water on the street will depend upon the cross slope of the pavement. The hydraulic basis of the nomograph is as follows: 1 1. For heads (depths of water) up to the height of the opening. (H 1) , the inlet is assumed to act as a weir with the flow passing h through critical depth at the entrance and following the formula: Q = 3.087 LH3/2 • 2. For heads equal to or greater than twice the height of opening (Fi >, 2) , h the inlet is assumed to act as an orifice following the formula: 4 = 5.62 h3/2 H' 1/2 L h This is a rearrangement of the standard orifice formula Q = CA 4-61F with C = 0.7 and H' equal to the head on the middle of the inlet opening (H' = H - h). 3. For heads with H/h between 1 and 2, a transition was used as the oper- ation of the inlet is indefinite. 6-40 1.0 12 , r S . . 10- 9 6 L. 10 6_. .6-` . 2 9 4-. r.7-...T W N - W --7.S - i- p�� Z b1 O IZ I '-L6.5 W i�� 1.0 0. G L .5 6 H 1.O- O-.st Z .6• 1L _ �,�•y .6. p1i ,0 6 �� Z a. .7 1.3 J\ i O• 4-L. ,•• '4- Li. W -49 • 0 .6 W ,/--4.5 i W --i O Si"- Z - .e Z t7 1 (f, 1� Z W .S c �_4 l�Qi i. d 2- Z y 'FPi�s 0 0 o z •3. O . Z r3.3 -ice Z • • W = 4 O I-'' ~ 1 W O ., ' ',i Z 06 - O V. .23' i .3 • J O - I- * 44. .06 - 4 .S •• p' • - • Z 1 Cr ty •- _ W _ O .04 - V. .25 ''s--2.3 Ls. - e. .2-+ W . 0 u. - d _ . 3- .02 a. .2 4- W C.) O 'L.-S d a. .1 Q 0 V O .I S■I .01 .15 - Q 0: L of . ,.. ... CURB -1-S w 0.1 a . z -I - 1.2 NOMOGRAPH FOR CAPACITY OF CURB OPENING INLETS AT LOW POINTS I ' sulle•u 07 PUBLIC 60603 ff\ .DIVISION TWO, r•SMINGTON, D.C. 1 FIGURE 17 6-41 �. ,, -2.0 T- - • . •• •.o.t•(4)." •y -10000 A .• 1M•.••77l got r' an 10 •r••.•• -JO -9000 .+•oa►•ar•M•.•T( 1•e•/ta• - - -6000 •r w••t\ -7000 t Al•tt....i .t••r•tart -.O3• - 1.0 --6000 ..••••••.•0.•••laI••••1040, -.07 - 3000 Aye.••,t•r0,».poi -.10 -.06 -4000 -.70 • Lia1.nLL all b•4•►rtll -.03 • 100 -.60 -3000 ••••. •• u, 1p . L. t/n••' •' N a0 -.04 -.30 .no 2000 •• cat 0 to ■ •••. •• •.•arI • _---r.03 -,10 .. ... _ ---'s= Z •s Z . --�- - Z -.30 -1000 _ a 900 a� , .02 • x600 z 1--......� _ riiN -600 IT 2 .6 -.20 -500 = • a ■ •• • ■ 0 .•400. - W .. Z • u.$T11YCTTOMf (7 .� J .01 Q -300 Q .07 W • 10••0tT •/n••l10•.T•t.ml Iau Q AS Z a .••1111•61 CT•a•rwl u.wT• = AS Z -.008 200 n.,.ul •MW TIM\.N•noel �(/�� .as Q -.007 ~/) � - l0• .Tt 1141u1111•11 C .01 V .006 W w - I M.•r.... •--.. -. .. -, 7 .-.005 W -•06 • -MOO •••.•n• t••••a\ 0 Q -• .07 -90 n•••••.•• •ma•t•..r. 60 -.004 -.06 -70 w•• •• W . or • -60 Q. 0 ...os -50 , r••t.trt , 1 • `•Th I"'' ,, -•003 ap -40 •ut••wl O. .11 • /' ( CO Cr _.01 ••••.••• o..�\ j Il) •.•r• •101• 1: $ f 1 ; 730 of Tea rs a••• • •M .n.. •.w•••a r -.002 0 1a71 'W •tI • T•0.Oil • r••■•• TO i••• -•O3 20 0. •• soma. • ••• ••••• Q •••(t) - � ; r•tal.pet SWO... . •• a • • POMP.w•1.M1.M 1 '- •• W -10 ..401.010 MN..N1 r 1.4. -.001 0 - swam• •1 8411=18411=11111 •I.W.II Nn.•. new T.•a , mama•atr •• •w•lH.0 .r• a,•••••• , -.01 . NOMOGRAPH FOR FLOW IN TRIANGULAR CHANNELS i 6-42 FIGURE 18 Instructions for Use of Figure 19 1 . Select the figure for the size of culvert under consideration. 2. Locate the intersection of a vertical Tine through the discharge (on the ap- propriate "n" scale) and the appropriate slope line. 3. At this intersection, the depth of flow is read or interpolated from the depth line, and the mean velocity is read opposite the intersection on the velocity scale for the "n" value of the pipe. 4. If the discharge line passes to the right of the appropriate slope line, the pipe will flow full , therefore, the design must be reassessed. 5. Critical depth and critical velocity are independent of the value of n. They are read at the point where a vertical line through Q, on the scale n = 0.015, intersects the critical curve. Critical slope for n = 0.015 is also read or interpolated from the slope line at the same intersection. For n values of 0.012 and 0.024, critical slope is determined by first finding critical depth, using Q on the scale n = 0.015. Critical slope is then read or interpolated from the slope lines at the intersection of critical depth and the vertical line through Q on the appropriate n scale (see example 11 ). Critical depths falling between the last two normal depth lines have little significance, since wave action may intermittently fill the pipe. • • • 6-43 ti.__,'" I 1 I III i ` I CHART 35 ° 11111111 U �o l0 I �,i` 1 Vb1_111111 at. o. ■tea. I fir,■ti.��e g im.1 i, 9. ► i,,, ■.. , .I '.tom.,, _A.W l I o� . . II JIM■ W •4, lk _�_ 'i 4.0‘1 •\ --°'-'vIP IflN�� • .4 x.! e, a- ti --„,... k 1 : o ItV1 ,1 - c t k liVNi i % t $ .. NINE u6 I %kik kCRV P % I- I Ili it t4 '. W b 11�1"1lliil ;►i17 x, -. -t--,06 m—0 e• a IVII‘11 k alliAl-k. oOtt II, b c• 131,1 \ , .s � v o i , ' As`.. 1► 1►. kl i a ,C t . . • . .. 11 X11► , ��1Ila��l . . . �...■�■Q--■ .. : i►.l.' , , - o E. ■QME��M •- ems% nimill ans ■IUU�I■R■ % , _$ . .wa a • � sr o • oon V ° �► M r °I.% V h . w Y ye;It w .V n - t/O' • (/ SI!-A -4J10073A to -°+ ti o e io w w y J!O'•U o e w . 1 • i I • t l 1 1 - 1 • L , Z I 1 O O 44 4 :+ : ti r O 4 r. 4 4 w .ao'•u •••:' • . . , . P/PE FLOW CHART' . l2-INCH DIAMETER 6-44 48 • FIGURE 19 SHEET I OF 6 =' • - - i � I 1 CHART 36 ° 0 (�\•O O , l J D H Ii . : ' o ;� -, In , tc e 4 ° I �u a o •o o 1 ■�•1111■\1111■!11111 i ° ..) =a . - • �11VAII \�1 IBir ■■ It aaii r►`tli►om sir.. ° to s . ;3.. ft- ■■ 4 �1i\ 1r111!rCl1� CW ti . — ad 1111111 Z 1r`\ 1 1\1 � ► z.m. � st C - III MERAtail6AEn. . o f . U -o � 1111 •1111■11111 1RIIfIIMAILISWII II;VI�MILIEWIli1 i= _ 11E1E111 cc. � Y(■SRE 11111_ •iI =z- 11h1► , CC!►1l o ti. ..! IE..= ligiaNummui ,,■1. . mA. :4:-. ,- z Rim . IlliSIVNak :'1M.MOM 111i `�Ni a il, '''! '. 1 :- z; 11111ii 11111 NI' W, ri. . k - cf INO1t =E • UU•1111•1 •M O. 1@R 1, ,o ° o loomto'■ •••mM•ss 4 ' 4o .. . -PM 0∎ . 1 1 Z .47 : 4104 o- 0 .°1 11. 0 0 0 . v o ' . w 74,►, Q w, v 11 gib.' • u Said -A - 4110073A 0 0 0 d/0'•(J o e Q e w •% ■ w % I 1 ~ I 1 '-1 l •1 1 l 1 J • 1 1 I. 0 o ., e h .': 4 rt0' U c e .. n :► : P/PE FLOW CHART /5-INCH DIAMETER . FIGURE 19 f ' 6-45 SHEET 2 OF 6 19 --,, I �_/ s° 1'11111111 Q MIMES CHART 3 7 °m_ a ° ��ME ct.z __11 MINI ILI$k , ■III ■�111nut a MC. 111111i1Mik. °ohiii•• I M<M�'�11uIi o- 1►�1►11i _ ° o�.e o� ■�� 11111. II o Mailir“.• I d.� 11EL .J1111 a_ 0 n lai '.. IINIIIII. - I, .... .. ... imssmatumma ME t m■ u- �1�11111■11111� ep o M mui mu Bunn �1[ II 0111131 t111 cll. : o, % 4 r!�. ,P �111111111 • III z \111il11�:li'�:\��t lit ` o°` ,ti � ■■ Slays ii1�%'\lrn i, :1�'n►. _ °° )♦...1 ft- Nu it 1�1t ��►�►!'\'�1!t�\1,151I \. o°` ot. MI MI •- Itt o ..b 'tt '1111�`�t►C!l1±111► .►\► . ? III MIMI 1 ►\\l►1a111i�11��;:\�1®i'�1iii.P..'/ , I " 1111 ; , IVIVE5igi` NINIVa , *4 ..: , liii i o r Iiii ili it iNi�w tiii 0 !.: e •tlRMl t1i►llIi\1A\ik\l\ AVISISlV1►t ' 4 :- 111111 r,P1,.,►„�ISV C, ��R �'N ■ii1•� II a 1�� o i k % z- ... soommisi IN MUM. III r 1 �, . . • o ..„ • l 10Ow Y~ 2.ma. o..4. 4 O 0 w - O1. e A V h i1 Y Z �" ' Y a PO'•v SdJ-Av4.11J073A 0 0 0 0 a/O'�L/ 0 e ■ I+ ti I e w o. :t A •e w I . 1 I . I 1 1 I • . I 1 1 1 l I I I I I a I even :, : ' A ' o ' e , 4,A ;�ao PIPE FLOW CHART /8-1NCH DIAMETER so 6-46 FIGURE 19 SHEET 3 OF 6 .� O �\ 10 I cHnaT 39 . 'IC . 11111•■=1111111•11MI 11 lo M!:, )y • ■■■•us V iu s ■■ us_ o, o MOIOEN. EIMIIIIIII Iz:It MI= 111•111111-- -. w% 112tag W` ■ . = k Z .i1 MIME- g ∎�i41► r pi;, iu ■•i'111i•; -AMAIN. °` 11111 It 11lli MONIIZ1MIIIMIXA °t 'e Mak iii - .2 NM,Pz ►►V �ay• t> iia•111millIuiui ■umma1tZi► ■E 11i■.o e„s..... . .insitemavitoi��i12mi- t.' I .,. , �l� z , ■■s �, . ow awasuniar��s•�' .:uI'a •� ...a>• ID • N■ - �11M Mk1111111OR WOMEN. ,D% O1�� . ME■ X11 �IVIEWIWILIC∎ % :\'aMIZ' • d? U1UR h ...7 ■ Eli z BiClu1 `1a1;.e1ait , II , b" 1 ®o°e. , - wilINIZIdL Illel nisi .- •iin 1'1110101�1�I\:%oll�sll\,l�1a3. - MIII- . C101Vsis.�IMIL ;1111\�RIalka1�` y ,, o II. : . ° ikiniehAggigil 1 , s■sss 1a,a1#�1I:\U7alalid •�•\\�a!<1C1\as\�+alamim '; IS■®ss1♦)�1111t►•f'\111\1�\111MIA 1•d1 a'atmIgt�i . �II®NIIM� i U\K\1I��UAILIII Zi 111iNIMVEN c 11111111111111111111__ 1�sn�1e��'��Ek ' . �∎ 1 • C,. MWSk1.I. \�11M Ki�; 1 • ._ -IMMI-1-, .1.1. 411` ILVIL11, MIIIIR1�11,w O « ■11��' • MI ` 1 1 ' ` o . . _ �� +,o.r'r w O q 000 t+o w ..'- -op tt t 0 wait*. �O OO OOO�O �• O • 4 it t `O..• 1• v Vi It w v 2et alt w, V CIO- a 4/ Sell -A- 4.S13073A s/O-t u O • O O b. ♦ 0 O A b ti „ *20'pi,/ - ' PIPE FLOW CHART • 24-INCH DIAMETER • 6-47 FIGURE 19 (` u SHEET 4 OF 6 =. t�� -'II..■MI I I CHART 4 1 '� ► . h -1�" Vim 1 I I 0 o #:�� N:°°' 4. 1111 e .>t,Ilr�. oe MEM ; NV s SINE. e 1x11•. wax:. p► 0 maw 1 •un O viii.. °o 0 1∎111P1i%∎ 1�"., • •' d. 1• ' NMI K) VIII' •111011l'3ZZ. • 4_.0 I EMS. A NNE; e • a�etwiscl►m..% e_� 1�►11111►lAr�i��Li . apse ! a 0 l��s.ol11��\\� airg. .%i. 00 1 ° Mil r �i\�l�>,.�1��1E11 ��a,�_ VIII.. 1111 lifkiltni■ g1, ikif X11 h O I- 16: 1,.. \\1"Il��,��,�1. . , 1 to y .. o NRi\tr141101•..IIIIM t\ IIIIIM\. • h ■■ -p 10 04 ON ° 1%11111 llial11Z I \1KNIZ16�U! • � 1.4 1BLIKI �D\l�Sl►��11►N;�1�\�111ZIWZ•°� _ •- c CC 1 .. kl\ . 1 • ti 1• ! 0 1 �1 A1.� ` ',I 1 ' w e 1 ,t ` ,�4\1 A l 1 iv• � 1L\1 , 1 ��1► r ►., o Invite. ;Nalawkultilk;ir 4.4. .- . . . -. VMNda ;M111‘..Vel .• • 1.t•illa\ '\ik•\tit■tla o NEM 'kM11\ 1r11M110 a • o IN 0 ■ w �O w O I O Y~ 0000. 0O 00 Oooe�1 • Igip 04�ooO• OO oo.oe� C• • gig' •u Sold -A - 4112073A O73A c o 0 0 0 .. 0 VC-•u o ♦ 10 w • b ti • 6. • w • w ti i 1 A l . I . .1_ 1 1 i J L I • A . ._ J i 6 O 4 .. 4 w 4 . A �. O ' 4 w 4 w ►dO'•u • PIPE FLOW CHART 30-INCH DIAMETER FIGURE 19 54 6-48 SHEET 5 OF 6 • e w I cs•RT 4 3 _ i° - o 0 Eil ., \ $° ' ' A ;_,.- 4 ■• Op -----ri .�� ■l: 001 .,°,' 8 ib 0 ect, • . . b h1�\1C\ \\ 70 . •t To. • • MI IOW IkZ1 i'AZ O d O O �►70IKII:MCQ o .,�J • • . ' ui TIVOIAN1W"--'‘7'1 .1;" t.- Vitha.karolt� ' ' ,. 9 0 0- O 4 1111,10:ilt\WOMri t o f o AI ci ° Ilart11a�ais�►Ac�a�:; ��aa��z��:ar;wz y • a • o \V►viZ\num®ZS t iia:unin\itz• NI assil lIMII.an L%stlimi sat. ■ . ` emxawamatto►dl`nt►tx I. • _.s \01\MOM&%ViSifi° „.- I • z a'I\S11� ' ' ,.• � SiCr . 0 SdI-A - rJJ 073A 0 ° o ° ° o tl ••(l b �. 1k w ♦ ti ° • A b w ♦ M ti• �i ti w o' Z 4 w i w 4 rt0. c' e :. r• ti PIPE FLOW CHART . 36-INCH DIAMETER 6-49 t` ss FIGURE 19 SHEET 6 OF 6 2000 —_ 7 _ -- `' t• M • Kr I r �� O t _ ' Save 5/.. 1000 i SUl*LIG[D OUTLET WlV[11T i{D111ING iVll /J NI/.M.M—lS. 800 -120 i/, w+4r uww sal wrnecgc4.cMl/Ms My b .6 4H/ SI I C*W$ r NV Nan", /►K//M/ 600 -108 _8 S 00 -96 �" M,o� 1,0 400 —84 / 300 L- T2 / 6 6 . 1/4 C, u~1 2 N 200 60 E ♦00 ♦Sly U l.Iro 48°'�e.� ..D.5 00 9' �� 2 3 ' / fie'' a 42 ap0 = 4 36 .500 F 2 SO t-40 a • 0. 8 I. O 27 •. O O 'e3 10 30 24 'O 20 21 16 20 10 15 • 8 6 12 5 4 HEAD FOR CONCRETE PIPE CULVERTS ' FLOWING FULL .U111..N Or .us.r Ia.DS MIA IOU n = 0.012 Figure 20 6-50 Sheet 1 of 2 r N 2000 ---e' I .----7._ — \--rm -- .4 1 'W- 1000 i "` "' 1•• .5 eoo - st... s0� .6 sauce= °YTLCT cAi.vcirr rL 1MC rUU. • 600 120 sow.IMO ta,-1.s. 500 toe r.' wtwe crown ..1 w.ao..p.,a..'.t. "IN .r .e 400 96 to 300 84 4 i ?f b O 200 72 '0 c' 66 '0 a yCA W 2 60 + W co O ?j c 54 o S. z 100 W 0 2 3 = •6 %. / �, -- O e0 ca 0,0 i A c • .. z `%o` °0 a W •42 �• W 4 v 60 ? 2 ' Q 50 7 36 �/ 03 5 u cc / 300 ( V1 40 0.» W 33 30 6 C t- -- 7re..--- L9•WlL W 30 "•7.5 3 0 i i 1T soo e � c 7 20 10 24 400 2 y00 O0° 10 le [-•e 20' 6 I5 5 2 . HEAD FOR STANDARD C. M. PIPE CULVERTS FLOWING FULL 0 LI0LJ0 Or PAL IC IMAM .1611 111413 n = 0.024 Figure 20 6-51 Sheet 2 of 2 Table 21 - Entrance Loss Coei'ficients Coefficient ke to apply to velocity head 2g for determination of head loss at entrance to a structure, such as a culvert or conduit, operat- ing full or partly full with control at the outlet. Entrance head loss He = ke 2g Type of Structure and Design of-Entrance Coefficient ke • Pipe, Concrete.. Projecting from fill, socket end (groove-end) 0.2 Projecting from fill, sq. cut end C.5 Headwall or headwall and wingwalls Socket end of pipe (groove-end) 0.2 Square-edge 0.5 Rounded (radius 1/12D) 0.2 Mitered to conform to• fill slope 0.7 • *End-Section conforming to fill slope 0.5 Pipe, or Pipe-Arch, Corrugated Metal Projecting from fill (no headwall) 0.9 • Headwall or headwall and vingwall& Square-edge 0.5 (I Mitered to conform to till slope 0.7 *End-Section conforming to fill slope • 0.5 Box, Reinforced Concrete Headwall parallel to embankment (no wingvalls) Square-edged on 3 edges 0.5 Rounded on 3 edges to radius of 1/12 barrel dimension 0.2 Wingwalls at 30° to 75° to barrel Square-edged at crown 0.4 Croon edge rounded to radius of 1/12 barrel dimension 0.2 Wingwalls at 10° to 25° to barrel • Square-edged at crown 0.5 Wingwalls parallel (extension of sides) Square-edged at crown 0.7 *Note: "End Section conforming to fill slope", made of either metal or concrete, are the sections commonly available from manufacturers. From limited hydraulic tests they are equivalent in operation to a headwall in both inlet and outlet control. s - 6-52 TABLE 21 CO Z vu v W 0 X • r 3 ; 7 v oo . e C p o U 3 L1ao{.� U 0 -I0` 1•1M _ c. 0 r---.7. at ., = u r r r W- so co J e , e u 1.. o v v a a f k Jc• O O J v a W o 2 c U J I- J #W K p o: O c° 0_ Q v S ir. e Cr I. r • Z o = W o Cr) v _ �; • W N 0 CC la H N LO ilIt u J S p W = "` W < W G� • Y = 3 �3 O .3 - J i Z N>Ia -W . • 0. •• • O . v e r . v• 2 3 O = Q O �u N . Q 0 O Q a U. O Z - - - 0 W VI o N Z W H 117) O Z 2 Z of e Q a o 0 et_ 0 Z VIA 0 U ` W W O O Z u z S o: o= Q . N 0 — 0 W CI. UJ CD Of 1171 E3- z Q -Q Q H M 0 - 0 J J J - H W W W J D: o: V 2 0 O Z } 4 0 O Q'�-. W p F• Q r r 0 0 OO W • N el Cr = > Z j a 0 u - VJ . 6-E3 FIGURE 22 STAGE-DISCHARGE RELATIONSHIPS Orifice Sources for information regarding stage- �. discharge relationships are: General formula is Q = CdA NrTig 1. Streeter, Victor L. , "Fluid Mechan- ics," Fifth Edition, 1971. where 2. Chow, Ven Te, Editor, "Handbook of Q - flow, cfs Applied Hydrology," 1964. Cd ■ discharge coefficient, usually 0.61-0.65 for circular orifice 3. Merritt, Frederick S. , Editor, A - orifice cross-sectional area, "Standard Handbook for Civil Engin- ft2 eer," 1968. g ■ gravitational acceleration, 32.2 ft./sec. H - liquid head (or stage) above * * * center of orifice, feet Or i f ice Stage above Orifice, feet Diameter, In.‘ i .. . . . 2 3. .4 5 6 7 8 9 10 I I 12 4 0.44 0.62 0.76 0.88 0.99 1.08 1.17 1.25 1.32 1.40 1.47 1.53 6 0.99 1.40 .,1.72 1.99. 2.22 .2.43 2.63 2.81 2.98 3.14 3.29 3.44 8 1.76 2.49 3.05 3.52 3.94 4.31 4.66 4.98 5.28 5.57 5.84 6.10 10 2.76 3.90 4.78 ._ 5.51 6.17 6.75 7.30 7.80 8.27 8.72 9.15 9.551;, - 12 3.97 . 5.62 6.88 7.94 8.88 9.73 10.51 11.23 11.91 12.56 13. 17 76k. • 14 5.40 7.64 9.36 10.81 12.09 13.24 14.30 15.29 16.21 17.09 17.93 18.72 16 7.06 9.98 12.23 14.12 15.79 17.29 . 18.68 19.97 21.18 22.33 23.41 24.46 18 8.93 12.63 15.47 17.87 19.98 21.88 23.64 25.27 26.80 28.25 29.63 30.95 20 11.03 15.60 19.10 22.06 24.66 27.02 29.18 31.20 33.09 34.88 36.58 38.21 22 13.35 18.87 23.12 26.69 29.84 32.69 35.31 37.75 40.04 42.20 44.26 46.23 24 15.88, 22.46_ 27.51 31.77 35.52 38.91 • 42.02 44.92 47.65 50.23 52.68 55.02 • • Variation for Cd • 0.61 or 0.65 Is only 3%. • Date: 4/4/84 (, 6-54 • TABLE 24-I -- Permissible Velocities for Channels with Erodible Linings, Based On Uniform Flow in Continuously Wet, Aged Channels1 Maximum permissible velocities for Soil type of lining (earth; no vegetation) Water Water Clear . Carrying Carrying Water Fine Silts SanddGravel F.p.s. F.p.s. F.p.s. Fine send (noncolloldel ) 1.5 2.5 1 .5 Sandy loam (noncolloldel ) 1.7 2. 5 2.0 Slit loam (noncolloldel) 2.0 3.0 2.0 Ordinary firm loam 2.5 3.5 2.2 Volcanic ash 2.5 3.5 2.0 Fine gravel 2.5 5.0 3.7 Stiff clay (very colloidal ) 3.7 5.0 3.0 Graded, loam to cobbles (noncolloldel ) . . . 3. 7 5.0 5. 0 Graded, slit to cobbles (colloidal ) 4.0 5. 5 5.0 Alluvial silts (noncolloldel) 2.0 3. 5 2.0 Alluvial slits (colloidal ) 3:7 5. 0 3.0 Coarse gravel (noncolloldel) 4.0 6.0 6. 5 • Cobbles and shingles 5.0 5.5 6.5 Shales and hard pans 6.0 6.0 5.0 1 As recommended by Special Committee on Irrigation Research, American- Society of Civil Engineers, 1926. • • Table 24 Sheet I of 2 6-55 TABLE 24-2 -- Permissible Velocities for Channels Lines with Uniform 1 2 Stands of Various Grass Covers, Well Maintained { _ Permissible Slope velocities on Cover Range Erosion Easily Resistant Eroded Soils Soils Percent F.p.s. F.p.s. 0-5 8 6 Bermudagrass 5-10 7 5 Over 10 6 4 Buffalograss Kentucky bluegrass 0-5 7 5 Smooth brome 5-10 • 6 • 4 Blue grams Over 10 5 3 Grass mixture 0-5 5 4 5-10 4 3 Lespedeza sericea Weeping lovegress Yellow bluestem Kudzu 0-5 3.5 2. 5 Alfalfa Crabgrass Common lespedeze3 Sudangrass3 4 0-5 3. 5 2.5 • 1 From Handbook of Channel Design for Soli and Water Conservation 2 Use velocities over 5 f.p.s. only where good covers and proper maintenance can be obtained. 3 Annuals, used on •lid slopes or as temporary protection until permanent covers are established. 4 Use on slopes steeper than 5 per cent Is not recommended. Table 24 Sheet 2 of 2 6-56 3'max Road or Maint.Access Drive drywall edge of driveable surface 8'max O x O drywall Maintenance Access To Drywells Maint.Drive t Drainage Ditch Drainage Ditch 12'min. Freeboard / 4 High-Flow driveable surface r �4 Channel for maint.vehicle 1•Max-law Row Channel -\ >j /I ,E____5*Max • Maintenance Access To Drainage Ditch 1 • Row-Control Manhole I.' _o;.:�.a outfall 1" Detention i si Pond �° 12'Maim.Acees drive o an 14'berm • 0 tee Maintenance Access To Row Control Manhole Maintenance Access Requirements Guidelines for Stormwater Management Addendum, February 1998 A Figure Pg. 6-57 CACII�(IY V12 He w S 3—29 �t - �. _ ENERGY LINL_ -- Nf H fi \ _ aNYOROULf�GRqpF LINE _ -� • ILW HWO.di _ N+� S. '� 1 }Z DATUM 4 1 _ 4 • MWo ---...�s- T L- _......l - -..4. T W = ho LS L ~ 0 p EQUIVALENT } HG LINE H HWo _ __ -t:.- ---.L.........i . s'''''�TW 1 r L —'f LS0 d. +D or TW•ho 2 Hydraulic Elements of Culvert Design Guidelines for Stormwater Management - Addendum, February 1998 MI Figure 26 Pg. 6-58 SP RECCMY The Soil Conservation Service (SCS), now named the Natural Resources Conservation Services (NRCS), developed a soil classification system that consisted of four hydrologic soil groups. The soil characteristics associated with each group are: Group A: deep sand, deep loess, aggregated silts Group B: shallow loess, sandy loam Group C: day loams, shallow sandy loam, soils low in organic content, and soils usually high in clay Group D: soils that swell significantly when wet, heavy plastic clays and certain saline soils ! The range of infiltration rates for each hydrologic soil group is listed below. S • Hydrologic Soil Minimum Infiltration Group Rates (in/hr) A 0.30 - 0.45 B 0.15 - 0:30 C 0.05 - 0.15 • D 0 - 0.05 Description of SCS Hydrologic Soil Groups Guidelines for Stormwater Management Addendum, February 1998 O�G� Figure 27 SPC Pg. fr59 W. X1KIY The moisture condition in a soil at the onset of a storm event, referred to as the antecedent moisture condition (AMC), has a significant effect on both the volume and rate of runoff. Recognizing that fact, the SCS developed three antecedent soil moisture conditions, labeled condition I, LI and III. The description of each condition is: ( AMC I: soils are dry but not to wilting point AMC II: average conditions AMC III: heavy rainfall, or light rainfall and low temperatures have occurred within the last 5 days; near saturated or saturated soil The table shown below gives seasonal rainfall limits for the three antecedent soil moisture conditions: Total 5-day Antecedent Rainfall (inches) AMC Dori ant nn rowuut Season 1 Less than 0.5 Less than 1.4 II 0.5 w 1.1 1.4 to 2.1 III over 1.1 over 2.1 CN CN CN CN CN CN for AMC II for AMC I for AMC III for AMC II for AMC 1 for AMC III 100 100 100 76 58 89 99 97 100 75 57 88 • 98 94 99 74 55 88 97 91 99 73 54 87 96 89 99 72 53 86 95 87 98 . 71 52. • 86 1 94 85 98 70 51 85 93 83 98 69 50 84 , 92 81 97 68 48 84 91 80 97 67 4 • 47 83 90 78 96 66 46 82 89 76 96 65 45 82 88 75 95 64 44 81 87 73 95 63 43 80 . 86 72 94 62 42 79 85 70 94 61 41 78 84 68 93 60 40 78 83 67 93 59 39 78 82 66 92 58 38 76 81 64 92 57 37 75 80 63 91 56 36 75 79 62 91 55 35 74 78 60 90 54 34 73 77 59 89 50 _ 31 70 Curve Number Conversions for different antecedent moisture conditions are for the case of la=0.2S. Source: SCS-NEH4,Table 10.1. . Description of Antecedent Moisture Conditions (AMC) Guidelines for Stormwater Management 1108 Figure 28 Addendum, February 1998 SKEW,CO�> IY Pg. .. , R42E R43E R44E R 4 5 E ir----N'' Spokane County -- -- Mean Annual Precipitation r IIIII aIk L— i-- --. - (inches) - 9 k _ _ .- 2 AT r 9 -• SautUS.Waher Bin= : • (19304 9901 _ T -. V AOMMalii li - Li" T 2 8 1...immi 1(mita_ 28 al %IL I 1111 -,7 ---- icz a • 1111 MS ''11141 IV Mil= T . ---' •' -— — P . CD , vourANNIED OM T 2 •Ni rm.:45_ _ __ 4 , _ -.1111E131111211 ......SA . — _ __ __ WI IliMiller T — - - - • ;7;II VrAtIlimiesallIMILIMpu 25 . •' 11'4222111* 7 7 5 . A.. s .?1, 10• A7 1 .'1 . —- • • • - • • 'c. C) . . . f T — 2 4 - •i 11 _ .._ • __ .-. -- pi .. . _. L\INE. . .:. r _ ..._ . • . a T z_ tam ' - . • T ______. ___._ __... . FE 2:- - _____ 1. T _ 2 I •- ' . .. : 21 A, . ih --.- _ . . . 1 . . . . R 1 OE R 4 I E Ii14:2E R43E R44E R45E ,.-- --,,, Mean Annual Precipitation of Spokane County .__. c Guidelines for Stormwater Management • iifil Figure 29 Addendum, February 1998 SPOKA1faXITY Pg. 6-61 • At, - Pool O `+ FbpN Nomssr Derr inLOntal Al Asymptote Cabral Depm o` " • At—Uniform Flow - at-8ecuwater from Rese oir or Iran Channel of Milder Slope(d>d1): • Mr—Ora i crown.as Iron Cnangee at Cnnriiiel of Mild Slope to Steep Sloae t C. and A 3—low Unoer Gate on Mild Slope.or Upstream Pule Before Myerautrt Jump on Mild Slope Ick dd. • f Natzontal Asymptote • •Sr Caterer Depth • 42""al Depth • • ( • • • • 5,—Uniform Flow • S.--Oownstream Pioti Atter iiyOraukc Jump on Steep Slope(C>ac). Sr—Drewdown,as from Mrto to Steep Slope or Steep Slope to Serape;Scope t cf • d.):and 5r-Row Under Gate on Steep S+ooe.or Crtange from Steep Slope to Less Steep Slope(c1cC4J- • • • • Same 'Design aad Coasutrcoon of Urban Stacmwara_ Systems:by the Ammon So of Civil Engineers(ASCE)and Wimr Environment Fodor tioe(wFF).1992 Reproduced by permission of Pb (ASCE). Flow Regimes of Open-Channel Flow Guidelines for Storrnwater Management Addendum. February 1998 llal Figure 30 Pg. 6-62 SI'(UIECOUKIY Head losses in catch basins and storm manholes can be computed using the following equation: HL =Kc(V2/2g) Where: HL = Head losses at catch basin or storm manhole, ft. Kc = Head loss coefficient, See charts below V2/2g = velocity head, ft. d =pipe diameter, ft. g = acceleration of gravity, constant The charts shown below are applicable to closed conduits flowing with a free-water surface. Square Cucuta, 04, 1 . r- l I l I i Shape 2 Shape 3 I! `. Wfo=2 Wic a 2.25 I jl Square 0.22 016 1 i f ' i li 1 C7 (1' , . ( ) ,, (__ Cucuta: 0.16 0,2 Protue Y I Shape 2 and 3 1 1 y (c) Head Loss 0.2 • _ A . .0 0, I� ,,,, � , 0 2.0 10 .-, Wan Flea(LOSS trrema, Shams la) , 2 3 Section lb) Sow "resign and Coeesaucaon of Urban Smrmwua Management Systems;by the FAu zn cnaaan m(S .o1f 9 2 ERx AbSy CpcEr)t and_stoWo aoP Eboc a ASt C U. Head Losses at Structures I - Guidelines for Stormwater Management Addendum, February 1998 IM Figure 31 Pg. 6-63 � NEY V 1,4 I I I I I — 1.- , I I 1.2 1 � f ' ° : I --– 1111111111 -�4 1 .� I o (a) � r t.0 4 03 .y' 0s,,,, ,— ,� o "'^' 2 2 I „v, a L...... _ I _ (b) 0.8 I Case t -c 4-- Bena at Mannole. I -. �' No StDec&al Shawng - I ' • r — r I _ IA — Deflector I 0 o , I \; Curved I -' NIL •• — . r0 1 . I _ M1111111111 =—I- 7 Sena at Manhok. �. (a) Curved or Detector' -+ 04 . r 0.25 - .. i ■ i S ham. 20 . 2oK • Curved Sewer i/D:2 0,V, � CI,N, L. 1.1 I• 1 0.0 t t )0 20 40 80 90 Defeo=M .7,Decrees • Sou='Detigo attd Cootauation.of Urban Stemma Maned Systems,"by the Ac i . o!Civil Fagiocas(ASCE)and,Warn&Tonmem Fedafoon(WVF).197L Rgir -•by mous=of Pal(ASCU. Head Losses at Structures, Combined Flows • Guidelines for Stormwater Management Fi 32 Addendum, February 1998 SaCOMM Pg. 6-64 • • • F.• t-1 7 Unpufar Jump , • • //rrrror//7//r/r/r// " F,• 1 7-2.5 Weal Jump Ostdiavng Jet ROliet e - + • r /////////////////T F,•2.5-4.5 Oscmat,ng Jump • " //////////////,,//// F,•a 5-9.0 Sceaoy Jump • '////r7//////7/////7 F.›9 0 Strong Jump 7 Idt t ; � 1 6 � �. ' ; i i T I . • . . 1 . 1 i ' - 1 , 4 , ' .. L . 1i ii It ∎—1 I S 1 j • • ' 1 goer - = Yf 1 ' ; i i Y. ,� Yf 1 i 1 L 'T 11 111 l 1 iT 1 - t _ - 1 . aa•vose w•w e.n►.rp..w...p . r Srene Ceres 3111T17iI 1111II1T Il. ntl-IriII71i iIi ,1 0 1 2 3 • 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 F,•VJ. yy, lengths and types of hydraulic jumps in horizontal channels (Bradley and Peterka, 2957; Chow, 1959). Sowsz 'Deign ands C�o�nstrud ian off Urban SSu tmwsuQ Management Systems,"by the Federation(W -). 992. Rqx oumo by Pamiaian of Publisher(ASCE). Types of Hydraulic Jumps i. Guidelines for Stormwater Management Addendum,February 1998 HOB Figure 33 Pg. 6-65 SPPOIME CO(J IY 1. 'am I n11) W16!.* woes • •_i 44 ultnunarimminiranaame.•annassl.nsttiaml.Isis..uumruannn>:aimullrammon>aau.Nll ull111111•.....11.1111.11111111 11111111111 1■11■IOIlllltlnllu11111t111uf11111•11.1111111111x11111111 111WIItl1111....111.11■■tl■/1101111111111 uII1111111M�...111■■■■11111111 iii 1111111l11�111....1fa1111alaullllllll11I1 Crushed Rock 11111111111 .f1...111aa�alt.ta.a, 42 IIY111111•f1>•.�..f.■1■!/Illllltpllll ....mn■�.fliallsow••'-" N 110111llr•al...f11a■aa!SIBIl. • Ho sse1p11111 1:01111111I1uuww.--..s.siaal//11111 a rw0111 RaMa- .'. _ Iltulln,a..•....a,.,,,,,►In►Ia••.....11tllllllul rii) a11nlu ��.alf■ ...aa011111111111111111111111 1 .. ■1/111/IIIlIHl a •"'":..r.f1...••I• ..1 1111liii i■/W1/1111111111uiIlltIIIIIII IIIMIM .■.■1.IY11.1 Q IT 4o micii111IN....1111a.a.•giiilutulllul■10In111111tIIN1lIIl11l111I..../....a•••" 11111611..1111...-..1tallanlllnunuull■11un Ificlimimmmnn.or �...s■.1riil�lll 15 v IM 111111111.1111r...ifaaa■!■111n11ulllun■■111 d n11111uuu "4 ., I ..11MI aH1 11■111111. !.. ... 11.■ ■1IH11I11IIn ! de II"! .iin1iI1:1.....Mnatoo 11 0 m Ilxulu.:/tall....■1■uitu11unutill coon ..suuUlilllllun........,u■ nalo1 G. m 3811�...1a11...ssam1f unni1 velY ../mllilnullltllllll:I1•..■....111■111.1101 o N ..l1IIIDx......f.■a■1111/01HUI .dII010IIIIIIIuillIIIInUUIImo....11_111■/pktm 1 cn 0 $aiim R..1111■1■■1■UIIMII' .s roll■l/11$11111111111111111111II�.....■f IIIIr11I1 co IlalIImso..smana..1111/P•:d1ii11111I■11111 1u11n11tUI 11II,II(IIIr.1......NUI1lWI IWCI111I1tw...11.11■■■1■':dtI0 1111I1I1 ■ tN1111111111111111(1111�......Ha■■11.101 Q 36 1111I11tMIEBAR11.f■1/ AIIIII0IIII1 11111.1/r[o11MIu1nn111u a..1.inassinumsan N p tnlnllmta11111ulio nllnnln omurunumllnuluLnm . .. filnissim m 1111111111. 1..111.11r 1111111111 11111111111111111111l1111111111 uw 11111111111,111111111111111111111111111111111111 1111111=11 Im1111111M...■■a■uL■11111U11111III119■111111111111111111 1111111111M .....f1111■1111�a1 e0 UIIIIIIIIII...Ii11.1■■■■1 1111.1111111 111111 11 1/11 11111uuf1111111 111I1.......flllt■11Y_, N Q .2411u111111 ...r/..■altalx1 111111 111111111111 110111 1111111111au1111u.I1�....O11115I1/L/1.1 lsminll1111./....11■11111a11■1111.Inu1m1I111 0111 1n1nn1a1u11111u111111......■llllfO.IIE! Eii .11IIIIIpL..11.■1■11111111111 11111 111110 t01111I111111111 111111uIIIMME..11111M1■1■I1111 . .11111111.L...11.11 a1gIBln1111111111111 1H1ltntlnnn1111un'nf■.fL..lt.f11■1 M1111111 IllmilIP..1..■■■1/111xxMIIII11111I11101I1I1//111111111111111111111111....1.111111■t./.. N 1 32 rnii'uiii�iiiiiiiiiiiiiiii11111 iiiiiiiiiiiiii•Iu unuuIiIuI1uI Iu•uN•U•u 11s wl i rllllullll ■.....111■11111111■I11lU1I1111A111a 010 1111111uumnunl11�.lsomm111111■1111.11sn .- • 11unu11��.1...111111.I11I111111111111111IuI1W011 11111111111111111 11M...q.u11■I11111t11.B t 111nIIIlI •...111 . 111!/ulluuIull■Ilpllnlulnlltlunul n�....1.f ■■- lillifullIUMIIIIIMEIBM.1111161111111111111tORMIlamisamm11111111111MIENEINIIMIllianiuliammq a .■s.ua. 0.8 1 2 3 4 5 6 8 10 20 30 Mean Stone Size, dam, in. Maximum riprap side slope with respect to riprap size (in. x 25.4 = mm) (Highway Research Board, 1970). • Soacc-Design and Cmsoumon of Urban Stormwater Management Systems."by the Amen=Society of Civil Emmons(ASCE)sad Water Environment Fedaranon(WEF).1992- Kgxoduoed by permission of pubbsho(ASCE). Riprap Placement on Slopes I Guidelines for Stormwater Management Fi 35 Addendum, February 1998 SHIY Pg. 6-67 Characteristic Velocity of Channel 1.60- Trapezoid Ch.nn 1.40- aag— 1..74 - 1%7 I f 120 - s 1.00 • 0.80• I I 1 2 3 4 .5 6 7 - 8 9 10 11 12 15 20 30 38 RAN R = Radius of Channel, ft. W= Water depth, ft Vss= Charact stic Velocity, fps Vevg =Average Channel Velocity, fps • Channel Side Slope Velocity (Vss) for Sizing of Riprap Guidelines for Stormwater Management — {, Addendum, February 1998 ��6f Figure 36 Sheet 1 of 2 WPg 6-58 /f a:MY • I 1 Characteristic Velocity of Channel 1,60 1- . ' ! / Channel Vsrlavg = 1.74 - 0.52L, 9 ) 1 l 1 1 i 1 1 1.43= I -- I i 1 I I I I iI I III I I I a I 1 r I I } 123 or iI 1.OaI � F i T 1 I i I I - — --, , , , 2 3 4 S $ 7 $ 9 10 11 12 15 24 30 40 4$ RAN 1 R = Radius of Channel, ft, W= Water depth, #i Vss= Charactistic Velocity, fps Vevg = Average Channel Veto#ty, fps I I Channel Side Slope Velocity (Vss) �. - • for Sizing of Riprap 'I Guidelines for Stormwater Management Pri Addendum, February 1998 91QQ Figure 36 Sheet 2 of 2 SKW.CCURrY Storm Gutter Flow rc4/ Curb Typical Road Cross-Section Road Classification Non-Flood Zone Width (L), Feet • Local Access 12.0 • Collector Arterial, 2 Lane 16.0 Minor Arterial, 2 Lane 24.0 All Other Roads To be determined by County Engineer • Note: Table lists minimum non-flood zone widths, L. To be analyzed for design storm event Gutter Flow Widths in Roadways Guidelines for Stormwater Management I Addendum, February 1998 016 Figure 37 Pg. 6-70 1151 Figure `. _i Iso C 10,000 _ [S1S i1 e,000 EXAMPLE C! 6,000 e.a wr*1LO tr11 6 (Z) r 9.000 O.N els (3)— MI -4,000 s•r• mw s, 6. 32 ; -3,000 0 law? E 3. r 6. m) 111 1.4 e.4 r .20 = F 2,000 CO 2.1 L1 'M s. 100 • = a) L.t U F s J •era., F S. [ • T r s6 1,000 r 3. I i soo s. C I -114 w -600 _ L r-900 L Z . t in W I - 300 • v I a, i / T I 1.9 r _ u - 200 — . • = 1-60 _ `,� ¢ . L 1.9 L 1.0 l. -3. o , ..- W • W E. T I00 / 2 ¢ p I— / e•— I Na T 4e Q r e0" a - r / a0 � W �/ c 1 =1.0 r 36 .- 30 NW ENTRANCE ¢ r.9 NA I r 0 SCALE TYPE W r .• `` - 20 III w.....n G I .e -.e i. —so I to • MINIM n•wlrM W _ u I 1•uo•• - —.• 0 21 — 10 IV • ••t,.. I i ~e - •1 r.7 F a L j4 r i i i 7 . 6 � I -9 t••••seem It1 r Iii/MIN/ I I 2I I 4 mr1re•wIt I•USN I11./r• - ,6 I SIN r•rM,ONIONY li••o..ep 1 —.6 I I 3 0 aee O maws,r moos.IM I{ — 6 Ir••m.�IM. le r I 1 [ 15 c 1 I I2 HEADWATER DEPTH FOR C. M. PIPE CULVERTS WITH INLET CONTROL -- e.a we-Bons ___ was • Culvert Flow Characteristics With Inlet Control I. Guidelines for Stormwater Management Addendum. February 1998 Mg . Figure 38 Sheet 1 of 4 S COL Pg. 6-71 Vy -110 50,000 -iii 1.000 EXAMPLE (I) (2) (3)asses (:(. - i. -136 6.000 p.at an.tl�t.ni - 0.120 d. 544 " 5,000 • 4,000 re ow i. S. 132 0 me 3.000 11) L5 &l - -120 m 1.1 T.. 2.000 ti) 1.2 T.T 4 3. -106 3. bit w1 !i .. 1.000 3. •-600 - 64 t- / 2. _2- r- 600 / L F 500 .00 / # 2. 300 ��• � 1.3 1.5 60 u - ZOO ..1-S , _ 3z / r1 . - o -54 . < - ` o., c 1 = - 46 //Q x60 . - X 80 6 -1.0 1.0 v lE : u1 50 Mw ENTRANCE ° o¢ ° .-40 0 SCALE TYPE ¢ -1.0 .9 �� .9 • ■ 36 30 111 s.t.r....r.rr. 3 - .9• W _ WOW a„ - • t- 20 . tC 0rww' .M. W • r( o I - w.t11 X — .6 .6 \' F. -• -.6 ` trti.arN 2_ ` r 10 24 6 .? 6 i.twwaft ft)•t3Iw+l.n 21 - 5 •i•rn.sttu/M wt1.111.„•• 4 w dr.Ntt WI WI u..w►will o w 0 ..t1.n..r r•wN M .6 .i 3 in.trr - 1.6.5 • t -Ill 2 CIS 'S -.5 L _ it HEADWATER DEPTH FOR CONCRETE PIPE CULVERTS mama ,u, mmi WITH INLET CONTROL 0101111109124 401114640 MIA 0111 M113 Culvert Flow Characteristics With Inlet Control Guidelines for Stormwater Management -- ( I • Addendum,February 1998 �� Figure 38 Sheet 2 of 4 SPC Pg. 6-72 CCXJMY s,00o 1S-ra/o'-1 (1) ' 1s'-•'. 9'-3' 3,000 EXAMPLE • Sias:sr. zr I ism 20 u, 3 -• • 12'-10'a e'••' � u ••• --.a 3 . . 1 r .. _3 • . 11'-S'. r-3' 2n uo LO :e 1.000 OD 112 L 1 2 •` 1 i 1. 100 172 1.22 :.2 t 1 . u al 9'-6'•6.-S. f iu LOO .0..Not [ 1 r 2 T 2 :a 500 I e'-2'a s•-•• E L 400 LS - r ' 300 • -is -1.5 7'-0•:e.-r , 1 200 -L 3 r 6'-1•. •'-r E ------ 0: I �1 Tz 12•a••' s 100 � ` .0 r1.0 E. = eo _3 . -..0 ° C .e0 t�• W — 0 i. 1 IAJ j :: /i c t .e i.e 30 - .••■ Z 50'•31• .^ t• // u .1 .1 I. ' I "- zo .tW SCALE ENTRANCE 2 ,. 7 •7- i _1 •3'•27• 're. - 3 TYPE _ I - 1 III '..."". a I .c I W 1 f a , E Io 07 .........star. 0 I r.6 . u � e .a res. I - •e o 36'a 22', 02 1•.. 6 a o I 5 ; i ° •s I• ea ! •s - .S to om.••..n►a 131 s....29'•le' I 3 a••••••rut M.ear 11►,.le. , 1 w Wood,.soma rr nonlimip 0 we 0 r..e.,-•r..•..w • f 25•a Cr 2 .w......... • II'a13' .1.0 0 • • -.4 • 'Alb •.s 35 11016711564.1. NM NOY 016 11:65650311 An HEADWATER DEPTH FOR U311D on Ms*IUTOP'$ emus C. M. PIPE-ARCH CULVERTS- ammo("ware auras aka was WITH INLET CONTROL Culvert Flow.Characteristics With Inlet Control • I Guidelines for Stormwater Management • Addendum, February 1998 �11( ary Figure 38 Sheet 3 of 4 Pg X73 Spey • -12 ,('. .. 11 -`°° — (I) (2) (3) 900 EXAMPLE -0 -10 - -10 soo v.res o.7s1.. . 7 -e r 0/6 • 161../.1 6 -7 ,-e -! - 300 10116? = '-6 -7 5 6 . 111 1.75 15 —S . -6 1p 1� 16 4 — 3 200 —4 • • 131 tm 41 • -7 3 ' - 3 ' f] Q -100 o - 2 ,-00 ..13,......2. o: _ M a -�` 2 ‘. 50 'I'-. t.. [ rt' c, r r L. 40 SL LS _ 1.3 W �► C 2 • 30 O I. O w a o x i ; [ 1,. z o 20/ e: _ F L WI 10 r r o,` F 0 L..9 1.0 1• U3 —3 /Y1 miss.n 7 l s o 1..1..1 o. r e ,7 i -•0 .p.. — D .0 1-.' 1 1 W - -7 ' Mw SCALE WI316wALL 1°,1 i .7 .7 2 4 D FLARE X 1.6 IL . 2 a cc r I11 70•n 71• I 3 Go Woo•Y .6 i - • W Cr Immr. j.0 1 1 2 .r.....1 • I I_ • L r i.S r.5 • - 1.1 saw 131es 1311.W1.' f rr..e...1 w w1..111,.... 1 .r mown+X•160 W UM* .• .1 1 D 1r 0 1011.01.6.omen.w ummesa .6 -.4 4 .6 - • A L.30 - J3 as HEADWATER DEPTH • .FOR BOX CULVERTS • WITH INLET CONTROL di4s 0.M-sods«M M • Culvert Flow Characteristics - • . With Inlet Control . Guidelines for Stormwater Management C February 1998 ICY Figure 38 Sheet 4 of 4 Pg. 6-74 • • „ Vore5: 1. CMPee=nd Sectfoa 840 mm; for Concrefe P.pt Bare/ed e=nd Sed an, See eC?S DWJ. 44. //. 2. 4// Stee/ Fsrfs 47‘,174 be . amp/eon/1.e" and' 45,Ma,/t Cooled frrIATwe/lt / o' be}L!I-J. Or LPEP.**w,'* 1,4eVIOIL May BeegelKaa t 3,41'D,a 5'0.70oh • 60,'S w/ids • uoe/d%d 4 riff/it. I4 O.C. Ma.' A /� 3� aQ Bor- �' • � r Ar e� I seve - OPC Ed SCcoh ,.. At. S-fr A.- 24'Cia Pipe 2'xS'Anaor 7",;”- 3D"O.a and /reeky age,obilf ho 94"04a 4 P ies. Spaced L/ntWIPP./y fshn :AV Ve aka/V. or Ales-Caiivsive 15o//k 0.t,i/1- Trash Rack Guidelines for Stormwater Management • Addendum, February 1998 �� • • Figure 39 Pg. 6-75 � CO= I .n l' . II II I I • .r H H. go P amen a.aoa1 2.41 _ i 1 CIMIEVIDI 2 kw..221 2.2,2 Y2'I2ft.C7 le os s-r Il I I it a :-4r II Z • k. Id OS 4-e 11 II II- •r as- s-cr I ..r - s i s-r I li 1 II n _—_---_ 7/ Ompr. _ _�............_ • Lao.. . . .or[.11•0 ONO rdMrMNI.o•. .. o. Pipe Anchor Guidelines for Stormwater Management Figure 40 Addendum,February 1998 � d Pg. 6-76 so T 70 eo • 50 AVE, 40 Trapezoida Channel 30 10 0 $ , 2 •3 4 5. 6 7 e 9 10 J F12 A1gDi Where: F1 = Froude Number of upstream flow Q. = Flowrate Al Wetted Area of Upstream Flow D1 = Hydraulic Depth of upstream flow • AE = Relative Energy Loss at Hydraulic Jump El = Specific Energy at Upstream End of Hydraulic Jump • g = gravitation constant Relative Energy Loss at Hydraulic Jumps • Guidelines for Stormwater Management • • Addendum, February 1998 116 Figure 43 • Pg. 6-79 G:WY • Sc zT■ =fAL- E10: J6TCN WM¢ �ID Rtne-Ra.'eV; r Pow N Tcri VIIla R +• \ WIDH T -�• _ (0 ' A . ♦h ? oT4 uUlrR 7r �vru NGOitt ►.v;m Res Lib Zt MG°T P FoRMANLP- _EAFft_e FOR CU.-WATER. A- A P/� *SeiCATiDP Cie.Y woo-4, r Anima - 04P1GZ - 9 GG..�� Y ge•1ezz .r .�ftAD Et � Cr,M..tT peiffoOLP440/..a Rernovsble Watertight 1 1 1 Coupling or Flame. Min. . ITIFIT cgiFirE . 'Max...... 6" 12•4141.6i. Plate Welded to Elbow With Orifice as Soeeifi-• . Elbow—Restrictor NO SCALE Oil-Water Separators • With Riser Control Structure Guidelines for Stormwater Management (s Addendum, February 1998 MI Figure 44 � Pg. 6-80 � p _.. i � �1 J Weir Flow Orifice Fkaw Too ∎fir—�mm� Cal r' ►moru• I 12 •■aa ■■a�arr∎rMwIMInsINdfMfriri=" :∎rdEsEPINr _a_a m ml ie==tiaa.f.a�*r��—w ar la 17 4. CO ,-. - —• _ i _ . l .;=:�.■-- p• Q it Wrs.rsfr n.-2ls■3..-!!#.I∎firi.i.iNiai IMW M■MI1MSlIl f►1/iri1A1AR.MI 119MW .MI IM 2 12 10 ■r#MjFgI# ioGil ∎ Niel. ...... - rr•�y�s.• •.•,.r.- � _- +irt _ y - I∎144 ..r.rsf,fsi..aFr+.4ann..-w. .............® 1 f/ fllsf,��f.im . 2�EeF • •-. . r, ,rov/J' aos�mmINP—ral7� r- mini �iefieflld Miim�tt �� r...- �..ws.., :. ,..P�si::_•• - •- • -1 w+•MIW•rivssrr rs� ni••sris • ... if fN, == at ik _ ti40 1 111E40 1N REIT 1ntrm019d tram aliT 4t filar! 1 SOURCE:USDA.S 1 Q,, 9.739 0I• 1 ;mix -.3.792 i Q in as. R and I-1 In tees I 1 , /User Inflow Hydraulic Characteristics • I Guidelines for Storrnwater Management I A,ddendurni Feb ..� iiif 1 — Figure fig, — 1 ...' ccx L _ 1.8Q + 7D, for TW < D/2 Dn La = 3Q + 7D. for TW > D12 D. Where: D. o Maximum inside culvert width R. " Q = Pipe discharge,cfs . • TW =Tailwater depth,'$. • W ■ Riprap pad width when chsaaelas nut well-dcfiaed,8. - • Nate: See SeetZm 4 for sag npisp and discrusiamg blanket nwiranacts 4-+ - D LL.1 ..._ -.. • ' `,' , , ," , .. , ._ _. • •. . , .i 1 .. .. . / • . .0 .1 �5 ` 1 I J J 1 • • I 1, Ct. I• 01. I. �eI .II� ' _ I.I��,_ ��—/,I1.— �� i. I 1 s W•3D..0.4L. W.3D,•DAL. (TaAwaier z0.5 0.) (Tasksrater<03 D,) Riprap Revetment at Pipe Outfall ,,, Guidelines for Stormwater Management • Addendum,February 1998 • 1191 ,... S Figure 46 Pg. 1�82 lf' ►l�COIAjIY • ',_1 • • • I 14 NN. wart. ACCESS) B'MN. (NON-YANT.) s T' REMAND "�i•Yi 101i�Y�`��i•Yri•1� MANTDw .�.t.,•.L•. . �.L•.t... ACCESS AREAS ' WRAP FACE GRASS CUr LIFER \\pia\\"O\\pia\\�i.\\\"�i, Tr mac . .kk•, 1Y IETNAr I' KEY N AT TOE atm NELL GRADED MATERIAL. =IPA= 3' sT 1A''N o LEAST "�i,\\`�i\\\�i,\\\ \\V,\`\�/%1- '`\V BASS Or BO TO BE CLEAR Or \\��'\\\ TS OMANI= CCAPACT TOP 12• Or SUBCRADE TO AT LEAST 90; STANDARD ODNS1?T. NOTTS: . 1. BOTTO I Oi P AND NG-Bdee AIRAS Or MAO DIAL BE S. NATIVE-TAE G SSSS ACCUITATTD TO ARV - CONDI TEN a THE BASE Or 1K OCRS SHALL K FITS, 11WTJnDBIG WIERADC, rim Or ONAIRS AND rat MATERIAL 3. STANDARD ODNDTT MALL BE N ACCORQANCC 1BM AM 0-1537. Pond Berm Minimum Criteria Guidelines for Stormwater Management • Addendum, February 1998 918 Figure 47 Pg. 6-83 � n Mn. • b Berm elev. Top of Sod plus•1.0ft Top of curb(Tc)elev. curb • 3 max. 2'curb drop Z �� prate elev.. 3' Top of Sod 16- 1ecncrete Top of aubgrsde /' dryvrel1 Grassed Percolation Area (GPA) Guidelines for Stormwater Management Addendum,February 1998 AA4 Figure 48 pg. 6-84 S 1`&COUM 7. GLOSSARY OF DRAINAGE TERMS AREA OF SPECIAL FLOOD HAZARD - Under the CAPACITY - The effective carrying abil- !' ationa lord Insurance Program." an ity drainage structure. Generally area subject to inundation from an measured in cubic feet per second. intermediate level of flooding, also referred to as the "base flood." It CATCH BASIN - A drainage structure which appears as an "A" zone.. area on the ini- ci—Tritater. May be either a strut- tial Flood Hazard Boundary Maps. Most Lure where water enters from the side or often on the Community's Flood Insurance through a grating. Rate Map. The "A" Zone is refined into numbered zones (Al , A2. A3, etc. ) that cfs (Cubic feet yer second) _ (second reflect the degree of flood risk for 'eet) - An abbreviation for a unit 57 that area. Flood Elevations shown on measure of the flaw of water. the rate maps must' be used for minimum building levels for new construction. CHANNEL - A depression in the earth's suffice which conveys water from one BACKWATER - Backwater is an unnaturally location to another. This may be either high stage in a stream caused by ob- a natural facility or man made. struction or confinement of flow, as by a dam, a bridge, or a ' levee. . Its mea- . CLEANOUT - An access opening to a storm sure is the excess of unnatural over dra ystem. Usually consists of a .. natural stage, -- not the difference in manhole shaft, a special -chamber or an stage upstream and downstream from its opening into a shallow culvert or cause. drain. BANK - Lateral boundary of a stream; COEFFICIENT OF RUNOFF - Percentage of nts confining water flow. gross rainfafr which appears as runoff. BANK PROTECTION - Revetment or other CONCENTRATED FLOW - Flowing water that armor protecting a bank of a stream has—been accumulated into a single fair- against erosion - includes devices used ly narrow stream. to deflect the forces of erosion away from the bank. CRITICAL DEPTH fDe th at which s ecific ernes a minimum - The ep of SASE FLOOD - The flood having a one water in a conduit at which under cer- percent c ance of being equalled or taro other conditions the maximum flow exceeded in any given year. will take place. These other conditions are the conduit is on the critical slope BASIN (Drainaie Basin) - That portion of with the water flowing at its critical the ear s surface upon which falling velocity and there is an adequate supply precipitation runs off to a common of water. The depth of water flowing in point. Often referred to as a drainage an open channel or a conduit partially basin. filled, for which the velocity head equals one-half the hydraulic mean BERNOULLI 'S THEOREM - A proposition depth. advanced—6y Daniel Bernoulli that the energy head at any section in a flowing CRITICAL SLOPE That slope at which the stream is equal to the energy head at maximum flow will occur at the minimum any other downstream section plus the velocity. intervening losses. 7-1 CRITICAL VELOCITY - Mean velocity of this location may be either a culve( . flow in channel when flow is at critical the furthest point of a channel or depth. inlet to a storm drain system. CULVERT - A conduit for allowing water DRAINAGE COURSE - Any path along which to pass under the roadway. This differs water flows when acted upon by gravita- from a bridge in size. tional forces. DESIGN FREQUENCY - The recurrence inter- DRAINAGE EASEMENT - (See Easement. ) val. for hydrologic events used for de- sign purposes. EASEMENT (Right to use the land of DESIGN STORM - That particular storm others) - It may derive from the common which contributes runoff which the law or be acquired, usually by purchase drainage facilities were designed to or condemnation, but occasionally by handle. This storm is selected for prescription or inverse condemnation. design on the basis of its probable re- The right is. not exclusive, but subject currence. to rights of others in the same land, the lesser right being servient to a DEVELOPMENT - Refers to total - area. of prior right which is dominant. Ease- t e project (i .e. plat, . zone change, ments for drainage may give rights to road right-of-way, etc. ) impound, divert, discharge, concen- - trate, extend pipelines, deposit silt, DISCHARGE - The volume of water flowing erode, ,. scour, or any other necessary out -drainage structure or facility. .. consequence of a development. .Measured in cubic feet per second. . ENERGY DISSIPATOR - A structure for DIVERSION - The change in character, purpose of slowing the flow of water a_ location or direction of flow of a nat- reducing the erosive forces present in ural drainage course. any rapid flowing body of- water. DOWNSTREAM - A term used to describe ENERGY GRADE. LINE - A hydraulic term that direction in which water is-flowing used to define a line representing the away from a given point. With respect total amount of energy available at any to a roadway, there are two sides; the point along a water course. Where the downstream side and the upstream side. water is stagnant, the water surface (See Upstream.) would coincide with the point or the energy grade line. As the flow of water DRAINAGE - (1) The process of removing is accelerated, the water surface drops surplus ground or surface water by arti- further away from the energy grade line. ficial means.. (2) The manner in which If the flow is stopped at any point, the the waters of an area' are removed. (3) . water surface jumps back to the energy The area from which waters -are drained; grade line. a drainage basin. ENERGY HEAD. - The elevation of the hy- DRAINAGE AREA (Drainage Basin) (Basin) - draulic grade line at any section plus That portion of the earth's surface upon the velocity head of the mean velocity which falling precipitation flows to a of the water in that section. given location. With respect to a road, ENTRANCE. HEAD - The head required to cause flow into a conduit or oth' ' 7-2 structure; it includes both entrance the sides of an open conduit; the crest loss and velocity head. of a dam, etc. , left to allow for wave action, floating debris or any other ENTRANCE LOSS - The head lost in eddies condition or emergency, without over- and friction at the inlet to a conduit topping the structure. or structure. FREE OUTLET - A condition under which EROSION . - The wearing away of the sur- water discharges with no interference a�'�ce by some external force. In the such as a pipe discharging into open . case of Drainage terminology, this term air. generally refers to the wearing away of the earth'.s surface by flowing water. GRADIENT (Slope). - The rate of ascent or It can also refer to the wear on a descent - expressed as a percent or as a structural surface by .flowing water and decimal as determined by the ratio of the material carried therein, the change in elevation to the change in length. FIFTY-YEAR STORM - This represents a storm with an intensity of a magnitude GROUND WATER - That water which is pre- that could recur on the average of once sent under the earth's surface. every 50 years. It may occur twice in one hundred years or four times in 200 HEAD -. When used as a hydraulic term, .years. t his represents an available force equivalent to a certain depth of water. FLOOD PLAIN - Strip of land adjacent to This force is the motivating, force in a river or channel which has a history effecting the movement of water. The of overflow. height of water above any point or plan or reference. Used also in various com- FLOODWAY - The channel of a river or pounds, such as energy head; entrance Other watercourse and the adjacent land head, friction head, static head, pres- areas that must be reserved in order to sure head, lost head, etc.. discharge the base flood without cumula- tively i.ncreasing the water surface ele- HEADWALL - A wall, usually at the inlet vat'ion. more than a designated height. to a pipe culvert, which allows the water to buildup to a depth sufficient . FLOW - A term used to define the move- to .force the, water through the culvert merit of water, silt, sand, etc; dis- at a previously determined rate. This charge; total quantity carried by a wall also ,serves to hold the earth away stream. from the culvert entrance. FLOW LINE - A term used to describe the HEADWATER - The vertical dimension be- inT a connecting the low points in a tween' the invert of the outlet structure water course. This is the line that the and the water surface. flow of :water follows. HYDRAULIC GRADE LINE - A line which The elevation or height of the bottom of represents the relative force available the river. The flow line elevation is due to the potential energy available. obtained from field surveys. This is a combination of energy due to the height of the water and the internal FREE-BOARD - The distance between the norms operating level and the top of 7-3 pressure. In any open 'channel, this MANHOLE - An entrance provided to (( - line corresponds to the water surface. drainage facility for the purpose o. In a closed conduit, if several openings inspection and cleaning. This may con- were placed along the top of the pipe sist of a circular manhole shaft, frame and an open tube inserted, a line con- and round cover or an opening into a necting the water surface in each of structure where the top of the structure these tubes would represent the .hydraul- is at the surface. In this case, the is grade line. opening may be round or rectangular. HYDRAULIC JUMP (or Jump) - Transition of MANNING'S NUMBER - A number used in a f ow across from the rapid state to the mathematical formula to determine the tranquil state - varied flow phenomenon theoretical velocity in a drainage fa- - rise in elevation of liquid Surface. cility. This'number varies according to Sudden transition from supercritical the roughness of the material through or flow to the complementary subcritical over which the pater is flowing. Often flow, conserving momentum and dissi- referred to as a roughness coefficient. pating energy. . _ _ . "N" VALUE - . This represents the Man- HYDRAULIC RADIUS - The right cross-sec- ning s umber. (See Manning's Number. ) tional area of a stream of water divided. by the length of that part of its peri- NORMAL DEPTH - The depth at which flow phery in contact. with its containing is steady and hydraulic characteristics conduit; the .ratio of area to wetted are uniform. perimeter. R = A/P • OFF-SITE 'DRAINAGE - Runoff which origin HYDROGRAPH - A graph . showing stage, ates outside the development. ' flow, . ve ocity, or other property of . water with respect to time ON-SITE DRAINAGE - Runoff that origin- ates . inside the development.. HYDROLOGY - The 'science dealing with the • ' occurrence and movement of water upon OPEN CHANNEL - A drainage course which and beneath the land areas of the earth. has no posse le restrictive top: It is Overlaps and includes portions of . other open to the atmosphere and may or may sciences such as meteorology. and..geolo- not permit surface flow to pass over its gy.. The particular branch of Hydrology edge and- into the channel in an unre- that the engineer, is .'generally inter- stricted manner. In many cases' where ested in is surface runoff which is the dikes or 'berms are ' constructed to in- result of excessive precipitation. crease the channel capacity, entrance of . surface waters is necessarily control- INFILTRATION - The ' passage 'of _ water led. ' through the soil surface into the ground. ORIFICE An opening with closed peri- meter and of regular form through which INLET - That portion of a drainage fa- water flows. Flirty through which• storm water enters a drainage system. OUTLET - That portion of 'a drainage" system through which the storm waters INVERT - The bottom of a drainage facil- exit. . itT y along which the lowest flows would pass. 7-4 OVERLAND FLOW - Flow of surface waters by excessive velocities at the outlet of before reaching a natural water course. a concentrated stream of water onto un- stable material . (Wearing away by abra- PEAK FLOW - Maximum momentary stave or sive action. ) discharge of a stream in flood. Design • Discharge. SEDIMENTATION - Gravitational deposit of transported material in flowing or POINT OF CONCENTRATION - That subject standing water. point at which the water flowing off a given drainage area concentrates. With SHEET FLOW - Any flow spread out and not reference to a road, this would general- con ined, i.e. flow across a flat open ly be either a culvert entrance or some field. point in a storm drain system. SILT - (1 ) Water-borne Sediment. Detri- PRECIPITATION -• Rainfall, snow, sleet, YE-carried in suspension or deposited fog, hail, dew and frost. by flowing water, ranging in diameter from .0002 to .002 inches. RAINFALL - Point Precipitation: That which registers at a single gauge. The term is generally confined to fine Area Precipitation: Adjusted point earth, sand, or mud, but is sometimes rainfall for area size. broadened to= include all material car- ried, including both suspended and bed RATIONAL METHOD - A means of estimating load. the amount of storm water arriving at a • given point. Determined by the equation (2) Deposits of Water-borne . Material . Q = cia; where Q = flow in cubic feet As in a reservoir, on a delta, or on per second, c = runoff coefficient. A flood plains. factor based on the imperviousness of • the area upon which the water is fal- SLOPE -' (1) Gradient of a stream.- (2) ling. i = the rainfall intensity Inclination• of the face of an embank- (inches per hour) based on the time of ment; expressed as the ratio of hori- concentration for the given drainage 'zontal to vertical projection; or (3) area. a = the drainage area in acres. The face of an inclined embankment. REACH - The length of a _channel uniform In Hydraulics - expressed as percent or w th respect to• discharge, depth, area, in decimal form (6% = .06). and slope. • SOFFIT - The bottom of the top • (1) With RIP RAP - Protection against erosion reference to Bridges - the low point on consisting of broken concrete, sacked the underside of the suspended portion concrete, rock. of the structure. (2) In a culvert, the uppermost point on the inside of the RUNOFF - The portion of precipitation structure. that appears as flow in stream. SPECIFIC ENERGY - The energy of a stream SCOUR - Wearing of the bed of the referred to its bed; namely, depth plus stream; by entrainment of alluvium and velocity head of mean velocity. corrosion of native rock. Also caused SPILLWAY - A passage for spilling supply water; a wasteway. • • 7-5 SPRING - Are issue of water from the rapid flow, shooting flow, or supercri t1. earth. ical : flow. STORAGE - Detention, or retention of SURFACE RUNOFF - Comprises movement of water for future flow, naturally in water on earth ' s surface, whether flow channel and marginal soils or artifi- is over surface of ground or through cially in reservoirs. channels. • STORAGE BASIN - Space for detention or TEN-YEAR STORM - A storm representing an retention o water for. future flow, nat- intensity of magnitude that could recur orally in channel and marginal soils, or on the average of ten times in 100 artifically in reservoirs. years. • STORM - A disturbance of the ordinary, TIME OF CONCENTRATION - Time required average conditions of the atmosphere for discharge from the -most distant which, unless specifically qualified, point in a drainage area to reach the may include any or all meteorological concentration point. disturbances, such as wind, rain, snow, • hail , or thunder. Associatediwith .Design Storm. • STORM DRAIN - Any conveyor of storm (S.D. ) inlet- time +. time of flow in. waters. • drain, That which confines surface runoff and UPSTREAM -. Denotes direction from the directs . the -flow to a point of dis- sum location . regards drainag°.�- -,� charge..• - . . systems.. • STREAM WATERS - Former surface waters •Upstream refers to higher level, from wh�c ay.e entered and now. flow in a subject area. . • . well-defined . natural watercourse, to- gether with other waters, .reaching the VV-DITCH - A .conveyance for water whose stream by direct precipitation or rising - cross section is triangular - hence "V" from . spr.i ngs in bed _ or .. banks of the • ditch_ • - watercourse. They continue as stream as long as they± flow in the watercourse, VELOCITY- HEAD - A term used in -hydraul- includina_ overflow .and mult•iple_-channels . ics to represent the Kinetic Energy of as well as the ordinary or low-water flowing water. channel . • • - This "tread" is represented by a column SUB-CRITICAL FLOW - In terms of velocity of standing water equivalent in poten- - a. stream, something less than criti- tial energy to the kinetic energy of the cal. . . moving water calculated as (V2/29) where uV"." represents the velocity in SUMP - In drainage, any area which is a feet per second and "g" ..r.epresents the 1spot and does not permit the escape potential acceleration which could be of water. effected by the force of gravity in feet • per second. SUPERCRITICAL FLOW - Flow at velocities is er an a critical is said to be 7-6 4t . • l 1 WATERSHED - (1) The area drained by a stream or stream system. (2) The divide between drainage basins. • The land surface tributary to a speci- fied point on a stream (not to be used _ alone unless intended meaning is made clear) . "Drainage Basing is preferred. WATER SURFACE - Top of water in lake, channel , reservoir, river partly full conduit. The"elevation or height of the top of the water in the river. The elevation of the water surface is calculated using the Design Q and the shape, roughness and slope of the river channel . WEIR - A low overflow dam or sill for measuring, diverting, or checking flow. • • • Z 7-7 I , Appendices ( - Guidelines for Stormwater Management Spokane County Public Works Appendix A • Hydrologic Soil Groups Guidelines for Stormwater Management F ;: Spokane County Public Works Appendix A: Hydrologic soil groups Soils are classified into hydrologic soil groups In exhibit. A-1. some of the listed soils have an added (HSG's)•to indicate the minimum rate of infiltration modifier: for example, "Abrazo. gravelly." This obtained for bare soil after prolonged wetting. The refers to a gravelly phase of the Abrazo series that HSG's, which are A. B. C. and D. are one element is found in SCS soil map legends. used in determining runoff curve numbers (see chapter 2). For the convenience of TR-55 users, exhibit A-1 lists the HSG classification of United Disturbed soil profiles States soils. The infiltration rate is the rate at which water As a result of urbanization, the soil profile may be enters the soil at the soil surface. It is controlled by considerably altered and the listed group surface conditions. HSG also indicates the classification may no longer apply. In these transmission rate—the rate at which the water circumstances, use the following to determine HSG moves within the soil. This rate is controlled by the according to the texture of the new surface soil, soil profile. Approximate numerical ranges fur provided that significant compaction has not occurred transmission rates shown in the HSG definitions (Brakensiek and Rawls 190; were first published by Musgrave (USDA 1955). The four groups are defined by SCS soil scientists as HSG Soil tertitres follows: A Sand. loamy sand. or sandy loam Group A soils have low runoff potential and high B Silt loam or loam infiltration rates even when thoroughly wetted. They C Sandy clay loam consist chiefly of deep. well to excessively drained D Clay loam. silty clay loam, sandy clay, silty sands or gravels and have a high rate of water clay, or clay transmission (greater than 0.30 in/hr). Group B soils have moderate infiltration rates when Drainage and group D soils thoroughly wetted and consist chiefly of moderately deep to deep. moderately well to well drained soils with moderately fine to moderately coarse textures. Some soils in the list are in group D because of a These soils have a moderate rate of water high water table that•creates a drainage problem. transmission (0.15.0.30 in/hr). Once these soils are effectively drained, they are placed in a different group. For example. Ackerman Group C soils have low infiltration rates when soil is classified as A/D. This indicates that the thoroughly wetted and consist chiefly of soils with a drained Ackerman soil is in group.A and the layer that impedes downward movement of water undrained soil is in group D. and soils with moderately fine to fine texture. These soils have a low rate of water transmission (0.050.15 in/hr). Group D soils have high runoff potential. They have very low infiltration rates when thoroughly wetted and consist chiefly of clay soils with a high swelling potential. soils with a permanent high water table. soils with a claypan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very low rate.of water transmission (0-0.05 in/hr). (210-x'1-TR-55. Second Ed.. June 198G) A-1 Exhibit A-1: Hydrologic soil groups for United States soils aa0.0 0 aD.Ttr C I •66/V. a P1DIMG 0 I •LSta a 440000 0 ADDICTS 0 164.0NCL10 C •LDIMO C I LI. N•UG. C C •001CLOU e 1 ANDS 6 alCDO C I L16/AD C aLStao 6 Lot A l pwTaNI. 0 •L[GOOS C I &LSTa*, 0 aatoall a •M6 a I •Ml&N11.. Deal•IrO,• C •1.t It C I 61.6100 C 6.6C D •O!4. 6 1 £NI•* !C • , •ICMCO• C ! 411 ILMO-r 0 46640 C LOLL. wet .0 1 41 1C06iT11 C Alec 0 .01.0c6L a a•LL00601am S 60LL610L 0 1 6ICG - O LLIILN000 C •1161 a a•aOC• • •t![ [ I alter a ale/•*Dais C ALILVTS1a C .Cleave a LOCLIN9 0 1 6116 w 0 •LI10 a at.Thaler 0 &este a aOtlt.0. c 1 61166#4. s1•I0T . c a1./LLCC C £LINOISE e aeao1T 0 6.1.161- I I aIL•y [ 410.000 a LL?ICOtST e 6eaCT119to60 C 616160.16 111/C1 6161,111, [ 61. •watt P 41.11,• C 66c£L o LO!N C I alwatt• P LiC • •6/■40 a &ar GG 0• &D(a• C •1 ag•aICv 6 aLCeall& O ALIO C a0C6a 0 LOGPO , 0 1 L1r30001. I 61.010•! CIO 61.100• C WILL a 601E12 P I 6116NCNt C LLGOA C ALTO" 4 61000Cr' c 1 601611 6 1 6,00011 G Alcor• eeD •LTOOM• C •LLLLLI a 1 60161 0 1 6115 - e •Laws-• 6 •61.1110* 0 60(01110 C 1 60105 0 I &X C is aLTUCa5 C •7101 • I 601UNILS . C 1 LJ:1L110 D ...ICI 0 &LIDS 6 ACES 0 I Antifts • I &TLC. C £LICel a airy.- e .,GCS! 6 1 aotlws. 666661 C I • alto. e LLU• aetLC.K C 1 &OtlML. all C 1 6660 S/O &LIoa a ALYm a 601906 0 1 •0.,o C 1 P. •1I(C041 P. •LUIS 0 aelOLa. /LGODL3 C 1 LDAL. C I ate(.• 0 &Liat • al OD e 66116 C 1 4006C C I •e10061 a aclStoce C , LLytr 6 ae0 c I •o01.D. 1,01 41.I[0u0 C MAO 0 •LVID• C 6600 0. I •Dos C I 6116111 L •LLAG•S0 a aLIISO o a60auGI6t 0 1 .001a« a.01 at►CC 0 £LU•cQt 0 aLTODeSt 0 •0011- 0 I •DIOCa6 C I 61.6001% _ 611661700 0/C 6 0 6[o. 0 I £CCeI C I LL6i.s.1 P 6166*1011. 0 £LIH. 00■1010 C 601606A _ 3 P LtNCLS 0 1 $L0C • CCP00SIC0M01. .LIMO. DOOI(CTCO C a60a2C o 1 •Iva, C I aufiO• C 6116.0 a •0.11.06 - e &OOatO. COLT: C 16►Lc• r I &LAG• • £LLOONN _ a 6Lt&r C 4606.11 D I a/0.000 7 1 664661 C •LS.t4KNT a •1.2$0• 0 £00100 O I at?0A Crol 06••• I atlt6MOS 0 .11016 C L61.00tgc C I *GA 6 I L6.6160I1•S C 616014 a 606000 0 &•Sear• • . I ac.a10a+ O I •L*..aC► [ alleM04le a •.LCOr 0 .es.lc1 0 I •Gar -, 0 1 alal•17Ut _ e LLLe00051 ., a ••*Lla e sestto C. 1 6040 e I 61.40,C C 61.11.(09 06.6 T a 6•Lly o Lesko. 01.020r0 0 1 64.611612 O. I £L•uC00097 P •LLCMS •.•t. SONY C 6 &6510« C I &GAT! C 1 61.4105• t aLlartlr( 0 4616046 C £CLCIC e I •06rNa ' r 1 66.00!•. DOLINPC ► at,lfOI000 , e •NLRILI.0 u 6CL0.0T C I 606111% 1 £L4601C.te • alter P 6656 ,. 6 .C.01. 7 I •CCNC• C 1 LILr1: 1.1../6/105 .0 &Na1a. NOD00•t(LT C •Car• 0 1 6010 0 1 •lac••• D •111&6CC I wel. 560 )T LC•MOD C 160 6660 0 1 1 • 666146700 0 SUP STaaSur •CASCO _ 0 1 aimal 0 1 ,, t •LEIS 0 6000 a •C C1Lta•rOO a 1 aCCCSTCN 1 6000$0% a 60016 0 .Ct1T1004.s e 1 lg,ts?06. COOKL, C, I al1•o0 0 .Ltat0 [ ANIMA, C &CLL. C I SU•STO.1t/. I 416560. C •1UC• a •Amoy C atolot• C I .66t61O6. C066L, C I •..D.tCr 0 •llOutt a_ 6.56a01 O .Cats - 0 1 •SOCS?OT. C 1 411(1 C LLNK 0 •0006• Pit •C6C0066. 6/O/ O9M016I1666 1 410t0aTIC e •106001 e •MTLI• C 6([6061661 C. 1 agog* C I LLOC•TON I •LMITILLP 0 ANtre D SCt•IT 7 1 •4MCO, C 1 alK/,1111( C PLOP.. C •01016 O •Cti1 T - 0 I 60061 C I •111061 • 6115.016 0 LOPMSON 0 Leal!,. • 1 *GOO? C I •GPI& P 11015.011 6 a.1,61CIMOS, e aCa.0&C e I •r*. r I •L[6160111 C £110 0 1-(6ICUs • 6066 teo D I aGW - • I al•Utt C 461001 C a-4.•/ 0 at.! c 1 6004 OULC( t I &Lewis. O0aSMT.. e •1001• C wits (/0 •Cot 0 1 1. PI 501• C 1 •15115 0 6106 t L LSP•• 6 60060 C 1 LW 50141.- .IGO 0 1 61.(6r C 61.111 O 6-[51001 - C •Goer C 1 •61MIaLl 1 66CI!lre a 610 C £.00031 _ 0 &COP(' C 1 6416 Iola. 5TO'T C I ...co. P £11106 C •016160 D 6C(ID66( 0 1 100601166 • 1 61CC6.6 6 a106a5 0 £0.11• _ 0 •Cott C 1 601161? O 1 0100? _ a •f0r6 a • 000 0 •CIPtl alt C I &GINO• 0 I &6001• 5 60006 0 •NC0•C C CCTV., I I 6011111515 11 I £lea C 610640 C ANCLC • •cute 6 1 64401111• P 1 6LO.. 1.11.E Pie 64.1501 • 6 000 a •Cur• C 1 •GUI•%! C I &GDS. C *Lew. e •000115 0 •CT C I £GUS110 P I •1010 D 41011 • 4-01 C 661• C I •rapt C I 66100 C 41.000 P 01051060 e 60.11 C I •.t C I £LCPT0ILl C 61501• r 61060 C 60660 • 1 611.S1.06 3 I 610100600 P 6(010 a •000100 C aO•NSC. 0 1 64At1t C I alC-IrOOGD C £1.05 C 6066110 a •\ •C•m s.ILLC C 1 •004.1 0 1 4101 t &LS • • •0%1!0066 a 60.100 7 I • • I .L0161 C •1500 5 •MTOr, 3 1• .OTC$: ITO M•00C1O.IC SOIL 400IRS.SUC. .s D•C 1M01C•t[S 1.( Oaa140 D/11606 INg0 S11Ua?10r. .001►It0L SNOyw. I.L.. 7[010(• SuaSIO.tU6. etre& 13 • SOCCIIIC SOIL 1!6113 O.ASe POUND IN !Olt 069 110(00. Preceding page blank (210-VI-TR-641, Second Ed.. June 1986) A-3 Exhibit A-1, continued: Hydrologic soil groups for United States soils ...!1.L C aWSLLPD. OCODOC' • •PCN a •..VOoalw C £SSUMPitON e a+. 0 5u.staatu5 aocNaeaL e hoot4aOO a •sTa e aaaaCa►a a •515.0 •eo •.cwqso*o •. • • amass o aSTaTULa a•' ausCOCO D_ aw5.1NG 0 &KMPP C •0NMr1■ 0 •STOP 8/0 auaCO.Oa 0 ANT Flat t aUCMtPOaLL' ' • C .ONO • 0 •ATOP. FLCODCO 0 ara5tIN C asT(L a aacuts 0 •a•oLO a •51001• " .+ a• £N*NY•C " 0 aNT(LOPt 1551555 C •OCNIN 0 • LaNe? • C/o Ara/OYe 0 ama.ITt D &WTt00 0 410.WIN. COOL C &DOTE - 5C C &la0 c a 0 ' •KNu1.cia ' 0 LPOL - •" 0' •TasCOS• 0 arasaZI C aNT50L0r 0 eaCIa C .001• C •T•T! • a acalOwe 0 •5150511 0 UCLat l 0 a0' C ITCalte 0 awauO 0 •51150 a &.c0 C aPeaO• 0 &ICO e &&&&&&DE _ 5 •511155 C auCO. OaalsCP r £.OaSta! 0 •tCNC 10 • 0 •ou•LT 0 asTIOCN D LaCOL• • •C aUCDONDO • •T(PiC •" 0 arCNO 0: •WILCO C ADO t •C .0018• C a?NeL.Po a aMCMO. SALINE- C ' •NTOINE a aOO[SNONt a ` aN155105 - 0 •TMtr• e aMCMOD POINT 0 •NTOrITO C ar ew/rota a •N 1CLa 0 aINEPTON • 0/0 •rCM00•Gt • aOTOS& D mimeo 0 ' •N ITOla 0 •11101 • a aMCto Tt 070 •raOOeus 0 •re['. we* C •aNOLINC C at•Ir5 0 aNCLOTt. D •NI.(.0 C •001(1. C •NON 0 LT4.1NSON S cc 10Na1 ANT, • 0 mUDlvtt 8 •a*OrwtaO C £T1•S D •rCLOTt. _ 0 aaIM0( a aPN5as e a 0 ATL(! ' . C rRtOuemli,t &Nall • " e - a.oteO a •Moto iCCO It •ILO• 0 FLOODED -- away _ •KC 100 • affil?! 0 •TmOMt SID •MCP C DOW• a ' a.c ' - a a. a • arms a1a C •Not 05[005'"" 0 Ara CN[ _ D aLtN• C LOTES la 0• .TOMIC 8 awOtQLT C. •.asul( • Matra. OP•la CO C •STESIaN 0 •IO•C a arOtaS C •• •t•CN[I' •.• 0 •i' •l'e 'a b1rOC • D •mot*SO!• a •••LO a mKrt?Svi1.L. a mutts C •TOING e• .5000' e' aDaR(JO - t •atsOSa • ''- • sUYJO 0 •1aSP• 0 aroowre 0 ar(LOOei " ' D •atNt.ILL! •.. a a51IN0Cl C .15105 ceo a.DPaOa ' - 0' •Ka a ammast O &0.a O aTStON. T1OI' 0 a0400ttSO• • C mot&Mar• D LUCENT 0 aasa0a C' 'LOOD(D ' aNDOeGC a &ris05 0' •.Girt. ' ' ' C .,Vasa C •IT'LL• 0 • •NDOCS - 4' •'Wst - a' ascDaauh D LSSESON 0/0 aTT(P • ( . araOP!eS C •Drat - 0 aOGOl• t aPv IILa ° a a►T!0•!IPT _ 8 • LUDDUSI• a' .5(110 • !' army([ r, aerial 8' aVTtwaW 0• &MOO, 0 .POEM. '° - • Witte C •120 0 4 aTTCPas. sty 0 •5011 5' •w4NQOIt "■' 0•' ..teas• a as• • auTIC• ' • e ammo O "r"awtwao. C .Elmo !' &&&&&a* 0 •TTOtaC' a .511.1 ' 0 aw lam ° • •Clots• C a10lll 0 CU 0 a5(T5 ' a' asvlas.• ` ' C &alrlrt a aSCaLON P• aT&'LL 0 art TN. 00. i SALtrt- "1 .GIs D MSCMR C •15000 0 arfiitca DID aw ta■. .t* C •oils,( c •scwOrt a au Gags a aace1.16. D •PISS. C(Clr1TICD C' •51:5 • •SP }'015(1 C� •Ya • •NGLLO • C •PPltDUSw • " • 8• •• • L• C 1SM*5t 0 •USaPOU! •'' 0 .55(1111 e. &PLtD(LLI• ' • C •0••••• C •S01005 D awettwauesei• • e amGIt C awLesale c •51.011. _ C .50555' a aver:*. 0 *ANGLE • aPPLCTON C afaCra e sDMOeL( e. wane, C aNGL(N _ _ c . t.t.G 8 •stPO•T a asNOOiu' 0 aUIUPW 0 aM{OL• C •Mow • a I LINE • a aw•usNO•LC O/D autOR• • &Pt e aPiTO* C •Salt• C' a rCO o •mGOStue•' 0 aoTas/StC r • a•1p a DPD O •uGGIt a awwal t D aarDS - C •0u1 '' C •salr Otis 0 avGSSUOG 810 aw$aa y 0 4OUILL• • aSt$5GTON C •5a•GaOve O •mous T• C asI.aS C eauIsas c •PLIrGTOM. 'mice a aim/mules, c aVGUSItwC a •511.10,•' a aaaeea0 D •0.LI* aMat wu• C 1111.0 D •mill• D aaaOa P •5(E ' ' P •55511• • •/D auR& 0 &mato, — _ t a0MGOM ... C .storm • i •►NLae to aU0[Ltt • 0 aaea(►a♦ _ 0 aSa1.•UPU C •aigC* , 0 a$NLtT' e aUe(LIUS 010 ANDO51 O *Waal' 0 &1901Cmama.CO C &SOLO •' e m00• C awalase L. • "aaaOawOt e10 a'NELtS ! &salrt0 a aussus o awaMDaLC c aOa0t(N C ;mire re0aPIS C •aNrmo 0 aUSTI& C aw•P e T • 0 •05(51• 0 .1501.1.1' 0 •UST1Sr1Llt 0 • aametralrl C anal 0 a5Otsa " e •woe? • •us10(LL O - arrls C a.a.aIe• C •oat%Par • • •TON 0 &UT C Mort'. s•L1uc • aaa.t 0 alntrseuaG a imam! a auvase& a .wogs. O0attC0 • aPa,tTea. 0 ae►IJO C •SPLIT LOT 0 auTOVvIll! • awNISOUIM, " C •Moll• C eSNINKTON - C •sa•POOt C •unva$5t 0 arwlSTOw a *es teat r aawlsICa0 C •ime'. • C •u[DUl a arNOws 0 &DOOLMS C awltame C •55th 0 ova C LMOCOI C aPODwC a acme 0 4110114. C r • a &OMDS 0 £PNCIMt D ase•eaS a avwT e •5051& •c aUsuCLLt a a0N05a• C SIPCO/ f• wrap 0 a.0.ELL 0 •UIUCSLt. vtr C 4100010 ' 0 aSPtRM0N1 a 1t a .....I D aUSUPUa C aSOPUP • C ISS[OSOm C •rimaL O aN5(L 0 aMOUS a aaSTaw c •SSaTt&GYC • •villa e - •N5tL5O 8 •OCaia 8 •*w1TSOMG C aSSININs a •v ii r .. auCtflt 0 ' •iui0N1( C' •aSSINMIOOtN( 0 a 0Ca • 0 1 \ OWES: Teo NvOOOLOGIC SOIL GROUPS SUCM a5 sec MOICaTes toe DaaISCC/iMOSa1Nt0 S,TU•1105. ..0OI,I1a5 550.5. E.G.. at000Ca su•S1P$,Um. 0tFto TO • seecIr$C Solt S1'les 'wait FOUND IN SOIL ■•o LtGLND. \4 (210-VI-TR-55, Second Ed.. June 1986) • - ' Exhibit A-1, continued: Hydrologic soil groups for United States soils • A.O. c e44LOP1110 C e mole' c ea I1 SON 0 OfaveotON 0 C - 01Tr$VILLt C C •VOg511aG 0 DaLOrILL a •aa,L• •CCUT C •VOND• a ••LO.OWIT•t" a 018/ICIO 0 a•1N C •1050*[[ 6 SaLDOCI 0 .•aruss O • S1041 • . o OCCtlt' a . •.omVILLt. a O•LOOCa. Ga•vtllT C 0.04F C ' SatTLe Cote[ C OICaW•" 0 *V1*U1L 0 SII•STS*tUN. !MIMEO C (•7TLtNCN1 6 e[C/S C •Malt 0 00•1510 .•al0 -• C eeCt1OW 0 AXIS 0 50L00Ct. 641.1Nt C S*RlSwlle' C ••uOtTT( a ILCtT0N. *ALL C 1111!15 0 S•LOOCC. s*LIK C 5•.[(155 t •autg • C 00•1510 Avail _ . 0 •ALOOCt. 00•1410 C •aw[tlte a 0WS1N C etCIVILLC - a 17101[ • •aLDwIr 0 •*KSVILLC ' C 6*4096• D 6 e[C[11tW 0 LTOILOTTI 0 540• a 5*[1.t• C S•U5CNto 1 SEC •Ttas.ILlt • 1151 a •/Waro O *W[ 0 erc•ar1 a - aVlrll • 5*L1. At7 0 1150 a •au[sOW S (11.111 e ••500 •J0 •1LLaraC[ 0 e451.1WG C •1ItNOAle • e (10111 1 • a.or . • •11.1••0 P 5*L011 e a 010(5 0 4.0010 C •*LL(■ 0 •m■••e • C •a[TLavILLC 6 e(o.OSO C •TO •. ••LLIN4t0 0 •15.50 • • C ••••NOW • a SIOINGTOW • e •awes n o 0111TO5N 0 •aISLLLCSttt e • • eto[t 6 avO6r/st c s•Llvaa a •*r[$ a OAV•Owo O • C ayster. • •all' C •aarCSTOa • e •aSeRTOW C •e0f1[a0 C atal• C SKr 0 •*51rts70r. • 5*V.I(L0 c 510..1 0 •Z1L71Nt S 11.151« • r0scaa.lLLT avaI111.0. o[T - 0 Ott a allalar C 51[$51'. SAL11K. C ••SStV 0 8•5505$[ 0 51(51 • •ZT1C a 51000(0 •••rNaSDT a 51•[15 P •111"1( C LZTCC. 14I60 C S 6 5155507 0 •a.re•OC • •c(CM4I0Vt • ••1r144.4. 5•LNO.1li C •awr1Oa1L 0 80•0U 0 •[(CM.000 C atule C SALON e •' 0 8• •I7•OLC a 01•0lO*s D 511* C aj.CLL C Sa.606* • •••NUN 6 •a•6NOwt 0 •(tt.•N - C Sa•MISM • ••.TIC 0 5.5001 0 aaVirOwt. 6 ettLlr - o Sap • 5•LTINDSt a e•w010 • Io5e5ATCLT 5(7 e1CLIWt 0 ems"miaow a •ma • e •*010. 5iT 0 5*VS1OC 0 •t(r0r1 • C SaseLHa►•o- a ••r•C • •aaw•Oa D 0 5(1505 0 • w Sacs • •• t• a 515.1 0 gamma 0 tot esCoat • 01CA. P1.00000" C • 5•50$ C e*Sett . • 0 •avvt - - 0 ecc,vlll[ s e WIC* - 8/0 ••NTUSM a •*•Ito F` 0 01,11(5 0 5((511 e . SaCNILOS 6 ••w•OI:SU ' 0 ••5•ISG1Or • a ••1.000 • 0 �_. '•iC50 0 am*T - • $155ON a ••i[TTC - C • SCG*T a 5•Crui c 04410i"• o •*iONctt , en •11111 a a e[WarlM • SaCCS*T o •mCas • C 0400T '. • BID •tACN • O •(MerO70s1 :a C •aC[•0.t ' '5 somata 0 5*saC • ` C • Stan C (("5156 0 • ••CLIP► 0 •a1C4C1/l • ••■•■••D 0 C atlGle a 8aC08 I - C SYICT • o east ' e •tat.•re •• a •t/war P SIMON• • 5150.6 e •*tINt - C eeALeS • 6 5(15161 • 010.11 _' • •*5055• • •mtL( D r afar 0 SEA •*Dtr• • 5/5010 a 5*mme• C J •eaaID" C •(JUCOS e•SAOtr1u6M _ ' • $55005 _ C 8•510 0 •tarttO$$0r • •tl•I5 • •' C 6•066 5 ••r( • e*7051 0 sa*55L1I • - C 6 • 5.066 170.5 • SaSGO - 0 5*5105 • a 5Ca51at1 a atLCWIa 0 S•olr C •*5405 • 6 SaaTO.PLat • ' S*a50 O 5[1.01" C ' 8•0110 C •*MGITOr • • 5• 105 r seas pasts r 51[0156 a Sane • 0 •*10a 0' sins a St* comet ' • •111w C 540015 CID 55.&5.0 .a 5•$111. • Stu La[[ 0 OECCCC1 O 640.47[0 • • •*5116 aD • •asCG C •ea. •5.1511 a e*Lrl1LO C S•w.D - 1 ••Pis • 01sC00 P OOOOOaLu c •(l/0•t P •160•0 6 ' S6a1LIC c 5.5(01• C 5(•505. C Sllw•a. c ••40071 0 8*5511 • S*5I0108 0 5t•wo5L1T C a SaG1(T • Sarre. C Sash C SC•00110W5 C ' Suss.[! 0 SANK• • SA55$NG C •*1551• Co (CaUCUr.CN • •tl*5S• 0 *aria • •1151105 C SaINt• 6 SL•a.O1T9 5 •(LJIC• a 5151. C 840140Ct • 515111 C 1[55•'•1 C eel[ • O 5•141 0 •Art•• AID SASS. C IN 0 • •Cltrat c .61L(WP • 51401 D 0•11.G1e• CPO •t*!55156 r SELLA/161a C sal L(VCSeta C 05694100 " ' I 611116(5. 0 e KLLE. • ••11.156 C'- 8•0•46 ' • C 5*05fss10waL 1111 C 1.CL1(CMCSt(c • • 01/$11[[1 C 5Y*5* - a s*5154(•. •1000(0 0 •IaS.aLL0, • C 5(101NClSr 0 841140 stilt. ' C 5m•T*41 4406 5*1(1/ a : ataSLA• C •tL4.CWr1Ne D •1160 505105. O •••5a10s• 0 $*5560 - 1 5I1609 C •(LLRVILIA • Sit CITSCwEL/ CO•SLV 0*84.5/ 0 •15(71 5 afa7SlCt 0 •LEES 111.[1. 0050(0 0 • 01100 401..4.0v., • ••awstwt o •155ric1.0 • !(amour sit r(lltvue • 4,4a/CL - •*$SOUS • •151155 c seaworo o •tLLICUN 5 SAJU•• 0 S*SOUSVILLt • sailor C *t•us/o. 0 •(Ll1404M•. • 0 ptCOrea o •*Cart e. oasts*. w 5(•01.05' 0 SILL1a4Maa. c •Kt5 C •*SCI • *seism a •ea ' C 06•1510 •A[t•1V nit 0 •*CLa• C Sofa r 'taus)re - C FtLL•.ss G. e 6*5C0 a eater t et*Ulu ls a 5[[10151 C •aLCO• 1 e*CUS • 61• •510 a 5t•115CO[CI a CELL*000 0 •••O C •m0 0 •aliNar a •r C •tlrta0 0 •l Lo(D o emote' C •airs • sea.tstLl e eeLNtLI e 50115: too MVD•QLOGIC SOIL 650155 MOO. AS •IC .OIC•1tS 141 r51irt0/ua05•IN10 SItUITION. ' uaol/ICas savoy.. E.G.. 5(o*0Ca 5USSt•aluw. 5L/(5 70 • *S(CI/IC 5011 SU•ICI ONast /OUr0. 1r 50*I mar lfGtr0. (214-VI-TR-55, Second Ed., June 1986) A-5 Exhibit A-1, continued: Hydrologic soil groups for United States soils • { 'N . •IL0001 S •CO10•r e •ILL IOGS. a eL•CI *..L C OLUC Lac1 • o*L000C a OIS1 sar0 • e _ .000••TELT slo. et•C90•o 0/0 Slut S\•o e • C et•WILL1 e/o Pt•9 el•CCP tP9- • C SLU65(LL - C 1 0 e[a.oL, 6 OILL•C•[tc. c sl•C••Uiace 0 •I.UCCNII/ C 8[1.1E0 0 . . • GILL V01•• 0 SLaCCSOCC 0 OLUCCStct 0 OtITON C SIC . 0 •ILT005t a lilaC[SaM • C `°• C 51105101 a •E1•0•N •/O $105[5 0 - !LAC/S•ae 'o` 0 Lai C BELTSVILLE C StSNt or , C . P 110 0 !RAVES/10T O Stilt Gao•1 C SLUG• • O 1!5010 ;, a •King[ ' e OLaCCSTON 0 6LUIGu1.CN • • SILUGa. 0••IKO.• C •tSStNf■ c •I✓DOD a SLaCC••OSN S •L11(MIIL C SLOPING St1s11 D • SKIM , e SIaC[TO! O •105000 C st1.OIII C •tItSOM • C •lKw■ - • . •lsC[r•Tt• 0 SLUt401NT • 5112•. - C 6610aN1, _ . C •IMGNa•MTON , P PLaCCKLL * , 0 am yemOS[ 0 5101041 -• • • 0110[. 0 . •t0GMaMVILLI,. 0 • 0 IILYt•0INT • StN 1000ND --• 0 SE TOW a• 0 • •115Ia - e SLAG 0 ewer/IP C 51NCNLET C ICT11CS0• • C •11$VII.L1 0 !Laid) O 6LUISL101 0 •INCL••t 1 C •ttNI.CMt• • $114 -. •• OL•1NC • C 81,1,011••IN C •5[010 • • Stilt • SIMT05 C Sl•t• C SLOES TONE D 5[001• ! Sf1011Wtt • •10100. 5(11510[0 • SL•ISYO• C OLV151MG • •• 51110101 c •Ct•• ,.. C 111••• , . . , e to C SLOW" 0 00N1•CLa C PITT[•aVl• C •IP•VS - .. • • 01.00 C - Sew!••04 - 0 SETTS S 0I5t N0•t C G1attlaM0 a •L11•P TON .. ' C/O ' SINS 111.0 .:e - •C SEVL•N . 0 ••ICCM/111.0 ..•n 0 s •• ., C sLUP050 C 5106.1 .0 015101'. . • •10C 51•000. -,ti C LL c •LU• c stow - e 0c•t•1049. , 0 •15905 • 'euLOCt . o el• . 6 5EN51.•N • • • STSISL• •• 51.05 ° c/o - C 6LTS000 • 51111$ 0 - S(S[OLT. c•••t1t• • 61195•11 0 • •L•0C• . e 0L•TNC 0 • 9C6 TO _ • o et, c •t•OS•os0 •, . s1.•$C•.•50 • 00•000•r 0 •CN4.0I• o WILLI.• 0 •unstct• • 0 •l•NC.c • SO•SOt•IC C . 510111$ C •tt•• 0 •t501W1ta ::.'t: • •LarCNC•T[S • SAP •0••11 0 51011.0 ,. • C OECD 0 . •t•SSECc 0 SL•NCOT 0 . $Cal C SL•0064.0 . • S[2I•NT• ,,•. • • •tam iKN.M , • . S1.•00 • C 00••ITT C •tM01KTON 1,••. C , •IN ,•., C •1001. , . 8 , SUMO 1NG .6 5001110 •. . • 66.0106I - • •, 0 - VISLC1•SI0GS.... • •1505( c •1.ao1• • 1600005 ti, ..,,, C 6[011.[• - '.' •S •ICC • •INL[ .;., • •garter , .0 SOS5 0 • 0 •1CC15D•Tt 0 •tiC•SO O Sumitomo •• 005T*IL C •[NTCLN C • e10ECTi .. . - O 51101• ,. 5/0 •L•01•00. _ . • 50s TOeN ' •• •tea LC taw •'- :. • , 0 • •ISGaMI. 6 • .00(55?ELT,Ai{T.-.• •OC• 5102 .0 •MI001[ ••••• ,e C NODV5•TCI• Ott,• .0 sac.. 0(0011stal+al . 5105 . .-•1 • 6 .• •IC0NbO• • 0 •1sG•01. '1Ott010 C 6La••(ST 0 00C•. T10aL . • . 11' . .51011• ••• . •. • •IC0000a. 00•1.10 C . •1.00• 0 1559 . C sOCa . t` SIOTI• . .. • • 1110011.•0•0 0 •1f+*KC - 0 • sLasoeLL - .. • , 66Ctro O. 510..•[ - • 11110011050 - t •1.0001 D C SOCCSTON a - •coullw + • •IOSeo _ ,,,, C •ts•1MG • - •LAS INGaNC• _ c •, toot • 51.Cu,06 - -• •ID•aLL 5 •10SELL ,e . •La5N , . 0 •OO(Cala • .. • 61161• . ,• '0 • •IS*O.51tt . , 0 .. 51.11•,50 _ - 0 500(1.1. ,• 0 5181• •• • C •51011.1. 0 ••1T •C Slates . 0 00050 - C Kt TON• , .0 55105••,... C •ITT[• - • : 100•510100 °, • C 000tMOuaG 0 5(.GNOL2 • C 0110511.1.1 • • . SITTMS 2001•16• • - 61.[010[ , C , 5001•E 0 5156%•00 0 SIG •LUt . 0 0 ITT6511001 •.• . C SL[ISLts•ILLE . 0 5000500.1..:. ., C •[.Gout ST • • •t. MOON • • •tT•c••LT1a , _ • •LLMCOt _ ., 0 _. SCOOT' ... • C 6[SG4 TEOM . .• PIG TIN[• -. • 0 •ITT00 -.• 511150 • .. O •Otl • . 515GS.1* -. O ••6550 • •19•0$ • 0 5150000 , • SOIL. 006 C 011100 • 516.1E •• •lSII• P SLIT Ms -0. •OCLVS a . •15tt • O ' 51651$0 ., • • WOOLLIES - C 01.5•101 •5(501 • seats C 51GS0D.M •t 40405E C SLtrIMT00 • 009111 C • 151 - 8 •16(105 • ; •1• 01• - • 611•6•1 0 , 501511. •00,TtC It • - 6 SIG51•• - . '• • •: OlaCI •uTT9. - • - elICNTON - O •OETTCNC* C 5101.10 - C •1G✓L•T-•. • MACE C•••ON 7 0 S11catMSTari" • •06•0 . C stew.• - - C a1GPOOT C • 61.51E C•N•••■ C 51.100 S 00608T 0 50•0110Iam 5 5165051 • C , 0••KKD el INS Tee C 60011 C 5(b•L 0 •16.•01 _ . .5 aiaCI •I00(°. • 0 5(100 C 5000• C 51..•100 - • •IGM$1.L S SLAKE,* C .LASS C .. •00••• 6 5(511•00 0 •101.111 ••• SL6Ct•0110 5' , 611111$ . C 60001 0 5(.0050.00 •• C •1051000.' • C 51.41,CCDU•• • • 0 - SI0CCNOU90-•, 0 y SOWS C 51.1.1501,TON.• . C •105111 • C [GMCICT1 • 51.055000 5/0 •••••0100 , , C 51510111.IL;.. • •6515(0. • 511035 DOI.,• . • C • 51.000 . 0 6011[0{.51 • 660IIC1 ' • $1051111• • •416t.0ol: 00.1■(O,• 01.000/.1110 • SOHICICT ,,, 0 SC001$G ' • . • C ' •16601110G 0 MLA CtWaL1. .. , 0 GLOM ING ,.•. . -, • 501151 „ - •51000. S . 11140 IN C 51ACIM•1.1.. 5•w,. • C 5(0001045.1 • :•OwcLT .. . 0 •$o 5/0 •19100CP . 0 SL•tt0a0IS•• ! 51.00• .. C ilMiwsaCl, • 5(50.0.0 • . c- •l4O.p C .t . • 0 . 1.1.000. G1•5q:Li• 0 SOISt/MST . a .. •. •14000 . • •Litt[NW9 O SUSS•••lU$_,. " 504•C a 6(51.6 • C 01160 • C 5LaCCM00Se t� •LOUOI . _ C 5640 0 •t•TELiam ' • •1162• 0 K•C•LttO • •1.05(51 0 50L•M .. SC 0110060 • - •ISLE?1 • S1.aC ILL IG C SLUCMl• - .. C COL•• C Scott[ a •ILLINDS C •LaCILOCT D Slut C••TN •/6 SOLO • S(STO ' O : •L•t.M•M C aim/ casts. 0 ••01.15? • 1(1.TCLOITI • •l•C•MOVrt • • TZ ON 106 . 60115 • C Notes: Two N•000L0GIC SOIL 656001. SUr•N •1. •/C SOIC•TtS 1,46 D5.1o(0/V10SatMlO SITUATION. 0001•1CSS 5005$. 1.G.. 1110551* I4 11••11•0. S TO • S•CCI•IC .1011. Sots ICS •51•11 SOUND IN SOIL Mar* 116510. 1 \ A-6 (210•VI•TR•55. Second Ed.. June 1986) i 1 . . Exhibit A-1, continued: Hydrologic soil groups for United States soils costa. C 0004[166 a 66*C(VIL%C C Dago C 1 •ROL(waODN 0 s011C&CD a •ORGIES o [sateen a COS0t0 C I SROLItaa 0 SOLID 0 SaaI6Na 0 ••aC.CTT C •5(ILCSS C 1 560.[0 . C •OLI.aa a •oozy C . 5010 0 S* 5TCO 0 1 LRDNIOC a SOLLINC C •oRNSTCOT C OSaDD°Ca • att.T05 C 660.0 6 •051.• C DORO 0 r a •RISUTI( 0 S•OMSUGN 0 DOLTON • •0110•[♦ C •OaDENTON SID SSICCCL C •SONCND 0 SOLTUS O SORStGO 0 SSaDINTO... ILDODCO 0 SOICINILL. C S106060. L010T • •Ora% C •P.KGUCaO • C 0 •RICCTOw C 10IS79•T0r •0M5SDZL O 800511 • O $SaD$Ma. . O elICO C S100IL1 a 8041S•7 0 500Ts C SOaDSON a 0510CC C 550050$ • 50005111. C 60008 510 ,roaDoaT a ealoccCUUCC C 8110r71 C 006 • LOSVa0T • 0 •1510• P S.IOC KA.60eON a 550011 , 0 •011110 0 •01..20 • 0 •S*DTVILIC C 09100E0087 0 5500Er1[LD la 006651• • -• •0SC0 - • 115 r 0.1Dcce a 500011114% 6 SONaPlaIt • 0061? • •FaCC t S•IDGCSON 0 S1001CLTN CID 60641AI0 • eos.ea a ' Sp•$aa a •RIDGC$ON. OQalrto C 55001.•6 0 41000 0 1050 0 SOII C •SIOCLT C •.ODESMIRC C SD.1Or•5N 0 •OS•UC R 55/15150 C •lIDGC.areQ. 0 0800[5101 C • 5000.1$ . " O •SOSSSUDC D ICD 0 •aICDWILL 0 650016TOw O/D OOOOOO.CN 0 •DSSS000. 0511.1[0 C leaar C 551tr • a SROOESTON. STONY 0 DONDUCL C POSTON c a C Latta 0 009DIS.ILLC D DOwt - - 0' •OST•Ua - 0 e.arLtTl t e•IGCS - • 5100►( e acacia a 'aos,.ecs • SS...0 s. C •SIGGIDILI C 660647 • •Io •eO6CT•50 - . C 60651Lle C 115*OC$ • SSIGGS.ILLC C 00011 0 e000►1eLO • SUS.CLL O SS*NCDO0T C 5014.1101 . VOID 0105051• • 5 506,61 C 505.051« • C D eaIGr1.000•• a GROSS • SONG • • SOTCLla a •Saw0C50UTC • 5011.5• 0 euOVGMToN o 50611.6 C •OTs.(LL - a 85•6005• a ••IL. • e •50.100 - c \ 50$IIa• - • .OTN 5 NI C 0 •NDASINC C •11551111 5 0 50010 - 0 I •0.1111 • .OT00 a 1 •.Iw?ICLD CM ••O.NSt•R ,' C SOwfTa 0 SCTTIMCau C 55101110 C 551.11• V •500110451 0 •ONJCa 0 SOTIL[ C 55a05C000 0 501557061 D 000UNt1L , a - SONS . 0 SOTTLL50C1 r•"•' C 0 e.IN1G*a a e•o.NrteLO - • ' ODNNtau - A SDULDC.- a •0•1TL(1 - c M 15G.Ct 5 550.111.![ .- a SO.1.1111. C SOULOCR LAIC O MaNt0N O M/NECK C eROV►DIGG • 0 •O,.oec a .OKOc0 room[ t SRasmea. .0 55101161 C SRO.NSCOaSC C 5000t.oalc 0 e0LILOSSCREE+. • • • •Ua15ri(LD .S 6615515105 0 •ao.*$C6Cfa a 506621 S .011L0IN a a 051110115 D 660.1110111 C SOI.ICVILLC • •0Ulrl.aT • C •5*U0 C 55100111. 05111110 C e.O5NSTO a SONNIC( • •O1MCC8 0 ' Se 0 J .510011 a 850.NiVILLE. C 500011 COD 80011010T , • •Sarlle - • 0810S • • 5.05670« Cie 500.111. bONOCD C 50115505 • • 5.551011 C ' 5./55.6[ a cacao* e • 5011 • 0 •01150( c Sal' 0 SRISCO - a •.DTtts - . • 5060 0 50614 0 PITTC5 c - SUISCOT • D : 66USLCI -- 0 •O$1•u • D 5w • D 88al5L105 O •511401. 05•INeo C 66114( • • • ..- . 010 . SDNT& • 0 . •Oa•aC - C. S •1170 • 65151♦ D SRUCII• IS 60611 C 50.51110 • • •aajITO. 1.1146 • SPISTO. 0 5514L1*. .1180 C 5006110 C 11,000110 C $U.eate LOITTO - 0 L11r6109T0m 50111115. GUIDED 0 SCRIM '. 8011110. T.ICI C 5.11100 0 ..3I/I/ a •Oat C •05005. 0 $511ra4t. gallium. a pauses - 0 •00'050 • C 60605( C • IaLINt•sLL•L1 - 060•0 C 56U10 a 5001155 D ewes' c ea/ cm c 55010- . . • 11066.6 •- • 60O(CLt5r 0 500!61 C .aal0•16 0 IN C SSU.S*UG$ • C $00LCD D •001$ • - r 601CCIIN51DGC SID •%01011 P •Ot C•r - .. O SOOtOUT C 00.51 • .SECaNOCI P 51101055001 C I.UNO*Gf 0 5002.000 5 •G51*41 ' ^ C •6LCESV*UI( C 15u0aos•D • C ' 5505511 0 u0061.a • 50.50% a Oat ICC • ' S.0.ONN5$T 0 •5365104 .. O 500661141 - D •0•0466 • C enigma • - C 560455005 - C 503150 - • 01O06TO■w - 0 SOampaa.ILLe 110 eagle,. r DSOASI1 IS . 1.11,5.141 - e ' • •OruS C 55190 5 MOAO.tta e • 665NICLL - a sODwts•wo a •0567.165 - AID 505N(6 - - C sa00tTT C •vus.carca • c •005[.111( • S01(40ee c • SStr5•. limos' - 1 Ovate D •NiS6CRCea 5 0005106 C •0•I050 C 6601110•1:016'- 6504[[1 • C •RuSIelS C 500.1101Llt C •11.1116 C sat.0 C SR0CIGULC• C 6611111/1 - a ' 5000511,1! 0 DOSWELL 'c Mgrs • 650CL11SS a SOT•. . SOOT« C 501 • 55100. C 0504661.1 C - T a 5001.15•! C •05CC • 0 SK 5111. C •soca0 e - 661 OILY 0 500TJ•Ca • D 0070 - 0 •Or611. S SSOC(00.1 • . D • •RTC•« a 50075 LID ewes I •.10.10 0 SUOttR040 C 551C1 D 50031LL*S C 001(11 • sprat 0 •.occssURG a 0 � .0511$0 [ - lotto.. • •.10100 • r 5001(700 • 0 .%511.1 -0010•..0010•.. h •0a c savLt • 0 Iarr1SVILL! C MOC10*T a Sue C DO5a.au O 501%14 0 Sat I .1041111 S • •3GUS e `�� .050• 0 •OTass D muss. • C 5600aLe C a3Uw C f •000110. - • MOH - 0 56(11[• • some C . 5111.0. GOLVCLLT 0 ■ '•00011 ` e •01[.... 0 00IETa.0 • 550[ - e •uCwaO•N c cameo a •6 0 555.•10 - C SSOG*N 0. 5114.111 0 0611513 • '.Act C T ' e•o .504000 a •11CN1.a1 C 10Tas: TAD .TDaasOGIC SOIL 560660% moo. •s *IC IsDICITEl tae DaaIOtD/UlpSa*NCO situation. .0011156% s..O.N. (.4.. •!0.041 1U517511116. weep to • st.C1.ic SOIL 51R*1S owas1 ►01100 IN SOIL SIP L(C(NO. (210-VI-TR•55, Second Ed., June 1986) A- • Exhibit A-1, continued:. Hydrologic soil groups for United States soils• OUCMLNau. TwtCa ! 5WCMt%I C C61.0 DOJO C CaL000 ' C carretw a SDLU. " eu,OCTT C C.SOOSC a Cal.00SA •: C Carrel 0 a - C eu`tw -• C C•POr 0 .CALLOUS! , ! CaMTIN• C aucte►T C eWGtSS C Ca6o1LLr C CaiPaC 0 CaPTON a suctcaut C alrtt e : Ca•$TG• e' C.lPt•c 0 CaNTON aCNO C SUCtutt • ' C eueleual ' ' C C.CMI - 0 Cal,twt B Cariots a auCtwall 0 StiC( C CICICVC C CaL.O• ! CaNTU& a euccwDUSC a SWtei0.■ C COCTUSYLOT C C•IUUC ,: a CanTUCNC • 0 •uCCINi a •uottviLLC 0 Ca000 • . 0 Cal ve5TON . C -CaNUT10 . S 5UCtLaAC' - C 5W[N•eCT a CaDCVILIC • 0 Calvin • C C euC[LaNO • C 800LE 13N are CaotllaC - a C•lv1ST• . 0 Ca■.ON 0 UCCLI a •ueLCSPN 0 caDlt - • r CalaeCIOS 0 .Gaon( C euCKLCeae S OuSLC.asm D C•orus a Coll*CCOT• O Cana, 0 •UCAIEy 0 eu•LINGtoe • • CaDOr• D . catmint! 0 • Cart 0 SUCILICC - C Ou•r•M • 0 Catsao • Cara000 a - Cant reap 0 5UC5L1CC. Twice ' S euNaC D CaGty. - C cawae1L10 . C CasawOla • O SOLO• - au•wsO•DUGm • • a CaClt • . C • Caw•OILIO. OartaCO 0 Caotal • D SuCALON - O etatrel • • - C C.GU•60 • D Ca•.at a CaPCOtom • D SCANCLL 0 OuN(Ttt - C C•i.IN a CANS. STON, e- C*PNDQ S Stete(' S twee/ma. • 0 . caw0. - • a C•N•Tt• • O C•PILLO C iucaPtaa P euSNSIDC - a c.TOra -+ . . a CarsaaCt a C•PtsTOaNO . . e INCAS a aueesmicLt ! Cole . a Ceeeleaw, _. . C CaPiTar . 0 suCCSN01 a estews.iC• B CataPO! • Cosines . C - CaPJ&C C SVCASCIk C SuSUT Lao( • CA110 0 Caaa1TM C CaCLCN . 0 tuCsTOi - ' a s .i•IVro • - ' e CaJ•iCO - C Cassel• 0 • :C*PLrs • 0 tuOC - C !unit - - 0 CaJCTt • P Cars•IDGC • C C/P1.el. °eatNCO - C IUDIw0L - - 0-• alit.t'. 0 CaJON. OvIausw • • Coasts ! Caren• tuOLClrls C out, Illy ` • C C•,10,11. Darr • Caste[ - • .. 0 Cao00%C C . WILL - •'- ! 6tw11LCy - • 0 . SuSSTQOTUN CaretSaCA a C•POS a lute• villa. O OWSON • C COJOP. Silty - • Cann) • C CaPSNae C 11K••ea• - I. 0 •U01 • 0 . Suelte•/U•. CaNEeON 0 Ca•lin• C ,U/ICDLCC• - -- a: PUOTON 'O . C•40.. 1.: a CanILLUS • P ' C.,TIV• • c e/0 turrINGto1. ! eUee_LL - .0 Cnc000aM • • . caNlas C CaouLIn • e 1 tVec - e BUSS! - r C4.Oa. f C•NTPaNA a Caa•COLtl 0 fu►root ' 1 I. C Dust a satire-allalt ' C.sa•LLI. succ a C CallaOar 0 ( . • 1 1{ITOm . • C instep e . C•JOu. CDLL.. • SUa$Taalum. :. • . CafaLaNPl a 1 ruNalG - C eus...a% e • C►t • - C.NPOtLL.,Oealat0': S CaeeCNGLI B 'UCC • • ••• C •USNNCLL C C&Jaw. GeavtLLV • • • CVN,SCLLTON C Ca'PO • • C •Ulst - - - ! 5USwvallf! • :C - C•JCN. COOL' -- - • • C•wNc.etec - , ,"1 C Cannel . 0 Nc0 A a pU'.•• a C.JOw. oasis • Carla . 0 caelor• . - 0 1%R3. mil w, •- C suss• .. C Cal•lao D - Ca100 _ C C62113060•11.1 C62113060•11.1 C . a/0 • WcaCeti..,, - •a::- ! BUSTt• e .- CaLarasas _- , e Ca_-p C caeclt! 0 _ UL•cC -• 0 OUST! 'C ' Cal•rINt • O Car, • - a Ca.OtwaS -, 0 "i': C 6USv.1L3 • - -e - C•Lari?! - 0 Caw,UL . _ a Caaotrr - - e • sL ova .'.'. •-s. .5 ' CUT•NO C C•l••LS . . a . camel0ew . : C Ca• ( Ot •N e uLL nW. N C eu!CNt • - c CaL.veeas .; - • e . Cana •< C Cae01•ct0 C -P Sue sto•Tu- PUTLI.-• - ^ e - - .! CaNaaa • C Canaan • D VIA. Te•IL . B '. euiLt•tO.rw C • Casco - •• cm CawaMI O a Caatrset - 0 41 • auTTrarlCl0 • • c . CaLCOUtta n 0/0 CaUaDICC - • D Cantu ,. e uLLC,etc • ' • .0 ' eutte•■tLC a Ca&Ciosl a c•ralOU . . e C•SC, lac( a - - -a eurrces - e C•.01 C . Casa.0a1GUa . 0 Ca• GtsT a - p%lroo .- c eUVTDM - - O CaLOte 0 : C66666e664 - C C•RGILL C NLLION • 0 eut•ON-000 .p CaLOC•.OW .. 0 Cawavtul • . c C•CteeL - a u • • C et'Ttosviuo.•r C C•lo.lLL C Caasltaw 0 • Caalaou - e NILOC1 0 surf., - 0 C•loetll• J,•1NCO • : C*UOfLaSla • a Ca*IOCa • e slat• - P Cut/Oa. sO•t.Nal 0 - colt • a , Casotlt•O • C Cats _ C uLluws, -•-- a ,Opal. oeatNLO CMII•S? . . C C.N0511tV • s CaSJO C sL•SAO - , • evcrON. stagy•; - C Cale, - . - - • C*NOlta . • Caallw , ,. 0 ulLetrt Le - - • r surioa.'poDtaaveL,. C • CatttONl• . . C. CaroleStIC1 .: c CaKlr!Om C PLOP 'a • .ell Oa•/KD -- CKtgO•• ., C CarOOS - • • C•eLISL( - - •/O sop - - • nun. - • . C.lt•• . - C Ca•K - -C CaSLITO , • .,. 0 u.COrnt ' • c e - o Caasl • Caat•Ot: O C .. &ID Je00 0 SPICE .,4 . r Calw0Uw O . Cowes '. a .1 c•eiOtl• e Jr006, •',',•:- - 0 : e.INGt.Is C CALICO., • • .0 , CaSiC . . . , 0 CaSLOs r .• D , 0v a •• C SvLts C CalICO64 • Costs? •o Ca0016a0 C JNDwar - • •1'• C Pith a C•ltPON - C Ca•lev!lLtl a . C Cant• 0.G. • JNCJUG - c spasm . '•^ • c Caliol •% . r C ti .• • c•alloa •e amCgO a !Mao ,- - C C.l l to • - e caw/ uds - . .0 • Caal1T•or - - C no[Con1LL: ' 0 - ...emit - ' • 0 Calli• a CaNISTCC etc CaSLTOP . C "sw.vt. - - C COSaILO t -- Ca1Alrs • •C CastItt0. Il-i.. 0 CaaraCE a Mt. • - C C•ta•T3. c C•.1.•I0 • -1 C Carl.t -a - C .ands - 0 c•1664 • e 0 CaLLaman - 0 CaNlow D - C11601 - a • JNletwelEP -• a Ca•aaNT C Catiar C CaNatLL B C•r.ICM•CL . C ,.iIILVILLC C C•SSaat. $.T,wVr • 0 CaLltivas. . . D Cao.ING , 0 CMOs/DDT C J.y•N - a CaP6a•T• Baer- CalL lull. •' C Cawror . a C• c• J _a.. • • c Mgt IC. - 0 C•LLISSU•C C CaMSOMrILLC D Ca.NIGI! C • ■00• • - e Caelw 6• CaLLC•aT C (sNOr a CLSNe•0 , ,; C JPCM•. - CouNt l • - C C•►r•o • r (•UDIO O/O [••mLv o JotNako o caalc . 5/0 C•LNtpa - • C Cartal.• , - e • Casette( ' C 'Cl: 1.0 w,000LOGIC soft c.ou•s suc. as etc NDIC•lts Cwt 'oa1N(O/u•Owalrt0 I*Tua?I0N. .Nelrtcas Silo.... C.G.. •rlto.oci I.JSS1.liuw..Krt.'1O • s. ciric-c011 Sf5[e1 •wa$C roua0 In spit. Mao LIGPND. . (210-VI-TR-55, Second Ed.. June 1986) I Exhibit A-1, continued: Hydrologic soil groups for United States soils CIDOLLO O (4.14104 C VISCOSE 'a C.•IaLetiC 0/D cMc.acL• C C•llow •/D CaTa.OUMt 0 Ctwll• 0 • CwaL?O' a CM!.CIa. C CaaON. .aaSMT D C•TaMO a CrMTIMAY♦ • CNAMMOCC C [Wrenn( a Ca.PCNTPA P C/TIRACT D CCMT(P C. CMaPMOCC. 0 CMIA • 0 Casa a CaTa.1M• O CCMTto Cacti _C MOO • 'ET (N1m•a D c•aaaCas Co Cat•saa C C U.ftwai*G C CMafo C CHIC/*f C e CaTaUla O CrMttiI1tL0 P COMIC C . CNICMaaTMa 0 C•..CRttc a 'CATCNcu. C CCMttPvII.Lt 0 'CMISenIJ•G a CNICC*KONIM► • 0 • CARRlI•L[S • C*iCLLI O CLaTISsi.a C CMASCVILLC • CMICcIMas a CA00110 • C•trwl - t CFMTPIL °JIM, a cMasc• e/o CNICCaiav C ca..OILS 0 CaTM C CC 1A • O CM•sT•1M D CMtCt•sMa a • CA.QTO•Ca C C•1NAaP I.. C CCMTa4IPCAK C CM*TOUON 6 CMtCCRttc •, 0 C•RSItaS • CaTMe► C CtDSa1 • C CMatCOLet a CMICOLiTC c CaaStT•S. ett a taTM(aaT .a •Crot!CO a .-.CIJ TtaU 0 CNICOT( - 0 C1610M 0 C•T•(O.aL 0 Ct•IM1 -- t CNITPtCLO a CMIfPLaMO .. 0 ca.si•IP$ .• (Aimee. a Ctwtal'. I c Con'M.M a CM$GLEIN. •- C Cao510.0 C CITMCO$MC C C(PIIM C CM1T5.0at0 0 CMIIIMIM C uor t CAt.ta■ci • r 'C(auILLOS a °W MT C CMILaC C CaofaG[r• C C•T•M O a!O •cc..c C CKITUGL 0 CNILCOTt C • C•DtCCar • C Callum - CI Stall C CMm0e00t . 0 CMILCOTT. GP•VCLL► 0 C••tiC • 3 'CALL• 0 CCIRICI r CwuMCIT C CMILCO/T. COOL. D Ca.ttc(1 ' .0 CatLtt► co/ CMaCw C ComUlauous C CMILDS a Ca.iNaGt - CAPLIM 0 CMaC CW - C (wvlti 0 CM,LGPIM • C c•eus0 • C. C•t.ao• 0 CMS, C C t . C (MIINOwtt • C CaaUtM(PSV111E 0 C•i.o. Oi CNAP•tC , D CNm0500 ' C CMIII 0 CaaYtP a C•TOCTlo . C ICOICrIN C ' coazOS C CNILICGTIL. a caRVlle o' CaTCOS• .. •CM*IM C **come 0 CNILCOOT D Caa,TO.M 0. Cat•OIst • .CMltwtS e/G CMtaMI .. - 0 (*I'LL 0 caoovILlt D •CatTCataa t • a CM•IIirS. D Cen,40,aao 0 CoILLY• • • a Cas• GaaaOt !: c .CaTtC0tt1.- • • cogamt5S floal ' • CMCCMI 0 CNIIMaat C (As t • . a Ga•.ceL' • coolly _P' 0 CKCcro - C CMILDOUIM 0 ' CaSaG• C. to*0Ta•Tu• CMatC7 0 CM[CCCTT 0 COILOr• 0 CASCADE C CAM) • • D •C0al.OM► „ C CK •OaTM a CNIL%OM 0 C6SCa J0 - • C•UOLC C CMaL.C.tiI a CMLOtoIP • a (MILTOM a CaSCaJO. COa0Lr ' ! CMIStal •C CMal.rws - DID CKOCSal 0 CMINATO 0 ':1SC ILL• •' a C wit• _r 0 C.a... •00t.aTtL• t CMCOSU• - C CMI0( C :aSCO a •Ca.•L '. a sloe Drift • c.RCaz 0 CMIMCMt• 0 Cast ] - CLIM•YG.• t towed'. +,-teat[ a CMCCcTO••c• 0 • CMIMMCT • 'Case, • D • Cave - • 0 Pt0MtaOlLtv.- CM(CG(MIM e CMt0a.01M1 0 • CliMTT - C C•.EGYLC. a (rd'... Cl3L C CP(M•LCM - C CMIMC•O a tatNItas a •dat,eatll . C CMaooafe t (.1(04115 t CMINCNmLLO O C•SN10. ' : Caviii D CMa.Otl. • r C.neouLPUM • . C CNIMCOTtIGUC • 0 Cal..•Eat 0 r Ca.iMDllo - • a CMaNP(•la.3 • C CM - a CMt.,M • O Cass.0.1 a • Ca.O 0 ' CPIer(PLAlw '• a CMt.LIU• • CNIw1•A • Casty[ -• 0 Ca.000 ' • C , CMI.ISL O CMt.e.a a CHINO C CaSIo"' D c••OUO 0 C•r•Oca.S C CML0 . r cm:NO. 00110ED a Cato-C. 000to•►(LT C Cat• • , D CM/.••GMe a C.f,N• • (MIMOOt a •Ci - C$TaGY• C CMa.PtDM . a CMlNIMGO • . CM/M •o C . C•s.OS • 0 • C•VIOM . C comsat' • • a CyK•laiLt • P CMIPLMDaLt ., 0 Ca a CarYGa C CManCC D CMtNZGI a COIPtOMILI . 0 MD - a catusc a CMaMCLLLOO C C.lwc, a (Ntatt• o (ASS ' S Cai•OCP] c Caaao.(. • Cmonotsolo C ens/me. • C (Ass*. C CAI•DOa t tower• C (5(1.00[11. a CMIMIM. 0 CASSIA. a00ta•t(L♦ a CaIgoO.Ia t CMIMSIMOM 0 Corona 0 SALINS.Al6 411 ,.. •►LL D.•,Nto Ca0Dll• C CoANMIMG P . CMLDYt$T C CMtM•.. C. CaSSUIO • . CtaOLICi• C Cw01a- - r (5(.10111 r •OO(0aTtLW..L1 Ca.S1043. LION, C Ct.t.NC c CMmwlito • O cor.KQt • 0 ($106A0. OwaINCO Co CaSS01aP• t CM.. C C1Y••MOC3 C Calton C CMIOOL• • [•St•n • C CECIL a COIPi.TOM C CM(M•. CAL(AegOUS a cal MtM. o C•STall• C (eel a comas. . . C Cal.at• COOL 0 ., col•.[.• 0 castaw - . CCCIS •Yfit " •• r (IY•.*M e (Kamm 6.01MG C CMI•6M0 0 CasitLA ' C CtD4.••O01•TaiN L CMJ?OT a CKMVNII. 0 • CMIa1C*MYA 0 (• IA .• u CCDa.4M D - CMaPK LL (at.1I - a Coin.&&&&&es • C•s/tllr a CCOI.•LUaP, C CMa•0015 C C5(fl. • CMI5Ca D C•ST(0M(M - C • CSDa.CatCr C • CM*Ous f CK SMI.( . - 0 CNIS.O.t 0 CASTILE S Ctom.raLLS a CW*PC( C t CKIImIM• _ C CMISOLA, • Cast1M0 C ttoi.G•• a (*,aaCOl a cr[%wlaOvs a CMISP• a Cast IMO. M0•1ipo• 0 C(raPNILL• a cola r csCSim'te 0 CMISIOCM1.a IS C•StTC 0 CCO SS P CoPOOOTON C CNt%Tta a CMITIMI C Cast ] (COONI• a CM/Pt?tl C CK 1Tt.T0w 0 • cutely. Co CaS1M10 D Me a • Co•IGO C Cult TaalI a CM/f.000 0 (*STD C CclaC' C Cru 1101. • • C (11(150011 0 CMIVITO C -"�` CastOw a C(Lt5te r C Sots 5( Y a C1M000R C 0.1.ouIVM a CaSTaC 0 CSLttOr 0 CMa.L!SOIS• .I1 C CK TCO 0 CMI••v• 0 . C•ST6Ov1ILt a (R1.8 C CM•.Lti C (Kilt 0 CPO C (aSUlt 0 CC110 C Caaaltst7a C CK f.TMO r CMDaf(s C C•SV•OC 0 C(LL•a 0 Cw.LtvOIL . P Coot.IL C CMOOCt 0!0 LL a CCLSOSPa1MGS C C1'IaLOS r CK►LION a CMOtee. o ,isue ,I•L IM. a CeNCs c tMalllos. Att o cK,,ot a Ot•at5s10M•L OTCs: l.0 MTO.0IOGIC SCSI (0000s suC• as a/C .Dt(Al(S TMt O6a1N?C/u0DO•INCC SitU►TIOM. ■OOlrtt.c SMD.w• L.G.. &&&&&Ca SUSStCalU'. • TO • SPCClrlc SOIL 5(11(5 •'Masi POuwo IN SOIL •d'0 LEGe1.D. (210-VI-TR-55, Second Ed., June 1986) A•9 Exhibit;A-1, continued: Hydrologic soil groups for United States soils J Oett. LINtsfOat D CLALLA■ C CLIW.EN 0 COE(L e. COL•IN. ovtSOLOV.,. C sus CLAN GuLCN '0 -CLIbatD. OD•INCD C 00110 0 SILINC CNOCCOLOCCO a CLLNO ' CID CLODIN1 O CDIECSev♦ 0 COLWOOD .SID CNOCS 0 • CLNs ' .0 CLONT•NI t COCLTILLC a COLT • a CNOCORUa 0 CLAN• '• CLOOUallw C COLAND a/D .COLTIN D CHOICE 0 CL*OeL.IIt- • C CLODU•TO r CKOAa C COA•O • CNC►OO •• 0 CLJINTON C CLOCUCT a COL•EUT 0 _COr•0 C 0.00111 0 CLAMED •a cL.OSct. , • C COLeuaa • C COLIC a CNO.•LNONT e , CL*.ENO•c 0 CLOTHO C/O COLO. e• C01•S e CHOSSA a - CLARENCE • •0 'CLOUD WEAR. c .COlocatts a COAT" - e CNOTC•U C CL&RINDOI C CLOUD •1•• e. CCLD[Nl • C CO•!1• 0 CHOV•N • 0 CLAIMSOI . ' C CLOUDC•Oel 0 •CCLC C CO•rO•T 0 CHRIS C CLASCVILLC C CLOUOL&NJ C ' .CCLC06N C C0 '0!T ,a/0 CNRlsrer 0 CL•RINDA - • 0 CLOUGN • C •COLIOa4TORN C/O CO. • DONOCD. 0 . CNRISTIaN -- C CLeatON 0. C •COL1STIRt C COW1Tes • CNaI$?Iara C CLANUA 0 •CLOTES SPRINGS• ' a COLVAS C. COIL• C C/.•ISTIaN•U►G- ' C CLA•s • P 'CLOrt•DAL! 0 COLNILL 0 CD•N(OCC . C CHNISTINC D cleat 000E --- '.A • CLOvIDLa•D C COLIa00 . . e COINSGI • e CNRIatOIr - C CLA•sCLIN - a 'CLOVIS le COLtIeS a. •CONO a CNRISTT C CL••s•ANG( C - CLoNt'S • COLIC• 0 COOOr0PI , .0 CHOODEO • - a CLASRS•UOG • C CLOrtaS. ',IT' C COLLAIta . C CONOOOO! 0 CNROOa. _ C CLa144CSDALt C CLO•r1I • a COLL*00 r ' CONO.O a CmorSLta C CL tIlt - e' . CLUT? C COLLATONI , a COMPASS . e ' Cwala0 a CLA•NO a CLU44lc --C COLL•a•N • 0 CO- "•TCC . 0 CISU••S - • C CLATO P . CLU•OC r COLL•0aa. CCCOLT• C' CO■STOCK • C - CNUC.LCNU1 0 CLATSDO D CLUSO .-'•e• .7Cf .t!Gto•LE C cOWUS .s. a ', CNUCC*R•LL• T • CLauNCH - 0 CL•ot .-+`t/D •COLLeGIaTE • • 0 CON. .•• C CNUtsL(S - . a CLartS•C1 C CLTNI• - .:r. COLltTI CONAa' • .Pro CNUCR•IDGC O CLCVICON -' C - ;Co6CNCLLA --- e" -COLLCTT. . ...0. C CON•L! •• ' e CNUGCOIECA C CLaWSOJ - C 'COaCHtLL1. WIT - _.C• COLLI[0 - . •,A COIANT • • . C CNUCTto . - a CI*TSUNN 0 CCONUILa' • e COLL MGT". •- .a • CONOSCUG•- •-. C CNUIT • 0 Cl. INGS s 0 COAL 00111 • D COL/INS C • CON•♦• _0 CNULITN* 0 0.ATTOr • a COaLSAWs •, a CCLLIOSTC•, a COO.OT - .o .' CHU•ALL ` 0 CLL LLUN - • C • COMLOALt `0 'COLLINSvILLE 0. CO/CEOCION . 0 CHUrIT _ O CLCaa Laac =. • - 0 ' CO•LO••• . • 0 C4LIIN000 C • CONCHAS C CNUNSTICS •- 0 CU..* Last: • C•-." COALNON? C •CQ■A - .e _ CoNCNO= . C CNULLLL0• ,- C ST•&TirlEO''."•'- - Co*ND•• . . - 'C "COIODO .a • CONCONULLT • . a - CHYRCH 0 . SuOST•AtUN COa•SIGOLG ' C C0.r(Vtt .0 CONC0.0 --0 CHURCHILL •. 0 : cues Lear.- .. C COAT-says: • - D C0.0 . ' Diu • CONDA • n CHURCHTILLC''' '- O •oDt••TIIT•.'Ntl CD•aT :- ,' •. • a -COLO. MAIMED 0 . CONDI[ - .0 CNYN• - e curium/loot -' - 0 ccoAtUS _ C' =COLD. NON,LOOMED °0 CONDIt . 0 CHUSa• D CLlear ttLO•• ,•-• C COCO 0 • COLOCCUN .. a • CORDC'N ••..c4. . 0 CHUIC • • • CLEAMPO•s"•' 0 CO0SSYO•C •- D :COLOl• • ' COIL . - -? • dells 0 CUM/01111P o CO010 - .A,, - 0 ' COL a CON(CUN 4•-• 0 Cl•tOut - • CLj&VaGC - • . • 0 Cont. - r CLLOW C • CONEJO • a CISO • 0 CLCCVCO - r o COOLIE - O COLONIC .: • ■ COICJO. VET .1 C C1.OL4 - a CLL 0 Cellar -- - C . COLONVILL[ C CONEJO. GSIVLLLT C • CJD • C CLE•TT 0 COOPS _• .-^ C COLDS a00 0 sUesTICTU• _tau t. C CLEGG -• a CO•U•G C COloOOCi . 0 CONESTOGA e :1Eat•• - . • .. C CLEGHONI - • C COCIETOP• C • COLON0N a CONTSUS a :ICNO - O CL5Na• - • • C0C44144• 0 COLOSO - _ 0 COHITOC a :ttRvO. ALKALI:' 0 CLINIWTlNe. e C COCHt'I C COLOSSI a COWIA•II • :leamo. I. 0 CLENt.Tire'. • • CCKI.O•r .- C COL• C CONGER - C ref • - ■ O•a/Nt0 •-' COCOA a CDL.aelr . 0 COWGC•. COOeLT 0 :110,0. •ecLa1Nto C GLOM - e • COCODast - -• C COLSav/GC - • - C TSNSSTa61UN :101C ' C CLI■•ILLC • COCDLaLL• ■ C COOLIE• - • CONGLC- a :IU*1SON " •. • C CLINOSN•N - 0 COCOl6LLA. ONAINCD C COLIN'', ., D CDRI . . 0 .10CI0.611 C .• cLEO•t • COOLIE, a COLTON ._ • CONIC- • , , . C :loco .e • CLCOM• •• e ' CODD•us - - c CDLT•oOP c COILtN - ., ! :IAWeowaansT • ' o -- CLCRr . C COOOUIN - : 0 . COLTS Nets • CORM' C :lotee. a CLI•a••N • • COOTLatt • COLUN•L*. NUCE D COootaUT _ C 'I 0 CLla•O•T- • D COO - • • SURSTRSTUS .1 CO1•Cl • •ts•IaNON'O • CLURtLaND .0 CO SICK - : 0 COLUISI•...D••INCO. 0 CONNtOTOO , e :INTO O.e 0 CLCK0L1 ' - • (WSW/ = C/O CLOT SU•ST•ATUO,: - COHOST• . C Iolta•D 0 CLICK .• ' CO>'r - --- C COLUN•la.•: .. C • COoOTTO! - e • IMAM a ClIPPOtLL - - • Carreto a . POOC•*TLLe VeT . COIOree . , . C IKLtaACS A CLIrvOOWN ''"• a CIOGON 0 COLuNASIA. Da•11.10: • CONONINGO• C 1•CLC••N C Cl1?PNOUSI - C COGO• • a COLUNSI•• FLOOOCO C COROCas 0 • ISCLtrtLLE - C CLIOPORO - C COGIWIELI C COLUoSI•. CI'T C - CD AD A10 taco a CLlrsaoc a COra1:EN o SueSTaatUN .. comma a ISAR D CLIPTCasCN a COHasiel - e CoLU445IA. SLOWING • CONSCJO • - - C 110VS a CLIFTON - e COAOCT•H .. •/D CaUR•1RC a CONsea .. 0 ITADEL C CLIP?? • CoNOCTAN. SANDI 0 COLUN•US - C CONSTA•LI a ITICO - • CLIOA•A 0 SuOSTNaTV- - • . COLuSA C CONSTa.CIA _ 0 IT•ONILL! 0 CIIN•s 0 COMIC - • COIVA•D a . CONSu"O 0 LaCC•NaS ' 0 CLINE C COILS C COLVILLE D - CONTACT • L•150•NC • CLINCTOP O CCII 0 COl1ILLC. 05614410 C Coon! 0 ` - L•IRt A CLINT C cos C - 0 COLTIN 1/0 COr11OE a i i Lalat.DNT - • CLINTON -a C1=EDAte, SSaINED C COLVII. SALINE• C , COUTIOt C t • Task TWO NTOaOLOGIC SOIL G•OuPS such •s •/C NOICITts TN! DNAINEe/U•Daatlt0 SITUATION. IoDI•lt•s $MOON. E.G.. StONOCE• • •CPC• TO • SPICIPIC SOIL Sl•I1S ',Aft •OUZO IN SOIL ■•O LEGEND. 10 (210-VI-TR-55, Second Ed., June 1986) Exhibit A-1, continued: Hydrologic soil groups for United States soils CONTINCMTaL c COaaaLITOS. SILT♦ 0 Carets • c•CVa 0 CUOCRC[C • CoaTO • su•staatu. CONtSiGLeW • cKVasst a CUS[••NT a CONtaa COSTA C COSMIC° C COWCta C COLVISC.Ctt C CUCaNUNGO 0 CONT•ART a CORRIGar 0 CO•GIL • C•CVS 0 CUCMILLas C corvtwt C coasON c cONHORN a cetoe° a CIICMo C cootas • coat• 0 CONICME • COINS - 0 CUOGNV o COOL - O Colltaoa • cam-axe a C•INCEO C CUOSMT. OB•INCD C COOCRO•T C come 0 CONLITZ • CRININ P CYOote/Ca C coOL•.I?N c COATING • CON000 0 Coif:FIELD 0 Cu[aoa C COOLIDGC •. CTMIIN*. 101+ • CilleSLT C CRISTO C CUERO • CDOL•1LLL C M V•C[ COWTON C C•ISTO. Loaw' CufevO C CODom•S • CC:Wen& e/D COs 0 CRISTOP•L • CUCSta C COONSKIN C CORWIN a COSIaC[ 0 CRITCNCIL a cut.. o 1000[• • CO•WIIN a CO,VILL[ 0 co.TT[NOCal • Cu[Yltas o COOs•W • coo. c COP:tLL • C Caoaha• 0 coevOL.No 0 CooTCa C CoaY00N • O COP O caacrta • CLLI[•TSON • coaact • cosa° c COTaNNOs• 0 ceoccelT 0 CULOtsac • CoPaLls C costa - p COraTa C CROCSUS C CULL[. C CORaNO 0 cast, . • cave? a C•OFTON a CULLLos• a CORaS TO+ - '0 COSH C COTLI t C•OGMaN a CK• C . CON[LaNO •/O COSNOCTON C COYrt " • a CROCC a CULO[Kp C COPELAND. O COSCI • a COTOTCCRKc,••• t cco.u[LL • CuLTUS a OCRaeSSIONAL-. COSTILLS , • cameo • CSONCHIT[ C CULVING C COaeNaI - • a CCU:mm[s C . c0?8[.6 • • comes C cueetalat0 • CO•CreaG[N •.. 0 . cOTaCO - C COZTIIR - 0 (•motto 0 cUN•KS - C cootta_ • COTaIL a coaplet[ c • COCOCCO omega • o Comm[. C COOrtD MINES 0 COTaN' D caaCC[RCR!EC a Ca0CtC0 cam. C cumotoGI 0 CoMTR RIVER. a COTaTI C C•aCCLcs • a Dia1NtO CIINSttLtT a LaCUST•INI - • COTtsU • C c•a000CC • c•Oaceo cater,. c CUNaao • SusstaaTUO COINS . - C CaaOLCS•uGM 0 FLOODED CYNOICC 0 CO•USR •ivzu. TILL • COTITO • CaaoL[Iau:M. C CROOKSTON 0 CUNO1vO a sus s - Coto • IaL lut-alcaLI C•OO. - C CuWNINGNaa c CORK■ ■tvca. • COTO•asl • CaaOLCSauGH. C C•ORLCT 0 CURCO C '•� l stir• SU5ST5aTum COTT • ORAtat° CRORR[R 0 CUROL& • COO►[• alv[a. • antes a CRAFT a COCCUSD 0 CURRCR . a GRAVELLY COTT:RAL • Coa►tON _ C CROSS. C CURK[s . C ' SUSITSaTum - COTTI[ 0 (Rai . -a CROSIER C CuRT 0 n cum...C000toc etc - • cOTTOom.. C CIaGO a (Pass - O CW00011111 • CO0000410 ' 0 COTIONINONas• • [Rain. 0 C•OSSOLa1N • C• CYRa.1 • 000•t•TON • 0 COTTON/ODD.• C CIAGOSCN D CROSSTELL _ 0 CUUOI1 C CoRWotc 0 COTTICLL C coals a cuOssvtLLt - • CURCCaMTt • CDRS[• 0 COTULta o CRaIiNIL[ 6/0 CROS•W!LL G CURMOLIO■ • 0 ' COOUat 0 COUCH D CCa1GS.ILL[ •- COOT . - O CWROa 0 COOVILL[ - 0 COUGa0aa' 0 0 CROTON . 0 CUURaN C Coa• • - D CWGMaNOW C CaaNON1 • , C CsauCM • CURaIE0 a CORAL C Ca0.t[Daa, 0 CaaN( 0 CROW C CYaalttCt 0 • COYLSTOI • ' CR•Net:eta C C•ON CREtg 'a CY•Tir 0 comae.. • COULT[RG a (••.FILL • CROW MILL C CuOTIS CRttI 0 • COa1ILT • • COYLTC•VILL[ 0 C•*NNLC• - • CROWCa.R 0 CURTIS SIDING • CORSIN • CDIRCCLOS • caam•TOr a caOv7Lars a CIMTISIOVN 0 CoRC[Ga - - C COUNCIL • C CROWFOOT... a CmameN•u*. . a CDa°[LL a CDYNTRTraN C • C Romano ail t C Cuu.ING • CO•DCS - - • COMITS 0 coati' Last • CROWLe7 0 CUS•MaN C CORD[ITOM •- • COII00[ • - • 000 . C CROWRST :0 Cl/SROOL C COODOVa C/O cOURtvtLLt C comm. C tom same • CUSICa a Cove, • CWRt • CB••FoRO . • 0 CSOWTK• 0. CUSTCO 0 coat,. SOO COURTNOUSt 0 CCSLCVVILtL • 0 CIPORDDM • CUSTER O CORINT. C C0.*TL&ND •. Catal C CROZIER C CUSTER. oRA INFO C co•estaw! O COMTNty O c•casev (F• comets 0 comma. a COaLtra • Cou•t.00z • cacao • CRuCSTON a CUTNaau • CORL[TT a COYDyIIL! - ' • Cale0 c CaUtCasIaUC . C omega? C CORL1• am Cams! C cetto.OD. C Gausses • CMTNS!•T• GaaoCD 0 Cd►rarT'•, AID COUSNaTTI • Caltl C C•uNNIN• • CUTOFF - C CO•NCLIA • COITIS U. comma • count • CUTSNIN • cormestiS C• cart - O Coerce[ • C cause • CUT? 0 COarNlll • COVCLaNO O CatIGNTON • Ceuell. Olatrt0 C CUTara 0 CORrtct 0 COVCLANO. Oa•IM° C CUCLOON C CI%RRC[• • WTOr • CORNING C CDOCLLO C COEN • - • CaiMival a (Tar Co.Ntst C COPE*, • C•COL! O MIST 0 CYCLONE •/O COSNUIT C CD►CVTOw C CRCS*I • C•WTCM C CTII.Dta a CDarvILL! • COVILLt • COCSOWR0 C CMITCatfR C CTWINIC 0 COSOLLa 0 COPING C C•CSCO C CamZt C CTNTNISNa D COIONa •, COTINGTON 0 CRCSaee • CRTLw• C CTNtNIaNl• 0 CoaoM•C• • COWaN • Cats.lr C COMSta. LAC[ • CTRN[• - 0 cosoza.. C comae?S C C•tsT C Caystal sUN/NGS 0 CYR1L • Coaolo • COVCO • C•CSTLIN! • CRTSTaL/UTTI a teas • CORO[MtNG 0 co. .CE 0 C•[01000 D OVS/aLQCte • OaaMe• a - loRR•L C CoNDR!T C CR!STVlLt C Cu all - C Da00a C koaRAL:TOS a COVC[MaN O CPC?! C CYO• I OaCEta c gilts: IND LOGIC SOIL CID1IOS SUCH •5 SIC NDICaTes tome Oaa1NtO/YUOaaINto SiTuatIwo. NOOI'1taS SN0ur. l.G.. 51000(5 sues...Iwo. steep TO • SRCCtetC soft states PRASE roues) IN SOIL NAP LCGCND. (210-V1-TR-55, Second Ed., June 1986) A-1 • Exhibit A-1,;continued: .Hydrologic soil groups for United States soils •c0*0 a Oa.l•ND P otctt••Illt• C 0.1.10. Cla• a 0150 •51.4. a .Coro. COPIL• c 0551.5• C oo•Ieto •- Iur• OCSCNUTCS . . C ` .41.170•741. O•QLIM.; a atCLO • - e ova.fo15 a O(SCO1 a• cant a oaRMs,aor o OSCOLSI• a DELLS C 055550 C cos v• O o•RM!lL C O+CO•oor• a 011.1.•000 • D15(K t . . C DC • OaeanN • OSCO•. C 0115• - C 0(5•• • 0 Ole• • 0 OuD. • C • OCC•OSS • 011.511• C I Otas.r0 .. C• 14i1 5 D••e a 055• t 051.0057 5 - et SI•N• • C G•L•T • C outer C 050*1 • a OCLN0.T( • C 0501151 .. a GLUM 0 0•oaoC• a ccorevs' C 051.000 C 0C101.a110N - e GOD ti e O.05OCM. le CDDOCt C Oro*1C• 0 011.011 a•o Ocs•a1• . e 04110 C Sues to•rur - etc C Otl• • OSIT•10 0 0411• C 0•05051(11 C DISCUS 5 • 011.111 • P • CE1 TER ' C 011• '• C DAPS II C Dirt MI C DC4.•WDU. C Ot K• - C 011.01.11 st a O•rsi C • income • a 0114.5 MOO* • 0 ' DS10U• - • • a • 1ci. O 0•01 • • '• Oft•CUT O 0(1.01.•15 '• 0 DI Vita a 104.5 C DetraOUT« •e O O Dete01ST C • OETrOIT - C Ilc• - •• O*.rt• a OfE••••e• a '-. em Ot Ur*. • 0 11.5•. 4.0x••• • 0 DNS.IN • C OCt• cKtt 'C 0(1.111••• 0 055 • 411515•141. - 0.14•(0 D PIRO •1.t • O(•e(s5IOO•L' • 055.0• - 0 151 - P 0*1111. - 5/D 5(1••100 • a COCK•IDill 5 ` 015(5 . 0 • (CPT a 01st `.a“ a ' et&& -0 eelsD• c• • 05•:Ls - 0 col• - - e' D•TCL•im . • . - e Ot(•4O•6 • ' C 0511•JD - C DC•tLSCSE(c C _eo a °aneo•ie . C 55(•L0005 C 011.70« a 01511.50•11 - . 0 • _a• o o•rto. a p55•10•. - • 051.515 • • OC•IlSG•iT•-•"• • e .Coke - C' 0.0150 C Otte1e•lL 'C OtL•1101a • 05•1550.- • . _CO • 0.' "tat IMO. .1 TOWS, • P CK•.c00 ' ,- ;0fe Ocuso 0 • OCC•1100•LL• _t ' - C 05571 • . a •e Oe.ILSGaIT..:_; -.; • a _S cat t• • • c 0141L Tor C ' Otft*1a4 • - • •5 i Dentin, a D•at5t0 • _[•11.1.1 - • 0 0••c•.• •• a or.imeet 'o : 055150 'a 0141161 • '- C .Niel 0 O••5•. ••■•1• • 0t•Lf• a 01517 - 0 Der ts•O(•o • c . .IaN a oar 1Oa1. a otrceo • • - • .•/S 01550• a C(50C 0 .14 e• 01510505 a 0t0•es01- 0 ° 0( •001.0. 5 orvoI Gilt S • 0 AC** c• OAR IS e ' 010650 • • •. .. • 011110414 C 0150:Gres. O•al«CD C • _l•• - a'• DaVISON P 0110(• •* a Der0NT•t•tLL( a oc4101G0(s• • C • • 11.1.5 '• C' oa•TD5C 5• 1(0eaw0 - • • e • 0100001.I1 ;C •eOT(CTCD - f .LCS•o5I 0• DartS C DI Car• 0 D(w0►OLIS• COOOL• '0 05.01 0 -10« C 05.0100 wro DfNara -- • e Dt•0S1 ' - O DC50el e • .wt 1 01.505 arc 51.•41 . 1111 a 051101 • . - . e • 0150• C , .2511. • G Dam 70518 • '.a.' ' C -, ot.•'RN 1 •- 011•011• . e DereIts .. --• . C .•SCUS • - • •/O D•i?• C • Ot«ILL - • 01501755 • - • 5 • O(••• - 0 •S.D.. 6 D•• .:'•.d.. C. 01.7.INC(• ;• • otNiUD •• •S/0 0151• • ' e 15•000 •• - c o•w%Li. . •• • ••` Otj•O.CT . I ': 005.• .. 0 . over re t1.1.5 . D .6i/1S C' 0111C•10DL 55 Dt C ' 01/19 WI/ • c - 0fr0I«5 •-- 0 row •• • 0: .41.1'05 0 05100• ! . Ots•• C Drew*LEA a .• - e. D••TON• O eet3.l. .• r D DISCO - 0 DC 1 a • - •••C• C 015.1ll5 0 ecL •(• •0`•". C•'• •tsM•ratl• D - DI• - C troll . - • 6' D12L .- ' C Dela C Oto1Sos . C .: D;a. 551. 1•L•*M5 0 ' C•.• . . 5/5 of r•55(•1 .. 5. 0cl•me SCR • - • • 01•••• ti . C DI•• 511 0 Da*•• -- CI OSICON • T•.••: a Dil•OCO ' . • - ' r. 05554•C • 0= 01151.0 0 Dec.• - . C ` -- C 011110 •• • atom is .. • , c tl•CKcw e 0510(1'.' 0. D(5050U11 C 011..05• . .• ossonl • e . o1•r•«rc a 5015.. - e 011301« a DLl•1I•` • a De wow - • o 0110000 _ - 0 C1ee4 - - 0• Ot50.000 ' • ^ O C • 0100011 0 01a10a0 $051MGS- C 1• -•- •io 01:11070• a oCLCO•? D Slob s . . D DI•UL110.1LKL . C J1• 0' 01••• • • 0- OttOCI• - C 0$•41e5 • 0law7• - C ED ' 0555 . ' 1 ou5C0 o• 5505(6 '• C 01.551• . 0 LE• C. 01.50•1.5 •^ 0- DELtSS• • • D. • D 01•5•.5 - a • • M. • •• ' •• • r oe•aso•w . •••••••• . - 5 otLt0M C'- DtKO• a 01•7([ e mt.woe• a D(••7TO• •V•C Ot1C5t•IP . 0' 01.05 ••• . O 01•2 • - C Lt it a O(arr•r •-" C 01(5111 •• C OSPOUT -• C DID0L5 C I J Deane "f' • • C- OIL'is• S. 0010•• - D 01.OLI. • . 0 - •450S C• On ail C or(•I •• - ;. •/C- OI•UT• - . .C:• DICE - - • SILLS C 0S1155C(11 C 011.1.00 - . • It 05.4 _ . • 0ICc(•SOu. 0 +•lo•LC • C Ot•COU( • It 051.011 •. C(•a1.(0 • DICES, -,, a itr • • C 051/.000 c •?LICta1 • Well C. 0ICtlsSOo. eaP(l5 a 1.04010 •- • 01UQI'�+'• t O(L[t CIO 015 • • D IC/tw10.1• 1..- TIL • !• C 0(•1 ! Qtll C '•OSK CPO 0, SueST.•t11e . :co • Dt•4171 • c 01lltat• a Deet.O• c Dicasesow. .writ° e - la K•4.1 S or Car - • C 0el1.5. 0re•••s01 • OteL• 0 DICK INSON. ■S•rtse • atN • OCC•MT!L a OtllC. 1111.! • C DISCUS . C Olcameo • ,•. • 700• • • • OCC•TsOo • • C 0 . 05.551.1.•• C 0055 . C . DICK SON ... C • 0 o5Cltue P SUtsts•TU•. rEI OEee1CC • a osee• o +u•- 11 •/O °etc• • 0t0. • 011 •OIu(S. D:• 5- Diema111.01 C ;o. 0 DECC•. 5056114.5LL• C 1.1.INC-acta&1 Des 5011111. 00501• C 015•1555 0 left I. i Old•5l 0 01(1.0. •fD1••15L• C 015•5 _ • O/C1.1CM C :gull a e cece ' c eel Ots••, • C 01(5• e :Carves_ - C 0•CCC•..111! " 0 01110. o••10ce • et1110•• c 01(155 c • c OSSC P 010«705 0 ,• -. . . ., ISO ...oam.O41C so IL 0e0U•S 1UCr •1 •/C NOIC•vet 1.11 a••I4tD#15.05.1rf0 111W Clow. •001rte01 5-0.•. S.G.. 100.00• Sues TeatU.. •Eft• 10 •'1•CCtrIC SOIL Slott 1 •••55 1.041.0 IN SOIL ■•• 1105•0. (210-V1•TR• . Second Ed., June 1986) Exhibit A-1, continued: Hydrologic soil groups for United States soils DICl0WG10 1 D .aw, • ODUCAM c ouCMtsMF • cooper c 01 0 °01st( c DOUCCIT, e 'DUC•MILL 0 DVSNaM b CULL t OOLotC. a•VOT s DOUCCLIvr 0 Duc55er a OURCer C 1)I61.•a0 C su•STSatUs DOU60 0 CVCCSTON •.'O OVSOC • DILL!' • *mice! • ooucar•ty a DUCO 0 Ouso$1/IW 0 DILLVtw a OOLtN • DOUGH?• . • DUDA a 0I0.5T C DILN•N C OOLCS • C DOUGLAS 0 CIaGCN 0 OUSLCD C 011.TO0 • COLLAR -C 0006vILL[ C OVGLCT 0 - OVttON •• • DILTS 0 0OLL•00 C OOulTIOt 0 DULL • OUTCNLSS e DIN•L C DOLLAIwIC! D OVuNO p ' DUEL. A • DUT!e a ol.!eo5 0 OOLLTCL•as C 00V!, a OUCTTC a-.: OUTTOI C 01100155 0 DOLMAN c Demos. CIO OUP. 'e DUVAL e 'DINO s DOL.% " C DOa • c5►rau C •DUSsUN• . a OIN•a• C oOLVS • C OCiactaC • OVrCa C oUrtt :.0 010• c' Dam( • DOME a ego/peso a O.IGMT 0 . 01NCO .t TICMCLL 0 DOVCLLT0N 'O Ove(LD a 0.0aSNa• s ' °toes t • DONtMGINC C ' oOVMaTa -0 DVI.ON • ovvea -•- a OINCVO t DONCSII - e•'• 00•N!U a Dopy vows T C OTC •- 0 OINGie • C DDOCt a oo`oty a moose • 0 DV!! ' • oINGLISNNL o' oo0o1NGUC2 C , D0101C,V/LLC 0 OLVV• .a oyL•w O OINGNaN C OOINIC a 00.05 a DI1GGINS C DVS!.‘ • 0 01N0CLN•N '0 DOMINO ( DOVCt • DUGOUT • CACWS e% OINCCLS s ' DOa1NSON • - SOVC[. Lo•NV C rows. C CaCNUSTON cur*[* a 0000 s • stw•TOatuw DISCS •-' CAD - -C• 01010•L! a 0001 &NA 5' •OOCt. NoDC*areL• C oUiaC C _ CA4aa •' °105.1 C OCAiissur. C .(T D%LC! 0 eaGLCCONC 00' OINV000T a '• DONALD C DOTCC. saND• C DuL(TLaC( - C £LGLCW•SS "'D 0INZC5 • • a ' 0004•LOSON a SUSST•aTUN OVLLCS D lai,L(SDC' -^S DIDOSUD C 000iva. s DO LCSTosM •0 DLCUTN 5 - •tLGLCVILLF 0 otostCL 6'. OONtULIL C DOOM • D OuNIS • • • EE 10C, e• �• DIMaM D• DO*C• - `[• 010• -C DUrat[s 'e tall* -s ■ DIPS(• a -- DONIC• • •• - - e OtawltUsTON - • ' COL• e' L-.1 OIOUC a'' OONICA. Lean, •'5 °510010 c ru10De? e- 'case s 010(60 o $Uar•C! DWaGST00 C. CM GL(. • C&K•eC •-' ,ISa•CL -C O001WNAM a 071165 • 'ClUisay 0• C 0 'Isauiei s' DoNCCNILL D;" •Dial.•( • • •OI I•LSTOS - 0 . '(U'.WoNT - 0 ISCO • a DOOLONTON C °•all r - `ouNSalocc s taaL00Nt. OOaIKO C OIS•wrs 0 ' DOiia D OGasvow •"- moire C' two. • OISN0*5 c 'Damma10 C ORan• C ' DtMCAN ' 0 CAASNLN '' 0 OISTCLL C 0°OIIa5DD • psis e - ouNCaNNON • 'ease• '•'' 0 DIST!*wrlr `C ODaa!L '• 0515. •tT e- ouNCCLCY • tasLCT -'C DIST05 C DOOiCLLT •a DStDGC e • Dolce. 0 • tai►VO • •• DIS■000 0 000I1!a C 00510[5 e ' DL*OAS sob cast rose c OtTCNC•SP C 0000IM4 0 oaCSSL(S C Cures• • 1L? LaS[ .. '• • of T000 C oomiava.00c 0- OWNING o Disuse! c Calla'Lc ' ' 'Oe Divot, ' c DODOL!LEOI a Dates 'o DwCLL!W • t•sICLN a 010(•5 • 000L[, -C Oseeli '• D% 010 • C taSItNOD ' • "-a 01010( a 000L$N 0 Darlts000 COO DumGCwtSS • taS?GaT[ e 0100• c•' DOOM! a 051115 - • 015.91119 e• tsarLLNO ' • 0111 '•a' 0005 • • OstSCOLL C Duda• C taSTDM --0 olaaLFTa o - 000••1 a Daft • oawL•TO5 • • • a 0115050 • 011• Coo Oe1•ta C ORLON! _ • [...Tow. 0 °sate • C 0055* 'C 0 D M • C DI • CUat•oCD O• 011.0W1 C' .0005 C'__• 000•AL, • 'C DMNIISL • ' 0 (STOW - `0 01505 Ili • oOcoesvta • -moos C ' OtaawlS ! 0 saa1G•IL It SIC 015ONVILLt C DO•URTOS ' • •OCVwwt•' •/0 owoov1Llt - , a taucALtlt. - D 01004) C 005110*? C oau55oND 0 OVNOIS C otWSC15TONat -' Oak[ •" DONNA '' •'` 054 • i OIMN• C taSaU.e tat - • ODLCUN 0 - OOROO*I5 -0 050 C•C!c C OUM*v. O0•1NC0 5 COa C 0005INs C 000010!• C Dst Loge C ism/N•. Na5DW1N • (sum - • oases C D000VLN '• 0 DUWaDI0( C - aussTaaTUN teats, CIO DOSCL 0 p0e5t5 0 0005511 • OV0sN016 • 5555 0 0011C0T .0 OOlSANC[ • °050(5 • OamSNUI.. C (SIC • .0 005505 • 0 0005 OW .• ►N C 00NCL$V(LL CS°Da • 0011, 0 •DO1ICT i ' OOTSALLtT C °willow • C COCOA. S TON• •C DOC•S • 00515110$ 0 OV'•a6C • SSMIL • COD* C ooCOCC 0 0011.44.011 '0 •Omer a matt - c d6110 0 °ACC.' C DOSS C 01Y5T C DUPLE. C [CCL(S - • DOCILE.. C 00511010 a olaaC(LL• C OtPO C (CHaID 0 DeCWa5 a ' 00115 0 OVSLCCLLA. C Dowel? 0 (CMIV a ooCT C o01.au • 6.aKLL• 05001C :-co [510(.°00 c OODts s - DOTLIC! 0 rlaattLla. COMty C 01M•005 • (CRC'? 0 00061 • DOTKUO 0 D151' • 0V11•L0C C CCCLt• a OCDGC•ILLC a . DOT!• • °MIS a 0155110 a [tawa* • '• 000100 C DOT• S -04).15• •1.300(0 C eU••MGO • (CCSaNT 0 DOCI. C DO/CC..! • 01515• C 0115.01 0• CCCVOLL • • -IGEN • DDUOLC ' • DUSLOM a °*AaZO a !CLI.5C • II!CUeI s °00105 t D1BOIS C 008515 0• CCOl a C UT C DOIG•L 0 015UO4)r • DU5tLlr • !CON • Coo N•Da0L061C SOIL GROUPS NVCM •S •/C 001C•Tes 1NC 06•1Nt001.05SaIi[0 SITUATION. .0olrte•s aI10eN. t.G.. atoaoca 5086taa1u.. area TO a SOCCIr1C Call 5t51CS •MA%( POUND t5 SOIL *a1 LeGtuc. (214-VI-TR-55;Second Ed., June 1986) A-13 i Exhibit A-1r continued: Hydrologic soil groups for United States soils econlrlFos a I lLeaSMLr'af a ELO1€a a l.4Ca..4L*!r+ C I tST1a D ECTUa p '1 E4eucr a -• eLalr ■ 6.alwEO I RSTtrr. T tD,LG4 a I EL3vrrq L _ tLO.43F -r f#,GL+ .0 I [#SEEP • COO INNS • e I FLCCI r... • ELS . ■ trau. ..C. ,I 1STr1 �0 IE061 a :•-I Ito • e .. :r41iF .e eNol E - "o" ,. I estCSLACE E COD., • C - I LLD,...* .i . -EL.,IE . E"_. .1'141411 t .1 FS1Pt17YELL! `'6 EDEN C I ILOtrr r r.; ELl1r6000 a - ;uptetpDG C .1 E#TO 6 Edlwg Owe R . -.o,... I ELDEO +,61.4.D. " -n ELSNEDE - ■ - eri{MaGr' .a' I CCC1CLL► 6 !DENT Cm e p EL.Deeon . e EL6.1 Dar . -6-•- e015•4*l , 0 ...r1 . C. lyfaly 6 .'I II.- !vok. 1 r716r a . - 6• EMS}ev e}'I ET{ihrar c EoGia 6 .1 ELOG4a , w • .ELTSaS C E* a - I ErEL71a l C EDGE •D- I CLdaw 6.. • ILer F4;{' emee . 6" r1 Ermar . I fD{Ew4LL .'-{ " I .LLixOaapd t LLYEr1tq[ { ';. EMrrRa r .1 fTfta1rJa .• EDu.!LE! C I :CLOtIDGC C .. ELYE■S 6J0 ELTt+l04GE ..t i rT1`EL1+aN 8• EDGE adwr 111,!..}.I' iLtelaa •C .• .gLY10.0 . 6!D ENT 0.. t Eri1t1g e - 1 epormarea E,• I"ILJ'RUT • - 6.: EL*!LL ..E..• ;kW/m=1' C:-, I giblet(. s#Leh! C EDGE.ICE -. £- -I 'EL=ta '.ems• CL.w■ r: Cr.. . tPt1LLJ! € , 1 f1+0116cE { IOGI+Grnu -CPO 1 E1rrCPEE1 • .-..0 eLa0OO ,C. : ['ROLL „I:0,...,1 fr1L EDINA a,: I EL1U10+ .>..a..- :tLg. .. e. . tMJrJ#F. ,C d !TOE • e E01E0i/VG {-,.i 1LGlE .A;• ILT6Iilr ,.L,• ,ld1. {-. I {rt,.4Le D. EDI*id ,{ 1 tt.P1Jw • ;. C. , !LONGA. f...: i0.■ p;. I .ITTTTIN . • . 6,: . EoLIN" ....E...1 CL•Ja..1 • . c... -Ea•YFL • "al-.., {71NOaIN E4LOE -' 0, ,i CL4u01D C:.. t.7`aoGil • C. ,, .f#+rpaTa - C.,,.1 ETI(L .q I COIIIII#ieu . . .._D - I.ILL IDia C;" (F•eDI1 0. ff41[ar . .0 I eT14 .e 1 (PoCkee 0 1 ELisa 0„• E fret sict ..C. EPLE. C, I ETT(0 i. e. ! CD.?0C Q. .1 !LC aa..••• ;er0LTr " ,.•1. .1101! r .- I ErTfs1114a4 •"e -. ED.WID • D -1 ELK. rro.LOa C' •erpm. - C. ,rP6!! 1. .1 (TTPICa MOD. E6w1r+DlrCLx . ', I ELS rDWllaIN i 1F'44OD _ r-e . ifpfuOrfTr !erof1 eua.a. .a ". .4 E4Mt a� 1 Roca C !*Carr ,-V. CPO 1101G• e...1 uELID Can TTOrw . . .t I E1.La*Co r S. .1EDENT. 6E440C11 . { . .EPS11 .....0 .1 fLJDGFI& _re.-. cortr<.Y ILL E _ •e . 1"14ECefa!( C... - suerieaTUw. ..,rpm. .ePY4a - D,,.,i (UTA ; e Goer 'c C. I [Limas* a O+FI4Ef• ." ECDES• 0 .1. Eui•auLa ...a . tD4d* o .1 RLiarrL43 8, IV C I. aJ'aJa[P .:•[.:.:. •EU lit i rLmo+sLte i•,. • {0.1 Dag Cr..;Ie!Li wDPw ,._.t. ErEeaLD "1",L . C. . I euLOUla ,{ . • Ep■asDI " .note-ELcFa% D-. EPtlALDa . MF .:, •lDaa' ..0 . 1 !LRCM.1 .; { '` (IL Fet.. I.IILrlM3.ILL! r,. .1Pl044N - .11.... .eeaeto.N .. u:.x.,1 EI*eet � " IELC4*r . 0. . I. E4! C'u.6 - ,.4.., •1r,isawr AX.:'4 ,E0■!F . . C-0 (Il5lle C."_.• EEL00la, ,° - .. -.,.Js." f'ELLKa .. .. E ., •Ta.IL1FT10.. f ._ .!OCOM .,-. :?:, ,I rukTIS . r' - Eva, tkC. ,.1; EL,44L 6 P,4 I . .,! .rib P.1:.P .fy1s■ ..e• {rr Ie ,C,..- I. tuts IDLE . e.. -t.41 r • • .C....; •ERTESON . -e...-,A .IT'CaLE . 0 Er.IMGIgib . 0,'. J 1LXlEL •.. " e . Er.4 ,g..„- 'CI! . €.. .r t.I,,N (L1164 € EG.+«r ".C. I ILe.7p. . - •CJE I*mg f' ..r: . Ei!r -.E .1 I•+•'a e E4a4 6 IL ELt,CCLLL ,"`.,o,.. IFS!1 ,r el:- .re.rEr ....r.- 1 'ryal.s.laP ".D EGA!. ;0 14"ELLLOCE .f,r l..r}w$ '.e.:t ri). .f emt11 4.C;_.j EVAN-Blew .. e LGECRT . •d... 1. ELLEN ,. , t r.. e�+T .,e Ire.D .:rq•,, d ;Es.Mi ',MLLE - efe Esher. 3T•ai1J!.1fa,{ . I. LLir r7 .• ..o, IIE• - . ,r�ri. :I F+aMIulft . . "-., . . ._r*r...rT . G . }uitta/Atm . . .1 1LL14Ea' ±- ' 111E 1E+01 _,4• t 'rr•YI0! , C.,. 1 Voter .0 • ..u.K* .• C . I. ILA.CCOTt IP...Cw.4464.S :.£r: aSeas0la • .C7.,-# . Sra e mar .rte- EL.Ju4TO.w .,:tr .A i* 1a( _ .- 6., ifCaLa1IC . E- -t Eats, F .. d t+er+T. Dila14110. .0 ly;J.J+LOD . ,- C.. EP�OaFla ,€._ set me 1• s-.C...t ?TE1maALt - .e E MIEN T. SAND. ••C + rU.1r4r .E CPU VC,' ■_. !{cats.# a...•1 eviar5T Suelr.a7y. ELL IOTTI.ILIA S.r Ewaa -C..„; •111C4ae0 .• c ,1 Crrs1Tr. .,a*0 • C00E O I. ILDP 141 '....,C s !al It .G . ...eta. " lit•.. f 0. T '} fur6'Pei 7 uw ..FAT ECELAN6 _ • 1,,L CU.I% D DL 0. Ems*t. rC1 ,C . : 13[41#440 „ .E . 1 .E.CectaDES ■tem. rG lrTt.aCN ..•C.. FLi-ISW ILL, . ..S ` ' ErGtr•.t4r ,f ;f}parr :0•,..s t*(SLr . # , .E GL 7r •r . :..t . • ecru:ma. • y'.A. tata•a1a Mg" -.i`, . rILI}OC 'b,...r _rlf.rt.r . C 1 .G'r'r ,, 0 _ eu-ree[ ...Q.v -.1.r[4EaaG •• _ 4 . aE *a4oa 4. 6 .;,J .rvt*lPw •-IC[f s. . .... ."..1<- E113TO0Ta• r ' C . !1•,Clit .:,'1. •esiiswO _..6; .I 1TtirrMJtE C . r-•I;mrrLaF .i" •' D-, lLa.1r• -;C... !.C[a. . �.E - t61tI!TQ ,.r I 3trlieemo a.. '1GYr.1Ll D IL.Zit: •• r,. "....-7.0V 1+4106 4- 1!!Llr 6!41 :YT�.iDDE .6 "1L .-f.. now tae*_ - . air 0 ape ato•1 ,. C-; • Ei!IL -, r...,1 .E■i F .�-*. #t1lkk 1:1.14011F .k s ra!ClCOrr -. •.€,: Et'Inat. + I 104 LI000Cr t saw .t tGaRMDOi. D I.0.61 I{.. . ror tl+Inptf F-...1 ; tuella/Atr 7.6 t.rm IMA . C-. rr1Oi#• ...,:c. • II.Aimt • D {t•E*•I•L =+ ,• .KIN C E1.01ia ;.i t"l*G. ,Lei Et!LIN 0 i•.1 EEC Lsino gore • o : (L.mo+1T - P. Eat? •,_ .e : tih r{._y;!a[Ntourt0 0 L 04F a. .,r , tt+r0.0e : 6-- rM►IILe 0 • • Bout,#!L .:.f,• I,F.[L0t! L •E•C0 ' 'Cf I to*IDCE '• E. 1 1L 00 4• 4 Sion . 0 .t .Earl C" L a aft Cr0 T .0- 1L4.41LLE E C .!11 a 1'ee. R4a±state r C. . CRiEtt• L SOLID .'• C E7aa■000 r.c 1.111 4 air s. 1.Elf!ID. 'PACE 6 La., a EL..I PIP s- C 1.*41.1Ew4>S0 C . (11. I SELtm - • Lau. waSDFaa! • .:6: EL'ae■a "a. I+�D C !IiaL. t .I rs!TrC F` yueftaa rum fid{Frd.aw 0 tn�D. ,7Y!R1LCa'm . " ae tiff* € I 1110.' R La NDCC �, E4-DC IN o., IKCE o-. I tlifa C . I f ILI E C" N.Si . C - CLC Ili 4, Err I1L C 1 essr#T44LE aim! ,D --. • Les+ILL! 'e', (IC.C.C.A. _ 1.. I RP.MI1 II 1 t314C#0O n I ELiu• C I LEE0r D e L04r D I RICCI. C t as T Ink I Erar C •Ler Tw F ELPeo4I e I ! C£w.4LL4. - 0 . 1 (51111 C , L ITTRTtx• E r �� L.e4+r P' [i000 0/71 • I I'TELL.INS' e I ITLtiu c III rEs: via .4 wee 4L DCA{ La ii. GDOv3 S1JCi. a a}€ Iw01E •r!11 4Nf O*a ll(eet•08a limey 1l Tub.T rpm- . ,. ..ceur mos 1 0.i+. E..,.- 4c000c. Suf}rPaILr,'a1fla ri a.sett TF]C 5D,DLs!witi *Nair 10'.J n 1r sali. NIP LICE M. 14 (21l-VI-TR•55, Second Ed.. June 1956) Exhibit A-1, continued: Hydrologic soil groups for United States soils EtOT• a IaeR•GUT C 0 rlaiQow 0 .051100D e ETNA o PANU•a a Pert(• C O FOSwaOea C tl•lN a FLLLLLL 5 Fel C P1AITOw a FOSSSN 0 Pa•lUS a /SNSIN•uSG • PlaretD 0 •LIaC O FOSNDaL( a FACET:LAI a ra*.OT C rl.aotc. D••INID C PL115 •/D POINtT 0 FACT • PaesON a Flat C •LIISCNNaMS 0 FORNOR a I•CTOST C PM SON. wet C P/OalGO C PLrNINL C FOa5111 C PaCTONI. NOtST a FAST• C P10DL15 C VLININGTON 0 FOesteD C r*OOIN 0 P•RT5NT 0 r10OLETOrw a /LETCMts. t ♦ORBIT a P5DOLL • /aSMING 0 PIDOVNCNT 0 Pl11111 • FO•SGRtr C P5Ga. C Fatale a FIELD C FLIER 0 IN • C PSINON •• PItLDCet(1 a FLO a FOOT cclltws S FaNtt a PaftN• a P KLOING a PLO(5 0 FORT NtaCI • PAIN C FSPIIG C P1(L005 •/O FLOCe O PORT NOTT a /a/N. NOISY 0 FamuC1 • "trip 0 PLOW •/O FORT NOCI C ralasaaII 0 raUNSOate 0 P1.1(LO C PLON•TON a FORtawc C .ale•uer 0 FaIOUIIR C '!L ION 0 PL0501 5 P0e►escUt c/0 /atSCMIl0 c 'west O PTttaaa D P1.0ODN000 a PORfu*• 0 P81505L1 a retiree C IILLNoat o FLOR•NONC • • PONTN1ft4ATe C - rat•Fal 0 Pavia a PINC•STLL C FLOR•15 C PO•Ttrou'a C FSISPICLD • Psi C Flat*. C ILOe(NCl _ C FOROIC C r•tSM•TIl a Paean S/0 FINCINWOND a PLONISTILL( C P05N4150 a Fa1aLJC O F re, • IIN OIJT 0 PL4RtOaN• 0%9 FOss . e FataLO O LLLLLlCrll.t ,• ItNGaI C 'LOSIDaas. O P01511o5 O P•t•NOUNT . D /at•000 C PINGIROCI 0 Ot,5KSS10N*L P05554* 540 ' Pal 0 F( 0 . •INLAND C PLO•IOSM1., P4.00010 0 POST(. C PaIR5OINT C a ?MAT I /IORIN C FOSTORI• a ratMO•T C /(AAA e•ttCS" -O PtrltT.OIMT, , a ♦Loa tss•rr c'• POONT•tN D /atRtat C rt•TNIRSTONL 0 Pt•NT(NT1 _ C 'LOalla • a POUR ITal C r•IRTOtLL C PeDJI • VINO 5 •LOTSG • roue &TAD. 00a1N(0 e P•INVLSVN 0 revue. •/D Floret. C , 0LLLLLL C FOURCNI a i P•/5.00. C Ploscacec a 'toms a PLO•(a(( • POUOLOG 0•_ Co /0.aM 0 •K•05 C PLOtD 5 FOUeNI . a PALS* 0 913 CNeS a - /tet••ll. 1 FLUITSCH P POUONIL( a F•ICOt. D •ILO• a/D .151501 s PLUGLC a Pal - a rain C PIO.o•. o rtortsrecL a P1u115 c FOtcU(rc o • ra.PUM I5S • 005a11110M51. P10157051 C rLUTaNwa C Io1Cat(A. oealalD C Pelt - C /(LICIT? a IlaN K1 • FLTOOs • RE t FaLttei 0 /CLIP( 0 P100 0 /LTG•ee 0 FO•NOUNT C ♦Al1NIS • C FtLIZ • /POA[ I FLT••: e- 90101. 0 '•LL•NDOA • • PJNStIit■ „ C PL.NNCOve a• rube• - c .allclttt c rtLIOaMIP .0. r/e1« c • ''OaO C • ratL(RT • P1105 • r1•T«. o•a1Nto a O /.•Dole r FALL ON , FLIT •a ►ISMt LL Naw D roe al 1.w a ',Amer 0 Paoa. M17 a 5vLO0Dto • r(4Ta c rumens, . a IOlDel 0 PR•ILTCM 0 PLLL58N 0 rlITMar • V1LMPIN •• 0 rCl• a Fear e PaLLSISG/ON I/O /MUM' 0 • •111.5001 C POLosat • ►wards • FaIOra - O ALTO• a . rts«L•st 0 •0.(• 0 rSSNCISCIN C • FCLTOr18 S .1s150T - C IOLLIT - 0 raa1Ctsousto c •*1.541.• . • O /taco • rl5Na005 0 PONS(NG C FSSNCITSS 0 • Pswl C PT50•LL • C Pt•MT••0 0 .050A 0 PSawolfN • PBNCMIR C P1IKLOM C VISA P •05015 C r••N5FOR1, C • P*ND*NGtt C 'Era - 0 FITCNTIIIt C roNrc• • Mt . C /aNOOw 0 FIN•TCS • IrTlUtaa4O • rOM5 . • ••LNIII■ e PsMG a rt.NtCC c. VItlNUG« - t FOaTaua • 955.551005 • r ANNIN S .. . . a. - • rltr•LOC( C VON/K a (N r ►• 5ZTONw 0 ►8050 C PINS C FITVNItL • .05,550 0 rSaarvIttc' e PSN•Nar • rl•OCLFOao • C P1RN11.1. SAl1Nt C POwaoa •/O r•sT(881040 0 Fiore C PeSOI5a.0 C 91110• • IOeat15 0 C PAW - • Pae•te O FIVIPINI O 'me.* O • •Ge1Rlt? • Paoli - C rISGUS • I1K1 1 Pewees c c o Free CLIFF • 911115.IaGS C POaacs.ILLi C P•atcalma e P•N 0 ►1.15.•00 • PLACID C P0N•15G 0 Pogo C • /(SNCe!Ct - D PLKG a ••0.0 0 raIDIN5•0.G C• 98 1100 0 91.00.1.1 • 'LKLIS • POROICe • P•eOtatCC a PaSISITA 0- P1•MCT :z; D FLKSTarr, C PON05[T . a retool c PS/LAN0 0 Ptatw•rtW • PLUS C ' 5ONtt.. VET C rKDOMI• C P•51.05 • rISNLIT C .L*.•SaU a PONOTa5N C PRLOONT(• C 5•e.Os. NIW C 9(0.0• • P1. 5150 a 000054- 0 PIKE O/O O&M/PALL Pt$N50151 a p1.5.50*. 0 P050TILL1 5 P•C(•USG c r•551Ll - • P15ea000 a rL5500tau a FOSILaND 0 IIglC( D 545515G1ON C PI•af10 • P1551 C PCNCIL1 a ra1100N c % .55515051« D Pleats 0 PLaalt 5 POSfS.aw a FIElOON. Banal a P•NNTON o u000 0 /1.55515 0 /OKST5URG • PUt(NDLD - e • j Paawar 5 Few•ON D FLAT NON• • POet5TD•4f 0 /•CILaND C PaaO.aN?ON C PISfal1NC 0 PLaTK aD • '05(51(• C rat(Nau C •ASNur e C /L1115051 C r0atf10N C PS11N&rTILL' a 11 HNUP. PCT C /CST ISa a ►IrT • NOS? • /ONGT 0 /.CEO.. 0 ...ma • PCTT 0 P1•10111* 0 F05I C emcee c NOTES: 750 w?OaOLOGIC SOIL GROUSS SUCN AS VC N01CaTes TNT DDaINIO/UNON•IN(D SITUATION. NOOIIII•S s«4011.. C.G.. 610.0CA suestS•lus. et51R TO • SPECIFIC SOIL 1151(5 R«5St PDU«0 IN SOIL 5.O l!GINO. • (210•V1-TR-55. Second Ed.. June 1986) a-1c. • • { Exhibit A-1, continued: Hydrologic soil groups for United States soils rotes• C I ruL.SwE•• C Gaoco• D GEO o GILISOIC 0 'Deft TO•E C I rug-STONE C GapO 0 Gee C GILLA•O C ••EETO•N 0 1 ruLTON 0 Gaye. oo•INCO C GetOURG C CILLt1SeR 0•Pace•••(• 0 I •ullS 0 Ga••ra.(• 0 CUUNORt • C GILL I•• C •O(EZCrto ► 1 •uL•IDE• • 0 Casa C ' G[e• 0 ClL.IG*N a ••etttou• e 1 r11.Te0 O Gadded 0 ' GEER/S(N • GILLS C wet lseu.0 0 1 ruoua• 6 GuIC a GerO • GILLSM/1G C rolrONl C 1 ruerlss o Ga•PVTI a Gel sel 0 GIL• N a • 'Reid 0 I r1ISMua 0 6aIC(NO C GCSE C GILUORE C •0(0001 C 1 Pull• 0 Ga11/Cf6 G G[(.G IC 0 GILP•O 0 0,0C•4CM000C[ . e I Puy,. 00•14iE0 C Ga•C1a • C GER C GILPIN C rOeNC.IJC••. C 1 ?VSUL IN• C Gauc IV•S C GIN. STONY G GILRO• C fatal •Par O ' I r1011w•0 C GaNCON C Clot C GILSTOW 6 rD1NC•toos 0 I C GaaCtll• • 0 GeaSON 0 GILT EDGE 0 rRtSNr•1e0 0 I Ga0aL7Da a Gorrer• r &tNar D GINL(TT 6 ••tSMO. 0 I G•36S C Ga0fI•I0 • c[NEGDat 0 Geom. 0 S•LINt-a 1 1 C G•NOW!••S rata 6 GeNtSet e Gilts 0 ••e6N0. 1NICS C I •CaCll C ' Ga•OMCev ILLC C • GINIV• 0 ' GINGCO 0 SOLD.. I G•e1C• 0 Gs/200W a ' Geom. • C GINI 0 •0(1• - • 6 I Ga0INO 0 Gape• r GtNDIa 6 GINL* D D 'N'sN1. O I CaCt• C e C(MIILL. C Glom es C• 'SIaNa O I GaC••00 0 G••r1(l^- C GIN••• 0 611110 C• •Ala., 0 1 4aCIe• :'t, 0 GaaWIIL . 0 GEOCOrDa C Gt••00 0 -610LO C _ I GamOES� - C . Gas 111410 C GLGNROCC - 'e GS•ao0Ct • o •ol[D4•N000 "C I Gaon• �.- a cattTa t Gco•Gcc.Ees ,e GI•D -" a '0lto.a« C I G•OSOL• - • - ' C ' Ga ' ' e ' ceoog TO•i1. r 0 GIST D •OIcoos - _ " c I .G WI•.. alt C •- C G[0•Get•ILLe 0 GIT•reo • C '•teNOs..tP ' •' I - SueSTaal'. Ga•LaC• • • 6 6100G1a C GI Tar 0 . • lti 3 I GaD•!LL ..C • GaaN( C GIPPO.O„ �• o C GI.IM C ro1Ltl•Nt ' a GaGee• • a GaRaa•►.' '0 CM.. , a GLaC1l'Cet!C' • • LIJCLLS 6 . 1 ..aGtTO.• Ga•NIL C Ge•PIOT "1-* C GLa0DE• a oIt..oLe _ C 1 Gar.IL ' - •• G*«rto • D Gt••l0 O GL•Cel '' 0 - -ateaS C I Ga•IC r ' 61.11'. r GCRP1O 0 ° G.•DE•ILLI 0 -RIO • ' S I GM D } Cairo 0 G[•O•tar 0 GlaOlr•1[O 0 010«• C 1 G•t►• • " b 4•.R O CEO INC e GLaOS Text r '01710• L I G•1•15 " ' C LaI•e TSO•- P G[•LaCI 0 GLaONIN , �' • � '. 0100 • I G•IrtSNC60 . • C C•••ITT - 1 • • GRIaNC ' 0 ' GL•SG0• C ' - DISCO - - e 1 Gal64S•Il.lt ' • 6a••Is3N a • GCOLC 0 • Gl • 0•-015171 e' I G•L•T• " 0 ' Ca00CCaaL!S 0 G[•aaNT00N •• -' 6 ' G.1•110 `• " 6 IIT1 • a 1 6a►6D1l• - 3 • GaAs Is r Gt P _ GLtaSON a •• .1[ICIL - - C` 1 CaICNV•I C GaPTC• C Glints 'C 6Lee1 C •oc6C•G O I Ga.t P Gas•eS0• 'C G!RONI •e OLIN 0 0000 • ' 3' I Gm. a Ga111N C GC(•••0 C 1 GL[Ml•• v. 0 BOwraq C` I GLLI••I 0 • GI••IN e/0 G00000 e..oPilftee t ' ceremoB.• off " C COLIC --' S I GM.LSToft. -."' C- 6.11"" Pi1 GO•S, 0 GL(Neese • • 0 est. - 1. C•' I GaLTST'.•- a•' aa&1TM• • 0 GASSIf. C GLtNel•lD - C fLf••110Nt!OO6 • 1 G•lt• el' Gas (scut '" G GESSNIO • N0 '-G1LN10.00s • ' D •OLIC. 'LL00La !' 1 LaLI/PC - C 11a$C60aD! ' I1 GCST•la a - GL!NC•RB • f Do•Powr 1 6 14aLIStcO C Gas IL ' P Get•••• e • Gar rc ass:vac•. C o0N?P•ia( • I G•LIST(0. C GISCLt• t GETCNILL C SaLIN( ' aoN•ICg - C' 1 Sat,IN!- , •1 G•ss•••• ` • 0 G(ts•IL 0 ' GLC•COe Deo - C1.1NTO• • G I GalLaNO - I 4.5$11LL( C C • GLQNCI•e. OOMOto o o,st 3 14.l4atlr C' C*S70M C ' GETZVlllt. • 0 GLCNDaL1 6 •.01•00 C 1 6•1,..i.1.601, • e" Ca• 't • &!rags • C CLINOaL1. ItT ' C •uTla e• I G•l•(• • e ' G•vit r Ge•SSN C . •1e11t C ' oulTrIClD • 1 GaLlla • ( G••CSC01 C GI C PL00050 •ul1nu•sT C I GALLI+: 0 C•T(•lt. '" - 6 Gt5OON a N GLe1O1•SO e WI•Las.* • 1 I Gm./lo•• a C•Te••• • C • GIOSONSC''SCL C GLEROIse • a LutTLas0. c I GaLl•a• - e &•TCbeat'' , C• GMMOS D &Leg00e. a/0 •GD:•:ISl• .•tT I Ga►LU0 a litl1« O Gt1Nt•"." • ' • C` GL(Nf02N O •uttLaID. •tt C I G•400 • CA 6•10• - 0 cl•SONgii&L,e o CL[NELG 0 *PE C 1 6141 C C•T•f1•• e• 6115CLL C GLCMD•O C ••r,eu•G a I,G•L•• • Gam.o• �' - 6 GIDe001 C &Lew all 0" I. n•u• 0 C 1 4.v(11t;.. • • GaY.(• C 6111.06 • C GL(Naa• 0 I. Gott« 3 1 4.4.1/:1 C Calls • • C' C UPI O.O 0 GLta•••.4 - 0 wear C I Gas•IR 0 GavILar C GIGGI• C GLe•• • C • ,PSLt D I Gay G•11NP " O. ELL* - •-`> a 611.1411........8•1 - C RG3 C I 4•+elt• a cogitate 0 611..5.7 - O-• GLCISON• 0 ,tGO1T• - 0 1 Gar60a - S. Gay •/0 6ILOD* 0 GIIN•OOL •• • if•• C 1 G••CCI C OavLCS.ILL! • 0 MOT . • • 0 clears/0 0 J•••e(, a a O G••L000 C GILC0OIST • GLCNOOSC ' • 0 .66815 • C 1 GaaCt C Ga1NCC • C GILCO • 0 G$.1N•OSS. . ' O .LCwf• C 1 Camaro O G•••ILLr 0 CIL CREST a 4lrNSTCO 0 • •LO• CM I GarlS • D Gattl1.( 0 GI1E60 • C GLARTON 0 JLt:a• • C I c wale t• o i•zOS C GILLS 5 GLINTOM. ret C ILL!•' • _ . 0 I Gar Poi• C Gat C CILP008 " - •/P GL(NTOSN • . .LLCO/Oe. • I G...sat D. •oNCtC 0 GI00000I • GILPMO. • • t` Gkewvi :• • •..N(0 0 I Gar. 0 G1••• • 0 11••11?ItO Q.t..tllt - C .L•fa. Da10C0 C I La06uT•(' • 6 0 sue N ' &Le.TOle O ' es: I.0 .••romoe tC SOIL LaOVaS Sua• •S P/C 6.01C•lt$ girt D••INtt/uN0•a urea St Tug TtON. •001•IC•S 5.101.,. C.L.. IIIO.00• su•S 1 Na1u•. a(•ea I0 • s•CCIrIC. SOIL $I•IIS await 'Dual, IN SOIL Nay LIGIND. t6 (21O-VI•TR-55, Second Ed., June 1986) • Exhibit A-1, continued: Hydrologic soil groups for United States soils GLOM. C COOSCriaTS D GseaceWILLC. e I GO a e 1 Cu••aSola 0 CLOO1• o COOS•US a COaIwt0 I.-Gwewaoa C I 0 GLOUCfSTto a 50000 e GRawetvl1.LC. e I CReaeol(t 0 I Care C GLOvtD CID come C .OCC aSIOrall• I.CReNtIIIE e I cum w e . GLVNDOR a GOASmw 0 - rL000E0 I GO(SM•w C I CUC•etw C GL•NN C GCMGs!, 0 GOartLC r COETOIVIO 0 I CUDGEL C 01.45.000 C Cr 040w10 ••, 4Oar5OUMI C CRC•154E C I WDW(• S 0LrPNS a 00000a5- SIC Gnaw° 0 GRCVDACC . e 1 Gu(LPM e GO8•0 a 00015 C 00ausNav P DRevO r 1 GW.K S e cOOeRwa000 D 000150 C Geer? r ,GK 500011 C I weak[ C =item a Gooses C. Clime'Mg C 0 GI•CrE6GLE 0 I G tw1Me0 e GOBLE C G0DSCCL 0. CRwIw .. .O GKVS 0 I GUtrwSt• - C GOSLIP D COROT o CO•5TS0000 .0 G0IS8Lt 0 I WEIRD C GOCMta a COMPS a GRaNTS°•LC . 0 0650515 O 1 000500(60 • •- 00006.0 6 GORIELL e , CS*N*IILt .• ,G•IOCt 0 I CUtS1 D GOOSE 0 GOl• 0 COaw TDN 6, G•1QLer C 1 Guns(• C 0000166 C • GOSKew. a Gaarlaa a CRIES* O 1 GUrPIN G, GOCIEEEe 0 GOSNUT( 0 00.•(•15! a • •GOleves P. I WGU•t C. CODrRE■ 0 -, GOSINT• C • .G6*P1T a GRISPIIM 0 I .GUI10(P C 000.1w 0 GOSLI' a , . 6oaIMUI C •GOire• f I.GUISSO .e 605.10050 C COSN!• 0 GRef•ER5 e. GRtr'Oa C I GULEP e COLSII00 0 .COOPER 0.. . 0065500. a 001GSe' 8 I GULP PeD 00555(1 0 005ORT • C -GOass•a -0 GOIGsTOW r 1 Gaic•ra a cosr.e•C a . GOSS e. GS*SS.LLLC, O. -COINS • I,GU15•c5 0- 000581C a GOSUN! o • -_G••6S•-Out?! • GRIw. STOP• a I .CUSeLE 0 0OL 0 COT(50 a ,. COaSS•CQwt • C015Sl6T 0 I.G.W8001 0 CAL C 601505 a COAT 0 .,CRINS110 a 1..605500?. 00•11150 C COL. ,0NSTOPT C t 60100•60 C ,,.GOaTTaw • . W IwSTOwt e I CU,01P•00CL. SaLINe 0 COL. C6•v11.1T ,C GOTaea•VOG a ca S • -C .681ra 0 I .0.1069.66(1.. 0oAisrO •-... GCLCOND• C GOTHIC C G6aVDEN 0 . 461 0- I CwO, C , GOLD comes o - cola° c CRaVELTOS -S/c CRI005100s C 1 40501 C 001.06506 0 „ GOTwO. aOOCOATEI• r .G•avtt6 6 . GRINDS TONS c I Cu54.0Cc C • \ 6 01 0 5 10 61.! 8 '..(r ,G6•,rCST a Goggle C I'.GUSN e 00LOrt5CM o .G01a0. C 5 -I COOL P GU*• aLS • 0.61000 C -C NNCL - 0 \----/r GOLOMtaD O/D COULOIMG O „6.1.060 .5 - CRtf Dal[ 6 1 C1wSI GMT 0 , 110Lowls.s. 0 40u10te060 D ....c****amp .0 40ISROLD e I GISNSOwE • 0 01.001111. LOaST C CCURDIS .0 . GOa•I*No. mauler C,- Calls .O rT C I U•STOCI C_ SueSTS•tM� . 6000.1.(• C . (w0. .. 6 _Caine C- , I .cu'Teo 8 001.01.61! a ,COME .a , ,.G6i?LOCO a, oaIses. wtT 0 I CUP. C 401.05•. C. GOve« 0. ,C5a•LOCc. Stow. e . •0015(0. 06.11150 a •1 CVOaN! C GOLO.Iat C-j, 4orC5Im •C G0•vlot51 - e 0.01121.• 8 •. I CUO000 C COLOR loot e, 606105 a 0.8.60150. .CT ..0 CIDOUTtt .. 5 -.1.GWItr C e0100u. • COUP , 0 601160(1 -C -.,C000aN a .I. 0.USNS r e GOLDISOOO 0 °Image 6 COATS. 0 , 0.00000 C I CUSTIS 0 cOLOSTOP C _ ,46.01.(, 6 600•SI1L C .05015Clost C.- I,441SISOa1NC .e- couoslRtar 0 CRiCewDal C .6 a1 66150 C. GROSS C ,I.GUIAIC 0 CDLOSto(aw. bear° a ,w•Cewa■e . c G•r•, PrND -.8 0..016.111 C *LOU? •0 GOL7UST C .46sC5tISLC 0 40(Dit. .0 GROTTN • 1 ,CU►a0 C. • GOLDV*L( 0 'COaoco C, .60(15 •L1Ir e. CAROM P I.CUTawOOTT1 a .. 4010•.1.1. 60N1TO11• C miaow.. . C.. Gotta c.w.o.., 6- GROTTO a- I CUr1011 0* 00LD6(15 C. 6N6Or 0 -56(501.5165. • C. .000101EC6Ef1 0• I G5CN. r 60L0•CC 0 4640CM 0 p 061(01 Slv!0. P , 000US(v/LIE C ...1.4Ulr 0 colt!• .0 Swarm D - $T•OMGL• Lel lam 0O0ve a 1 C61.4. 00 • C GOURD 0/ RD .0 &Damao 0. .. 55 01v10.- P GROVCCITT a 1 -C.I.'.' •0 4OLL•ICP o C6•IL C ....1x0050 650056. r I swimmer?? e ■ c 00.150116 .,D .001(0.6.65 C 0.0500 a 41 Genf* C 671.T•v • COALE• 0 GUt1Ns0I ell a Grrovevow • 1 4.6511( • .. GILt• s GO•LIC • . 005(6CS(6* a ,,GROVRtN C I.Ct•Nev2E e 60010• 0 War . 0 ,.1611C808/1.0 a :0105L(0 • .1 45800000 C 600052 a_., G.eraTw 0 • 0.1(51 • ,_6•CVTOm 0 -1 Nab* P 000.5 CC • Gesw•T •ID .305(0.151.0 6 Avowal 0 I . 0 . CONteGa C , 66.505 00.05 0 , „CKtr•I(LD. C COUSII*C5 e 1 waccee C . GOOCM, 0 CO0SO•IL10 a .waaD•aw . • ague* 0 I macs. 0 . 6000!54 0 -45.560065 0 SuS6T0•OJ4 • 081L18 0 I.wact•r-1, 0 . 6000I0CTOw 0-• CR61105000 a GOa•61al(..• a Ca1N•NtT 0 1.wac(rlS 9 . 40001./50 0 O45aNOVIS. C 00(160O0r 0, 0*1 95 . C. ,1 waC0l0• 0 60001.0. • It.. o8st5T0 0 C0tC008.ta0 6 ..401100 C .1 NMCt•ODD S „ 60005.6 a 40.55• a 01(105[5 5. GR•C1.• 8/0,1 e 600o51Cwt • Gaam6E C . C•(tN•aw C 0&C05160 e 1 waOSNCattt C ,_ c000PaSTCO 0 4 8.4(50.1 C 605(50000..1 a 045061.005 e I wanes a . 0000•ICM 5 C•aaCfVILLC. 0 005(00605 C . iva.fr • o ;1, 0 GODDSRSI5GS o eaa1Nto. S1.0P150 4015.106 C �. Cusp . 0 1 MaOStlm1LLE 0 60006111 a 00*N0tv1l15. C 00r16vtl1.e. e - uremia' P. I waPLISC(• a /- .mil 0000515 5 Sal 155-e I. C05(5t INC 0 CUawasawO C 1.58655 e W c .et 66(!5.•1(0 a Cw06J150 C .1 w5515•a0ta a GOOSE COUP a CR85certlle. a 0atta.•T t• Gwr1C• 0 I mecum D GOOSE Carle. .e, C Sal1MC- 1 G•((r.00D •/0 ,41.00 C. I. wsGtSeas C DOSE last 0 GS• C(,ILLt. a 0•(w•Lr5 C GuarOLatt • I Naseasva.. C ., w ostuu•r 0 030(••501 Met 4PCLL 0 600.560 • I 11.0.6• 0 50156: 110 w,DOOLO6IC SOIL GROUPS SUE' Al •/C r0,1C*Tel 1Me 0.01610/10.OR•INLD SLTU•1105... . . •OOIrI(RS S00w5. (.4.. •(D00Ca SuO6TSaRas. CO • 6•SCIrIC SOIL MEDICS RM•SC r0USD 100 Soml 5.0 LCCtw0. (210-VI•TR-55. Second Ed.. June 1986) A-1 • Exhibit A-1, continued: Hydrologic,soil groups for,.United States soils, , N..... ,C I w•..IOOt. •t380C( C I ...sass.. • nay _ a I wt1.D•1. a 6•LI•t- 1 1 Sues'••1Ur I 'raislo. C •••tC• • :I 'Ni I N6•• C • «aG:!O•• 'a - I M•N*S C 1 M••s11wt C a 1 MitSC10N e ...cif•0I C I NaixIMIS C 1 MYS?011 - 0 nevi/,$ C I NCISCTON. stow, C nib GUI • I ..•Nas 0 1 Maaf 0 w ILL a I' NC1SC TON. C ••IG CIDI Matt s•III[ 70' I .ast c••• o wave Sot ST C/oI SILL Sat- I ..•1Gw TS • 1-N•MY SVIIIf• C I •••Tt• C •Now;SOO INGS a 1 .•I IS1CO a-• • N•Itu • _ I MDarLo0oto I easel[DUO • tia•EsTOaf a :I 'NZ 1ST 0 •••Il11•w 9 •I e I wail SG a M*K[T t I'�Nt1•T C ..11a( C I'wavl• ■ 1'na•?ILL 'C Mav5Lty • ' I Nr/I[a 0 «alai. 0t560C• 0 --•I !M INN. a 1 M60TL411.0 a "Nat TUN 0 . I 11CLDT -C• SUBS fa•vim I MaN*&M•iCNtt 5 I Mai1LC55 5' si•reo II[ 5' 1' NCLiNY1O 0 m••s• C I M•'•MI*G • I-*rail L[TON P Ma•CD II C 1 NCLt •' C - waIACAN 0'` I Nary C' 1"Na0TNI1 C MaTOlw 0 'I M[L[MO•Lf a M•la.a 0 I ..awO.to C 1 wa6tseuoc 5,D c I MtllG•TC a ...Loral ? 7'Nais C -•I'6010Tst.Ls t ' N ILL[ 0 I 'w(l4.'16 C •• ..•LCDII Ci05'Na5SCI, C 1'N/WI•w Oar 6 •N••tiV/ILC. STON• C 1 veto. 0 ..•Lott C I aroI Ma•TV ILL.C C wa•rICLD 0 I N11•(0 C' • ...LC D ' 1' 0 I *5 MCI 1Cl1 C - iia•►DOD C. 1 -Ntt•[•. GO•VCIL• 0 ..•l!• Ooa IwcO C 1 i.irt«n -.6 I ••••• O 5 as•1111011 P . I •SU•SOII ...Moor C I-+..1tl c I '60r5.STt• 6•° ..Ma•Na•ctT O 'I .111.10'. THIN 0 aaLE 1'•• • I Now Tt. ot• 'c `1 ••wrt• 0 M*•No'o a 'r.54/6f aC[ M•L[• e I ..ao a I-w•rr/•. Of DUCT' •C ••a••011T 0 1 KL••S. St11511• • 0 w at• 'oDN 9 I ..600002 .6 - I' -t•AT Tag lye. Or, NaVia[Is 0 I [00010 Na - • •I N•OJ•C( C I•Maa.00D C *5115,1( a 1 KL7&ICC 0 «a 0 -I -Na•N[T C' ' I oleic tlL -0 -' 'Nii aCSS • I PILL Teo 6 w•L I t •6 I'••••L[ t I •:•s6 MS -C "■I.•Vo•Cle C I. wet:et ft• C «•LI IN.I5.['' .t "I ...0011 -0' 1 Nasser C 'MAT SWIM 0 I NEL' C *roll 1 1 1°•«aaaaaw '• 0' I-*as5(LL C • •aisI• e• I 'Htail.c '-a ^- ..all aaKI's C 1'U•aa•a1L1 C'• I wailINGS . e '''Mav/t• E ., 1 11tI'C.OS6 '••e w•11•NOast a,0.1 'NaaaN• t 1 11[1 •C'•' NAT11 0. 1 B•t.ING5000 .0`. 'aLLaNDalt. 1 10.1 0 I'aa•6000 ' • •- I-MaTULSD 0 *51.1151 C I .410•15 11•0 e ..*LLC•trt • • -I MMC•r• S 1' Ia•TCN•- C • '*5•••000 ' 0 •I 61.410 a/0 • ••LLCC• C 'I=•• CO 0' I`i•••CN: Ga•V(LL• .-tT ' ••l[1 C I we Non atom • a - • wLL(Ct. GO•V_LL• 9 '•1-•M•OCOT 4,DI N•TCK•T C - ''I,&111111 0 '1 'niMOOu •C• sues vas?us ^'b •• Otr•r •a- 1 NaTCK1• a - •att• . e 1''-11L•i0•ICCS O Yf N•Ll[t75.15.1.1 '0•,r•4•0 0 1 3•• - 0 • 1 •0V(N00.0. 1.4ICc 1iatL(441RST C I 5,t MOT C •*LLtION C •'1'.1•00«[1 -5 I• 101... ''PIallttag 0 I'N5NCP[0 C Nall Dass C'..`I'M•0Dlw'. n 5-M•11CN!1. 0••.145.• C - 'MaZTOM 0 ' 1''�.i'Nylt a t• - •.•ltt, C/DI ...RC!Stec 6 I •NaTCKT. 3'.. -C ' y°K10LCT • I livNn IN 5 wit,Sr -0'•1-•man OIL • 1 a I'M•ICK1. C011111• -C "kio011gatees a ' 1 K ale♦ C _ •.•..•cco • - I M100SC.a1LLt 0 • I wiCMIC 'C '�wt•ct 0 �I-KrwLIN[ C .ua•CW0t0 a •-1-«6001610415 5 -I'Nave.NVs C --'oft ft ait.o iim c• -'Irv[• "?Ce' • ar05'M100V C' •'1.11.1(6101. f • re-446.16G t I 5,t rwect C •••6Lt• -•C I waft.ILL a`>'13•w•t*5iia• 5 .4111/•111111( C - 1 '(N111[•1. 'a ..••00.11 - • •- 1 '•asee•Vt --Cr-.1=waTlt• 'c°' - wta•M(. 00.0(0 0 ''I-..itN+C SST a• Nawe•16M1 '.0 14-wYJO . 'I uaILII/ i•'' N C - 1;NfUNCi•• 'e°" Ma moose 0 I--'eas[OS C '-1 ..•,reel• C '.rto1MC0a1 C •1''Willa• •'!'� ma,y• C ' T»..a•ct• .0 '1'maim/at ti'''t«( a.' I 'K•IN INGS S' 1500[.. 1 I",Nai1NCSi C -t1- M•T11( •`'( '-N[aTCM a' '1'1'tuNINGS[w C -a-ct C .1 --saur • I-•Na'ter C 'NKeSaONVILLC •• I'siesta tocc. -• aro w6.C65.• C-_ I N60L!, , 'C°-I 'aw s • 'C •= mese,- • - 1 ;raw 1(V ILL. • ...+1t 7Jw 5 •I 'M•aLtr. CM•N. t6 0 -I' aT •• IT tL 84511.•84511.••11 84511.••11 K1ta1 C I NITS• 0' *real(1 t . I ••.•1CStCa C I wale)160? c ' -_ 'tlo c I'wtula s■ C • ....ass .16 5 -1 mass leaf.. • 0- `I-w•laf ere =1155.0' • I Kwilt• o •• ....e.t.a • e 'I•`ma• a. '0' '1 i•aif•• • a- - M5Ct1• 0 I 1t*SO1. !' ' ......10..1 06 t' I aaa.twt :C-"I «•11 1041 - "C . --M(CM7••N O •1-wt•lf• C. ...w•Swlat --'C 'I 'a%wcN• °'C I wauMtwtt - • - samara r 1-'Trr••%1t «aN•i0a ' C``I MiSNf• '.•' t Nam • C" Mtttilow O• '1' K6atlt 0 '' wawa[ • C/o11041101 •' -I;:wiV•L• • '• '11CClg • "1 944000T - 0 • ...wave '5 5 Nasal. 0 'I '..[Vora 5'' 'i SCTO• -D I'KMN••• C - - ..•N/e.. C I'-M•••t•$V 15.1[ -C " I ••■flOCC •00 -wtDG(' O' 1'K•O 'C NAN. `a--f'MU•!15, - • `-1"wa•eN a 'Keats C• •1•'Katre.0 e «&w•0 I I• 0- 1-'• 001t • =1•iNa•taOa0 -5• naval C" I .facto C . ...acre :c• 1'oai•t SlO1 w•1R0111•O. ' C 'wee 5cc 9' 'I' meet tram •e - ..wat.t I C °I NI••Sf!• 6/01 /100(a&T(L• S.LIK• ° K01Timm 0• I NCrIOMG • 0 ..•N•«•uly • I 1110•1 e 5 awn soma. • C •° KOVIIII • 0 rioter. 'C manC(VIL5.0 0 I'-..1DVa C• I MARK• •C--' 'K(CK( • 1°K•r•MTO.N • C ..a NO a ' 1-01a0•aw 5 - I -M awl aa0M 1• •NUL•' • I K•s(SINC. •a war•••• '0 1-..aaaIt1 C I LLLLL1oa a •% setae, a -I airmail STO' a • a.. • I saa•l+•N e I M•VIl•wD t' J' N5I10 0- t 0•1••06 • .,[.105•0.0 0- I ••aaj.•'. alt C 1' •••IIL•• 5' 1 14511. 6'-1,rita••••CZ a wawa* C'- I Naas 1INC.to. C '1 •••11M00011 C I KGl et - •6 I- we NO Ow e •••r• -a I Naas IS Co 1 weal". • • ! I Kest 0 I K•0 ..a • .....•o■o a I NasalsevOC C I ••..r. s•Llrt C I w(lOtl - a' 1 11(000 0 • ....1Gi• 0 v - I 060111IS0.. t I ••ve(, a.m.'.,c1• C I 11C1Ct+ 0 I mega 1Cc a - .4•400 a I •••••551111. C I a/I - I welt 10644 C I- M!•S'' • «...G70.r P 1 Du• 0 I'' LL Dm 1 I 1155'*TS 0,01 0411•1N41 • 0' 11•+100[ 0 1 11501.1 eel I Na. ' - t 1 111$L . 0 1 11[•7, O ` '01ts: 7.0 ..T000LOGIC,SOIL 0•00•S SVC« •5 6,C IMOIC•TIS lac 9••■• 0/uro••■•[0 5I?u*?tor. •00.•Ic•I s-0.... t.4.. 9[D.00• SUSS/6•TUN. 111'•(0 TO • 1•cCTV1C $011 tr•11% 54151[ •OV•O IN 00 IL a•• L(GIMO. A-18 (210-VI•TR-55, Second Ed., June 1986). Exhibit A-1, continued: Hydrologic soil'.groups for 'United States soils .tscM a NILL%0080 a 04010[0«001 C N000Tt(. a OO.CLL C Nes•eP a NILLSO*L8 a . NOLOeSNtst C NooGoaL c No.LaNO C' aesPlala a NILL10 0 . MOLDI.1G/DOD C *MIA! ! NO.SON C N(sKauf a NILL.000 0 NOLDS[GC P. 0OOtsaw a omit 0 NcsslL Sly $ILN*O •-0•. NoLILLIP.N a NOOITOw C NOTLC?ON -C Mlss(L•COG o MIL■•D. 06*INco O. NOLIa0O a NOOLtwa 0 No.Pus • .ess(LTINC ' e- MILNOC C _ NOLI**DL*LC a 1001• C NOTTT ILIC C/0 N8$SIMG • «ILO • NOLLINt1R • 'Nao.al 0 MY*CNUCa • •"C N(1Sl•*. C 0416060 •• •0 0OLLIS COD 0000(D C. Muala•al C N(SSON C NIL? p NoLLISTfa 0 ND0•tITON a Nu! 0 04(•15.• C' NILTON 0 NOLLON•M 0 NCO■LITC D MJMOaID .a NI:TTINGfD co/ NINCALe• • MMLLO0lr - a NCOSa 06 N 0 1•a•DOTON 0 ` M(4tse0 C., «101015 C NOILOT C '005(60. a aveott.t. a N!U?(LTO0 C NINl6au0G C NOLL0.a1 a atone IC , a Nu086L? O. 0201111 0 NINi8P C MCLLOaTUCe C M00St[O.tll( C avocet a NEs1 0 NIMAL! o *IOLL? 660 1100S106101 • Nu0Ltasaua( ! N!?OCO •- •01NN•N C NOLLT. 03040(0 0 .01301 0 1VC8LC6e■R? _ C, M(TOL.UPP 0• MINSOaL( 0• NOI.? SIDINGS 0 MOOTTN ._ 0 NJCLL[OCC.t. NIGN ,a. N!?TOU 0 , •NIRANSOUNC C. 640.1.Twill. a N0000 . C *al f • 0t/CL '0 0416106[ 0 010 ?.000 0 010.01*. a NUONUT +a .1 NI TISTa C 011SCNaa.t • C NOL■*N • NO*Cea . 0 10sow c NIaNC .C•. NI$e6a C NOLNOCL C wO.CINS a w!C0 C.. NI••O ,.c 011S!!' a s4 is .. •e 'MIDLAND a MICL .. a NIO e OaD - C... ‘1114.E ,;.! D N0L00A01 0 NOPL!T 0 Nut IQ NC .0 N lee INC, C^ NITCNCOCI 0 , 04060«4• 0 NOPSowvILLt C wtNlwC. ..0 NIOt6011* .C • NITILO a u0LOO•N 0/0 NODUTA« . a 000leltCLi .[1 _ NISQIT(N 0• •MITT 0, NCLDPa.. C 0000 6 W(ore Pf.,OR•IwrO. ,Se MlCtwaw -0 NITaL D, DCPRCSStOMaL NORM C MU8.'•NO _ ,, 0 0418[01? C M 1.014 _ 0 MQLOIa•• 0• wanes. 6DAT11L, a put. ..D NtCLS a; NIeaSsfl f • I•COY:MTLt $U5$tR•TV■ ,. .!,F INC a NICKSTILLC 0 - N10000 - - a IL000ID 0401NELL 0 NUPPw•N 0_ 0IC(STZLLC. C• MISTON .0 NOLSINI , e /1066/106 . .0 NPPPI0N 6 O80o0CC ♦ a010006? -. C NQLf?(IN .a MM•MIT0$ 0. wUGGIN$ C I SUOSTRATUN • MOS&C[!a ...e 140611004 • a 140010416? C. 114GNCS a Mora 1 e NO•AN a am? •e. NONM$TILL( C, MiGNCSTILL( C 100660 • . 0105.1 . • N0.tts . .0 NORROCRS . •, . . 0, NlGO 0 MIDATS* 0 NO6C*. • •. ..•0 1404.?LC 0 wORKCaNP . a. Nusul , a, uIOta.a? O MOa1 ,• 0404.TON .. . C 0001[01060 6 MUGVSTOS 0 04101.000 •. •.D 00008.6 c, 010.1TILL! ,C '40.6(6.10[ 0, NNICN*C* _ C 04180.0 . a NOD11 C NOL►Ot( . .0/O 61001[1«1(6 .0 NUICNICa. PONOCL 0 .41661011 .0. No00 . .•;0, .;MDM• a . C , 0405168? 0' NuItau - a NIGCINSVILLC C, 'MOO! 0 NON! C•*0 C MODS? 0 wt ILL e 10I6N GAP C 600601404? r• 0.. NQ0llate 0, NO•T0M.14Lt ..0 , ..!.art..(?? ! Nj614•010 ,• ..0.. '00 SON .... C. NO■!L*NO C, 04 C1$ C •. mutt.S. - -C NI6040•M1 .0 NOOVCIZN . 0_ awe* - 0• NOS!1'61«4. •t` MILL? a NIGwCaMP •.a MOC■ ...IA). NOKSTas! •C .!0161? - . 0 wlua 0 04160411(1..0 -0 NOCwtlN --21. • '0'!08.0 a 1504!• ..,,.c 104.1 As N 161.10.01 •-0 MOc!I«SON r .0_ ,MONt.00o . C tsetse Mt ,a uu■•C•o • 0 NtuNOac • 11MCEINSON. C, MDI-C , C • NOST*6! .0 .iu■a1•S c NI Gay o1NT. .• •o IaDt.•T(LT v(? 140t/R(. 110O!•aT(L-• 0 Not L*6!.,;,.- .0 1b■aa•68o - a 0110NP006 •-•0 NOC*tNSON. DIUN(o;�• ;.T• Saar/aft ft C 101016 , _ C M16M?0010 • -C 140([6!? r C M0r0&*$$* . 0 0.01C1((0 .0 011000160 ii M16w Or .000 •- .0 NOCaI(?. ,.•o N •4Nay C M01CL - �C NuN50101 ,0 NININaNU • MOD• .0 110«[4? ..:.a NOTSN INGI I .0N50L01• 0 NUON!5 C 0100(00 C NOMo AL( W 0 NOtt . • Al 1. !• %• Nlt0 . t • 0100(045?1. _ • NONOOwe . a 1104604 . • S*L16!-011.0.0L* MI80 10110161 '5 '006! . - :a 14'01006! 0 04040601/001 - a/D NIM•OLD1• ,..• 0116.168 , 'O MOO6IN6 -• N0/e?OC* C 010406011011. •0140(D 0 • .U0D8Na?t1T •t?. , «14.0040 •. 01006100 •t • ■ONeV6*Or( . 0 1OVGM?ONTILL( C SALINE . IILOI•R!CN? - C 1400.04«! t'- ,• NCM*TJON!s .• NOM C '460401.0?. 0001,.00•,2 NI - 0 M6'/Law0 0 NON88Th.! C 01046• ! 1/50661♦ S•ll0(_ NIL[& :t'.•.• D ND.PNaNTILLC C NOaNItt . 0 NO4LA* a muNIODLOI. DR•*NeD• a NILOS 5 M0/P1T•OT '.• NOMLMt • C MO •CLA$I . 0 wO6NIIN! NILG(P • 0. man., C 010041*!. 00401«50 0 mouse NOUN?a1N 0 141.504.0?. _ e MILGS*T! • 0106.0[50 t• NONLV . •III Mo41(• 0 ■00l5•?!4.1 .8? 041616$? 0 M66AN101R6 • Ha6N 0 N0411(•0CC _ 0 N40501.0?. O*a1NCO 0 MILl04C • O w06•aCt . C MOw0.1a C NOU11*t( C mum ova a NILL•aICt 0 NOG! r C «0101** a NOUlTON .0 swam C NILLCO • .00 .al*T 0 - wO010LU0 0 01045006 560[1 0 NU■(STON C•0 01lll[010401 -C N066t/ 0 NOMOIN04 a NOTO( 0 NuaMe0 • C NILLf•? C NO' 8 NOMO■CGaM a wove. 0 MUNa1046TON C Mt LLe1 8/0 0101'*'' C NOMOIL I4L.I 0 NOW!M1(!P C M1046N.t,6 0 $1ILI ICLO • N0t0 'C MON?•S a M00001 0 OSIOP?u4.LS 0 NILLGAT8 0 '43.50501. C 1,001700■ 0/0 NOTB? C 144.11!! C • 01111.50 • NOL•100a 0 N01,1*ULU a Novato • Num e 1nLIaaD. C NOLCDNS •0 04000 a NO. ILLe a c0J■cMaact 0 �■DOISa?(LT .(4.l Na0•.•r 0 NDOOIC a 0O.caN - e Nu0ODa. o 0.1M80 000.0804 a 0'@0000 O MO.CIC( C MJN(.ILI S• .14.4.001 C 040.010 a '0001.01? C No.t C 0410160? C acme: 1.0 MT06D.o61C SOIL C RDU•s 540(01 AS 0/c MOIC•-TIS TNC 0.•IMtD,UWR Da1■(0 SIacme: UATION. a001/1!Ss s/O.N. 4..6.. O8Oa0Cc $ues?!•TUN. • • suCCIIIC son 6[51(5 NN*6! POUND IN SOIL 01.0 626(010. (210-V1•TR-55. Second Ed.. June 1986) A.19 • Exhibit A-1, continued: Hydrologic soil groups for United States soils. NUrw10. . c 1 ILOCC••O a 1 'PIS- C J•C•GUaS a JI..T•• 0 wwS1.G1• 6 I ILOC•O.S0 a I' IPSO. 'a J•C&N• ..c. Xtlt• C . .UO1C PS e 1 ILCS C I tate1CN '0 JaCet •- C., . XLLICO . 0 inuPTIMS,ILLE 6. I. 0011• 'C I iC• C J•CIW'0 a,-- X.C1 :C , ..v TI■ea C, I IL11L1 D -I' 10••08 " ! J.CC CRICK • •.i • -Jt.• e wrtINC. . C,, I *LlC D" 1 IltDti.L C/D . J*CCtT . C. XN%IWS C mufti 164.106 Si 1 ILi.ae0l C. I IPCLakO C=' JaCSL•NO: •0 XNt IN50N - 0 •wirtrOV01 •' 1 ILL•rtt •'• I' Walt " e. • Jac leaN •.e' X.15 6 ` "! I t5•Ttaa VIsT•Ott e• I ILL[• JaCC•I'C C' X•r(SS a •1011Seu0S 0 I ILLI10 0' I. I01GU1 • •O J•Ct0001 0•+ JP.110106S C rliarsvtlle. 6 I 11.10w C 1 1016 •• C 'JACKPOT C Jt•a•T 0 swiss a 1 14.a.00 e ' 1' IP.NUmo J00 0 ' • e JaCt3 C.• 0a C 1,610110S 0 1 tau "'I. r 1.00r. C J•ccsok e JeoaC . • o Nloleut C' I I.CILee a 1100w 8L0110•• • C J•C(Tore 0- JIPMVlD - 0- .wiPlt• 0 1 I■.•• D I. 100. wOV•1T•In 0- J&COt . ' O JR IICWO - •0 .01•a1C•NC C Iea IG ' ' C'" I 1.0w •IVCO .- e•" ...coasts - .0. Jerome 0 .u..• a•c( 0 14.0160■4.t {'. 1 111i0000 P • ' JICOCT 'C••• X•RT C' .aj•ava•C• • ''e - Ism ttalte. •e/c1 IoOND•Le - ^ • C - • J•COT -' 6:' 'J!N•VSLU -•'C .0101,1 0' II1001/alet. - 'r 1 IPOt •tt a '• J•CDUIS ' ' c • JIM/ e «.04.0••c e' 4;4001 11101.01. I IRCNSOOIwG6 - - 8' Jacouftw •C • .11I level 'e• «Vise '0 IwcGC NT 0 I 10(1:10w C'- JaCa•II C••+ .J1 Seel . 0 «use• 0 I see It. ' ' a I laccuOIS --8,0 JOC•IN - e 31111 Casio . 'a NVSS• -' G I.0•CT - ti I I ' '•'C •' .1•011 ''e 'Xtt*110106 : a wutl•. C$•Tt? ' 'C I00 cu laf•L - 0- I ;sm'« C-" ' Jae• . at.• .11550 ' -C• SuelTO•Tu• ... 11ga 0 1 1.1oN '• • c J•GU[KS - a • WOMAN :.•(•- Null•. ■DOtO•TCL• C I • -C I 1091.4 •.:.C. • • Jil r -JC/CO• '0•'••vll .' ' ':.•: STROT1•ICO • •.-- 1 •10vI•411ti •-'C • J•l •O . • ` . 41151(0 -C. swiSS•. Da1IN[D -''s' suestealuw 1 tug l• • :O ' •••CS o' • • Je TT e. • NVSSCLt. li0,•1.! ••• •" 1 ISAAC - ""C .1U0[1 C•N•O• •••-C'° • Jea15 C . .VSS■•w ' O INC/LL - 0 I 1S•ec .• • '"-e ' ' Ja•[s Cawlow. •','•ae. JCYCTT • ^••!• wuSW '`' N ICNau .'C I IS*. ` - ' '0/0 D0•1Nt9 • '•• JIGG: •I, • NOT Col IN50• C' INCNCL:to • •''e' I ISactt i/o 1•0[5•'1 •� C/D ' JIGS*. C - - NYTCNLCT •• "O' laC• ' "•"' I lsrel4. a J•NISt ••' :- JllsO. 0. .wTi0w -5 ;�O•PT "C 1 I SILL• - R Jac*Sn• Ov100l Ovo.' ••• J16 C: . 011 •'''' o' 1+0:t - .- I 4.S"I •Is..1 .1 4.•a.Irto '-• ' • Jt.e0 • '•I ' NUT CON ' ' ''' INOI aro■• t'•'• 1 Iiw•trlwG a?' JaNitw • .e' ' JIl•Ca[t• C' " •LILT• t"-,'c' lip 1•61 C•t![ • ' 'to I *stoop te• JaeVO= '-r,'!`•' . roses •C:•,7 wuTSINc '1' 10 :••13 "C' 1 lsteat C-' JaNUOt. CLOT -='C• 4$-IO t ' C'- ". , : .' 110t•NOL• - " a•' I I Saba 1. CJoi. . ..'G' ) bwe V• 41••.•1! a r ..v••• I9 a" (10i0 -a 'I ISLa•.0 °- 'e J*Oae • • 0 ∎':JlareaSON ' C '• .i••t e' HOL[10w • -e. I's •)_•. 0' Jaonel 'O" ' JI-Sace • P.-• +••1191l1..0 "`•'C• 1NDV1 • 'TO -.1 154.:5. SL3uG•. • -•/O 41.01« • 0 JleiONN . C G ''•'D !K1 ` IS- '1 1500 T- ' •=!•° JIRC•LCS .•-P- J FOOL 0 • • a ...01, • 'Sill- 111/1.•Nam 'D I Ilea• -'a- Jaa1T• '- eau. 3100 _. e • ...Deo --"o' ' isr.•LLS •s :1 tire' "xC Jai•ILLD -'.- e' JO•clue u •. O' +.ORO `'-C 9.1.101.3 "' =• •1 lSC'LCC `:- • 4•101.• ' C OM •• •'C TT •"a' I;G[a%xl - 'I r 1I I SIN. -'.•.• a a' JOses •TTL,C •'.0' ' I.GO at. '. .0 -1 Ill(• - •'C Joust • - - -a•• J5.•t lc •0•.v• s . ::6. belt• '8 'I IST000OG• .''-1 -'i/0 - •'O° JOCat. "'•a .ves•toit '' e• - As ow --o' •1 t1•ro • c." • 400815 • •'e'' roc 11• • •'"a :.01.. "b.'--"se ' l.000. 05•1000-- •'C I 1'1■lCa" - - • ".e' 401C0 • •• •o JOC18T•. l0•• , ' �'C- !Pima M '`'D L-DSa 'C '1 Ill? ,.! J•so« :': -0 same•Ct s•.,� :•SNOT - `d' INtI ' ' - o .I ITC• '- •0 Ja1•e• • J p;0` OC10 ' •' 6••i.T00 • t+ 111N1Tt• `'_a8 I 11••C• ' 'C` JAUC&S -' •. JOe[•0 • ':•e critic 7 lea.ow °'C 1 It•a•,• '"-C J•VC0S. Simla( C. JO L • O •D - - "0 ImaCNVt • 0 1 ITOO . • J•UR IC. a JO(emt :..e • Slab• • 'o Israc ' c 1 itt.oct - . '• a J••• - 'K 10• JC • ' '0 Call I• ' - -'0 ' torn •• I ism• '•�•c J•VSD•.4 .-7,,,.-11-- ' Jas • -e Cca1C . '0 no 1NG[o ' • c I Il• ' 1'Q C POT -c- JOt•es • e castes ' 'D /.•1reercc - e 1 I.ar r: e :'IC : JDI.I1 . .•C •C••IDC " o • Ins 0 I I vase cc ' -'C Janet - '0 , JD•Ot55V•C .• - - •.0'• cr[tucseac ' ' 'o assume' C I :..epic[ " ' •"o • -- ' a JOmtS00 a.•' CICII - ' •:"..'e INS&IP C I tvT• ' -'111 Javta ' .w_ . NNSTON . 0' D• • e 1NS•'L• 's- 0 1 1.1•11« ; 'C' J•..cs • • '-e• ' 40$ UO.N ,e Dastl "e /WI.ipso • a I t ti • • • • e JAimee .' 'c- . JONN$R000• a- Dawa.e 'e :NiON • 1 Ives. ale '' 0 Arse .'.a' 40.50100 ' -y 0. 060061 - - .0 1.815NCSS " - e 119It • a 4105 Lett . :0 30111 0 OSt C 15• 1.1•111 C 1 181.1 C JtaNCaetTC 0 JOt0e5 6 3LeaILO 3 1 Iry 11..1 • 1 1•••11.0 '•..rC feat e J0000OwSCI 0 SLAV ILO. oa.16t0_ _ 10 Q I Isl•s• C J190 .' e JO$•• 1 e' 1•0• 0 . IOltau C 1 1•1•1 - •'•'0 JCDSCJaG - 'C JO.1tt . .0 ]D!lm `C ION• • IN 1 1101.00• - C 1100 C JOLL• C :(01 C 1001• •• 1 1740 - 0 41001110 C J0/6•L1 a :mac to C IOSCO P I 11(1 ' C 3100110. - P JONaS -. 9 ;0 r 1051•• r '1 I10 • ' 0 9aLIN0-allall 401.10.1 8 O 1011• 9 1 110( '0 JP000 C/o JONC• - C ., • Cw '" a 10•Gt ' • • 1 111.1110 -a OA) JON'. 0 r4. _- I•. '0 15.00 C I 'art/ 7• SON a JDN11 - a'. t` •CNCTON(L 0 .10014. - - •a 1 J•au. •t I C JC•••t, 1 JON,t•ILLC o,'-• Cs: 4..0 .,0•0L0GIC SOIL S•0u•S ?WC. •5 eft 1.•01C•ICS I..t D••IOTO#V•0••1 1110 51!MATHS*. .0011 ICOS 510.0. (.6.. 1(001x• SUSS T•atu.. •T•e• 10 • S•CCII IC SOIL st•IlS 0 OUro 1N 1010 a•0 616[10. 20 (210-V1-TR-55. Second Ed., June 1986) Exhibit A-1, continued: Hydrologic soil groups for United States soils JOwNIC C [•Haft• _ 0 c•al•N 0 KECI 0 1[1017 • • JOSLIN C caN&NUI 0 (•5011 0 [C[(EU a 1f C Jo55• a Kamen .. 6 t•.o11sIN 0 KCCL C (tee t J01•161 1 CaNLOTUS 6 [•OT1/t a (5[1.0.0 6 C JOSOaN 0 KaNOL• a •:a■UNtcawl 0 [CELE 0• ((0[1'1[1.0 0 JOOGE a Carta O K*0•■IN _ • . KEELED a ((••IC( 0 J006aN*r 6 RAIDERS 0 (•6a616ra 0 (ECLINE 6' (C•ovILLE C JORT 0 (AM! • 0 C KEENE C, Ce•SNar • • Jolly. ST0N1 C [aILUa • talCaL 0 KUNO • C (EISICI 0 JoS5U6G C KAINu A (MIOL 0 KtESC . O ((OSVON •ea JOSC■N C (*1.•510 • [*06[56 0 1(55[11• C CE•T C JoSt.NINE 0 (aloo101 a (MILAN C_ £SCSIaw 6' (CSSICO C J0$6u• C •• (*151[1 • KAOLIN • (METER C (CSSON 0 JOS1t a (LL/L[ 0 [•[1.0 0 KMCraTIN C ICSTEOSON 0 JOSL/N a [ALaLOCN 0 (*0556000 a KEG 0 ((SNICK C JOSSCT C K•Lar• C (allslurt a (EGCL D [CTCNLT 0' JOWDaNION 0 taLAwaloO a - C•StSTKO •• 1CGCL. 00*16(0 C KCTCNUU a 0 JOSCC 0 KaLaP• e [:5405 • D . [(Gams. a (ETON• O JOT a [aL•U■a'• 0 Ka0o* r IT KCITCNOac6 C - Juae 0 eaL55?**I - 0 (*Dada( 0 (ra(a• C KETTLE 0 Juaw• DIAZ ' _ 0 (•LC[Tar. TILL C [MINES E. 5[605 S (CTILe6[LLT . 6 JUBILEE - O OI•$T•aTUN Kasa( 0 (CIGICT . P RETTLCNAN ` C • JIIO ILLE. 06.16(0 8 [*L IION Sa♦ 0 (*O5& _ 0 151516 a KCTT • a• JLO• a 56.10* e D cMI00 [ WIN a G5*T(ll�•,; • , JUO0 C KALIGa. 5100050 0 (• 1 • K5IT$VILLE C [Mote 0 JUO[LL a (ALIN! 0 cullsooftEo 0 (tame* a ICUTCOVILLC 0 Jun ICE D £ 1.1155LL 0 [*OT•. C l! C Ju017N a K.LLKASK• •_ • (*0760 0 •., a [(TIN C JUOTIN1 C [ALLID C [•556(00 .. D (ELK • C (5VaCN - C JUDSON • (•LR*•V ILL[. •_ sec £•311(11.* a• RCLLCO c, (erauwee c JUOT C I•LN1• 5 KWIC, t ct4LC•OUTTC r •• Ju0 a (AGO C (*SOT• c [ELL' O ([T• 0 AMC, O (AL6c0 - o (*111[0 • EELS[.,- 0 ((TES 0 JuGN•NDLE , e [•Low• C (*SSD1! . C 1[130 C ((TCEROIN1 0 JuGSON C - (LL116 0 c•1•r• a (ELMME, . 0. (t7MCD 0 Jules • RLLf TCO 0 [•T(■ETC KITTS' _ a C JtLC$•44R0 , a ca*acc a 1*1650 C ([1.T1.w C [CtSTOw[ • JuLIN D laracO• _ T e £ate eeo iceman D c[i!w 0 Julio, _ a (MOAN _ 0 (*15[66[1 0 ((NAM a £5110 C JUNPC•[CC C CANADA _ a 0[445• C 1(■•C0[o C (talUS C• Juror, a- (•r&OLC 6 (MIT 0 [[600 5 (1.11 C Ju65SD c (06*TO C (*71(1..1 a Keno C 1t MAN - 6/0 JUr■.00E, • [AM[A 0 1AYD(0 0 ((■•$TILL[ a 11.015 e Jurso►• C KANC1.a C (at•66N 0 KENAI c 110551LLaN . C JuM•LUSA. _ 0 [*MIS a. [*Maul• C R[w*w! ILL& • [ICI•ROD a JuaC•l •. C £ar■vILLE C twee • 1(50.1• C ttcte•TILL[ a . JuwCOS 0 gamma t. SWIMS 6 /MALL • 5 KIDD _ 0 J1NCTION. 5 KNINKaCT .. • 0 (•r!TT 0 ills 0 [100(0 a JNNt•u • (arata a (•v0■ - e ICK • 1I0ra6 a .01NG D•• (a.a0•,4a 000 ur•I0•E C IC[ 0 ((561 0 JUNCO a (.1MI•N21 _ 5 Rara111a5•I 5 [(61(65 , 0 [ISIEL C JuNISe6auT( • (awls* O &&&&&&Gan c Keu■oo0 • (I • e .01615[60 6. 488,46441 a v.arica a at66 • MT 6 J11.1US C (•NaUN• - 6 tar41411.JM C 144N*N • (1(I - C JUNCE11 _ C '1••O•LT, • £lTNINC C K.N(•ec .r 6 K((Ow1 5 JurO •, KAMDMK 0 ••TD _ e 15.11([ U 115.0• C JM.ouITes C 1•N00t• • [c•nt, 0 K(.0E51C[ 5 (IL*•C 0 JuTua• 0 KANE • amma 0 [[6657 A KIL•ut* w (M e JuIIT[0 3/0 amat Sae WI • C (Cal a[1[ua • CENNET LAS[ . C (IIOU•N a JU•• 0 (*6106( • (CALI• C [(NO 0 [ILCNIS w 0 Jj1•V•*MaN C (•6[300 • 6G 0 [(NON* 0 [CLODS C 1414 KS[N C KANC• • c (rwotaatt. C KIL,OtL C Justes(N. Loa6T 5 [•6G C • 4e8•*7 • • (ILGOae 0 suOST•aTur 1.110*S • &&&&&WAGS , ' P a K*LCC.6T. _ r• Ju1716 • KamID • [EATING C 5[.5(11 • KILLaa.cT C Alva • (*01.1.10 • 0 6 (ILLPUC( CIO JUT'', - 0 Karla* C K(ar*K10U� e SENT • '0 KILLO4455 " 6 • • 41144.*4CC ' 6 • e 1(6441(• 0 ((LL'5T O KaC6Ew*K a KMI1.55 _ C ((Co 0 [[.TON 5 [IEEE,. 60DCOITCLT C [acmess a taxor• O creme a KEE S 1ST [ADC • 0 Kar03a C (5cI$a0A° C tenet* 6 KILLINGTON O [*01.511 • a [•111(1,46• 0 150• 0 ((011.6 C [1Ll14CK C taoOCa a [MIUTCNAN 0 [(0015 C 1[OT• 6 4Il0•w•06 C [*(6• 0 Karl* 0 1[01010 C (COrNS 0/0 MILNER C 115160 • [l►a• a KC( e C (ILMCaOtE c — c*Gra• C i a KC[CN(LUS. C K•s(O 5 KILN O • u GraN. Teri • 1 . 6E060C4 C tItC11 C 5 (n.6► • • casvetlT 605116171, . KCCra 0 [(•N•7oCN a [11.011.6• • 0 Karim C ACCCCCs ,C ' st•L a ((405a4 C .OTC1: 760 N'COOLOG*C SOIL G10ull SUCH as SIC NOIC•TCS INC 00II0(D/UNORaINtD sITU•ttoN. ■OOI/ICRS 100*.. (.0.. •L000C[ s115ST0alU■. 5[556 TO • s■eclrlc SOIL S5Ot(1 •rase r04P IN 5011 11.5 LEGEND. (214-V1-TR-55, Second Ed., June 1986) A-21 r : Exhibit A=1., continued: 'Hydrologic soil groups for United States soils a1l.,..1.G O II 0 (<aD• C (a(SSON C LaCOlonto C Ala 5 eiTlllas. OaaINCD C t0lwlt0 C asertaMICtN 0 - L•COOCKCC 1 0 [I.. SaLIMC C IIIINI.GI 0 [rtLC 6 aatCO 0 LaCOStC • C alma - 0 (ITtsON 4,.. ' C c01D[C a .•I[Sl a L•COTa ear gIN(aLL _ D. &Iva a tCeoLIN. c ' RcOu D LaCa(sceNt o c1N60SLlas . _ 0_ gleam's •• IC(IMCu 0 RSOTO ' '6 • LaCIOL 0 cloaca/La e' [tiwUtaa a [D►• 0 ' cau!aTC 6 LaC' • 0 c1MaaouGr: 0' 1J•D 0 [Era. S*L1M5 'C (1ICG!O e LaDD a• M clgtaLsaM - O_ ._ C cCtr GO 6 [our D LaOttL( •- 5• LUND C . Oaa1KC c [OGISM " ' 0 [IRIi[ e la0ral♦ C 41E050 3 tLaOl1Ct a ccMal• a aunt t La0M5O • 0 alai• a [Lao,icc. STONi a cclar a eu ICR C L*OOGa •• 0 draft e. au.atM 0 (Otte e ' [yell ''Y • 0 LaOaON • 0 case-(Lot _ 0 cLaccLmt5cme 4a' 0 ecetawot C [UC(Oa • a L*OUC is [Ammo a &Laktame(cat Pi. ' C lm0 a twice ' c " L*O,COr6 0 xlmo5o C LaCwil1TO1Ne "-' [D(Ct•M1 C ' Ru_lae '' O LaD.SNITM 0 x1...116 0 YJ ' •,-• " [O[D11w1. stOM, • n RUM 0 • lave -"' • D [IMO, C Cat ' c c0'0•0 .. 6/D cucalaU a L•rITTC b°' 0 (Il.CSaV• I. 6 RUuS - C (e •c - 0 &maim,. OSOROCE C ' Lan a (tNGOON . ' e (Lassa! 0" [C%S(OG C sliSSTOatUw - LaGitOS C [IuCrlS..co 6 SI. ' 6' cO.tcCi0 C [Lta' • •- a ' LaGLDAI• • a • etwCrOaw 0 Lecusraltt • ' £011a C [KILT' • t' 5 LaGNa/ 6 cINGtLC C SUSSTSaiV. • cc'u. 0 cl�SauN C LaGOa0a • C• (1w61MGMar C' I C IoLLUTUR D Emma a LaGaaNGC • 0 4155x*.. ' 0 tla...00-' IT [0.O• C • CDI iTON 0 L$COOSS a t1NGrONT ' 5 (maim NT ' ' ' C [0106 P Rtlma'OSM • - laCusil• a 11MCS •-i, 0- ciZCC..t( ". C C .0fl. STOW C (UNta a LaGUMIIa. ref• C •CINOSRuD, 0 ILLEINPUS► C' c0.D[OLO a cla[u.Cla • a •Masai• 0 RI..GS0055' 0 CLSJ Sr- a ICLAm011_ - r• [wiwi 6 LaMONTaM • C ctrGSlawO r/O clam[[( C to r- (1MLLeo' '` 6 laMalt• . C LINGSLS'#' a JamC(ll., " - a (lala ' - 0 ctaytawer ' P . L•IDIG 1 0 - CINGSOOINT a (tIC(SON 6 [d.a.a - ' - r d1 Nc•m0r. • C 1..1(1.x. C [INGSTOP' e' KLINC. CCeSC'' - e ((Amyl C [pD aaTtl, .eT LAIL C RINGSTILLC •15 WPC. PCMOCT!C C tlr.Cr'. Oa'ai5r0 C• CURES • ' a LaSSO ' '` e cINGTalw - 6` £LJwtS51Ll1 ' CAD (oa.•1 O sIIO - 0 1.115015 ILLS 0 (floc!.° C aaIsGCI a [CL..ry. tailsrr' e au_TM ' C •••' •0 c INxll C [LISrC. C [IReCT I C' [wi•ti ` C 1.a JI 1•S•"" • 0 [INUUL. GS..e1L' a aLISTeN (DMOC'I. T.IM.T r sI11.aNtaNtr` O LJtxt a VINCDya J' [LONDI<! 1' ecustl P [L1(0t.lr • 0 La[!. CLaYt,'" C comma.. C ILO*: r (OCt au C' suit.ire '. .. 0' SWraCC * .-:^' cl+..0aa S aLOPC..•a.. C' c0051C•. • (uTCr C lace CMaRLSS 0 tImm(v 0 (IODIC. .. C' (011 Ti 0 cutLca " c lace cocci' - c atraOS3 a/D cloy/Cwt: a (OOSraaca r [u1 ` a Lail Jaw55 • a cI t (101x5 0' cCOSRIa I cNtCNac a' laclrl(L0 e ' 1lmifow'�` i am &Luc. S [CO/cwal - t eel° a' LacIMLle« • C• aimta a &LW r. x0.11 '-- 0' [TOWi . ! U(CMUDS, - a ' (15To5 C [lame a [Cereal - ° r 1110aa• 0 x50 a c1MIll rt '' ■ glUeima - . _ w 5,3505S I a eeltale. ' ' 0 La[SNON' - 0 (t° atl• .a a 1060.15 - -. .CAC. a r IRS 0" La1trrol - e aloft. 5 arararn r ' - 0 [CFlw1 - - C [TLla ' ' C LAacsmoOf 0 4101( a awe•olam S [C•5rrn.. e' nil.. O Lat(SiD? • a• [NCO 0 tmCCLAs0 ' C cCfoOra5O ' C la 0•150 0' NrtSCL" 5• al5LIN6 3 (K• C (0(0515 . • L• va•GC r C alOOe% ' - a Kr1CR(aereira a [OM' P La realm " - t Its C (KIDS 0 •..ILL' C [CSC lulaO a La GaaMDC' C L*(e.Iw e KISS' _ I r5t••1.. C £OSt15 0 La MOMS "' a• Latr•000 ' • a cN9'Slll! " 0 a..IWt SIC aCSrOS 0 L• Laa1Dt C Lac' ••' t 4151 O sad( r eclat ' - e La Samoa, C La[IN a [t•[rs0•LL _ ' C (.t(*1i ' e eossulw ' 6A L* PDSTa a Lace• a " c1.•(-a. - C [rla5• _ C aeCit• r la O5al51C - ' a LacOra 0 ct•4LaM0 0 C50q MILL a neap 0 la 66S5 6 1x[•106( ' C c Ncsr• . C cast-STOP. C ICtt•.5 e ' Llgoeate - e LaLaaI a cl■c•1Llr �C [NDCO o away C await C L•LJMe• e c1SLt. C (acme . .IP [OVID ' - 0 LaSISM • 0 Lalltc _ 0 . . ai0VL(,,' C a•DLLI _ a •0T(w • • S Lan[!' • a laLOS • '' a a1551t C (5055 C ROvsIe • 0 L aSO•CITa r Lar 0 sIS,IN. 6510(0 O [afit1 it CeTUruc • L.SOU C lira C mtSatCMIt . D amCaltS a ea/cut P ••sour,, o lar•MG• C t1Sweme 0 ('Cl• a tats( • Lagoa( e • 5 cISrONa. alaalt C ImuLL a [tar Om 0 LaCIMarT 0 la C ciI.IS ' G ,C arcfls(N O tarn. 0 LISU - 0 La•aatiNt C [ISOING. art 0 &Ones C [5*0sc1 0 LaSUCC a Lar*TN . 0 a1SSICa C lOetw _ e llaSlNUR4 • a L•C•ras 0 • a clsllow_, a ( CL _ 0 ram. 5/0 Lacer°. D LareI•T - a , sI X•11.1. 2 eat. C [Saul( a lacw•sCLLe 0 La5Sttr. r cllCN(t CRC(1 a [0C... 05aINC, C •tl•rt0 C LaCIT• a Lewam.N 0 cf t I 0 aelaa a a•!SS I Late..aMM• C LaM•a-ING C ( ` I allsae C afloat. .nwrLooO!O C Ref. a Lacs C La.000es 6 l\ c1TIt5LL D OrIat a a1C.Lir ' r LaCLto0 a La.1NGTO'. . 0 ..oils= 1.0 w,0001001C SOIL 000U01 suca aS •/C tiOIC•tes I'C lOalrtOlu.COalN1O SITUaTIO.. .•00Ir1.05 awp.w. C.G.. 9t0OK a SuOSt(alur, &VITO t1. i SPSC1IUC SOIL 55•MMS DMaSI r0U5e Iw SOIL ray LSGci°. A-22 (210-V1-TR-S5, Second Ed., June 1986) Exhibit A•1, continued: Hydrologic soil groups for United States soils La NtIN a LAD I*T 0 LaviNa a LEE TONI• C I Lf.• e LAND C l•DIm a LavON C iCeva' C 1 L!•aEACN C LalloILLI a 4..a0,NCO • Laval a L[/O0 a I LCdOLaC 0 LaNONOt a la'to$C*NO 0 I./MCP, a L[GALL 8 I LevIS 0 LAMONt C LA•CIN , e L& tf [100 LEGAULT 0 1 LEIISM:10v a LimONT • LaDs so» C Labe T. a LCGGCTT C I LI•ISSUDG C La NONT• 0 LaDNINI C SaLIsC-aLLall LCGL[o 8 I L[VISTON C l ma/SE O La•OOUt a LAILED � t LCGO•C C' I LeVISVILLE e LasOTye a LaD01I 0 L.LLLLL E I LeNt' - C 1 LIVKaL6 C L•NOVOI C LaQOUOtN 0 La•NV000 0100 LEN'S*, C I LEX a I.awP•SaS 0 L■SDV 0 Lavr.000. 0 Leamars G I LEXINGTON O 1-AN•MI1D a LaDO.. OAIINCO C GIODCSSION•L LEND e I LEITON R . LauDSMI•t '0 La•SON 0 La►•eNCC C LescesveO C I ltva• C L•wSOM e,0 LaD/ON A L U•EMC!VILLZ C LIIOL C 1 LLV01N C La'AD( - e L•DU! a La.S.t 0 'LCIGNC4N a I L IRO INGs P Larcas?eo - a l•Nus. a LA.SON c LtILC NUa - ! I LI000 0 Lawct • L&DVI[ o La•INCo 0 LCIS• _a 1 LIOCOaL 0 LAND C LAS C la•?ON . C Lel• '0 I LIPOID,/ _, • l'aNO. ooaine° • Las aNtmas C I.a►vto a LILaNO O I LIOD•D• 0 Lalloavaso a LAS ILO•ES O LaS C. LCraN • I LI0VSC C L6N000 C LALS LUCAS e 4.41111L a L(Ne01 C I LICNa e LANDED C LII DOS•s C LUTON ,C LENCO , C I LICt e Lawns 'a LAS VEGAS 0 LAICOCK a LIN[•T 0 I lICCOa4e , 0 L•NOLOV C L'as• • L ALTO 1NT C Limtl• ", O I LICKING C L•NDNAN S LaSaLLC O Lavvea a LINING C I LICISIILLCT D LANOSINO C La$aules .'o LaY.ICr . 0 l(NitaS 0 I LID1'. C LANG C LASCO . e Lat*L: 1 0 LEI N. .;8 I LIODCLL 0100 L•NCSe000 C LAS IL 0 LazeaD • 0 LINQLO 0 I LI'DIIvILLE I Laves• 0 LASKa �` ''.0 CC PAR 7e LINOND . Sf01 LIP' " • LaNC• a LaISCI 'c I:c SUIUS • a L['QNIK C I LI!e!•Na• a LANG .t C Lidice,' 0 Lea C LtNOO•l C I LIEN 0 L•NG/ODO C L&SSITCO _ e Lamp . e LCN•I.a C I LICSN01 0 , , LANCNII a eaSTaNCC a LeaDO•( a LEN C I LIGGCI - a Lawa1MSC 0 CaTaN 0 IMT C LEN• 41001 LIGNTNING G j' LaNGLOIS - 0 L•laN. NIG*. '' C LraovaLc c LEN•. /L00010 .0 I .L1GNU• C L•NGOLA a •a1NaaLL. o•alwco L(LOVILLE a 0 I LIGON 0 LaNG•ELL V~' 8 LavaN. Doalie0 C LCaP .0 LINANEE _81001 LIGUDla 0 LANGSD•ING a L•I•NCO '0'[ L(•►DIVCD . •IO LINaUee. DONOCO - 0 I LINEN ••LANGSTON 8 LalaNCO. 'CT 0 LC•PV C LIM0e•G . C I LTNUI „ . a LaNGTev 0 I aTA'Ito • 0 L(aCLIVILL1, BID tD C. 1 LIKES • LaNICO • LaTCN "• • LealSvlLLC 0 LCNOID 0 I Lila/ a LaNIGlo a • Mil LPN! _ . 8 I LILED, 5 La.IIGC°. GOaVELL. C La?CS C LI►LarDIC " .0 LENZ. STOW ,, C I LILaOUDN a LaslaUSN '0 LATEX C Llasra 0 LINt. tau. STONY . C I.LILLINGS e Lawetw C La/Nam O Lca•TO G L(NZSU•G - a I LILLI00G10w 0 L•aiKTIme C LaiNt• ■0 Li* S C LCO ., .1 I LILLTLaNDS C LaNOac a la1NDOD e LCatNIN •C LCOLA a I LILIEN C LarQra • LallGO , . a , LeavN[•Na% ' 0 LION . SID1 LILT e L•wSDALE a LatiN• D LeaVl.VO•TN . 0 , -LCDNARD 0 I.LI• C LaNSOO•Nt C L•I ILA - 0 Ltw Vr•S e _ P I LIN• e LANSING P LaTON 0 Leal/fit 8 .Leora•OtovN ,M o I L10010 _ a LaNte•N a L•IONI• , [ L[•IITTVILL! . 8 LCONI 8 I L*NCIILN 0 L•1111TS a L•tOUCre ,11 LEE.. P LEGUIIU _ 0 I LI•[•ICK C L*NTOM �0 LITOU• , 5 'ma'am. C Le•Das ♦. C I.4.1•C•IDGt 0 L•NTON. LOU C L•TOUSILI c e Limits 0 Lt800 C I LINKING a •RCCI•ITaTION Lallall . . 0 L[NIC 0 LENOT 0 1 LINOm C L•NTONla _ • ,Latta o LEGO . . e LISSOV - C• I'LI.ON. NCI o Law's. a LaUOcaD LC o LI Iatt C LeSNa•a • I.LI•ONes T' Law,: ' o Lauoe•NILL •eo Luc MILL, - a L($NO , C. I LI.D1a . c LaNVe• C Lau/e• o LlC•IG O LESLIE 0 I LINCO • LANVON c10o Laucewous. “c LID.P•O . I LCSON 0 I.LIN CLN a LAD ,o -SU•ST•a'U. LCOG(►ONI a. .Les•ale e 1 LINoaas Cu t ITa C L•uceNaUS. SILT. • iioNDYNT C Leaves e' I LINOILT C . N•UUa. • wWSTwatur Lt001t. . . • LCSVILL e I LINOCLL C L••CO 0 LAUG(NOU•. OSaINCD • Limbo C Ley. C„ I_LINDEN a a LauGNLI' C , LIDUe I . LITCItte .0 I LINOt* • a Lama'a 'a L(OvITN e/0 Leto. C I.,Llroce• " C L••IMc a Lauctl O on 0 LETNLNI O I LINCODITN I ft• C LauRtLGOOD . • LIC•[NCN p C LCTNIT a 1 IINOSIOe C L•00N 0 L•u•CN a LEEDS C , LE1O' 0 1 LINOST•ON 0 6.00•X1 o L•u•r'.TtaN a L(r•ICLO . . C LlIOST e I LINDT c C LaVaC•Ctt a LreCO c 1.11.1 81001'LINO e 1 a L• a Lc[t0. va•m a 1CuT1a a l LINIvILLC C a Laval( a L CLasIU • C I LING•NODE • 0. , L•DCNr0UNT a lamem.. C Letup..? 0 Lg.CLION <' 0 I LIsNaOT a LaPDELI C l e LEe41• 0 .l[VeITON. oQa1M(0 C I LINING[° C Laing/0 ,0 Tara a Luna, 0 LIVC0115 _ C I IINITD e -" L•RES C IN C LrISavDG C L[VlalNal e I IINEUD o , aSCO 0 L•.IC a LECS.ILLE ( • Live P I LIM[.ILLL a NDTes: TWO N.O.OLOCIC SOIL••Oups SUCH as •/C IuOICaTCS INC ODaINCOIUNODaIwtD III ,atION. No0III►aS S..OVN♦ T.G.. 'MOCK $V0STD•lu.. 10 • SDCCIIIC SOIL motes ...Ate •DUNG IN SOIL NAN LIG(NO. (214-VI-TR-55, Second Ed., June 1986) A-_'a I Exhibit A-1, continued: Hydrologic soil groups for United States soils Llgil l61G6 6 4441 8 LOn!1 r* LDtmap a LTLeS 4/0 ' LlId C LOD.CO 0 LOar*I1i F_ Ld;E{A 0 LT*a.* CrO 4alrN[t .. C 4_000 0 Lusee- r LWLCUELI I D de C - L I purr LIS a kOf Tus C LOwACLtr C Llarea e - a.aE C .LJMD 6 Leers r LOLaId. _ :Loo Lune C LTA{r P L.p . e 6.1341r o LOE.ar a LutaDCK 4 LT.CM6uJC E 6141164SC a LASOLLL . C 1.001r A LLad*!€OT _ € Cria"4• E LlhaL a■ 7 LW.016T 6 LLF00118rM C LNIE 65 OF LYI1+ MtYE I 1110 'LI Fir r LR:I°4UV; a LODE al-Hr I.LLr C ' LLcc € _ * -. D LIrTOr , 11 LDf.LI11 C Leer LLI f C LiIC1:1Xar-e .•a LTr1lO'TL I LIrT!LDT ! Lem* el trot 41-P. c LSKE8I<L T L.TIME sea LJrv1LL! 4 L'PdLCP C 'mektO s., ,Y , h LuCEO0 E rLLC C L l rrC4L C L.0.1.1 LLe I. - C L€Of TTS 6 UK lea C LIN.",MID + LJMMDDD 'i'0 LpdIdC ,a Lc+114•0 c LU[1LE. Mdp'!RJ TEL* C L.+Y 8 LtaIII 0 LpI1iEar r I.CrrAlm . v C �r1r LtrlICRIrS e LIerr p Lf11CC T L:GR1i _ ! LUCIL . C a1M[Y I Lrpwar tl LtaellicCTT Ire LOr1a € LOS. /La..3r, _ C LLCIErr4#€M C� 1.-.:$1361 _ C. LJawrTT € L Diem r € LCS ea.601 C LIKE PEMLITE r ILIA _ 0 LILIUL a L1a'rlea+. , 0 'Las Gar EIS C Ly#Er •C L , LI U?' '• LtltDC p P.LIM!=■ .IaL1. 1.93 #14•1+!IS C LIXPT Lion E LV+1 a Lfl<•w r _ ■C. LCS DID! t LUCEfelCI. _ - L.1'SraIC . , e LII4pr e Llttl=r. - ,i4 Lt-I SR1I415 6 LAX., . „di LTIELL C L13CO C LaL1rf- 1 Les lamas L' Lao 11 4;T*SL4!! 6 4..E scams s lox atef */C LC3* T,I.U.0 C 1.1.0=11 D LTa 6 Liar a 1. a4• _ D LVier . .6 LIF IKTCw 4 ■ar&ME o -LISwA5 4 40.aL11■ ! LC.TI•ait+ C L101.41. € ■a EEL C '1.11.raaeE 0 i0L4r.a. 6 L LC1rCflle 6 Lul4L4. , C, , sat IN _ C LITCPVICLIS a '•'LOLCTr. . .... C 1 4CIi17ra ... I IF IIl 0 a.All 1 C LI1I.l C. C L11LIre .' G ! Lastrietair 'e !CL1.!*T ._. a amaRiT 0 LPTtrEE0 # LOLO 1. ' P 14'"'1#Iratw; , i LUGOrf '. 8 7 , e Lt 141 TF '1.01.4; t ! Lpf T*aLLET C 4-LP*211 ..,,6 *AC mete r0 D LEred 0 , 1.0.00 GS a I 'LE. 1S "6 Linz _ € NAC! " 0 - ia LrrTLI ..014•1 ° C 4a C I LC1i 4•{T € LLILEM ._€ - ra[ti`0yla ,.f} E LI I' LI POL: 4 .L4+rr1 ``b I L.CT..+a14 " C LLJLA C uetehoLAftE 0 LIrtLC 4•CCD 6 'L4I1aLIa ' 6 J LET1 - C Lai Ian ." P rAetaLIt y _[ � '4Ettt.tArt 0'' -' LC+IavT {a r 1r-tI. C 4%ume. C 011C0115 ix • LI rrLErlae ` "! 'iosl. ' P ,I 4GTIJ P7Irt C LLP"Mlc .., C# Ma{hil 01.0 0 ELI 4•w '"'�' C Ld1C1a -' C ! Lair 'e 4uM1r*Lr 0 it ICC • + 'L tfftf4Fr ' C LP'ILL 6 '1' LDUntr:NIC[ C LYrsl1• 0 4•A€Ja L4arI C ■ '11-P11.41?EN a r1.0r1i1• 1� "�0 1 Lt1u0La ... c Luna, "L' 151 •yy!SIRaILra •-LIT Tfara C DLO 1T.'S _ C r ti4UCdrwIL.LIL { .4.4•0001. DesIAL# . C , riCelr fl .1.1"Z. ... .A- 11.1F4rhC r 'C CL.CLIC LLa 4 ' L1rrUS C PACE(DE IC. -- a LIr F' I L'hCwC ' f 1 '4iti.1F�GPn `' C LWa C• a{1[{. C cJr-Q•r '- h I LaCalt d I *du le _ C I.UTnW D r4C I•YOG - --4 4I*Ea+L1Cl -' ' - 'h I '..16600 'C I LOLII(Cat 4% �t 'LLJrDE _ C ■atatAL - . 7 ' LI-i11 n I 'LplC4r0iPA• €.rei LeArI+• C iLJ1 . 0 rat'Cr0 'e 41"1"GLTn0 .0 'I'Lor' '� • I tI1I1 a 1.LwITa4 s I1tCCter4 r 1.1.8.•a ' '5L. I 'La.! RDc. ` t I *cur alter.' '-r I LW, C rarer - ' w0 1.1:C a : i L oat ilac ' 54 , I Laub. _4 I LL7f I. 441610 .17 4 LI;44014• r I LII11bL• ..• -'C ' I LCJ<FLCVa t I Lllllr'G r iAGf.aif. e IA-JAMS 9 e I Lawry vat p' t 'I C Id!1 C I LIPlladf0. .IL tsar c k.ardr IT C L6■11C . 'I. I 'L3a10l0Gl •a "'C I LOYICC1 '1 I LW0*Dra ' . - 4 :AOOOCR _ a Leal!1.1_ 9 I 461IS1 I 0aC ' 'e • Lamy 0 I 6 616P103 C . NAVEL lA , fbfe 1.rr314T1 ILA C 1 LOrC1PSC a l Lea"a17T _ C I XW.TQJM , •/'D YiD!L Pal A L9eisG C I LWt*406 a 1 Lrye La#l. e I LLRuDa1_ p JS L4errq - b' 1 LLr1CC1511 4 I L11814.iMO '' r I Lama C/0 Mar4l e Lffh 1.1 OS [' I LPI• C $ Lry!Lar�. ' 0 I •LiRa• _ -y .C,0 6.466 ILL .a- LD6D .0 I L4UGJIr •"' 0 I CLffarIlrM'i00 ''ll'itimelEL "tee lealipr `4 _LGCU•N '9_' 1 1.4/101.01 3 4 $ Lail 44 C 1 .. I i USE IT . I ■100 .L C Ler art 4 I,L d1.6+a at r I 'LET/LOCI ''C I LYIa ''' C ■60CM. C '.L0CC* C r L011 W10r' ry. C I LCTCLCCa a _ 'e I Luca -''4 si4111# C LIDC L ENSSa - C I'}LC IFa it ... 8 I . 1 L IN/+Aa.I .I I L Ulan ' 11 iaiy010 LUC Pia I C I L C.aL C ■ I LTRLder. Pier I. C I L Il - D maDo Liar C LOCKE i -I 4s4C.Il• ' •C I Lr'rfPELL e. I LSTy'' C +at41rrei - a LDCSEPt* [ 1`La1;a.� -I I-LCr.I'M ' ': € ' 1 . �0 IArs e 4ir€tr es.• CAUL!. 4' I LempoaM. Ed�lL. C I-Kerr LL - C i.`'LUTEl - " # MaGALL04 ' e L,p#;4TtrT � I SulIT a1Lrr v I 'LC.!11CMEIE a • i Lure* 0 DaGOALlIra ' n t.,.: LDC[f001 4 I Limo l+ . i I Lawrti6 • I '1. *1 e 4•141.0# • LCClT41l I I. LQ1ra 01 I Ii 4T -"I I 'L47[an ' ' C - **GC IN -C LCC.•CCf 6 I L•_rur! I LVas C/01 Limps 4 1•aG' ILLS I LCCar04C• •Ct C I L0"1t1 9) 1 1.074 111.1..f '4 I LL1IEra C ■aCCI[ ' C LOCO e 1 L.1:114 I4•Gl.Lali , C I Lra C 1 '4.711a¢gE 4 1.aG lair IS D L000Da 4 r Loarau1 C. I .1.001.[4• £I¢1 Lr4a C sa;ra . 0 - LOCIi.I c I L mac a C r Leval. P I L.4I Cr 0 4•a LPlT C ' LCp aLie• 4 I 1.0aa 4•a '0 I L Opal.'C6 U 1 L.ITC.* D UAGrOo ' C Londe 0 1 1.„pa. C 1 L Del TILLL '0 I Ice 604 -' C r C l _ 1.Gbr aJ I I_ C P 1.4#1 C I tIiCY1; ' e ...cur.. D _ +n re 5: rr4 rV0a0tCCIC SG I.. Rd67Pk 1.6€4 1S Fr( 111r.VCairl% 711f rod fel3FU & J1 CC ST1WOT"OM.. t'.. ■11n r 1'Ica; %morn. E.L.. Ar:C`p4Ca 11.045rea'Fur:•DpPI. T] a SPEC'PIC S01L.SFR ICS • ■05' ■4LFJ18 I+ 5011. ran LeG€4•0. A-24 (210VI-TR , Second Ed.. June 1986) Exhibit A-1, continued: Hydrologic soil groups for United States soils raGO7SU O •aNaua C raOCO a ra5PST0N5 C 1 was • e r•GY•PO C rwM•YOr 0 Paola ! _ C I ••t GaV O MAMAS• 0 rwCCLONA • •aolaNa C M•SSODIS • I NaT•CAra C SPILL' •/D SaMCMC • .0 laS 0 r•t••Pt • ( ••!SELL • KAMAN C ■MO•N a ra01•TliLE O N45Cara O 1 ..•6 C w•NaNA 0 •allosol. ' C raolC•0 a ■a&Caa[NaI C I ■•Pees(+ 0 O ' M•MOCOPItLO d ■aO1cOO• a •a$CMfTIM • e I ra,et0 0 NaMOGaM C •aretTILI( a •ao1CT1a C waiCOTT( 6/02 MaTOOL 0 • •4.0.1.6 0 .•N00 C Na41LL• C .ISCOtTt. 0 I aaato , 0/0 w.MDOSVC • smut, a ■a•IN(L C 0eoa.t:sterol' I •alts 0 N•MTO01t01 • .aM►•PD 0 •aat•tL. S•aINCO a raStT O I ••rPI(LO e RaMTO.a CID ' wasGUr 0 r•alw• 5 magma. 0 1 •aaaa0.10 C raYGEO C ■•MYt ON• 0 rawMa T l•5 • .••h2 C oa111e1 0 1 IralMt r • O .•t• ` 0 NaNN[IN C raO1ON O .aSMUIavILLC 5107 w•l11tM C •••l C racure a •a:ttu e 1 .ay.t•0 a waLLt • .awltaw 5 •acINOS• C MASON 5 I w•Trtep o r•Irs►AT 0 Naval• - C ••aiSCal 0 Masowv017 O I raTramO Lail, • • r TTLArO 0 NawISTEC • Naa;SSa C MASONTOWN 0 I MaTO 0 ■aJaoa 0 Pasha C 5•11[5 0 •aSSaCC C 1 Na,OOaas - 0 NaJY•a C .aNITO.IIN 't sa•tCSa.i' -. a Na1S&Ct. 0S•11tC0 0 1 raVOPO•TN C e NasLf? ' 5 •••art C was5a5O■• 0 I marmite. e rata. 0 •asL1iS .. C 51•15• •ID N1ss•rpTTa t 1 •a.iooar • e N• 0C Maw. •A r•5LNar C NassarWTT(N t 'I •a,SDPINGS 0 .aua.ILi - e • NawNING • •a•tl•tt • 0 Nalle•CM D •I NITT•G 0 ■ 0 •'` rawrIGUE O .aatlaNO C aaSSlo• C +I Patter. C 1 a r•aoa • ■aaiLCras5 _ 0 •ISSIt 0 I ■•rwILLE e NattN• • 6 5&M1!LO 0 ra c lOr C w•:T[D:ON •. 8 I 0411,000C • e Satl C NaNS►ICL0 0 •• l• 0 was• C I wala•N - C N•tlti • e NaNSIC • 0 ratlatt • D w•IaGO.Oa D 1 51!5!!5 CIO • •aNSKts 0 a►iLr050 0 ::::"W V* C 1 rw1DaLC a .ato?I • ■1.5051• • Pasha. 0 NaT• ! 1 .•lOUat• C Na?. C NWIICM1l C .ally![ a walANlaS C I •*ZUNI e oaLa • Naw1CC• C ■aLL0P C •al•f[&EC a 1 •C COOT 0 waLaeaD t •/D r•wtt° CIO auLTO.. c raTawar c I ',twee' c Nal.aSao. O raNTts • • •✓.a•I. • ■a?CMt* • 1 oc LLLLM 0 Seoul 5•.705 5 • . coot C ■•?IICLD " C •) ttCaLLI$TC• C • 0 mow C ••••• CIO 01111G0 O 1 wt•LOiI C ' PatOU(ITLT 5a1Stl • rN OSa 5 •ITN[UY P 'I wee! , C 14.000e0 0 waw•l.l. Sa.I MC C •4507l C iafwtss 0 1 /Kit t« 0 C' NaNlaNa• C Naa.• C N•TNPDTON 0 I SCSETM. SILtNt C waLaCMP • •WlaNtt• C wag/l001. 0 Na IMCSOM , e I •ca4TN. O15•IN(0 C NaLaG• a ' .a52•wITa. p ra.DUVTT( • 5•71115 0 I •CetGGa. C •• waaCa. S10NT' • • G•aS u mmutl C SITMIL C I NCBDIDT 5 L ..aloft. • .aNlawO • •Ns 'e 5•TMISTO5 _ C I •CC•►rl•T • NAL •GO . ' e 8.104811101.• all • C riOTT a Na?101: 0 ,I •ccalr C I • O Nult NOUNTIII ! Naa•OTt•ONC C ■aTtacwa C .1 .CC•ltt e N*Lat'1 ' • l••LtC•ts? • worn.. T •ra1N'rlaT a .1 KcaLl e• MaLCOI. D w✓ICNILL C ■aas(ILL(1 • • e NaTOT C I KC•LLT YletM a w✓LC?O. - C 51151L1 a r*TT*•CAtPCT' • 0 I NCC•••ON C owlet• • 5 u•lrT08. Stow! CID ■•5 0raLL P waTT•N 0 I UCCA... • 0*LMC W C ' 10•51•C( C saalsar e/D ma&&&&&& C 1 Kcatt' C 050.1L' 0 1 .Y*SUCt • ••••N•aco't 0 ••TTa.Or1 C I ACC.&&&&& • wall. C •••••• • 080880aLt C •atUa•K( 0 I NCCISIMT 0 • • w11•t NON 1 Nae1M0aL[. OaIIMPD C IIaU C 1 • c•ia e olllOa! C _ 0105•L( • 05ssoeICLD 5/O •IU•IL• C 1 •CCLaVC C Nato C waROL[CKta e •✓SING - e •atiO( P .1 ■CCL[••• 0 NAI•Cla 0 .ue.1501.57 • _ oast ' • rai/OLIN P 1 •CCL(LL•M 0 •wale • r•N•LtwOU►t: C raaYtl " 0 ■•YGala. C I •CCIOUD C Na o C•t*RN!IT • C aays(P C 1 SCCLU•C C Na&OTT 0 0a*C•00 0 ...Sir C wau•fC aA I •CCOIw O Na4O! 5 esaceLlral D Na.?IS K 51 0 1.11/110 0 1 •CCCtI 0 NeeC(LLON C •✓Theta 0 ■MIN C . 1 •CCCLLUN w 515115! 0 SILSt•ON • ' .ahCttTa • r11T INSI ,- 0 1au•t1a5 C I KCOM.CI P MILSI•M C • N-SCI•L 0 a11T*M1 • •11101510•N D 1 NCCON•IL. 54000[0 • 115•.4• 0 SIICLI! C ■1121 sumee P 5•552CC • , 1 •CCOOt • 81'800 C •aaCOL• , C aa•tlsIOalt 0 0115! t 1 sCCO.NIC( C waraN•• C •aKOwl C ■sat IRION C 5auwalS C •1 accost 0 •••••aetlw o 011COTI C SI•?IN{PILL[ a SIPCO C 1 NEC*, C re N•wa C raaCOU 1 w11T IrtOM C NaPC•I ( C I •CC•tt • O aa•CUN C •..loS a a•Ttr _ Peel •LC•Oat 0 D. osastLl. C ■11Cu$ •/D ••a/ISCO CIO Naval • 1 ■CCaOSarT • lu•S7a•Tts. ••ICUs( 0 N•tt, 5 Mau!• - S I •CCYlLOVGN 0 565*11• C N•ac♦ 0 w•5Y51C0 C •at • 1 •cCUIL' C wam•SSaS 0 mare gip • c ■a.va. 0 ■IICat[t 6/01 •CCU•O[D a • NaNASt•SN - C N11tMGO CIO •*55(17 a rate! C 1 NCCYr( 0 MANATEE •/0 511($0• • •115/5 C sa55I(LO 8/01 NCCUDO! C • a•raYtt. o ••so•tt ego •a T a, . a •agVOs P I .000TCNCN o • Otq(SIIONaL 0•'C1SY. a sass C Nai,ILLE • 1 -Coast c Naw•T(t. PLODDED 0 1 ••OGIC C •✓!$&1150 6/0 sa1.(LL 0 1 •COaN1eL e •NOTES: 110 1.150DCLOGIC SI IL G50u*S WC. aS 0/C •p iCal(S TNC 10•IM(O/UNDN•INID SITYaTION. NoOI►IIDS some.. .G.. stowing suesl••TU.. 5(915 70 • sOtclrtC soft stalls •Mast POUND 1. toll ••N LecIND. (210-V1-TR-55. Second Ed.. June 1986) A-25 • r Exhibit A-1, continued: Hydrologic soil groups for United States soils • • .cocoNo,! , '[CILew'tugG C I MROCr C Mlalr. ■CT C r1NMC06a a - KOOK e •!COS!• • I .r•tCI1M a 5U4S•0•rUM of C •CioOr•LO C •CO. It 1 NIMt,a • C NI[[aL0 C N*MMttOMa• 0 •CDDN•LDS•PIIt C/O. MCO•W0 C I Pelmet. a NIL•C• C N/Na1C/ONaa. SILT. C/O NCOU'rr C •C0.•• C I rtwlt•t&M a OMAN 6 SU4S1•alu• - MCCLNC C ►e06Vaw a I 0.1p100 C NILP4. ' C utN.C•aut•• a/C • tL.OT a •CDCC 0 .1 +ec[tl 0 rile. a sm iot(c( . C ocelot a' a .IwPOa0 0 I NC4LP• C NILCaw C NINMt(PCaa wCra00(M a rears,. C 1 r(cre•l•u , C NILOP(0 - C aIMNItO(aa• 0 rcr•10. , C •EOICIwt 6 I ■TN HILL. 6/0 'PILES P OVf•eI0'r. Mcraol..c . a «col., .. a I accra e r wODO e/o CO - .ClaUt. _ C %COLIN 0 I 0IO05 a «ILNS• 6 MIMNICPtac., 6 •CGarPET . . 6 •,DOraa - . , p 1 rtnoICR e .11lt•O, a oatOeLOrN _ ...coma C reseed t I rVNOILL C •1L,. MDLt.Or: P MINMI(•ILL[.., C NC Ga0VC• C atDr•• _ e ,I r!•otll•w c MILLa0ODC ,, C MIMNIN•uE C .CG•O• C •ILC[.NCT ! I P(•ol••C •• NlllaaO a NINai,M C "'cermet C rteet.O e 4 •VN6t7T , 'C PILL6000 0 MINM•C P • 'CGllVta• _ 4 'e(Maw ,! I sloe ITT• Cl...(., r MILLe.00[ . e MIMO• C •CGINNIS _ .0 .tt•6 N 1 DUCSTData.., Nlt.Letl•rt . 1 .i.ocoua etc rCGINR• P PettertSe C I Cp•IaaD PILLED _ 0 MIMICS O 'cot•• C NrG•LO: 0 I rtooftT. 0401000.r t ri4Lt0L•at a 'INTO C • •CCU•S. LO■ . 0 •(GG(TV , _." ... 0 I NCOtNOM C MI . 0 rlru O POCCtOtealtoo. . r4GOMOt,- C 1 ...epic*: , .r ■Ilt.(•tOr . . - a M1 e • •C •D••M . e •00411• , . .• b I +(all _ , C• . VllLt9Vlt.l[ . •/O NIMVCNO _ 0 • • K GP•tw* a NEWLMOSI• .. ;C .1 _ a/0 NILLCT7 . a N1N•CLLS C 'Coat• , _ 0 N(I5I. C, .1 rats/ _ ,',' _, a NILLGaOVC 0/0 rams C • Pcourvr• 0 •'1451 C I •r . C rll4Netr C N10PON C .CCUIDC _ a rCCINOC( 0 .1 .ClCaL C r• lll.Nt 0 NIP . C• • .CwtrQ• :! •'5Laa.• - ., . C I OCSCKe00 C . MILLVOSO(O a N1.•CL! C NCILVaIUC 'e MCIaNO _ C .4 'Pict .. C NIt.LICM 0 MID•GI . . , C , rCIMrQSM 6 .. NCLODUaPC .t '1 '(SPUN - a •ILL IcONa C .Iaar•w 0 •CIMt•.e a rtLP, •, ., a I -tiStO C * '• tLLIGaN . C MIDawO •• . D .CIVt• _ C 0,1.4.0 _ C I •(t P PILLING . , . 0 N.1 r 0 .CU«IC _, O KLO4• - a 1 rtT•«O•• a MILLIMGTON 0/0 ',tots • •• • •eta. - • w4Ga 0 I NCVC•LS ., O - WILLIS - C • MINIS, STOUT., e =VICE O YtL•O•IS C• 1 wilt• e . •ILL•ar C ■1•[•DOC - 0 . . . •C[C[TM O NCLIT• _ • 1 •etN C ■ILLPOT - a +10.00 • - - C MC(CL If _ • ►[lt[MTMIr ,• -Q 1 rltiGOS M! a .ILLa•CC .. 6 .I D.OD l•[( • K[CNMa _ 0 . r4LLOo 0 I Nr?CLIus e , NILL4OCP _ ., a ■ISaD j• e -CI(rr•. C0a1•C3• C NtLLOD. !T0illalft C ,1 Nita, ,,. .0 _ •ILLSaP 0 MIS Pac(f.CP- C •calilf( 0 • :UOtlaatuw , 1 rte1 , •.P - M4LLSOalC' , . • 6/0 PISNaa C Ka1MLC• a NILLOTI ,y_.,;. .6 I 'Pale° , O - V1LLS•OL• . 0 r1SMat. 051•1400 C t . •CIIrr.!• C KLOtNt ,, __ C 1 .talsraaia:. ' 0 ., MILLSII( . O NIS510r , 0 +canto., ._. 4' M(LOL.r0 a. ,C I .!VSTO} P ,ILI•ILIC P • NISSI80Y01 •„, • . •CLAIM f,. - C '(LOOSE C t •M4-0•• 0 'lILNOOD O 01SSL[O a . .tl•ur IA P - w!LtOM 0 tip •larl a , NILNCO 6 •ItIOUL• : C •(LCOO e . NLL•ILL( P .I N:a.lar C , PILO'', a ,, .ItCM 6 NCLOUGML IN '0 .ILNIN .0 .1 '1Cam0Pv` C _ 'ILDITIS• .0 «ttCN. 0.0ELi , C .CrCer , C rt.ILOO5t _ C 1 .ICCO P,C .ILO,. c ►LOCOS° _ ,. 'C■ILLC e N!•OMIS _ .,. C .1 .ICNILSON ! . MILTON _ C •ITCl!L. ,•_ e K ruLLIN . , 0 •(M•MC• • 1 •ICNIG•«M! C,-. rile.°. _ C afTIV.a4• C NC•W01[ _ C rtMTIO „ ! ,1 •PICCfV O wl•6RCS 1► rit[OP 0 •c - 0 rttaSNa P I •IC•P• , ,C MHOS• _. C . NIICOr. NOOEOaTCLV C .c•W.a,. O.•IMID C •CM00 C I •IC-aS �,' C pm. a off •CN.•T .D . •EMGCe34•e C • "...tt.CO. _ • N1r66006a a +I/•t , ''' C NCMta _ P +[NDel1Ma 0 ,._1•.ILOLr • C Asia. -�- 9 «1 r•1wG C .cull . • _ /remotatoe. • 1 ofOOOO•w: t ( . 'goat • rtrrrr s• Kama'. . e l•CUs/01r( 1 •IOOLf■aatN e: M1•.TS•C 0 NIa1D. e KOaUL • SultST.•icr _ 1 •IGOLetnrw • 'r •!MCP!, . ' 0 �• M1ZIl • 0• •CP••1• a N-MOrNMaLL 0 1 N1D0LC•O.e O PlKMi IMO .O mom C r IC 7, KIWI . 4 r1O(LI.NT • . r 'tNCO -- a NDaG - - C . "'cover. C , •f'OOCINO . r . 1 '10(51• . 0 'INOPCO .0 •oaMO O 'CO.t 0 *(POOP - e , 1 .Iro.r ' 'e •I.IotN .. •a " Neaps c ac c •C,,Ula r t •lOL•t.0 ' O 'IN( • '°Nola ' a efiaCCLIC • Newer[[ 0 . 1 •t0•CM/ C•t atonal.. '-- • _ NOPaTr _ 0 •C•C6aS - _ O ■tales . . e I •IoolGMI , 0 'tw(• 0 NOertttt a pc.tcReas C 006A.0 0 I .10C a rIM(..L C MOPING _ J 11 MtaO 0 0E0O C I 'IO.a', C ' NI .DUNI.IN C 'Owl e OC•COIN a NENO[tN , C I NiOV•LL C ■I ILLC 6 •°!•1001 e wt•OLama _ • C •4MONIMCt I , I .IOr•'S a. C - •tNt5$NGfP C 'OC• - 0• m(a00•8610a. SOD •!•110 c 1 MIt•.•Ill C .10t+. C rOC••f• O wtaO4.Ca••a C •e4VD• 6 1 •n.w _ e •INGO - c /*coo _ e «t•00•t.•rC C NPM((L 6 I •$(SlN C" MIMGUS D •Teat.(• 0 «ta00••IILf 1 •(DUO' I •lPVLiW a 014100a• C •OCNONI 6 'taNS . C N(' ROUGE I. I ■IC(IM P NIN4LIO 0 •ocilLtNC C •ta0(S 0 •t•C[D . 0 1 •ICUL► 0 NINLIIM 0 POD• 0 . . +tear P . •POCt 011 0 I *fat CI 0,10'M(•• C '°COIL! C rt(•a.ICS5UPG C 'tact• C 1 •15158$. C - rlNNLISca '! - NCOrN• O ''Cat%.ILLC : C .t•CC• C I NIIIV e ' NINNCO•• • e rC0(STT- c j _ a motes: 1.3 M.DODLOGPC SOIL 000uPS WC. as S,C INO*Ca?4S t4! V.aIre0/Ure•a1Mee SITuaTlO.. - ' N4OIP1'.46 SrO.M. 1.0.. 4000OC• Su8ST••,u0. •(Ito T3 •,s•(CI►IC 101L S4PltS aM•S( rOU•.O 1.: SOIL raN LCGI•O. A-26 (210-VI-TR-53. Second Ed., June 1986) i Exhibit A-1, continued: Hydrologic soil groups for United States.soils amass* a N0NtC4L. • wOOTt.S0W C PUTS r I •50Na. wtT S .00(1M C .057E O 000T0050N. COOOL-5 0 ww10[I011( r I.ow** C 00001 C wONf0 COISTO 0 WW1 ON a •LLILICO . - O I ponies, • C • r0950w C .OwTCC1T0 O w0OSaL 0 -rIRILTC0. ODalrlD C I .5011[ 0 000 0 ■O040000&000 0 ' 00507 • •C •wuLaf 0 I.•5S1Cw • meow C wOOr1LI D POScA a NYL000M a I MSSTIC C . .01.110010 o •o'TOu.o C . TOSCO. ' C ruLDUOS .0 I raaLCMu . 0 ro[o1TZ 0 •0100000• 0 11058 • C MILCTI C. 1 »a4L[MV. 00000C( C .00,40 0 000T0OL4 0 005t5 0 IULG0w O I SuesTO•TUN - M000 0 w0r0C10SA o Noses. 000LOI•' C .uLM*L1. e I M•OCSra - 0 MOGLI• C sprits. - C .10SN400044 5 NI1Lw0lT400 • a I M4C»[f - 10:OLLOr e ro1TC.aLL0 O •0$M(, 0 'rulKO. 0 I M404I5a e 000010 C 000Th 5 .05.10* D MUL[t♦ C I w4CIwI001O C .10001.1. 0 .100160.1(05 0 00S»[051LL0 • C .YLLICa C I N4CLINa 0 000450 - a r0NTICeLLC O •CSMUO C 0KLIG S I Nacocooc 5.S - a row4.c a 050110TH • a •0051d4 a .4.4.1.1011 0 1 NaD• 0 rOMOC[00 •'' C 00001.ID C VOS tree - a r1AL50w D 1 0460 411 • r /OIESE - °-•0 .ori.o.twCI a •osL•poCo 0 .1)1.5»0[ C 1 0401.10 0 NO111ES . C .10010154 C WWII N6r 0 w11L5T4? C I wawa& 0 • NOIN00Na 5 swims* a .050 r 001.1 C 1 1.81611.10 0 .10J0 C • .Or1000 D -.0501)00 9 .1)1.705 B I war/ n O' -wocCLUNN{ o ■COTOY• o ■0saoC 0 .ULTMO0*N 5 I N*61115 . C 000[04 C 00.710[11500 c -Ne5S.000■ . 0. ■t1.101ema • I 0401.1 a 00.01•[ • rOw10O51 C 001.101.1. 0 5107041 C I .*600. - C racers o: '.Ortv•L[ 0 'SC1a • r ruw0CL01M a 1 MAMA C .000 0 .50.150001 aro .000k C 011.5.00. 0 1 .4.1411.0 C r0m1L01• -0 •00101.0% C BIM 05 a .1)0055 I! I M4M.a 510 055.45.1.• .0 w0MT.CL. aL[aLI ' 0 ,501001)• 0 504701 4 C I. wawa.: _.- 0 001.000 O 5001)[ 5 .OTT 5 01I/11 0 10aw5V0 • 0 001aS •0 •0005[00 • 'NOTTLaMD O 0 W111NG 5 I ra.Vr74 - C rOLCAL ''-a .10007 5 .0010 0 MUMJ00 a 1 N•Ira 0 00ie1.4 a ■00.100 4 ■CTT55Iltt: - • room . C I sac.. 0 .00000 0' .N00LAC[ a wOULTO0 " C MiMNe1.L 0 1 • 09L1lCT C 50055.IGMT 5 ■OULT0IL • 0 tu1140' 0 I »AKIN• 6/0 001.1.040 6 .90.15.1101 0 001)00 - - C 01N1s01. • D 1 04(501 D 001.1.511.5.1 D -00pw51001 • C PDYr0M*5!N • wONUSCONG 6,01 wa(oCwa 0 0011♦ •0 `r00051LLE • . ro1i10o4•I01t - a/o 01)040 e 1 waLa(I C .1010[41 -S' -,w000CVILL0 C '000ND.eaI*l1. 0 SYaa0CM - • C 1 041.00 0 wOLSOw 0 `NOOSE 61stS 0 .011900 O0DOC a I Noll 1' '•.0150(1)0 0 'moose!) C 5O1w/05ellt a r1)500C1 C I wa-50 P 0D00L1 • 5 NooliLact •/0 • your Nowt . 5 muse• 5 I N•.,,L• C 4.504 °5 00050a Uwe 0 C rows 5.1)1.5 • C 010010 • r I .14.10[1 0 NONaCIN • C 00055L•U[C C your a ' • a rYaOC 0 I wa.O5 - 5 sONaCMC /' .0040• 0 .Ouw141w10' •' 0 .1.1..»• • C 1 waeUO 0 r0M40 a •.00404 ' 0 50U*IIIwSJaG - C Mt/1*ICI• . 0 I IN _ - a wOwaDIOCO 6' -N000aw. 0 .01w01aereto C 7010.111.1 a I wares a wore 0 '000• C wOuwlalw1160 C 01[1710 0 I 045141 0 .01..500 0 ■05400 C .OUNTaI0,IILC 0 0111511.1.[ 4/01 ■40010 - C MOraS1te10 - C 00001!1 D 0010.1.50 O .USCa110t • 11 1 04001 9 r0N*VI5L[ 0 00180 - 0 001MIVCC. C rJ ( .0 I Na O •.O.SYITC C .004.1;0 0 1100(041[5.5 001 SUSCLI* a 1 04.150.0.0 C ■OOCN• '' '''O 500.005 C wourSole. : e .U.1C( w 1 ...evert r NOw0•N1. C 5010 C 001)100 0 OUSINI• a 104551.sf0 C ■0MOC, C 5011081) 0 005111! . C uVS.000 • .• 4/01 ra.IUS D I - 5 .01CNe•0 C 00.414 - 0 0415[[60. 05015 • 0 I Nawla»al• r merle 0 .001501)50 0 rove,. r NUS[IGO. CL65 1040 D .I 04.115IT[e0 C 0.01.6010 C 50055.41.0 O 50.10 C SII5 . 1 .awv. 5 So0ICO C 00[ew0 c 00oIC» 0 OUSCIU.UNGC 0 I wawa 0 .101.10• C 00101 0 .0011 0 .USCIMGU. C 1 045100 0 •wowt[000 0 wee t• 0 •05111 C .1)1(06[1 , C I .051.11.!- . 6 001.11[41) C/O row ITT a woreasor o .1).01000 C I .•501101 ••0 worttoo C • 54641.8 C •051.4 ' 0 NUSOUlt • C I 54504010 c wONJOMI 0 . 001G•0►ICLO 6 wt. •IO' 4 fault(I. t 1 0.57051.0 5 .OwOCLIr1 C 00010015 0 .1. Caaaall r wU15Cl5NCLL-- • 6 I ITO C 0010060am / w01/106L C 01. WOOD • UU%5[OWILL C I NaoerJO C ■Ow00• 0 w00L55 C 5t. OL15e 1 01)55(5 0001 waaCl11t C .0.01568011.4 C .001106 0 01. ttaw0N C NU1taMG •/pe NaaCOOSStt C 00.000 5 005000 0154 0 51.1854 C 0UTN&I• 0 I ra.1D a .0ww015111t CID N000CC0 0 SUCIALtt o u,UZZLSO 0 I .l0[L 0 0005E 5 .00001 0 01)0 5/.11045 C r a/01 040600 0 000500810 C .0005 C 0UDC0 • 0 - . 0 I was, C 0001(0471. 1510 D 1.0.0» 0/0 0YD1151• 0 DI0atSSPOOat 1 554010. D • soroaCE 000015.1 5 01)0,45 0 0 • TIOa1 0 I waUrtil 6 .01.5Ow C/O .01015 C owes C 05.77 0 1 0400.. 0 .000.611 0 01.15110• a over c 05101 • 0 I 6*05111 5 '- .00745.to C 000OIS70.0 C mu4 0 wSr 6St ILL[ 6 1 raoOaGYlww[0 0 000040• D 500.0• C w1GG1N1 C 0500110 0 I r4000ts 0 • • aONtau( C r0/St 0 ■1)6»Du%t C owlet• C I sa01• 0 .01.10000! C w0/StI '0 .01 .1,1 C 0505• • 10451) . C 50015= 5.0 MV000LOGIC SOIL 6/0U55 SUC» aS OIC wOIC•T15 TM! 0541.00/1)10.1a 1010 SIiW 1100. ■OOIII[oS S.O.N. 1.6.. 5(000CC SUB 500011)►. a[,(• TO • SotC111C SOIL St0•C5 Ow*S1 FOUND IN SOIL 045 1..00000. (210-VI-TR•55. Second Ed., June 19861 A-1-7 Exhibit A-1,-continued: Hydrologic soil groups for United States soils e•SEO d NtwaLtr. ►LCOOID C et.aLOIN• MUCC' • 0 mutat 5 feOON•► 0 rase. 5 w[wa0 9 Kl STOIVUN. • se It!• 6 NNDPaN - ,-C N•SN.t AD a Acwalt. Stow' C 'rt.•Lete. PONOCO 0 w Strut .n • NDP• • -a Na SPOe• .'C 1•t fat • C -Nt••LL• • • . 0 . etc IS••a. - P NDS•C co nasN•ILLc a w•ICC a Ne.aNAa C •lei•so. a •ocie[PT 0 .asrraua c w(n1D•i a Nt.•st C •PI 1L0L•I • n NODS .;•e /ease/•G - C 'NCISSP Oaf Dr. C Pt eagle. o• •0i0 o AIL•AD •C , •loacae C Na 90r C Netts C 'Ne.•a•. 07w9L0. - L wilts C N000 e Na1Ow. Gb•YELL. O petite 6 COLT - 'o ILA ao - • e ''moos. . a • ...ass 0 .!(ON. 6 • •[••t.IUN e• Nloes* a *scoot if - e ••••S•U C 'efLOOPC - • D ass.Imo • a r1•to1Ct .0 *moo IC - a NaSSCT A •etLl• e -out.eCLL .0 MI-•O -D NO•O I COL a rafaG• • NLLL IS • a mew/CPC. 'e .61 I1••oD C NDPOut IF • e Na T•l 0 agl.ar •C etwP•DG. A!T C clef ., - ! NDarOLa . .•e N•taws • •C `NCLSCOTT C revealea -C AIeuf , 6 NDPFOSE 0 raiCMCC a NLLSI •• a Pr barna♦ . •C NINC. - e 'NUPGI • N•tcAllocNtS - 0 rILIOM C et WP Oft P• NIrPCLP . .0 NOOG0 ,••.0 N•TNa Lt • C NtNa7JI • • N•KO C MIN!wILE • '0 .MODS• • .5 N•i•aDCP - C .NINa• O sit etc C 9 , a NIWC•IPt A NO0t001 , 5 ems I'oDOP. .t wstaw•• a N[Pam. OD*Iloco C. rtkbaIS P .N'Peelle •.. e *Wei milt - a Na1wa0o. COSOIV a NttlCD n PP*ELL •e. wile tea(• • . .e vOPN• . 7 N•II C 'IDIOT! • • NL.0 ILL tON O YNICSEILL - •.'C anNra• OPaIMCO -:_C Nattteat S • NtNOLra1 C Nt•e'CLOS . e w1o?• , n *DOraNGPI •1-0 NAVE?. - 6 N • t we.rl•Y 0. .'oIOT•tt C NDQN•a I• e lea 100•S e , NteaO - C N►.rOoc C .:etet . e scams ..c , w•Tao• - . C NCOIe D Ore*01040 C . e1P$NTUCt - .• 0 -.00551St •C N•TUDII• a ALOtO%• a rc.tl•DUS a rt.P, NODPIS "D r•uc•I I ' D Ntwat.TO • , 1c5.Nar , • .•rleta« - '• -. : NooOl STOW a ...are WI •. C M(PL$T• P et trwOUft •- ' e' 1•101 ••, a, :MO%t1 ^ C•.ausCO e - .CD., • C .w[.<IPS . • .• o .talc -+."C •N!DtIP . C %alit[• • • 0 N(DO'Stt • C w[.LaN0: . . [ • 'I0E ...,.c ;01001.• *0.010 C 1•a.•J0 D r(tl•ll • It Ntu.1VDf. •a.1• C. NISErf 5 •66Ca1N6CP0 'C w•s.,. 0 0101 eft! • . Ne.III. a ...tsar. --•CIO •N0I1$Ca'.TL[ ■6 .•v•S•N • • ltAtSOP a . M[.NASS .• C. 1e1SNN•■ 00ar0e0 ..n RCM TMCOTt C/O ( 1 Na•ID•0 ' • 9 w1151 It P . egerat• - C. . w1Af•Or • 0 ._N00i.0aLC • ..0 1 . - esv IN* O KSO• t At.P•SS • . • ,. C .NSSO4•lL• n•1• NO;1Nr TLL0• . - C. Na vl • ... 7 et SNaN:Nt ..... P et..O0I • • -C , C) . .tsul• .P -we*I POOP E .• ,C 1••.f/!• 0 AESwne• C .r..• • • i.. e •AI►cost♦ . .- -":a. 'woo!rave C part D NEslc• . 6 wt.S•aw a win•. . .SD- Ntwtrs7.O C ►•allt a wtSIUS • a New$O% 'S.• • ••D •wit, "A -1•/K tN.*TCP - ,J•.•e N••! C %5Sa•N1 - a 841101,00(g , a. PIM.1t , .'.,c %•SOD tr.000 Nae0•D • Nt%CO.Ir. C Pt.!ItaC C U••• • 1•.,•P ...Woe SON -1•,C .•volt O also D rt.tnr . •I0 1•1.01 . •C- ;al0 TOAVILLE , .. C 1•6e a etSDtlt• - C Nt•TCVIl.. , 1 t • el• . 0 +was.rLt . C - 1•llator •0 et 1S . 0 Nf•?O•w C ►Ia• •, C NDA.IC.• ,_D ruusce c • . 'asset. • e Nivut• • A olio% . . e :maim-clop .:y:.e rt.P•GO C N(S1(• •• C ••t.•ItNN• . e wl,PwTO•. e ..s.O5SaC - • , . .5 Mf6ttto - C etSTO•I• „ C/C stet,ILL! • , 0 NIlIr► .. •• ,NDlal ...0 et 09•14 : N(ST•JCC• . .,, C .(PG•t . - c ....a O, NOtCw1• •e et.I SP - a Pit C 612 D •C!. -.-. . C SoP• c. • 6011 0 .,Carne• 1 0 Pft•0Ii . p wwto.•u . • P Nft;L( - ...-•• P wOTer0 e wt C•r ICU. • e 1•t TCOM; a . •:G•PEO• ., t &Cel[TOP - C- ' WV/ft Iro 0• rfCLSSIt• - C 0110 • P ass toar& C .CSOCC a -140716.• 0 •CCPC C '.116-1 .0. • ••CLOt PUS • •OASCCV • - %O?••• •- 5 maCOPO• • C rgtP•C '• • • . • .UC5U,p C .GA Ur• ,-•C 614110. C reCT•' C w!ItleS - e. .Ksl+P.c. ••- C .c(erw , , • C NOtu%. *wire° P NCC• C •!TTLP TOM . • • ^ C rl•6••• C 1•00•.•• w 00044Ue „Co oco shoo a ettet DI . • • a at • , A , 00001► a NOe•C•N O %leas[ - a Kars • C ell Ia.• . - 1 ►COlwt P . NOV&et - 0 _ Pet DC• Pt at ••- C reus•LI• .... C r1.Ort • ...Of L./. . 0 ; AOv•D• 0 'fetal' 00a4. Loam• 6 ALUOILIA. saNC• a roost• C •CG•l C . 1•CV•ID • 0 suesfeatu- wasta•1w NISICw C 0,1•.1LI - 0 espele• . e rtEDlt Pt•a. a f•P41tt - - a NICINC. e . *AA•sle*I , Min NO.Ail a P ICC•SIL . IItt•0•riLP - C Atcw.xel•1 .• C ADLa• - . C Pipet* . DIV •100000 NC•a000 • •• • . •ICACI I• C. wee Pe C NO.ot , _ a NrtOltTOw • rt•••C C NICwKf P NN.aN - r NO•!0 • refutes(' C-- ac•a1 • e WICNCLSD. . C POI I(Putt? • .o.LS cIo PKCDPOO( C beet[ a le ICNC L V I LLC C laCo I• a aM0 C et ELl• A •••t DS IPP 0 N sea l► a •OLO C NOVSON C net% C %[•lis! a gotta IN a ►t\der C N4ars a 'ogle. et, 0 • Nt•ILIA. 551 C N$(1S.ILL: C •0.a0a sC PUS It . 0 .glee,, ocaiNeo a rests. 9 . NICOose.% • a. NC-N• C .ww•. 90•1•40 C - ..:..a.. C retreat •. a 010.00 NUS. •LCODeo c Aor I1 • •.11e•. einrrc,Cf C .t(C e • rt•s• •C NICCL•S • NC'Soal IOP t . NUC C - wt1ses - C N.,O•en r •ICGLCtt a %C*CPaAU , n PLC tOLLS a , weesoear A Me•Ia.. C •ioo C Neap are IL., s 0 NUCI• C Pt•• C r2•u - C wit 1.1(1• C eCO. C wiCl: C *of Lll• a op. Car7•la C rIGN?Pa.a .e 'ccaecr•'us . . 0 1•ure• e et..Lee • I w•vat.Clw e/D NIPILL P 0.'00•I•Ct C Mole' C ewes: t.0 e•tmeLOGIC SOIL GPOUPS SUCr as 0/C IPOICa It 5, to 0P•1NiC•4.ODa IKC SI IU•T10•. -OOIri[.S 11•755. 1.4.. 'EODOC' SL?Sto•tu•. .15(0 t0 a.sagely IC SOIL •10115 Pr•se,rCUNf ,r •011. NAP LPCSNO. A-28 (210-V1-TR-55. Second Eel.. June, l9.Ai) . • Exhibit A•1, continued: Hydrologic soil groups for United States soils wGEMT a -0000410010e I OLD CasO 0 OreNLatt 0 011111 8 sUCOvw 0 OCOate C OLDerauve e OK OUO• C 010008 C MULL• '0 OCOMTO ' a 0L0048 C/0 •Dar18 C 01e0•r. r0O(o•TEL8 0 MULL1Gar 1 000S1• ' 0 OLDS 0 OPIEI ca0 0 .2T warn • 0 OCOUCOC a @1,D C ORtr C OSCA8 - 0 Salto• _ C .ccovfoC. • OLDfrao 0/0 06410 0 OSCU•• • . C M rulraRea 0 w0oeoately 'ICY OLD1.aC. 0 06010. STOsT C 01(000 C actsTCA C 0C.a1G 0 016atSSIOMML 00.3461 C 0181 0 suss C OCIaGOs e OLLLo . OOUlId C 016•.• 0 wu88. NOD EEEEEEV a @Ctavl• a 04.210 O O•a C O18ROSr C 82T 00AS 0 CtestaNG• •/0 OfrCle 0 01lOrt 0 wymNSTON C ODELL • OLLOU• 0 0848•[8 0 018Ter0 a 6.34.[7 " O 00er • 0L112 C 011810 C OSteo 1/0 MurseO 0 0008108 0 OLC1 a 00a8 a OStTO C Busker • 000.80tt • • C Olr •1 0 OSaMGC e 0 Olga C mina - o 008180T1. STOMV a OLGa C 018M6e.Y.G a 01 a 8711,1, 0 COESSA • D 081 a OeaNGCvale a DSO C wTIVOLl a 001r - C 011.4 C- 0UCa0- C OIDe• - 0 NUTLev C ODNt . -• D CA.IC41 a 0.011 0 0101,1,1 0 NUT.aS C 000 ' a OL I 1 • • OKwatD • 010810(2 0 wy1010 - - e 0008821,1 C 01.1801 1. • O.Cey • 0SOT► ' 0 w. L02 • MELO. • 01108 07 • 0110 - II OSSlas a/0 wv0•! C OCST I 011Vt8ral8 • • 0 OaDSa 0 01810!2 0 Me aL1 - • 8 0017!•1,0 C OL I V I LO C O.Oa1•MCf .t. C Oil . a wet • '• 0 .Orrlrl4CM(. C OLJ2TC • • a OIDv.v 0 0171,20 C MVJACI C oru • 11,1,21 C Ogress' - • • ei1888020 ' t• 888082 a 04•T8 ' C OLL1t0Iv•S • C. Owe A TON• - - 0 01.•10 0 8 • -OGCtCwtC • •/O oust To 0 oltJaI - t Otaa• - 8 88811 C ' OGCrr. C/0 01,•173 a 0811,11 0 O12(8 •' C .881•108 8 001822 .. •/0 01,601 ' C 02781.4.• 0 OTe.0 e 48 0 0 OGL a• • OLMIteo • e/O O.CMoa • it 01M1440 C/6 o•.wt(a 0 OG4e a 0188$ • • 0128!.a - C OIISCO -- O•stlu a OGLES•, • 0 e O•POtO a 081•8*LL2 • Dare • e , @Gaol, a 01.0881 0 0.0000 0 0112, 0 \ ' CSR GLEN , 8 . Or8CO C 01,08.31 • C ORICee 8 07080 0 I*C (008( -' a . 00004 C 0108081 C 06101• C 0100LE C .08111 0 0011 • a 0108041/ ' • • O 0116 1 • 07110 6/0 110110 C or0P C CLOT C 0.160 • - 077(•8011 a . • • I O.SCOV • 01,02.818 a 0.180CD C 0112880r • DaCD(I -• 0 OIOt■ • 0101C • • C 0510 I/O 07181• • Oases a OJa1• o OL108 0 00108 •c ' Ottotet • paerlll • 031.81T , • C 01100 -' c' OSTTA - • .- • ' OTTOSer e *Acmes! 0 03220 C OLUSre0 •/D 011Za•a 'C 017.3[.• 0 Oaales0 C OJITOS ' • • CLv1C ' I - 0011104. 00.1800 a 01.1? - D 0181.28 -- C @casinos • CLVrrIC a 081,8 n 01.811 C oacLITaerl, C 0 00001 0 OfL•8D • - 5 01.18 C 01RV*LLt • • • 0148 O 0.aa - c OIL Area 1- • OU1cM11• c . Ore.000 8 • (Maw • anaa • a ' O.LIC C ouaI0 • ' D a . - 0 Otte • Ose NA .• 8 0884111 r C OUla D OASIS - ` 0 02(!080•(2 •/O Or10 ' 8 0.811TOr C OUrICO C DaTLawO1 ' • 0RCCL*MT•_ . la,0 0881 0 08488•• C 008■• 0 0•1.1a 6 OeTeLA101.. 0 08•0 C 0•8.1.38 r OUSLev • C oatuu - o Oe00e111t00aI - 0.8101? C 0110 •IMO e =mesa's," a Oa/8 C 00tt8,a8T8. TIDAL • 0 oeK G1 C DOG Ga6.08 0 CUTL1T C 0111•10. c Otltta.ta. 81000[0 0 08* t/0 0.0181U 0 0011000 • - 0 0111110 S 0(12121 0 400010 • 0008000 • IT 0.374.001. 00a104E0 C Omer •• C 028818 - C Or40.3t 0 . goose C 01• 1, c 0011*0 0 011018 0 08..81A • O.Ovapa a OVar 0 O••►ST 0 ORLa.co a Or4S00 t 0888.1 • C 08.4800 • o••av 0 0RL8.8 . • • Prima '0 0888• a 080 C MOSCUolee a OcL•a.awa •/D prose, a 0888801 0 . OvI.LaNO C o•Sl•vaTl0w C 040 0 O006.a. ' • 088 • • 08 C 00001 0 080. $8018 C 08IC0 • Ow. NI•rell.8 C OVI•TO8 0 OCaN C 0200031 I/O OMttl C 1W CVI•TT If OCar•CC - C 0101031. 00810(0 - 0 0880•18 • 080u0 0 0■10 C OCAS. • OeOOOO1 0 Malts C ` 08vILLE , C . OVTMa .. a OCCOOU r • • 0 ales ' 0 stye • . co 11 • • 08181• C OCCU8 • oatST ' 0 088(80 • 0 Oster a O.ecO 0 DC!•8(T 0 OttaNa • 01101a • 081180 a Oat* cReec C OCEAN', • 0Rtt8•CMa 0 0811.08 • O.t!8a a 081181 0 OCaf,COaa • 01,• C 0481.110 • • 011111.0 8 OV(.TO.. a OCaLOCROBCe 8 04.18 • OrTCO.• C 00tlaG 0 O.MI I 08140 0 OLAC 0 08100 0 ORT11 C 001.2• 0 _ OC8OCO • C Ol•8CM• 0 DOO 0 00108 0 O+LCaw 0 oCaOret •/O Ol•80 • 0881 • 088888 a 0.0000 e 0(12 C Olast• • 008.1.• A Muir a/O 08121 e . OCILL• C 0 a 00028 0.81( e !leaser a '<IL(f • 011182 O lral C, 008000 0 01008 C I. 0(t •/O °Lou, 0 08(1.Ia• 0 011(1 0 OaCO•(L 0 TES: Teo rvO.OLOCIC SOIL 000U•$ 1m8, •S SIC 80-ICa1IS TIE o.a188D,t000e1M10 5110.7100. 0001r1Eei SWOON. 1.0.. senesce 1M•St011U0. 02820 TO a 16202810 SOIL SE•Ies .rase 80080 18 SOIL ram Lects0. (210-VI•TR•55, Second Ed., June 1986) A-29 r,, Exhibit A-1, continued: Hydrologic soil groups for united States soils 0 MEND INC a I oaLEl f I a 01f C P4!ID C r Pr LEE • Oa{L#11C f a11_L1 C I a+Pl WI AU C Far4T a I o;4Ci.IL. 0 OrPORP 0 EAL. DEIC.... I I Pa06441 G Pirr1A IT I-DCLH4• 11.0.0 aiyeiO ` P C.aLr+ f IT Palls a . PP IDS C I PEI.CC D °CL[T' C a imcse (` 1 Paila{r[WT: 6 P.1lpOt Y ELLE • .0 I PELlDr IWO O D CaLica.01 JO { I Pa•aC.ICE C Pala/C.1 i E I: •EL,RLE a OTMUT - C PaL.E0 Ca/.TOr C I Parallel r: PPM!CC - e I •CLLA 1.0 OTLCU - C 0a11Pr0UaLC 6 1 r T , C Pa1.9416E C. I 011.1.E.11.s L. 11 DLPIC; p P1yrE114 L•fDi PfCaraTi "t0111IrC6. f *SIFT.1lII D I •LLI.ICIFI 0 1.1+r .o P*Lrt CID. 6 I saLirlf . •ar TEf< • a 1.PtL0 CILL0 a elcuLee C Kinn1.l2a%a4 1 PI•IR¢1 - Pall reemeui6 • O 1' UO{tlla C 4.11-971 C PaL.41 EC= e I PsiC eL*S F - par Teo - 0 J 81-11 6 CC/P5 0 oaLe#. p!C0aa5.• a}I11 FiPCI.TIN • o - PrTTII~iQa1 •- C I P1-M400L1. 0 Da;Ir1 - T1 aM.• , •PalsFO +FDl DAPCMIR. COAL a PAT Per r1o1 PC+EME - . r OPP CD r - e CILP.. P17{50 if4I F PIPDP L 01 CI PlL - t 1, PIP C Paawa;Li . - r .. Pair"... POri}Ela- O 1 Parrflf.I C. 0;uL01610 e I !CMa a +1+110 .... P 0 i4}�. 147r4,.. afL l PrRDee Y#LL.! r .IY741M4 - .-0 I P C • PaC1aaPFa e SJL*i7R afki - - I Drill.#r - C PALL#0111 6 I.Pf'a*3CC r - D PaCMC€O • E Port• CRf!'CLL'T. 0}6I PI. ! -I . 2/CI P SWIFTLLE = E. I OE'C1 e - PPC Me CO, DD+Ire O= 8 LLIeSlualu. I. IP*I•TO . CI PaLabc$ 1 - . e I 0l110 Oaf ILL! E CPICD rr Ca .-. . E Pit r raa E 1 ajUIC •TE C 41ay0$IyGUMT O. I 0*0Dfr• a aaCT - C PILE • - . 6 I PAP Eli . C Pa J1 am II a* Is C vaisaPU - •- J . ■it6DIJ D '. P I ■iR11.1.S. fa ' Iliu'(La , . 'r I- Prime,. - '-E ¢A[cQP ` 11 P•t4=ia l,, •'y- e J ■aP1IULE! a C *aY#JIi - .0 I P{MR'CP C OACC Isar .. .1 PMLa.a1 -. ° - ... 1 1 Pills* . P PalirT - 4`r 1 •}.11¢CPG11.1SS D 0*CCFPIIL 'C 0.I4.0.11+0 P I PPPPPPLE P _ •a!!R . -ye p Pe KILL 9ON C a rte i Due ; 8 PaL4w C I PALL, I Pa*ILLI0r m f I 0(1161'DT U Pi[p - C oaL401.Ir0 - S I P . - I tPRO ' - C I 0E4/EtaS O _ aaCTL.TT - - 11 ' 0II.0 PeDOl aA i 4 I Da . C PPr6r � :.-r 1' 0CE r 0 aaCrpLr./ '4 PatoI ! .. I 1 PaIa:r.11.1.. Ore •.a C##11CR .. a I De rClLL.T . 0.0 - GarrD-US - •a FaL56Oegg :. . a ! Pikalti#D1r - T' o.a•11Lr6Li . . 4 J. PEIrCITa . . € , L arCITO[E COD- PILLION ; a..- I PPel i r - f 'IMO M P I strielarimi.a . 8 _ 0/0F.+1 • C Pa.PSOH - -..,fr 6 1 3 Prci111. a Osegue -' 4 1. OEr1IS14aa - IT 1 Pl41LLa -. C . P+.ILICO • 0 I PIP!VILL, a rarIC4 • t 1. ■earlteaT! e Ga#fra I Paa9+ r 1 a sac•DOD *J4 Fillip' • - C I PErLLIT e 4a Or'[S - 6 . 01MCpeL C I rarL3 P1 ' A •PIY'LLC r ' 0#'611 F*IIM .- C ,.. •l G ail 49ai i. t 0+4/1..4l,ES .r P I PALL 114 f PEPET T{ - e I. Pf/rLt{[aMR - a lt- a4oL1C 4IIr ;6 *IPA f ^I PreL • . . r 9ara*tr[4 �• O I' Pfi11ILL O 0401JS .. S - ■rr+Efa . . 0 1 PPR1'ELC - .. a •Aril . - C I. PC WPC 7' Pas 54 a niwat :'' 0 I P" PCLOP - C YtrRIE CITE I . 8 I P1-11111{i1UCf . -.8 9 Kcal)r - . 'R .. •r.lsaa a .1 Pa3.CJlTLi . _' P . •PYSIP • 0 I PE PPILJCD - a , •.GCOR44+r ... a . P1+1M1r1 F 1 Pa9PLrio .. . C I *CRC Kim ' O I P[r1O [ D4GLMa .:rr"L; C / ■MIS0' IIC . 1 : ,CfII Pa4111.LL - . . CID •tLCla aa° . - ". O I' PCI141M9 r E aaG46a ,m--:.., .0 01a C 11.141 , " P.-.•J PiPCMa7 ! PRifL ' 0 I• PCWROSC . . 0 ` L , •IIPO,=, , . .. - e '1 ,.PRA - F ' a#OOO - ; a I mtP - CI O4G1011t . C - 0*1rOOI+ . . .r E P ■i•u r •F.1P}0.L .i.. - {z'- 6 I a a..+ii r ;P•a666 a - o.,0 ■arr Is1. -. ( wTa*LCr r I 0!1112 . .. ' ..a .I- 0 as MOE e . 'aro 1•I>*Duaa .4 r 'I Pare I la -. r 11011111K AA 1..1, P I 0! i1aWlailaGa1 - C Farr ! :G PafI' Ll. •".,. ! • #Bair•! • C I PC+1+446 ,--- I a+.niatiaCa I. Tn+T. .8 0arr,B0* . P .1 tali! .. CrD 911+r,CC n I P-CPC LHOC ■. E 0000L Oaalaorl • 0.-DLQINI ITCr . . S :I P4RI0 i C' -: afelweRdIRI , . C I PECC:1 - C PaMa■11Ge . E PPPPPPC11r -.r..-:.~ r 1 FIETL D* . „ L-.' PPC.1 TMI£i -;. . C I REM. - D J}a1allal4 C 0a1+1JLL f -,', 8 .F •aLIC* :.7.. D r[Stra■ = , C 1 OPOra. CialME6- C 0LrrP P{ , , , O c*w34 :e 1 ■AP4a1 a peen 1.1101... . . •r Ja I PEAL* C *sour r1.P C Pada I6{i,JL P 1. ■a•i R 1SOT - 4. i algae,.1 . . . a $ ■EP O Part'l WC WV I - 0 •ar 10 WWI- ACT ,C I irl*aGSr+S F •#CHIME `1 .. V I ILCIM(r 0uIIP10 C ea la a 1 ■*r11[yrr •• J P - C +'1.!'4`.1 7 , O I arour4 - P Pa ICF a I P*L.tt C -1 041E6, OP/1K0 C 096C! - € I ITC TOW , I'D F■ILO - -• •r ■0+.40 C 1 04/50 Sea) I •!0 04.Ps , € I 01011 b Oa ill,!1111#C •- .0 r •*.IOCMK IP I PIIiPLK IT - C PSCIGO - . C I Pf0OOr 0 aa7MT 4 I 0l00C1*1. C .1 865014 11 J.. • e • r EMIT ern ;,iek. C 1' K•+!• . 6 aallLfr -. . 0 1 14LI14*- -Ir .I 840e01114:.t rein •. .. 0T64LI - .. C 6 • - . O RA FT - 3 I OE •1 •r1LPUf TT J. 29.a lot D C RO•ICE r 8 t PfoUIo INC • a P L . .- { i 051OL4 G i 010 l 41aals COI 50604 • C I Skala a -. 0 Pal*P1TO - - • I P.1h4P S I PISS ;ALYIal . - C •CE■LC' C I Ore4IUDP L „ ■ 0*.duCL# ., .. Jw I 1,11p1T104.all a .* I 0.a11.am I . !b#E11O - . 0 I 0100.1.la - C mac/. fl I 0a.r02* r.. . 'l' 1 Oil ■ ` C POOL , - - C I P00+120 V ir lit a.■ ■ I P++tf# c . I 1II1i0r 0 PEULR• - 4 'I •PPCEIO• . e Par/PIT • P I ■a11111+e . . -e I 0l19f rr .0 PIOPtfii . 6 I •PPCNIC a APLaClaui 6 I ■+11SCTa •#1141 ris1f.PIVI a P I T T! * ..1 tOOCILLa • - . 0 Or - C I FilrfCPa C I PAi14.111W 0 PPP PPP - 4` I PERErYaI. C 5} r I •4M11g Ir C I •ilalta C PI€•*ROLL - C I •{PCCLI4 C 411 0 I OrgIOr 0 '1 O./ •{F IN • r PIKil,tc . C I •ERCT S.O P+L+T 1111• 4 L wain a • I wit' C PC14.10 6 1 •tu Dim C 6 I 04EIL] T I Pi CI L:ICP - P PCG•+r - 6 I • - 0'O PAL+1ICI C I •I+*a o I I'ITEIII C Pea•T C . 1 • e a#S LOOrt i I PAPA[ C I Pai.I+n ( Pfr[ra C I ■OO[4+TEL 9 irll Pat71wO0 C I P1*a(,Lla C I Pal ILA.al. f •,Lama14`MI! C I S!0 *. e aaLIS*44` a 1 Para1 - a I Pal ILa f, MIL arl E I PT•I€O 6 r J• Ole 5- 760 i•T DROLO41C 1.4IL C. PUPi 17.1.C1. al 0{C lUOtCalUC r.( CPuI 0f4J4O0a1MEP •T!UItIO6. ' v0CIFII13 swam,. r.L.. elfD+OC1 i{,1F•J.1•L1U*° .TD. # IPICIFIC SLSIL ICOiCI PwaIC PPPPP Ir -1411 •aP LIGEMO. ti-30 (?]O- S-T'R-55, Second Ed.. dune 1955) ' 1 • Exhibit A-1, continued: Hydrologic soil groups for United States soils PCRIDGC 0 PAULO a PIMCLL•s - 010 T 0 POC(G[w• t PCRILL• 0 PMILDM•lw 0 OIMEIII - a 01.41a a POE(N*M C K R/NOS C °AMMG 0 PIMCtOP C C POtta C PERITSa C PMI0P1 C Dl fluC.T 0 PLAINER C POtt•GAP . a PE•clos C PMLISS D PINCIUCCT. GOADED C 0L•TO C C MOILS • eagee6 0 PIN(v•L 6 Pla?O.O 0 Pol•CC' . C PEAL* C 050E It 0 •INtvILlt 0 • e ool•Llt( C IeDLOA O OMITS D PINE/ a •'ATTE. ACT • 0 Pole? a K•140 • olaNC(Swa• a PING•(( 0 PLATTE: CM•NNtl(0 0 •GL*TIS C K ON 0 P1asa - 0 0114«005 •/D PtaTTVILLE a OCL •10 OasNI TAS C o*Olco 0 01N1COr 0 eL•eCO a POLE 0 OCRNOG D O1C•00 - . c PIa1TOS a . 0 POl!CR1lc 0 KR14T? 0 PICaCMO- • C •551(1 • C •1••5000 c/o POLELIA! 6 0E•OUtMaNS • D PICANT( O ot14CMA. • C POLCOaTCM • •to*Cau 0 PICAYUNE _ 0 •IMSSTON a ',Leas'"? C POL(r C K001,0 0 PICC•MCe C PI•rl•CL!S C PLEASANT. 005010 0 POLFT. COSOLT- 0 010015E • 0 PIC C 01550000 ai0 PLEASANT-GMAT E POLICM C K•O/5105 . C PtCCews 0 P*AMG•Ir - 0 PLEASANT val1 0 POttING 0 OCR*Y 0 PICKETT 'C PING C PLEASANT TI(,' a P011a•O C . ARA - 0 PICtr000 0 OTAalr •- a OLeaSANT0. 0 O0LLattr a KORYVIIIt 6 OtCRM(♦ AID VAMP - O PLEDGER 0 POLLY' C KRSANII C PICANET. FL00000 0 •WOK% C PLIGONIR 0 GOLLY • K•sATO • D 'DICCRSL. - 0 PINRIDG( 0 'LEI•IC O POLO. NOO(0&T1Lr C K•SN1NG C P1CCTOM ` • PIl[POING' - C •ICIO,ILIe •• C SLOP PEON PE•s11 a 0tCttP C •1.w/aS • PtSIT0 e - C POLO. NOD(R•T! 0 PCOT O PzCtaics • 6 01•ll•P , • Pltv.a . .. O 0[•N1aallltT Pfau r., C PIC° 6 P1MTO, C PLINCO a r 0010510 0 0E0vIw• 0 P1Cos• .0 Pt*TUR•+. .• "LITE -' a w a P[001C•0 C 01010[1 0 OINTP•TEa- O *LONE a POlus a DISCCICOO 0 PIOIN(ew • 0 01OCN( - 0 PLOV5•'• - C PO••OL 0 PCSCa. C OIL C•C(t D 01000115 Cr o PWC& - C • • C P(SM*STIM P 011(05 . - 0 PIPCLINC 0 Plumbs a 0006r '... C _ OLSPeret O otep•aN 0 PIPrr - C •LYNN!• .. SIP •01•T. OAT 0 0055e C OI!MIIM6 0 PIPCSTOM( '0 PLUSH a 00ae110 C 011500E C P11•PO1T . C PIPPIN • PLUMS .O 00514[51 - C 0110 • , C COMM O 0100 '• PI?.OYTM-- • • 00N000T • Peso.vO - C otCaowt[ • -141.00(1'. - ' P •CALL. - C P000 - a ricrac• 0 PIER! - • •I.OUSTTC--, 0 P01•CN 0 000014• 0/0 P(ral C •IITOPM a •MNN . • P(StR . C AoroAa. .. 0 PETaN .!a 0 01G1a IL .• C •ISG•r . . - .0 •OCALLa• :• D/.OtSS10Nbl 'ACME TAE(•:- ' - 0 •1150MY•.•.- • PIS••cU* , .- c0 00Cag a 00.0ANO • OID PITCO■a* 0 vice 0 015140 . 'O POC•SS(T 6 0050.50.: 0 ri Nam; S►NOT :C PIEf•ILlf - 0 11t . 4. 0 •OCatlu.o e D1P•CSSZ014•L- S S51•artri.. •flail° a PITCK0 • a •CCar•• •0 POPP•NO. FLOODED D alc•LI •ItCMUCC•- C •1110 - 0 001110 . C as D KK•S D PILCMYCC. • •lIN!, ,, C •°COI• 0 0ONO0510' C PETERSON MOT(CTPD • PIT1w"w C ri000•060.• POw05D 610 DONATO* e PETCSCRLCC. STOAT .0 'ILIAC 0 •ITTIFS!L5 1 •OCONOC[. 00•t11D 0 001400• . • c •CIESCOICC. C PILL1FEA • •IITSIOPN . C POCONO - e OONC• E (SAYELLT •11101 0 PIMP C •CO(N v Y - OOMC1Na 0 •CTUIC 0 •I1L$ U • PT C •1Y/1 . 0 rD°•.00 C PO.CMA • •(nOLI• ,C,1 PllOr •(a/ .- c Pivot -+ • •17DD C' DOACIA10 .- , C 14[1001 0 PICOT •CCs C Ping, . - C 000450 • POND- o •11$061kG 0 PILOT•(•[ 0 •IITA! - P •CDYS C . 1.115 C KTTICO•I -e o1LT1O.M a •L•cro0 0 ODE. '. c •014or• • - O "tritium" •/O SILT/ C . •LACterl• 0 •OG&L -C •ONIL 0 PETTUS C •T5• • •L•Cr•ITOS. F ONGAMta• . C •014111• 0 •S TT• • Piste P 6.1.105. D•AtNEo PCGANCAS. - 0 PIN•OICO v C • 01541. 0 •LKIOIT0S.. C .61I•,T•atuN . 001410 - 0 OE0.50 -C/O •15.1550 - a 5•.151-aclaLI 005.0(••. lumiw! O •ONTOTOC • K•TO• • a •IN•5I -•' a P1Ke0I1101. • •00.0(5•. N•Ga. 0 0014700( -. 0 • (IPPCO • pleura C .ODt.aI(LT. 'BET Oat all . 00015.14 . 0 OMasc • o •1Nav(!tS • •LaCf•ITOS. %Et C •OGAKa•. ST•ONGIf 0 00014 t• • Plumb* • •LaCt•/IDS. 6 &Al1NE . 0001.EF 0 •Ma110P C PINCN(• C C051NE0+' POG•0E06.- 0 000L1vILLS C PM410 • P10CM01 • PLACID.. PIP 5KO1e1TIr P00SCaL • AAA*. • PIACcAcy C PLACID. - 0 0100010, 0000•a e Pmts• C PINCONN/A4 Pb 0 Cl -*014.1 000.0(6•. 0 0005! o PME[NEY C PIA! FL*? a •1.150• F•E•UtMtl? 0 $•L1K 76Lt*Ll 00014A1YCt a PSCLaw 0 elNCal a 91000(0 - POCur a o •511.1 a •IMtSuTt1 • PIACITas C POMAKU•Y a OOP( 0 014[1505 0 •*NECK ct 6 ►LAC• • 0 •CIA 0 00.14(05 C i •MI/EPSOM C PINED.. etc OtalA00. • •0150 . P 000l[ co I MAMMON 0 0IM(0a. 0 PLAINFIELD • •OINSETT a P091101r0010 C • 014*1015 0 OIO CSS10NIL 0461ST(° C POINT C •0005«1• a 01411100• C 01010.1( 6 PLANK , D POINT I C •000T0S• •, • PMIIIPS•WG • • DIMEGUEST • 1.w/Or, 0 •II$ONC•C(t 0 [TON • ' 0-$ILCN(' 0 •IMeat/PSI A ►taw° F POJO C POGUCTt( • 0«1111.1 C PlAttaLe 0 PL•wt•T,ION 610 00J0•O1* , 0 000ult• • AWES: No M.Dao1OGIC SOIL (SOUPS SUCH AS ••C 15011.111 IM[ 9••INCDIU500.INCO-%*tUa/10M. NooIVIEOS 1.o■M. E.G.. 8100 aI 0Ca 1U•S'• Ua. sere• to • s•CCIF/C SOIL SINKS •14•5( FOUND IN SOIL OVA 1.10100. (210•VI-TR-55. Second Ed., June 1986) a.a} i - Exhibit A-is, continued: Hydrologic soil groups for United States soils .00UONOCC c P.c.,(. a PuNCSO Owl. 0 OW elt ITC. C 0•0500 C 'Dorf 1*I0 C Patel ISS c oust C ow 6/D w•USOCLI 0 PO5R[TT O •K S• 0 •uMGO 0 OuIwuC• C •aOSOILL. D5alKO C Io'••oi! • 555 Sue• • a .uMoew a QUINT•NA • awn!• 0 POST • PSCSIO 5 •WS1T C Ou101 TO 0 ••USM00r 0 POST (•ROM 0 PSCSTON • PUNT• SIC OUINTO• C •1U* - 0 Pan T•GC 0 PSC•ITT • • rum?III•• • S 0UITeat• S •4*Cf C 000•&GC•1LLe 0 ••t►' •s - C mt ceu.a S GUI Mau C •aOCMOS(CO D POOT 0 Pal CC a SUSCMCS C Out vet•. • C ••.0.00 C OMSTALTO • reIDA• - C DURDAN C QUONSET a OaNDML* 0 roe Test ltl° C Pet Dr a. O •UROT O OuSD•N• 0 ••880000T 0 PoR•t•S • •a1CSTLACC • "ten TT ' 0 OUOS•Tasa 0 O*NON*N ,- 0 POa Tea"ILLI O MICT• O •WGaTOOT C 0•0017[1 • •a t'CLM/ C r0011•0 f1.4.• 0 Mir 0 vulanCe 0 O . C •ANDS - , C 505•1• C POI re*Ut• c rums - 0 SI8 10/U1 P wa0OSeueC. - 0 •05,1N0 C M1 Amer • 0 PUa1Sl[T a tatuS a 0 • 0 55/00045 . e PURIM' o sacs • a RING[• C PORTPOUNT a •e*mace too • •uSesaTaw& - C R•CIN( . 0 eaNS*PP . 0 moire we 0 Pa free:ILIA C PUIT01 • •*CteR a •aosl0 - 0 •00,01*' • Pa1NG, 6 WTrao 0 •KOO5C5 • e •*5100 .. e POR,sNOUTM •10 MIMGLC " 0 PUTNCT 6 a•COON CID RAIISTSIN • POauN 0 f r1 TCw•eD . .0 PUTT - - C .500!■ - • a 0•5110u1 -• ° 0 5014•5 • .0 NITCNCTT • ' '•C •UTTSTS• C MAO. LLCUSTRIMS C •a•a Tee. 0 POsew- .0 MOCN&SCa '• LID 005 CO • SUDS TIM TUE: e•►OLJC •• . a Pass.-. . ••• e ••OCTOR - •• a 5W ODA/ ' • e Pan. I4.000(0 C ■5Pr - • e sosev•*La.e C 5.0005150 - '.,• 4C PUU Pa • • • e•DOLt • • e 0•••0 - e .031Tas 0 raw tlt •- •• .0 Sou P•. NONSTOMT / •AO/O . 0 08•1005 - • .OS[IM •- C 550.0 .0 •{AK&L• - •C 5ADIRS01,1IG:' a R•• tt - c Paso . .5 5.000 C *outride- -- : - • C ••05050 a ••PR*waNMOCS. - 0 •OSOS C •5D•N151TMow c•ID •v•allu0 - •• - .5 ••Olt• ' 6 "•-, e Pas, '0 Perot PCCT ._ s PTRUSN '0 0•DMDR C ••SOSN . . C • POT•rul • • • •5015(5 '0 Pyle - .a 1 O muse icc' - C • PDT CHUB -C 5505158 'C IRON 0 O•/TON 0 451105: C ' POTCCT • • C PIO1I•*N C P•0•[ • • ,55• C ••Se•50 e j `. POTCLL " -• MOW C P•a•010 { -0 04.61.•8 - • .a WASllle • '•t. a \ POTM C amity•M• • •••• C P•PNONT 0 50054* . • '5 •*1110 e - POTL.TCN C rave 10CNCc .0 P•50OMT._1C0.00C C ••405* • 5411(• e POTOMAC . "4 500.14 'C WO •*GO C c •0,011 a P50.O '•0 PTO/LL 0 •04.15 • '0 0 POTS•TZ •• •C Play° *Ay., ' 0 Guar SNO .. _ C ••GSO*IC Oro S•TNsur - C - *entrain', C Pees O ou•tga • . C •aG$0aLC.• 0•ta.•1N'0 a•TMDaur:' y'- • 4 c aRUD. - • • mote colossi-. • ••C 010 vowel .• .0 RaTI•cc- • . 0 *OTT15015 : ' •0 ring ' •:n•'1;:-, • Guar - Pro ••NIL - •c w*T1e5L•T is -POT.TS • • '0 Pau IT TON' •. S Oua•0M - ' ' • SAN. •'ia,.: C .111'tIt• • : 0 • op l'1801084 • ••/0 P•wlt .• •- • ' •0 ouw:aw • Sar.a•TN • 6 55105 , .c,. o 3 POwae i'' • : D P51011 _ C 010001• •e Salt • .1t• • .0 ••TSO. .. . C 00014000"' • - 0 •PSUCa• .-, • OU•rTICO • e•ILC ITT •' •• ••1TLCP'' ' • ' 0 • 0001.1•0 - 0 PtaSNlSaw•• • C OUaaL11' 1 :"• o 5.1weer SC .05510.;.'-. ' .' C , PDU•C[• 0 •WPUa .• - D Crag 1. " C PaIN!, .: .0 RATTO. -s108•. •D ►D•SSTT - 0 •WtA.0 ' • • OUmeTZ•ILIA • •*1N11R .. C eau* C- ` a05t• • Pl N5*. •• • 0 SUMS C MUM' v0 e•U0M, 0 Pg.Dg••d• • PUOOIt a awl TAMA - C NAINISI - 'S/o ••U•ILIA 0 •DtOt•NO•N C PiCRCO . ' . '• 0 OW • ••INS.•,SLOODtO '0 ■LUZI .. 0 ro+D5:ra5M -4 c •000T• o QUITO• • a •*5510050 C I , • 0 - 00•158 " - - C PKST[CITO 0 OUCaLNa.'+: . - C ••IM$•1LLe - e .a.aa.tl. •C000CL • Pos1L1 • 'c ewe TT ' 0 osg•cT 0 SII4105N1 :e SUOSID•Iuu • agog* 0• PtlI5f5.•'• • ,. " 0 OLC•S•0L - - C ••1110 C 5••55 • . • 5g•gaL1NC - C 'PUGC1 %,- 0 oUCtov - • wacaPt C 515500•.! - 0 • agOLt• 0 VW( C GUCCI* a •art 0 Uyp.cLL 0 •0.810 i• • • C "PUGSLI• : ••• C OlxaaoO-• - C •4c ICO C mamma C . PO•••Nttt '4' • 5050 ' - • ewe sea 0 Walt 1Gr 0 0•Vt•s*000 . C 0050•,51 - C PW1N4U - 0 OUC•C- - C eaLL00 • . 0 amyl• - . - C agT - 0 ' POI CC •" *, C Coign Nt t•. a *MALI,.• •• 40010 0 ro•G•N • SLL• . . • C OU[TICO - 0 •aLP$ . ..• saws C .0•405 • P$LLUT*1'•'.:: C OUICISCLI C •*L0M5T0M • • •5•t C • •010 C 'WASSI' - • OUlCISllee• ' O e•LS[M - 0 Rang • Solo •LANCO • PUL.C•r • C OUICcna1 c eaea0s.0 . • 4.LINS • mac C OIL[NU• • °V1oes a ••• L• t .: C SAMSON • 0 00•1•1IVILLg • PULe.eas' . • oUleIsue- c wa.•OUILL(T - • ■a.SON•IU.0 C maw ISS`• ' C 010.1.000 0 GUI[TVS'-' •1. C 4105L11 _ 0 005[1105 0 05.15[5 C PULPIT • C 0514*?, • ••.1e[S •C O Ma TLC• ' C PULS e Co OUINI • - C ■awtl C SAT/050 C MATT a PULSIPWCI n OWL.Came' C 5a.0 C - D 55[•{055 a 51LvwCi-- ' C OUlll••U,t • 51.05* 0 Os Ta0sD10 Illt 0 PSta•OC11 •IC own. - • 0 OUILOTOS•• 0 5.1100•. 5.50 C •a•K • Mta Tee SON • Putt,. 50NGPL•CLL• C GUILT - 0 Suet IAA fur e ( l`. ' M[•13M CID P*.1ot5' - S Ou1.• - - e R , • •a•NN•■ SSI•LC 0 PUNS a OU/NC• a SR. 0 ••••CLOS0• 0 ` M[LO 0 PIMALW • •••' ' - D OuW5L•N - C ••.PS a ••TON ILL C MO?tI: ,.O NTOSOLOGIC SOIL G•OUOi SUOI as set 15DIC•Tes' INC ouatNeor{IMDaal.eo SITWT108. '.001I IVD% 15050. C.4..•5101015 Sue STS*TUS. 5(515 TO • 1KC II,IC SOIL• 1(5.ICS Pw•S5 •DUNG IN SOIL Nao LEG!N0. A-32 (210-VI•TR-55. Second Ed.. June 1986) Exhibit A-1, continued: Hydrologic soil groups for United States soils C OCOS10Mt • OEN01 O RICOT G RITIDIaa • Rat 0 •EDSUM 0 RENsNar a RIC65ST D agvmER C OaZITO • • •[DIN*TNt a O(NSLO• O RIDD C RITO • R•ZOR C R[DIOV a RENSStL•[R 5/O MIDDLES a RITTER a 11•20ae4 0 REDTa.t C •CUs;[l•tQ. C. DIDEMOauGN 0 •ITTM•M C R•ZORT 0 RtDVIt• a NON 1,1160 MIDGE a ell/ 0 • R•ZSUM 0 RUMEN. NET C SUOSTaaTUN RIOCCSU•,' • C DITU. DRa1NEO C R5a01MG a RCDYINE C •CMTILL a DIDG[CRLST C RITZCSL 6 6t•DIMGTON C 6 newton 0 01005061.5 - O. OITZVILLS 0 RtaOL,'M a a5C 0 •CNTON. DSa1NSD C SIDGCLaNO • 5/D 0Ira1.155 a RE•GaN a 0E600t O •SalSaC 0 RIDGCLarw 0 DIV(•D•LC • ML•COR a OECD 0 RENTZLL C RIDGtLa*$. NET 0 O/V5DNl*O e *Col • 0 O[t0. OD•IN[O C OOOOOODs 0 •IDCCLI.T( O 0166D0•0 0 05a11.1S a 0550. oSOTCCTS0 - C 6569 a 6100550RT 6• OlvERSIOC • neap - O - •tsoe• a • 655905,' a elute IFS.+ D DIr(RTON • StaloaN C •556(6. COOL C RCPYBLIC 0 WIOG(rl1.LS 0 RINEevIE• e Meal/ILL( C MC(os•URG C OSSCU( a •1DGe•000 C. D11515Da 'CID 05.5 5 a , o55O$SORT C *(Sato 6•; SIDE,' C RIrIEP•. 0 6(5* C • MO' D 55506? 0 RIDLr,' - C 05 9CSStONat REVEL 5 65[1.1065 O 55101• • •100?? C Oil/1(0a. LI.CSTOK[ 0/0 aSCa.TUDC 6, O[5V06T C 055,'1MG c. RIEDEL C. SUE cm. DOCK D . O[[o0 .e; C 656TON 0 RIEDTO•N- C' RIVIeS•. LIMLSTOKL 0 RECLUSE • • •5555 C MTT O RICO( C SUOSTO6TUM. aco *AT a Sttstu C •evasev(R 0 .15151. •. .. C O[.RCSSIOM6L •_ RED SL , C MEESrlul5 - UM C RECOUP C RICTSROCL •C alrD 0 &to SLUt!. 0 etSYCS S RQT•VOC C• atria 6/0 agate C • GRartLLT e- ,S(,L(CTIOM • • *Era 0 OtGa 0 R11OM C R(0 eUTTS a R P UGC • C R C 610005 C oil - O R50 WILL 0 •EG•L 1/0 0 •IGGtNS 0 RIZNO 0 WED NOD[ C •EGaM •/D .SVI.0 e00 RIGGS 0 012020 - D RED ROC[ • 6 05656,' C. 0551? C *IML[,' 0 6o•5E C RED SPUR - 5 0[66.0 .. .•A . •56a60 a MI C aoaaNlot •-. C , •eoa•aor - Dr •t66(•D -O RSZSYR6 a MILE,' -. a •OANOKE 0 •tDSaM* _ - - 6 55OG5•0. COOL C •tzrO50 C WILL. a 50.1156 a 500111 a W!GNaDS C Re7ODlir 0 •11.1.150 - a ROC soy C REDBIRD O.• 5[651[6 O MELDS . •151.1.0 O e0•*5• • 616505 - C, .CN•UVG C aurae 0 OWED C 501.1 0 SOeT 6 •0115!0 a *EVES 0 619151 • .09CC ._ C R(OCa6(0ON , 0; •tw►15L0 c C •svaoi• - e •1.055 O WOOF. . . C *505.• O!; •('NM •: C T 0 110105 - • . C • al5 C asoCaO. 0, eciCess • •(tavE O PIN a •0.1•Tsr ELLE C •EOCNI[r • C: •CICN[L 0 ••••T 5 *15500 , .,, ..C, 4110SIM -. 6 •CDCLIrr C ISIS' - •, • •0C• 0. •150• O. 000•M1TTL • M(OCLOUD 0 •(ILLT - A. •NJNSSECI . 0 010006 0 50•IMSD5VILLt e *Coco 0 'Clan Co •NOaoES ' 0 615065. De•IaCO c •06020 C Rtoc.Uc 0 ouMaCN • •NO•.t C, •15LARSON 0 500.005? e 6(00.1.1 D. WC1.5• • •MDa.(TI - C allay 0. 506500 0 OCO0ICS - • 51500 O. •• soCT1. STOW: C SING C SOS• .- C •COOING O• 0 ••abn5 5 •1565[ . , •• •MOC• • 50(15 • •c.a,' • •t• S.* M6MG - .. • UOCNS D • Mt0KaTNEw 0 SCLISMCS C •1St•6 • r. . • C ••.GO • o SOCNCLL( C RCDOIELD 0 *EL1t 0. 1159ILL 0 61050000 . 0 500090 _ c • REDFIELD. 115? ' C *ELLE,' 0- 111000 • 0 •IRC10 ...0 tl005[5150 - a 150FIa1[ a 5EL505 a 51Ct0050 •/D O10 0 6OCID • C 6[OMOUSC 6 •ILUCIIN C •ICtC•OSS 6 ■t0 a5•tea 0 50(5 Met - 0 5016 • itssc•T 0 ■ICtOt a 610 01611LO C •Ott •E555 0 O56t5GTDN 0 IDS C 5105100 - e •t0 00a005•.• e •OCCa61M C OSOLaSt 0 C •ICtr/u5 C 010 c, • RD C 0601.aN0S • ae.1.I1 • RICN C 510 51(0*a1. 0 •OC(O OIDGt 0 *5055551. C newel,' • 111101. *ET 0 01011LaNCN0 C •OC6C*ST1.0 O 5(01.0060 - o •55.50• 0 •ICS*OOSON • •loCO55N0. C ROC[Ral( • *eDSaNSOM ' • WE.OEC • •IcwENS C 01011.0• C a0 • •(DSOMD• - C OCMiCO o •1505• c •IOM • aoccs.S - C • •eDNOUMI • 055U.D• C *ICMItCLO • •10tt 0 •OCESIILD • 5 SCOWLS • Ot5US • •1ca•6010 a •l►Lt,' a •Oct/050 • ODMtc. 0055105. C OSNO•C 0 •1CNLaND a •Isla,. C 5OC1MOUSt • 5505UM C •ENCaLSON C 4RIC0.ON0 0 SALMI- 1. •OCIIMCNa1R C •COOL• 6 •Taco? 0 •tCSSUN • K T •05[115. 0 51005• 5 Os 0 'metre* a WIWON 0 ROCS(,' 0 500500 a 550155 0 •ICOVaLC a .Loll 0 WOCa0• 0 550005 C •5N15M C •1CNr1Cr C •1.505.5 C ROCKED* 0 •((Monk • R(M55S • •ICNVILLC C aisle • ROCKWELL SOD 010610 CC • emit( R O 0 .1(05000 a ausares .0 •OC[r000 C •[OOIr66041,11.0. C •emote. Da1MC C WIC[(• • WISIC,' O aocs '090 0 5CO50e C *COMIC. .so?SCTCD C •sCcerTs C 5155(1. STOW,' C 0005T0a0 5 • OCOSO5a• 0 '*ta0• o •ICK.a. C •ISUU 0 80060 0 I 51055015GS 0 •5NONIIL C •tcc50aC C •1 • Mooch o 4505051565. (•5020 0 65005 C 51555(.1.1. 0 *11• 0 50050 0 5 OMTOE 6 •(NOTa a 61555 • 'Mal, O 5065556 0 NOTES: 150 MT000LOGtC 1011"0*OVOS SUCH as •/C NOICITts 105 OO•105.0/NORaiMtD SITUSTZON. . 600151(11 51955. C.G.• •COROCa s*a1T••1u.. 55558 TO • 1oSCItIC SOIL 5501(5 OM•S( .OUN0 IM SOIL N10 LEGEND. (210-VI-TR-55, Second Ed., June 1986) A-33 • Exhibit A-1, continued: Hydrologic soil groups for United States soils • 110121[ R +104E44.1116ce C 114117 A 3■!€a1T9 s 1+m1a11re.0 • C a a13SE4raL1. • D •11e1'14 ILL F 6+51 ra • C Sari S1. S str.rarlS�124p10 _ L RV II.1{ auCw a •. 0 opEDUCE Jl 0ps{+1666 'a 10 MICE gal SMILE pJ'6 SArOtSI 4 1213 ELLrh 0 9 OS{•LTLT7. r•-T - 0 111,11'.LLF3 o 54IC E 5aroa. 4 124€,1112 C Ring wCq!+1 p pueL.eke C #.41.0 Pit/IV . 6 .• 601Tea • o Gos Fir 5P'Pl re.5 ' a "L1OC O • SaCNETT C 6 ' oar lfi a scam( SPRIhc$. . C - 4y€'5.I1 . D 5604 D . 5+10516 - C roam. - 0'' O.■1NfC .r: 46113!!" • C . 5a[1taMl11243 .4 •. 6JO ' COQ;RSar b 40]+1861 a Oim,malp • f -. ijCTi15 6 ear MECUM a3' - IN 50fe12T Cr 4OSI.IF e ' alutal.aer E L#CIJL - ' C • S;M au!9n e f46wueJr" P • 41451Tas .. . - i . ia'ALL6 F as.1UVLl .0 5tM /MTOMIC - C "haul! a CD311 as- 'Cwa.1CT C R4"46 ' -` . ' 4 se trial 0+Cr. CJ'o SEA a11CaC1 C C • .t.w1. 5 lug 5 Taal yie • &T1C■a L 5*fl0LecaP ' • 6 Sar 4Ew 116 + - d 110+1.€1111.6 1..' .' 5 a13illai- - C ■VC. e ' }riot Foote • . 5 6.. (ADZ ' 6 661.06.0.1..- • ■E7 64K1.E8 r - #.O •e -•3-=. .a said ce RY.la k-• • 4 .. 11.45 • 0' CCy11at.'.■1<T - , C : ■IMI x11 4 ii-0 1s , ' 3.. C. • SAE TSt5EL,.'. a Poi( D 8036+1+1 e'" •ut5CSL € l:.A13Lra •.. ' " { • Seal JOOUTr• 9 "10.14 • - Drnakaal • ' 5 ° .UIrPC1rT - 6 S+■►ELL ' t ham JOa1 .. L -'-IiOL.E 7 T6 .- { Loudly ! putt • ' + = sad. ' } a Sal, .1123E 'T 6 r0L-!.-.‘ + ' • C- R4i6 - . w JtuOO ' • a s.GIMIR!G aim Sad JNJ.h.=.r• - ■• • 11061€ • • 01' FOSiburt ' e..1 Rut, - r sa6a5[R 4 . Saw LUIS € 041.355 .1- ' - 8'0O 0055F1ELO • 8' R414re LE CPD'CR ' ' • 664E - 9 3■M OE reo S '5466'6. - " C• 11041 1.UPP '. ' 54 0/45510 C S.1LECaf€C �. - a bah '•1611€L • V 441.5 1.1.451141K . C fl 6s s rnlra.5- ._ - ■ R1A1■OPO `5- e• 16rar PAL[ '• - C 1.•M IAD+ 9 .• 121367{ 10' C0l.6LL • . a C1aLr* • • S ' S•CEr1LL 61 Sr. 8E6E3111a* el 126L13la r - C PM.* ' 0'. DL.-wf# € !*Sff 1-012 :r: . e arid #€+116+1' . 0 12O.eeR4 ` C 051 ad€a . C 04lsoar ' " ' L` SrCrdlr w • SaA TIPOICO { c#a100 ' C. 1201aM C' awe LE C.. s•CtWWWI+ .•'re C Paw r321)1213 .. p 611+1- P £01 rlCaN :5 •Laub{. '{ • Sete.e ' -. e ' Sar[Mrj 0 a1CIEE4 - L•. a0TallErdr C.' SWIM • • C % S.1e.4 p = ammo_2+PENT/. 0 D DOT he+r - • e.• •Lalrtl."!#G CAI 6.100V w< --1.-L' C• 35+18666 • k" C • F 111.wCww • { 1$7t 4410u P. 11141•1‘g - F i S.G611ll1. •606114ED 6 5 j • RC.Id - - el pore • C.' 1111h11 • • • 4'' samudiCML : •••••,• 6' la 5CRErs -• re : 12 '�� l• oOrINt 9 orrTy1.!E .1 C plot 4. .. . € CaraL le +• ,. e.. w - - • SOINIn2L4 C- 1111011111 IX ale - C' •1.R 1w a4 36AL11a'4Ia - 6 iar(WILL el 48wre LI- rJG omit 1. rg. 4LTSC0 P. C- 3116 '�' " 1: - 3aM91a e ' a6.iT4Cx - - 1I• ■OUL14C11eiC•• et pestle. redrPeC ` C 1.1105 . 1- law0S1E a .1CtiuL.12L . . 4 m1,41.*L4Ca r t ■1.3[ .;..r• . ' C.: }.rLar.T C - 5a+10prati t 111APl.ar0601.1 ' . - L.' PU31. t"= thIt Il. ¢11.il+lr4 • 5', #.rDP S64r •* a C• 120061E e1.L>t Tt n• Ru14a'L+4t ' ern 3.1 Pa* • i p" 1ad165mm idle. i' e PC.7a au AM sroul.w30424.11 :1" r PUS"FOE* . - ' . I 351. : 0 ' 50004* - e ' e62101.1.1. ' 11' ORWDeaar Ls' ■WE*"ILL E !: S 8 !■«4115"• . • '1 C .•CPO 450laa•'"x. , S: 40.21410401 MI r.•r • 8/F CLaIL r .A' 3ak.1E41• _ Cr. s■Ntrr"r . • F II Prawal#. '1 '' c r01F1-12I . . C- modal,- • �u.:•.•. C` amaL • '1 c-, 3rM0*i31. - C .1O-iia p: R5LSh6#ylP.-.'' x - C: ■455 `7,+:�•4 ft 3rL r ' , .: ' 0. Sir4.'PER'•'•-r - e• col.sod. ti: 1 FBUw• - C I ■ESSELL ' - " ' !'• 1 3 .. • I.• &aw.SL! • : 0 4O0rC1 D' I 5.DOW T ' ' C I •1.5111.1* . E,' I SIL6i ' ' • €• i■wrOPP - ,r e 0/00551 . . C= 4. ruusYrl aLr • • • r= I &USILr• C. I i■LCrare1 •r a wra..CCP '-i • 0 .: 4p55trILt '�°�•..' € 1 CoL1TDM • - - - 0'.0 I BUS' Ito F`• I. IILCO 6 SpMCO C • RGO1 " • 6.141 PCVT1 C I Mall ilia lC - C: sal"p - • 6 a...10°1N.• .- e 0/42DI .L ':. C" I wawa'. " • L 1 PIA TCM. .. R'- SrLl•h1U3 : : €• Sam IOC L. - . 4,,' pi; • 466-a r F'JTJ1 14010€M - ' y ;• C I msa e- sat. rim l r1 110 SAN ILaC . - e ' !t - 6' I •a.ST . a ■ulaa - s s.1L6i C Jamie • E 81idaaaaa- •- .. ! I Nowt I I Purl Pit 4Ll<S C- 1■1.100 -. : • 6 1101.+.(PiD•° - " € 1 ■erCL ' - . •• . O I auIw"PrOwa €• 4a.l. $ . • 6 L■a"rl€ ,. E - 5a1.nag.a .IL'1: - I ram''..- . • € 1 r4rL*110 ' C 1+16111208. ' • C 5■1.Ft1Cn....•. C • 569612[0-".'. ' • I ear 6.aMS• • C I P11T4LCe Ede ea&t 1 . Cr SamirrtL - 0 o 514k111. •. D I 4061L.e. - '` C 10/#a4 - a L#LR Lrd P I. -r - C•POIawtr` - C 1 ■5464 • 'r ff 4 Plf; •#aFR .1 SELL IS*" ■ 541471 ... 0 ' 001+0 TO c i am am+ . e I error • 1:+11-L 0.11.m. - € S•NT■ CLa■a C • ■05{2-- .4'''' 0 I UCT6iLT +1 1 •r C9 C 111.+14 CJ'0 Barra i€ P 4LSCCrrG�. ' • 0012 1 Idol!■ 5 1 prof .. •- €, 1.■1.red. • !. Sahli ti■SIL • a 0/016 [fe• a ' 1; 1 eirmto* C I ■'Ct■ - C' L+LONTE • 4 Sr4ti LVC-LA . C • 04 51. Ce Cep: a "I ■OT • F I Cwp7LP■ C 511.1 C.4UJCK •. 1402. r.•la C pea poi 6'. I ■ota4 ' `. S I CTLL+1[ C 5141 L•.1E 12 Irbil kg •WMr1_. - 12 15•Se.'iaGLEr 0 I +OTC, - c I erFLL ' ■ 7.4LtaIP -a 1.10114211 p .OS!lieo*. 1 I 44+1!.00.€ r I 4ytLI.. SAL.Idw`.• S Sa*III ! i.10368646 • 4 • rbStCL00r 4 I POTO5d • a I •w#1Fit€.4 ' C tla.ttr* 15 16RTICuJIM a '''''apou Gd.':-.' a 1 a6TV# - c { myth C sikfrIC p Siwl■a Clia . e , . PoStl+10 9 I eor 1.2 DE( ' P I worts . ' a pa/.1'1■€ € CAE,re P , 0911€euaL '' • 4 1 ■Ora { 1 •Yr+r, { Sa11rOr - O shop?lane • a • 410$113.4.r :r: 5101 12128€tL.ILL E-: • le I awer■ • € SALuSa C arm/err c ■osecLe.' 0 k u0iC11. ' - 4 I •r•or a sat:.I}a [ #Frlei s • apse raT*w ' ' 7 I 0.511[[5 • - C I ■TN# ! 561.111 0 3arTO To.1aS-_ e *0501'564 ' 8 I rude. CfCh 1..114• • C S&L/UP R. .P.0TCC TIC C SIUTDML . 6 .+i ' 119;€Ladm I 1 PIA LCOM a 1 5 sea ra - C. 5■*411 0 Sr*YELL a :t'"✓� r9S€LL. • 4 J rum to ce04 i+Fahr SC{d - C t&Nem cr0 a SAOt+1K • 11, day€1...5 `: 4 P 1u!ICM ' r I tart I iampar C 56■IL0 4 iD7CS: ar0 MT 5I..64LC 5411. Culu.S SUE. aS 110.{ Ir491£a rel. !EC 6mhlr{0JUr44aI1.1€4 11T416'1611- . 'Ego1J If05 5u0■r'. S'-1-- ■LCLCCa 1.1.1e$TOallrf- serer TO f SACCIR IC iCIL 36121{S 11+1a S! 0.0 J C 1.. #414 ■aa 1.116.[1/6. A-34 (214-VI-TR-55. Second Ed.. June 1986) • 1 Exhibit A-1, continued: Hydrologic soil groups for United States soils saPINf*O a S•.TD•N C SCOTCH IS SEITZ C sHacto C sun* C s C SCOTCO A SfJTSa o socceSPteoe e sAMNIa[ C O SCOTIA a SEE15 0 SMatOPtt• C • 'AmoINGTON . 0 C SCOTT D SCEIU - • SMaL&(C C Sa•a • Saw • SCOTT LAME , • SfLaH C SHala[O 0 sa•aGOSo a SaVaDOO. a ICOTTCaS a SCLOIT a SM*LOa 0 s•eamselLle 0 C SCOTTIES e , SeLOf o N C SMaLCa - o SaaaLtGUI e a LCOTTSVILL1 c stLeess o sosLcao. Dosismo C SA.ANaC COO S*TLCS 0 SCOUT e sCLratoG( • SMALCltav 0 $ C. G&aVCLLT C S•rin svlLLe C soaOe Leas r sett• c SNALCI 0 5405T0/11 Um • SCIIIIIMIN •/O U.ICraN 0' sNalo«a e 0 savao c steano . • Selcrac • C SM4LPCP 0 saaarCN c sazt - c • ice Ise c ULLt e. sway 0 uaA1a. • 5551. • stalleaaa C SeLLeeS Cie SeaN•D e Saone a sCalaoC •- o_ scaivaa - e. SELMA 1/0 - e saaCILLO • 0 • SCLLPso a SCS* GIN c sn.ac .�,• 0 1waNOC.. ., c s•sotwta • c scaLLt, a &Cta.Ltn . C stto5 e. s5a5a5aes. e SaUOIS C Starr.. 0 SCUPSCSs0NG. o SeLTt . _ e, SMANO[o e/o SaaGemeT 0 SCat.OA.D C . SUMMIT • . • C scot.* J e • sa•fLDa C SCaMTIC .. 0 St*IIELD • , P SfNIa*M100 D SMaNGHa$ C i•a1Ta • , $CaPONIa a 5,aCRTM 0 SfN1alat00. o5a,lw5o C Sw•5GM•1,._.0aal IfO • 16115..51 0 • SC•• 0 SEAGATE • •/O SCNINOLE 0 SmangLCD a SAUNOSa a SCa00000 . 0 SC•GO'ILLC . D StUPSD . , ,.. C, &NANO - - e r• Sasp -. • SCJDIO 5 sewn. e OV a SS• T , S. UN 0, SN Saes, a St C Seaman P 55NC5Cat C SMA0a1IM e SA/TELL . • SCaTLaSS _ 0- 'Chose. ST10MGLT C SCNECAVILL[ a sIaotswoLT C SaaUCHe - 0 SLAVE _ C SaLINC •.. , e 0 C • SOIaIreM•Rea' • acaNao. sooeoavttr C SUOUa,TCNIf e S e sasaucuaa c s - a !KT $govt0 ��! , a SM•5OM e• S•SCO S SLwaral0 a sU•outl? c• SE000ta 1, c SwaRDNOat.5 e . sass. ., - . 0 SCMare , C Mao _ e 555055 • a SHARPS C SASoa-MCO _ .0 SCMaP11ILLe C• SEA•INC . - e SMIRK C Sameose oG • • sASSU.as - e SCH*TTCI C ICaoLa a SeooCO ■ swaDDTy• , D SASf[a a SCHAUSON • - ••. nutlet C Seeells C SM•avaH* . C• saTaco 0 SCMa•awa 0•. seea e,- 0, Muse NTawo.... a SM•SE0 e SATANKa c SCMCNCO _„ , 0 11 ILL[ ; , 0. SSROO • - ', C s5asell. C SaTaNta 0 . $CMS•aaSD a seat - O. 55.5..10 •o SNASTa ••• S H D. SCHI e, , .. a Tarnow a 5(055SL5ta • 1MASTIN• e SATELLITE C SComoTl - C IC•TTLC D ',MAW. •. . C SM*TPwC( C 5ATILL* - . D SO.NtOLT• . 0 11•TTLC. Oeatoe0 L 5CSP( ... . C SHATTa . . C • sane • c ICWNZIDea . • at 0 StsSION5:., • . C SHaTTIICL., , • . 0 'ATS00 . • •. sow.;weEll - C, SCAM ILLO.• . • MINN - D SN*V10.. , . e SATT - - • c sc?.NoOssos C. se•ac0 . • - 0 0E7 .. • C SMa.aNO . e SATTLtT , 0• SCMHCISU$H. a IAN t SETH • C c SA T TIDE . 0. SCWCDSON • . , C- Sera sMock,, . c sfTTeas 0 Swavto . e SaTUSN -,. . e 5(501115 . - • stet•• P#0 sETTL(NtNT . _ o 'mama .• e 141 _Ms . • SONDE IELD .. c SESAME . . c scTTIeNETCa . ■ C a SAUCeL • •• 0- SCoOfteoIt . c SI••ING , 8010 s5Tt5ta5TEO.,, o T- e 'auL2e0 • c S II LE. • SEIKO a 5aLIK- I SiuT , , 0 savor • sca000tc - o mecca .. c seeeLeet,Ep. ,, O S5AT5a 0 SaUG•TYCI • C, ScNCOLCaaPT • sects., • P500050 ; swim, c SAUGUS .. s 5 400LE1- 0 •5CONOSET . C s(TTLE«ETei.-Cool 0 1Mea.ILLE, D SATK a SCMOOLIV. 05.5.0 C 11(55? Clete( • SETTLEMt Tits,•• r INSPaNG o sauLICM o scummy. C mecusITT c csaNIt1L5o . $550505 c . saw S e • OTtcleo • sec c scum,. c '55041100 C savorous 0 sc•.DOangemt • • seta.( 0 S55?NNILE a 111(00 c 'a11MMN . C SCHOONC• • • SeeSErteLO C Stye** ;,, • ., a 5N50Ho*-.; 0 seuTE0 • sc*u OS• G $t5Gu•v _ E stet(. - ,,. • o sMSec•a e SAV•le • scum.. 0 seo1LL0 , e stymie o 555105 0 Sewall. MOOe•aTSIT C sC•.cle•• • seoae• a See, a Sweet e GMT SCM•OC( a al0a0m00LL5T - C sausage . • sweep comes C Sava lg. PSOTSctt0 • SCw00N • sew 5.5. C SeUa•O • a SMEIPCAI • Sau.ol• C SONvILtie C 1EEDSooDeS 0 15.515 C 1M1t Poe ae; C 5•551 s. • 10.7515E - • $U4.?1 • $(L 0r; c/O a151P•OCS a 5av*O5 • •- • C &Comm•CNE• . • 5 51011551. C 16404,0_.. .0 suer:Scot ' • SA•*GCTON • • • $0 ,5Te8 • 5e[ST5TILLe a/D SIENA 0 SNCCTI•pw C s c 50:11,558 • SEELISv,ILL1. o smug . • c SNSrrltlo..•. o Serene( a C SCIO • SLOPING • 5N •LSIS 0 Sorrell' 0 • $1.0 c 1CtotowiLI1 c scream a swigs • swer*Letw • e savor:. • sets. C fees c SNaDCL*ND c 1«[5.1.5• • SA1O1• c SCITICO c steote a s..ao1LLa, c sMtLeUDN5 c savu5 0 SCITWTI c serrat • c slump*, . e SMt.5T 0 sauATCM - 110 %CLONE . • 51G1OAL• - 0 aGOOVE ,, C 1MCLP.TV(L55 • e sae/Duct a scoop a SIC•10 C SMAr/TOM a sot LCI- 0 saucing. C scoot* c SCGUIN a SM*PTSD 0 s«tl5 a • S•IOUST • SCOGGI. o $tcu•a 0 'SAGA 0 SAM&&&&a*Geo • — sow/JILL 010 scoot, • 5 ENO NE C SNaGa.ltT. C sNCLLSLUFC e - sa•Tel. C 'carotene, • setae*, 0 556.•56. c SneLac•eec c S1•TCLPCA. 0 SCO•uo - C ISIS C C SNCLLOG*1t • Notes: TOO M,oaccociC SOIL GNDUPS SUCH /IS 5/C• I•01C•TES TNe oaaIveD/Ul.daa 8550 SITUATION. ROCIPIeSS snows. L.G.. •5D5OCC Sue 1T•aTUN. able TO a $ CCIIIC SOIL '50115 05x55 POW.* IN SOIL maw LIGtND. - (210-VI-TR-55. Second Ed., June 1986) A-35 • Exhibit A-1; continued: Hydrologic'soil groups'for United States soils SN[ILRDta • SMOTGU•. .i C : 1tNON - e • Ss?NICM C sW0*0•NCC. - C SMCLr•OI'M_[ 0 •S«O?*ell 0 SINON• C 'RTCOPISN a pain••TCLY weI SMCLOCII• _ e. S•oM.S P 111M0w1N a sort.ICI •0 SUMMON 0 - SMCLTON C 1.O.atTe• _ c sIMCNtOM ! Ss.LIK •D IN• ' • a swat.. 0 SHO•aL TER. $TOM. a SIMP•aC• 0 SITNDR V SMO•NORC C IMIN•«oc•M 0 SMO•l0m c s,MP•Ttco a S0t.0CC 0 SW1PO[ 0 Spin_$ 0/0 stone a ssMsON ' c • SEITILL•GP D SNO•SLIDe - e ••iweaiON a srwe•O!• • •`r • I Sts • D ' e swoop.ILlt • -- O SMCN•ai ' 0 $.we*se.iRT C■O S Ira I ' ' C sue 0 - MU//UL C SNto a SKI INC • ' e SINaMOi 0= ova e . e SHCP•« C swot 'C s tNcL•IS • c • $l•te$ C s0•PCReea C w SNCPO•RO - •• s. oulS •' 0r sINGITIC • 0 StaGLC C SO LPL*AC 0 SHIPS TER 0 1w•11T• C $t*GCDTON a SI••••CE - 'e SOt0 '1 0• s.ICUwO ... ' SW[ C $INGL ` - C • SLATED. C C . 10018a • C SMC.•R -. c SMUS•SN " • st«cs••s a" StauicvCO C soap•• sHe•auRNt ' C SWRSaw •` '_•' c Slates ct suuGN?PDTI4lc a waot -- • C swill ID... • .' - e` $WI[ C alas SO■ - • e " C SOaP•Mir • a _ sN[Rlesi r- -'1 w SM .t.I,U•C , • c si oc *•' '• "'�• C ',Lay - C LOOSDM C SPIT*LOCI a 1Wpl• c %titmice •.-''<.V. - a O SO[O•RO • C• 1410011! 0 SWU*•T D SINNIGaw o SLCa.aa - c SO06 4 a•si.LitlO•t '- - - ' 0' 'SHUNC01-t' •A•1 •• • C. sINTD* • • e' surfs - c SOD* LACE. ' - 0 6,4[001 5'- el" SNU.IC•• •>=i''' ' •-• S!NW •' • D sl lcc•occ a soo• Laic. vet ' c SHC•s.. &Tow. ' e 1 s$Tao . '"°`- ' C'' slow - e • SLte,CRees - a • SOOI••T - a smarm TL - ' a S.•/TILE er SIDU: ' • ' ILIDCLI 0 • 100-SPRING e a< - � 5O000000 0 $I C StOU:D•. • a si saws$ c ` soDEPT ILLC - • Hl.LIN '1`.'• ' C stet&ta'1 "" a IIPPC[ ' - e•' sltcitaw ' • c soowouse o• swtoLeo ' e'•'•.' O $IDLE.' ••• •- a stose, a striot ' o • soous • "" • C $Milos V C' st•leiPILAY'e - e• iT " V '• • • sLt. UTTf'- - e'• sotletos r'-' - e SNlrrno - - - c stomas "' '', • •ro slot • a seest '" e'' sac, c situ.: -' ' - C slc(LCSIP[Tl'° a $loo co - • •,� slimmest 4 • c' stT►••cc ' '`'VJ'1'4. a I sort• ' •-'' c• SWILOTT '"P'• Aro $1000■•• - • • S1R11e0 • 0' SLIP*&« ''' a' sorTK••eai(••``''' C• S•.IN• ' C SIDell - "' • • e"' sl.PtrT• '• ' - ' c SIOaN • - •i0 SorTsco•ebie•• a two wON' ' C !1 . C' 111L C' Slo{rt[ • - O' R•Re1T../�00000' fN tM•cU"'• " 0 $100 ��' C S1f[t.pU • "9'' P4 1LOCYM CV. SoGI C / '• SNIN6••• ''•' - 0 Steat.i``•+''' - ''' a $list TON"j' •"• L'• ILUICe ' - c SOON 0 SNINDUp ' ' • c sleet.: •j`-'�' •= stssoM' , '.1 ' • • ' P" $11.x• • C SOSO - • a• SNINto C snot( •- '-.14 ' C• sisre•s. . • - • IL. 'b" a- sac:se - a• _ sat tact. ' • 0 stele' - _ o sit•• '''°t !' suacsOU, - •• 0-' SO,4a'P. •`-•' • a• SNItcLC.itL:• •`� O SICROC.off " C s:to c*•• • •' 1PAtl ' ,.. C•' SOJUD • • • 0 Sp INCLt TD*N 1'' ' - C 11!D•• "• e' 'S'IPEs '_•''� • C' sR&IICONt -'s'�' • - o' sOlas - D SHINCECT ' - C steaRa•IL =+" 0 SI*elt '/I-" ' C• 4N►•ri •'•I"" 0• $Ol•NO 0 " SNINNPe•i ' ..-. 0 Sltit• ..rp.�e 0 sta•e•eow- • ' 1 a' s.auG .-q •" sOLDa TN• - a SIINROCC'•'' C Ste•CO• ` C' Sta.ILC '11" ' , C' SKDLCT''= -'''14" D' SOLD HQ • C SH IOC TON '' - • C Gtr TON ! silt* •' • 7 a' stet.re pc.- Ct sOLDUC . - 0• SNTOT• '1 • SIC '�`' " 0 ss►401=''C C' Sulit• ° e/D scico.o - "=" e • $wrote. 0 SIGNai' C Scat'IT e- - 0' s/ILp,Ttllt^''--" D sot.fro 0 twirl[•.' "-- • - c Sicu*o' a OOOOO•. • 4 e. 1*ll0 `•"' C SOLIS C Sa.1NC- I SICCSTD.. -- • VO taut& •- i' sea TM•D•O • • O- SO.LCSS C 3MtIM& 0 SIL'af • 'f •• It a sotsswo*Le --• a S011to - 0 s.•IDNocg - • SIL"lS. bat-* ' • c I. -• • 6PtT.wrCIO • c SOLO - C SMIPS 0 sll-at. Ga`ivtlit C s1•.0 • • C' SuIt.•TaC1•. o0aluta a s01.o•ou• -• 0 SNI►SNt• ' • ' 6 SLIMS Ta•,t U+ M C ttNTO O N ' D. t0. M& _ • -r c SWISS - C SIL•w• • Semi ie • ' O !•-sritNVillt-' e' IDLN•• a SNtQLet' a StLCO: `• e t ent • • a Mltw*ICs- o - O soasowoaO.• • o SN/w0 C 11LawT O •Lr0.00Le o snooper( C soaswe•o C sMT•fI•il ' a SILA. • ' " • stases D sWOtt." • C s0•t•S V ' r 5 SIN MC l.•' a SILC•TON a Sat LI.CCa• • a 1wet.am ••• -' C scat owe Lt.-•' - 0 $,411,10.4. - '• SILNOU"ITC ' C 11.11.8101 C Somme. • •M so•scM c sNINLu• - 0 1ILI C SKUTTM. a SNAG a SONaNsi•IL a S.OaLS c st1.51t C C SWMDPISH • - 5 IDIDO• . . ' e SMO•T' EL 0 $ Stt° • sslre -" • r sweat C SONIC? - • 0 .-. SNOB• D Silva C StS00006 • 16156 4O1.1:0e' . • swot an _ C $.Orris C lILwe• 'C s11NMes r MeceLus . ' 0 SONOIT• - a swots YRINC - '•• ttiwe. Cotta -D •5t ,� a swine. .. e •Oao*a -. -. c s*O1eN, 0 tl1wt••DC'' ` • •.100Pa' 0 •1600 . t C •o:ow.. NODtSasame is SaONa1M 0 sILwe••cLI. c sctwoU ' ' •• O swap - . • D Ott. SALIN!-,•• s*ONti. -'C 'morose. _ .7 $I L0WISN • D Sett/PLIS' - C 1ONDe*. s•L1.e. I • sNOOPLIN 0 11Lwe•CNItP ' ' c ewcwo;1iN. o.AINto c $Melt C 0•aIKD,-.. MoorCt 0 $ILTPSCLIre •a sack. a •wet.LING • • • • 1OMOM•. Stu,1►Ito 0 SNOOK ' C SILT!IO&t.'[' • S1oOauP C •KLLNaw - e SUBS TR•Tu. SNOOCtO ' C 0ILveou • ScOS 0 SN10e0 C 1O-DN•. 0••turD. 0 SMDYCCK C SILwrSTON '( $•0uP!G•61 P SNOMO•ISP 0 SLIGHTLY SaLINS S$Oal•000 . C 511.11$'' 0 'st.& twee.. C swore C •oNOw•. ow•tato. a SMON1. - C StS•s C • SWI•CU•C• C SNDOa o •1000tD ..• SMONI CRetti C st-COP C ••1111*•C D s«OPOC ! $DNOu • OR•IKD !• SoDOTCDT C SIM[ON. 11UNPeN C PNODWLuIf C 11060** - 5 • SNOPTNoIN' - D stattOI 5 viola. C SNOOO*N a SOwT•G - 0 swo•T.Oo& _ C SOMMOIT c sc.Te•G • C sWO■ a soo1•0c a SosSNONt C $IMOD• C s ea C stereo mace o soON•Het _ a • Nose. two NTD•OLOCIC SOIL-GROUPS SUCH •S a/C NO'ICitt$ are o.•IKOIUaO•atNeD SITUaTtON. - , : - pool!1tpS sw0*N. 1.G.. OCD•oCK SUOS'I•TUN. PtTe• TO i SK CIfIC SOIL S[PICS P*•IC Poua* IN SOIL' Mao ICCCND. A-36 (210-V1-TR.55: Second Ed., June 1986) . • Exhibit A•1, continued: Hydrologic soil groups'for United States.soils SODN•CCP • C SPINCKOO 0 Stealer E. Steusta S STRELwa. SILT,. 0 SOOS•P C SPINCC00• SaLINE C stag', a STEVENS 6 SuesTD•Tur SOPEA C SPINEKOP. C'' STaFF000 C' STEVENSON a STRC•Cll e SOOVLL a rODEDATELT. NCT STAGCCOaCM . a SttsaQT 0 STSICKER e SORepSEN 0 IDINRS - • • STAHL C STtv•aL. 0 STOICKLaNO C SORF C SPINLIN- C slat C STICCNCT - C STRINGaN a 1oa.ENTO S SOINNE• • a SIaLCT a STWDN/M 0 SIRINGTOAN e SPITE° 0 SP/.es O STALLINGS , C STUN a STRINGtOAM..GaaDED C SOOVw 0 SPIRtt C S/•M0•YG« a STIGLCR D STOOLE C SAS• C SPERO • 0 STaNFORD 0 STILLS C STRO■ C SOSTIEN c 0 SOIVET e• Slam. 0 STILGaR 8 e SOTIN D. Meow C StaNOCOC 0 STILL a STRONGHOLD 0 SOUGNt 0 SOLENDOO• • C STAN 0 ST14LM•N 0 sTROwGMUa1T • . SDuL•JULL. .. C SPIITEN 0 SEAM/LET C sir LLNaTED 0 STOOUPC C SOUTNaCC 0 MI/N0 , . 0 SIANOUP • • 0 STILSKIN C STR011 - C ' SCUTMa' 0 SPLITTOP C STANET • 0 STILSON • 0 STO•CH 0 SOUTHFORK 0 SPOFFORO •- • O stawp/510 C enema - a ST•TKSR C SOUTHGATE.-- 0 SPOFMORE C; STaMI$L•US • C STIMSON 0 STUOOLCFIELO C • SOUTMNOUNT• C - SPOKANE •- Cl SI*MISLaui. NET 0 STOICS 0 STUeSS; C • SOVTNRIOGL 0 SPOKCL S. StaNROD - . C STINGAL 6 STUCET 0 SOUTMNICE C • SPOMSCLW/ e- S1aP•LOOP a STIN0000N 0 STUOCO•KCP • SOwC•M .. 0 SPOOL 0 STAPLES e/0 STIPC C STYKEL 0 SONCAM. SONENw•1 C SPOONED Ceti $ta'LCTON 0 STISE 0 STUMBLE • P000LT castor.") SPOTS YL,a.I• c6 C ST•PO C STIRRUP a STUHPO • 0 !Oka . 01 00,0,108000' 8 StaSOUCE 0 STIRUN 0/0 ST/morose. • A space CUT.' • • • SPUMES/it . 0 STaRGO a STIOUN. 0000E0 0 STUNNED p some - 0 Soma, , e STARNOPC • 0 STISSING - C STUN12 - C • SOAOYa IS So.CCCeL1 . .• c, sT*RICNKOF .. D STI.LRS•ILLE • ' P' STUaGEON • SPAGEO - 0 SPRIGGS - - C. - - • C STDCSaoC - Oro STURGILL • 0 _ 1MG . • - •. 0 MOOING - C . + C slot's/mica! -. C STYRK It • - - e 10AMa 0 SPRINGDiLC stoma,iilt • STQCLCL 0 sTUTTGa 01 • 0 SP • a SPRINGD•le..STONY a SIa.wau 0 STOCCLaMD , a STU - C `- .J - • 0. Sp0INGtR . 0 STaRO • C StOCCPCN D STUTZMaM. ACT 0 • , 10aN4 , • e SP.IMGER•ILLC 0 ewe//OUT . 0 %IODa - a sTUTZ•ILLC C ' •., sP•MGeNeURG . . C SPRIMGFILLD . O st•seo., a STOOK[ - 0 SEVERS 0 SP•MGZNSUSG. 0 sM INGGYLCN e - e !T , 0 SYTZ 6• • • SPOINGL&Kt .. . . • S/ATCL*NE 0 STOKES , 0 WAR C ' SPANGLED • C SORIMGNEVED, . S StaTleR . e STOSL,%. - .. • S SuS•CO . o S 0 SPRIMGSTELN . C s 0 1TONa. . C SUQLCTTC e SPAR«Ar 0. 1.w INGA•TEO. C st•.CLT a STONCSCRGED o SUBLIGN•- • e SPaACNULE ' O SPODUL O SUTTON r sTONTSWIG • ! IUSNELL “ 8 SPIRNO p. SPINCEDALI • 0 STC•RMS D STONEMaN - . t SYCaRNOOCHCC 0 SPAOO . - C! SPUD •.. C STECO.« • • 1TDNCNE&D C SUCCESS • • AVAST*. SILT? CLAY O IOUDOOCK • C S,ECus C STDMCLiCt- a SUCCOR 0 LOAN sum TTR•TUN SPUMOUS*, a STEED • STONELL S SYCNCS • • 1PaRTa. LOAM► • • SPUR 6 ST 0 S.TO650- .r 0 lUOSUST,. • . 0 SUOSTRATUM SPUSGEO' • C STCEDNAN. STONY C STONE•ILLE E SUDDUIW C SPaRTa. Ma•T>SO • SP11RLOCK' 0 ST C STONSNaLL" C SVOLt? 0 SPARTA. M•aiCSO a SOYAL-iCUN 0 STEELS C STCNE05LL • SUDYOPTN e . Space•. 8EOR0Ca • • SOYaLLT- 0 STEENS. C STONO ./O SU!PCRT C SYDST0AluN SOYA. . - • O svecpciN D STOINYNOND • 0 out• 0 • - C SOYa.CREEK• • 0 STEM 0 SrOMOOa C SUFFIELO . C weasel C SOUaNVOC, C STUE.CN S tSTOMOCN' S SUPFOLE - S ' - a SOYaRTIP : C STEP. C -STC7L• O SUG•TOOL - e SPEAnrisN 0 SWTRCS -. - C ST[GALL C STORM TT • SYGaR.Dim .. 0 SP!•RMCAD - . a St. •Leases ! STEIGER • STOUT. . C SYGOROCE - . . 0 1PCASN•M 0 St. •NTIOM, . 0 STCILaCOOP C $101155 C SUSaRLOaY • e ELLE C 11. AUGUSTINE C 8T51Mau58 - 0 STOUT 0 51151.0 e Specie • O St. •UGUSTINE. 0 STSINSICK p STONNO • C SUISUN 0 SPECK • • • 0 OwS•p IC-' Sts IINS.URG c STONE • C SYl• e SPCCTaCLt C S,SST.aTUM • STCI05R C STCVCU. 0 sulll•aN s SPCCTEr C S1. CMARLE$ 0 STCLLA • C STD, C SULL• • SPCEL•al O St. CLAIR D ;1151.1.AO • C stRaSCR C 5Yl0AF p SPEER 5 ST. ELMQ • smote. - • C STRaMa. .R suLPNID• D SPEIGLC e' ST. 51 .G! ' e STEMILT • • S sTaIGNT. C suL • , 0 D 0 ST. 5C 265C. 1SLINt C SttNlt? . C 5TR•NOl155 a SULtaN C SPENC50 • ST. 5(0651.-6et 0 STlrPlE 0 ST•5 0Uts? ./o sows 0/0 SPENLO S ST. NELINS ' a STENO/EL C . •• S suM•S Q SPINS • ST. IGMaCE 0 STSwomen • C A 000 0 suwaTe• O spews, C/O St. JOHNS S/0 STEPHE NVILLE a ON . C SUMS C 1Ptia*TM C ST. JOHNS. .0 STEPPOCK 0 STRAIT a Su.NCS►ICLO . O SPMiNi D OCPOESStONAL STCPSTONE • e STRa.M . 0 SVMNERS p • • SPICED SOO ST. LUCIE • 11EPTOE • STRe•tos -• D/D SURNESTON a SPICERtON O Si. MaCTIN D ITERLING 0 !T0011.«• . C SYNMM,ILLC 0 ••_ SPICC0000 C ST. HARTS - e STERLINGTON .0 1T0CLM•. 0 SUMMIT C SPICE a ST. NIPOL•S•- 0 STERRETT- O L•CUSTOIME Woof I•ILLE C • 1PILLCO 0 ST. ONCE a STETSON 0 SYOSTCa*UM LUMP/ 0 SPILL•1LLC • S St. PaUL 0 STETTED 0 ST.ELNA. TILL 0 SUMTED C SPILOCK 0 ST. TMOMas - O STEY'SN • SIN STO•TYM SuNIER•ILLC C rotes: ,N0 HYDROLOGIC SOIL GROUPS SUCH AS S/C INDICATES TNL OSaINSD/YIOS•IRED SITUaTION. NOOIFICRS swamp. E.G.. BEDROCK SYSSTSaTUM. 05'50 TO • SPECIFIC SOIL SERIES PHASE FOVNO IN SOIL NAP LEGEND. (210-VI•TR-55, Second Ed., June 1986) A-37 1. �. . Exhibit A-L continued:. Hydrologic soil groups for. United States'.soils }WWI& 4 1-axrO04 ' - 4 I 1a€u}a 17= fseek7[ 6 feMFxa • .- C }EMI O 5-ath.*ILuc ,: C I 1aCua.IC - C.6 rapier - 8 re 1.151.01 A - iwxarf€ • ' " e S■axM1€I€ - 11- 1 raC00514 - • tea 1a•111Lu5 r• 11 . #!I6!* { Swab vol. 8 1■*Ras e I tact CPC= - 17 7a•111Lf. .'x {IC EE.411 0 awe Wa$T C S-r<OT 1wOL7P • C I Tif,Or .. " . - 6" 1 Mew iA a -s -- 0 1ua1¢lJ4r 6 5w4RTI ' .. 0 I tarela £ 714E41. 04a1ME5 . C e SNUG r Tr 4 1.2455T 6 I TaF1 C 74411ri RD C . T[c!WINE.:. e su4CDoc • a y*43TIe■ c. 1 T 6 lime 6 ire[LSGx .. C sign C Sy 4i1F 0 I TNi..1a - • a 1a*CO O rSa :r• I SLMPiM[f 17 sea*ei[ C L_14GG art T -I: C 14444 6 C 111x641. J. 1■E AT MAN .: t I 1■41.+4r .. a ta*ICT CIIES .• D iEKOa• Est e • touDELL 6 #TIDE I r 1a.lEENI1ta* 4` TaRPa.e. • elm} Sloxt 'woo.. a scrim .- C I 1 awe... a rasa s- tEU 111xe• a SaCemew' 6 I 1ax01Jla ' ' 4r' T451054 a.. TELCI'SL • e SLEW I ELL a 'weer C I 1axOVa T5 , -- ' 8 T*RG.•!E C TELcciR - 6 sHwL1 cm.T '• • 0 S■EeE.150Lf*" E I 1#1x1611 Cns Telex I4GTON c' TeLf/17114 ' - C suala vim r 6 1■EET GRAY tS - e I 1a,Ia C. TaRt10 4' TELEN'eM• 6•SuyNrglaE 5 5'wet WA!tr. 0 I taefwCxi.. ' C' taeeL IN • ' ' C - We 4 1L1r./T*4Lf'- • C sae I TPERG e. I T se'IL-xa'., r TiLCPC L..7?... : 8 , TEL fSCOPf4%'' ••• A • ' a Seel rlag.. - ' ' C I iaaeln .1.. a - E E+0x sums ISE ' C '1[N .7.'}.• C I 11'a4P6C.ia4 - a TarRwf. f. . e T[L..PUER" `• ' 6 SL7aFS[7 - 6 541.41004 . -1. L TihaC. 6 I rast.e T P TELL • 8 M S 4 S N I M! • C 1E0E1 e I T aLAP.x1E5. '� ,- 'e- lanai SUNS TEE C 5Y1FT CriE!¢ .• - e L Taiax'e r.• 7MP-eel '!ter 4 TELL ICC ' ' e 5.1011.1a - ' "' 'a 5011010M - • e I t 1.L a.US'. .=A' r TIPWEfe - . - -. 6- 'rELLMaM e• 'Whir . , * SUIN4e•E C I TiLeo7T T E. 1 C TEL4up. - C 5.1414.1 ,. * C S*Ir5 t e I T•LCC ' .• C. TAP C' 'ELPS - C 105 •• '5 '*1 NG Lea . , • . e I 1ALC87.T_.'•' Wee fisa Tr< . - C TELeT16 ". C smaaM - :LI 5.1 MGL*Aa-.1Fe r:r C I taL].Ira - 0 1a#C45. • , ' E-! .. e 5 5.1aruroe . 4 STRONGLI.:S4Ll4f 1 1 . a•4 . 5: 14.355E • ...... . C. Teweibe - 0 5.6,ReRSf1T.r6r- a 51.gbaLtp. •ytT C 11*LLa f. 1a55E1iIau�:•' •- ' 0': tece5.caI. • 0 • 10.011/11.11:°: C 5.4xe s,e" r P I 1 RCA aL --'4.= II' ..11/11.0. :a; •• ' e- TSNP .. C }VaL{!.•:.• b #furor rim • . C I laLLiP!GA '+1'; ' C" 1a1A1 - - ' C'= • - { • 5.111 C SII.1T e 1 Ta4Lagents+• C 1art. .:• ,ry • 6. 'revel-ETON -• e ( ' _-- 1 suer ilee a Swtio00 ... sT - 6 1 1aLL1T.IL.i•e-• - e• 1aTIPKE4c . > ' P Tf■r1E• - • ... .E • • soli 6Kr c U-ttt+1tc0. ••,'.- e 1 raLL52401 C tat ITet'-"• '= -^•" c.. fe11460" .• • - • . G 4101C.h. a SwlttTU4 • . 6 I 7aLLS - • E E414114-; ,'-,. ' P Tlalfxa . . e .1616.11.0. • ;'-;. '' , 6 5*1 t - 6 I T'L4WLa - - S' TaTOI,IE1 -..._a..,,... 5. it MaS a,.. . '--i e . swar,Lus - .- C 1■2 7{r'4arr C I 1a4L4 t' 1aTIckl. ... • 0: recce, , CI • 51.'P001SC ' 6 f*ITXEPLaiwt},-k'; . e r 7i0.raGrt ••. 15 ra7414""' - 57 TEi■4D'! • - Co • %wart ale,.:.-h.. v 10rC0t : ;"t,. C I !.-ID • • , 4 TE4Mr1a l C.. TS4IEO f'Pt... • I . moat 77 C 3•05,41'I1'L'F tia . - •C I 74L•G01 - . . . C r. f'INEP F ! r yak--!14155 • 6 S*'c!D1 ' ... C I T aL6+i - • • 5 ralwaw C. 7£941010 4 . C lifawIa 'C i*b L Ox:" 0 P 1411/• a 1-045 a/'4 ..re«ccLe- C • }USaKxa k Cec 5TC a•491. ••'.V!'- 6 I 141.11011. , rep 7aY[ai •' - . • • C TEfllr6 - - . 0 41r1.4..111.4.4"- - • .P xgOEOa!ELt.:w!'1. I 1aLuer • - 0 1a*L41! .. C. Tlxa5113: , I Su#IC. CRESS. C %A41xf ! • . I 7.-.a' - • t 741/145 CR!ES'-i.... [ TewnT. S • 54,41T1.a . -� • P 5.C&•CS4• . c 1 1aw.Sr. - , - O 1arLOPT.1,L CI''.-.••. 5 7'ENP1a. . 4 SiM.r1We144wial ',.'.. 6 044E-1Ta L• 115X • I 1APa LC• " 4 1a*Eels/~47::11. C T!-IP+c..• u ' 'Wta - P {L4w'r 5.18#r.uarur I .+.ILaaI5 C !ALINE-'Lta4.I' '. 3ilr[LI!s •6 'Tear:05::.'. •C 1 Iaea.1;Ea . • e 1aTLOC9wILL'E- • . C 11E550 C 5611.450 .1 .14•.'.1/f 7 . 1 1 ben IL 4 1&ZL lira, : - t a', re rel.LC5P - 6 SWEx[154i..4Lv' * Cr 5ccaLmo.E-.-.C4A1MC0 f ] 1aP!t' t 11ii11LF. -r C. TEN#04111 8 sirpmeOL1. C oLe•' 1.00656 .1 1 rile,La 6 1Ea!!4w - . L• 1ei.1t'CM * . 6 iu1c11• . C. s7CAx5PE... Cear !1 I T War O4o V tlrL#P!. .. o ICE . E• • IUTLL1 5 i1.161.TO41i.r'" 1 7a-tl+a.. 'OM ft.' 4 rc1*w41.1. or tEe{uLL.5 5 SVEPwEm• '.., ., SlCax • . A I 141411 1.6 ' • 4 IIIM441T , P T! - . , a SLErpo C 1 weLi . ' .1 1 4 f.11 - ! Tievir5?a ' •fa turrtirP .p seCCLTee '-- • . P p 11•.'aice . • - ' e .Eris■01'. :.., r 5. Tie AOa e ivTTO.. - •• 0 171.1 Te - ' .4 r 'art■,.-' .• . • 6 lea5000x.. , • Co. Twee 1E1 .• -. e . •. -6 56104610.• a I 14..4'1 . • P 11Pa• - - f 11.■CPCE - . el 1 ;eaE.ef ^ . .w ',LEO c I 1 4. Ey44E4 a 1enii' - • ' r If*CIA R 1■Ca S irti4a•t • '6 I 141140.1. a0OIPa'fLT C 1150 . . r. lrtI.0 • r a S10E4r5 11'" - e' f1. L*i.:liF C I EC .• 1IK1441161..: •. 6 1ERL*. . 4 - sx.100iUr - P %TL* • • '! I 1/ma Ire - it Irbil 1CI • • 4• IIPLCC • • , 8 1.1+61'' C 111..*1/'4 f i 1ixa/ja f 1[{0 f re Pk.1AC.L.a 4 11.1.15. :5 `E4C5' - -- ' C 1 7i4,11 ala C .1tC6kOTe-..;:,. E T!P-110rL r a C •0 S••r.TC. • I 1 1alI0. .6 T#Eaa4 13.-. , o TIP.O 4 So-LC: 5 Se.1artd!.• - E I tat•.«- : L rec6+a.._ . • r 16•0porE - e 1■aLE5IL*E- - CF 5•0aCId1! • ; ' e 1 Tawl' • •• C rebeem - e TEPOVG[ . C L " ' liaaa ' - S k1/15!15 - row 144Gilu . - C tiEL a rl.Pa Cr ii 6/C %ea.. 5 'TQL!1T C I 7 INC.I- C tett@a': ; . . e. TIPS'. :e La. .1lo&L P S*i NO 0'. .0 11.!1CNtOI4L: 'C I 11.441E • C TEErII. , z p 1/!..E Ce1a. • • ■ ••P••]' 6 1E!ROr4'.: • .04 I Salty• a 7EE STD. -- . 0 Iftoue1041L7 }.axe a'L 4 14CL1 row.1a lip - '4 • L farm a..I'LL .5 11E TEAS C 14 'f }.4xxE11 P 14{.154 5 I 1ixwl al ... L 1e!*.11IQr. F TE4P4D : k I!. Sr 44511 • 0 I 14001 . 0 1 I4....£°• 40. P tier 10x C 1E-PETQr 5 14•ts Pt - C 1 I aCiPl - 6 I PRE i 11/11*11.0x .. tee L_C . . 4 Te11+C ram..510x1 £ S-aarLr - ern! 1 4a'41 - `p I Ta44! - F Irxaft.ao1 - , C Teel IL • 6 wOTES: I■G wry D4018GLC SOIL r.POuri %1TC..' +S e,c !x4}C■VC} 1..E .u04Ix£6/u.P4tIPf0 S11N111P.1. . . . ; • + 1.00lPIS LLLLL. 1/.G... utpFP;- Sue'5 11Pa1L.... #i,EI. le a SPEC 1►SC lox,.-sec Ic5 ....se,1/11111111} IN .1011,-,!/41.0 LEGCI- -38 12I.O-VI-TR-55'. Second Ed-, June I985} Exhibit A-1, continued: Hydrologic sail groups for United States soils TEe00 C I IruRLOKI C ,L.TO►I a [C1.KC C rOSSIDO a TCOO. C I IMURLOI a 11N.TOr.. 0 1OLUCA a IOSTUGAS 0 tent D, I twaraa a TICCaaO, O TOL.aR a TOOULL 0 Tt2.ILLIGe11 C : I taaaSaONT a 11044 a ?Craw ! 10$00 a tTsaJO a 1 105005 c itvaaw e. C tora.arc a TOSS€° a fessrl.e D 1 11.00$ 6 t1DP[CaNOE a toNaLtS o 105100 C TETMPICC ! 11ta1 • C 'meta C Toreseet C Ta16.1 a Teta,. C. 1 1106$ 6 TI a TOr5S1 C TOTEL•CC 0 1(10016 0 1 11001115 a /1551560 0 100061 C 1015r a T(1OKCa (001 115$ • C 11000 C TONOSTOME a 10th° C t[T•}mv t1.. 0 I 11]SOm ! Tj 'oo ! 1651[ a Toro _ e/0 _ TETOO.ILLC D I t10000NES D TIPT6w.IL*C P Toots 0 TOTTEN CIO TCTONVILLL. C I TIC, 0 TIPTCP a TONED• C IOUCNST C I riot. a 1100 C T00Cp6• CC.I'TE0 0 10110[. 0 ?(TOIUr C I ',CELL O 11!!110• a SUa$TOafUM TOULA C 'Evil, a I T1C0r05 _ 0 TISCN 0 TOOICNI ' a TOULON 6 Ter C I TICINO C TtSDai( C T6035a 0/0 TDU011 C tt.6 e. I TIC'IPC0 o Tts$a0 a 10001:1. 6/0 tour..outs) e Tel a l TICtaSOK a 11501116 0 ?Ors C twos a relaNa 0 I TIDING; 6 111.001w C TONSNE531 _ C ToUt&E • 1(6.05 D. 1 1100(1.1. 0 TITUS !ID TOOT♦ 0 101111.[. 51.00050 a lit al 11.E 0 1 TICOOa D TITUSNILL[ C TOOalea C TO.ala C TE500• 5 1 lteaPaatGPf a ?LOLL a ?00•$0[1 a [Ora.( 0 Teruo. C 1 11[510[ 0 11.1 C -TOMil• 0 10.011 0 ?MACK!° 0 1 11510$ !. tf.• a TO*Cawa a 10.11[5 a ?w6CT.E01 0 1 1155.5. _ POI TCa0Laat .. a fore.. 0 T0.0LEt • c 1063($ C I ?1-10$ 5 lOawC r -TONGUE 01.50 C TD.NSCOD C ?NAG( C 1 11410 Caeca. t TOiwO • .. . a Towl° a T010SawCT a TWICNSC 0 I 1IGaa0. a 1Ce,tco ago Tanta CO I TO 010 10.116•• C 1 11:11 C Icel.. P 1ON5a.a0 a TO. 0 ?Nava( 5 1 1101.0. a 105150 C TCO*•ua • lOTa« a 1'.(11[1 7 1 1101!• 6 TCSLSO P !COMET a/O 10.1161.• 5 T11[80 0 I T I:.O$ O 110!05• C Tent 1K a 101E a _•, 11150611100 - C I ?ICUs C ICS. r TeOtrIN. aOOESm-V(LT C t•aOUCC C 10((0:( _ C I t IJeaas,., D 100.1 C KT 156($111( - a ' vue5aS C 1 1181 • 0 TOCaLONi' C TONES - C TRACK 0 15!0000 0 1 11:5(0 a/C tSC6• a 10005•$ a ?*6C5. DRAINED C tuf D0 "I 1 111.5000 a TOCCC• 0 108105 c ...cos. 0 . ...Cots., 0 I TILLED• a Tcct c TCat9.t5 a 106C• e 101,0101 D 1 111.LICu0 a locos 0/0 TOMO& A tOaOfO011ae a IMTOr5 0 I TI C TOODItD , e Tcw0 Ma • a T0•E0 O/0 IwtarOPOLIE 0 111LL0)r1 a 1000ST6... C TON11 -C 1060 a INESi 0 I IILLDU • C TCD0.ILL! a 10.1!(0 0 1040. COOL C treT5060 a I TILE• C 10505 ., C ToDLIS 0 T C ....loos S I 111511 - C TIKo5•D • e raclLCSa0RD • 6 Tall • IMI1501.c0 %/DI TILTON , C TGEJ• a 'macs . • 0 10.11..00 ,J, 0 111151 . 0 111-06:1(1 D 105• C 10001 C 1t61LCP!5L. c 1115[15[0 C I 1105!°4 C 1OGCra C TOOof. 1.065. 5 10.11.!1580 a Tuggle 0 1 TIO6t.ttao a IC000MI 0 SUPST0*TUN.•fTON• 10a1050 ! 11110501 0 I ?Irately - 6 TOGO a TOP C 1561.075 D 101011 - 0 I TIrefa.ILLE IT TCGUS 0 TGOEtI 0 106.06$ - C tmes.Lesu00 5 1 ....Isl. _ O 1500$• c T0a5MAM 5. 'Mara, 5 IMISILSDT. a I lINSUCt0O C tClrl - C ?COl1,. 0 1aa8/OUtl10 C VAMP' 0 I 11/11.1/6 a •1015( a 1:101.155 P 1 la e '!Tomas 0/01 11er11.1 : C tempo, 0/) 105000E c laaPOER a 1ro1015.1. a 1 /11.US a tempo.. 'ours° D 10055.151•.. o , 10*001s. . c 1000, D 1 11.11$ C TeI.•at C 110051.15•. COa1Nto C laaaes a 111QawauSGM • a 1 110r(Sr8N 6 TC••• r TOPS(• ,e tease c 1.oalloaLE a 1 115000: a Touts. C ?MSC. C taa.titSS 0 twasmOttE' C/ol tlre8aut5 I ?OKLaf C tCCUta.ILkf 0 1•••10 5 t$Da.00s D 111 .6N000S • TCSOPSr 0 ?ODUI 0 ISa.[et1Nt C .005r/0M 0 I fluoaa0001. C 10.515. •C 1001105 a IO6.(%St5L6- 0 111000UGwa alt 0 I bDt••teLT WELL +11.0. r TCP 0 1.8011 C 10000 0/01 00811.20 lout. a ?rata.. , A T•65500 0 100111 e 1 flOPleP a IOICCO • o ?CICNlmmal a to•.ICe - • TWO. • I rtwla P VOL,* .l 10001• 0 1011 C 1..01$0$ 0 I TIN* C TOl1C0• •C 10•0= 0 10!•01•. 0 ealNas11 a 111M8J8 a ?C15. r T00Nurf6 _1 c wary 0/9 Tun!aDG ILL. a I 110a-Ou C TOLL • 100+1[., D 1a e • 1A000CA00 r 1 11.011.•• 5 -lllLGa If .. P 100.1110 0 10EPLOC 0 tr°tt00. 0 1 21501$•1. Gaa.2%LT • 1OLL1.OU11 0 10001114 a 105000 C ?MACE[ - C I IIwf A 10:$60 • 0 tra00a 5 155510o 0 1M7terlL( 0 I 110lraN 0 111.• 5 ?(250.10 C 10155°0. K0K3100, C tma5510P C 1 110[5•.. ■(1 C TOLD 0 1000.00 lac( 0 TD(SK D IMOOCI c , TINGE. a I..ONIe6 a 100000$ c 10(00 C _ 1Mt.!P•. C 1 11111[° C 10130$0 O 1650(00. C000I.T 0 TOE C 15115 6 I ?INN 0 10LSOMa. TILL e MORES a 10511 it . i W 1ourCSR8100 0 I firmer A s 5106110 TCOeO . e 10[:00• D IWUOatA 0 I 11!.$:11 • TCLSTCI L tloee SID 105r•1•f a ! •0(51: I.0 r1DO)LOGIC toll caouPs tut.' as BIC $DICa1(5 tat CP•IMLGeUa0a•INtO Sltw!IO$. r0011T!lS %rO.M. E.G.. 5(000(1 $U5$laalum. 10 • special( SOIL 1101[1 5o6S( 501100 IN SOIL 565 LEGEND. - (210-VI-TR-55, Second Ed.. June 1980 A•:19 • ( -. Exhibit A-1, continued::Hydrologic soil groups for United States soils i EEEEECS a roUSC.et. 0 unison C v,E•ND a ulia. - ?ItrOLts. - c tOUSSIL C tuelON 0 INLIC a ut•LINt O rO0laa'CLT we ,IU.a• 0 tuS•ta.. •`• C uML01« C UTE D lOCNO • C ToN t,,,N mO O tu1C aN 0 ul$t• a UrICa e TatuO( • ?Sim! C ruSC S C URI aN O UTLC• 0 Tag NOeaLCau 0 •SCN1CON• • C TUSC••ILL• C USA C utS0 e Mew'•• a. ISlaiU C t wit ota a uLt• - a utuaco • e tot API OIL• 0 ¶50511 • IUSCOISO 0 ULID• 0 uvaDa - 0 tout a ?US C TUSCuset• 0 ULLO• a U 0 1•tntON ' 0 TIa•C C TUSCL 0 Um* C Vat a teto« o tu•t•tt • C ¶lust. 6 UL•aNT a 51••1• - e loco - 0 TagaNNON C •US[ 0 ULUIC C u It • e TUGS MZRN■NOS _ 0 TUC[••o( a •use ANON• 0 US.I(NCR • a UZONa D 1•CSaNO a Tureen c rus[etc0 • CIO UL VOA 0 v•et■ 0 !RISCO C ,LX[go■aN - 0 TUSLCO P ULUDaLACUa a (FAIR'S C T•ISTLC - 0 TUCSON 0 ,US0u1tec a MT 6 v•CNtOI( C I N 0 ttCU.Caal a tUSS• O ULYSSES - e v••••0 0• 1lfalN0 00 0 'WRIT • • C TUST CL. C visa a• v0!• • a Tet,LaC a lv•0 • ' • o Tustin ' ' e• U &PINE 0 .aDN.IS •' C Teri • twNlLL O TISTUNtN• P u.0PI8C. 'DRa10C0 C' v•DO e tRIaNGLt 0 0 1UJUNG• • 'MC ' a UNaVILla a vat0a O TR t••tT C tit(• ' C TutO ILL a Urea0G c var0!« 0 TNICOM C ttUNMI[ C TUTNI a U•! D vILTO$ 0 TO 10 C lU[•IL• , • • 0 TuTTII C UNI•1 ° O valve 0 Tu10. MONSTOwT 0 lli•ILa. OR.l•tO C TUTUILL• C u••Loa C 'aLav C T•i09L1 O 2511• C TUT,11.60 ►' WAIL '" 0 v•LCO • C TOIC400 0 rla•ra. 011•1040 0 tu.6c. • ' e u• • e' wlcoecE e• Tots0 - 0 Tla.aN•. NONPL00000 C TU[t IAN 6 UNOCOOS .0 vatCO(st - C•tot.a0 ' ' ' a ile•c¶ O EMC•• ' "' O uIIruaP a v•LOtl. cl.•tT o TUMBLE • • ?MARGO • e t.e•a. raot6•Tttt S• Una D sues t••Tun - 161s.r0 C tu.aSOSi a act uaaOtll• 0 'AUK/. SALINE 0 Talrlo•D 0 lus•st IT tK••. Den sago• C UM•[• e ..Lott. CL C Tot«It• '0 rm C* • a I►(COT C UMa[•1[ 0 IU11ST••IUP. Togo '0 tl .tCaN • '• - C Tet(MCO D Ura•!!R a S•LIN( •s T/loss_ ' ' e tu[eL*[e O Tout - 0 waits D' TaIOCI. OOflir[0 C ¶61511 C Tut.i• • talc 0 UNCON.awca O '.LOOS'• • r/ , f•lelln • tUlt[ • 0 TNl1Cw1 a UIOC•SOOO a vale a 0 teYOOU 0/0 rut.LaNaaa et--` c toll C•C•[•. • a u.051s• 0 vaLCNCI• -• a• in:en a IuLLea • 0 T•1•iNG C UNGC•S 0 PatlNr • tats¶.• O tULLOCE • . c T•INSI •' c u.itol - e vat. link ' • • lotto.' 0 TILLI C Tu/SSCLNaM C UNION ' C 'ALCO• - C ills a TI.OSO • P T.Isstlaw•l.•-- 0 O uNIONTO.N ' 0 vaLNalu `'f' ' a TM0CCIN • - a TUNaC a saLrMt--al[al'•l. . UNION.IIlt - • a • 1• - 6/0 TOO/oh .- • a TUeaLO C KT - UNISON - a VALI••I•• 0 mown " C ••••••10o • '+ ' O tats atl••M. • 0 units O OtootSSIOr•l • T•OMSeN '! fungCrrow.' C tat ten-At gait' UN1v6W - 0 Pall•« . • 0 ra0o1 '- • 0 1UP•U.• O t•ONILC I C/O UNLIC ' 'S PaLI( • a T000E��'S•LINt' C tUe•alDGI " • • 'C /•Otoe t UNItt a valITCi TOT 0 t f. - 00 TWINILI 0 TY/O .. 0 unison 0 v&LLIOPO•• a• Tannic a'• Tunic: 0 ?not 0 u•occaal. a •LL%(S5 c ¶6041 0 TUNIS 0 T'Ga•t 0 1501(6 0 vaLLetCITT• 0 TUOS[T • 600 TI•.ttaS C TYGN • C UPSaT• • e Tatua0 C t•OUG•S '0 TUNE '' '. Mt, C UO3•■• " • — 0 valNON• • C• to 010• • a TUN[Na.wOCE a twD all. C U►SON • INK.. • a• 1MoUT''Cett[ 0 C •■•••CL - • • TPIO.LI. D.aSwtD • ulnas. sTON' • C valMOO C 'soul alvtN • t.o.r1SON co Twee - • Ue%O C.U/N - 0 ••LOIS ' • 0 tsoITOaL( C TWwt •5 TvOee[ •• 0 UKttte • C t•OUIto C- - TUeILO' ' '• 0 Tvet •alp U0TN00 C II c TOUT V I II! • T UPuR tut• •. 0 T O•ONE C •1•110• •• C - o• • Toovt ' • • T1OUt • Tv{ON a uswtLLt - • 'a4 TOM • • te01!L '0 TUNS!vILLt C Stria[ O IA•CC• ' ' ' is val. 0 row's' • _ e tue•oT.;Lit C WMa • '0 U Sa.sa' C Image ' -- 0 t.WLt- •' 'C TITS VP 1161. 11 WOAD' • IRT•0 D v.NONI - 0 laud[ • `C TURK '`C U•Y 0 '•UritaL - 0 VAMP . C • leuCMOT`b` C TUe[t,s.aINGS '• UNIN••• . C UICN COD Par ovum. , e mutate C fulls!'t• -e wt[ e ululates - 0 van NOon • T•UC[tI. OI■INCO • TUOIIN 0 Lift? • a IR11Rn[$. C••'ELLT C Paw NOSTC•« t C caucaT0N - • TURLOC[ '. O WOKS • • U L.ND • C .aN Paco«(• 0 tslJOau • tunrow 0 0 u0010 • 0 went e o IeuD( • lu • ci - C UCOeb• 1I • uMCSS 000 vawaaDA • a Tour•issUIt llwa • TUIr•ULL 0 UoaNO a 826. C .aUaaUNI C T• C TU•K• • • OWL 0 UNSINC 0 waist( C r•URO' O T1R1rtaC•tl1' C UOti. 1 - 0 i WT.N C .aNO• 0 T•uL•t 0 TSRRMle,IL1.0 • moos into 11/01 51•511 C 'a«Oahe. • O roULON C tusk!' I U►•CNS , S I US&L C •••o•N.t'• a cowman 0 T5Ma•N' C U••lns. •Lo00tO' C i trans. Clatlul• a '•NDaNOot 0 TMUUSULL 0 TUOO1I 0 uG•• - -0 I Us•••• a vaND(•.0I•I.• C tour. 0 nos 1• " • ~L01 a I USINI • v•rOINNO.[. . C �� 1OUNt D TU01114. vt' C UNi e I VSa C T0a/Ota4.1P • Notts: Too Nv050LOCIC SOIL GROUPS SUCH •• •/C NDIC•Its IN! Dolt IKO/wO.•INtD St Twat MN. wool•I(65 SNOvw. t.C.. •C0S0C[ SuaS/H tu.. Aare' t0 • SelCI•IC SOIL S OILS stair •OUNO. IN SOIL- ••• LC G(w0. A-40 (210:VI•TR•55. Second Ed.. June 1986) . Exhibit A-1, continued: Hydrologic soil groups for United States soils .•.6693 C 1666[ c .1666. Da•IW!0 a 8,0 6.1.61. 066061066. C valve • 0 VcUOCL 0 VILOT ' C 6.5.110. o ■•L60RD 810 •••G a v66DICO 0 .166166[ r 0(01106110.11al 6 8 .*Ncua•o C .[11010913 a .IN• a •6a••a16(a O wile( C ..MMCT60 C .[•DUN 0 vINC!0NC5 CIO • 66615061.3 • 0 .•1111 8 ve.6CNDsr2 •/O •INCCMT C '•Me11 8 6.1.60*. • • C .Ammar C 6[116.3 C v1•COM C •*•VILA C ' - 5a11J • •• a va*OC(t0 a .[06(91125 C vINOICaTO. 0 •*C• 0 •.Lg• a v111015 'O v6•.atem D vIN0G6•ROON C 'V•C*Il0Ot• D .6LL*CC a .*M66TT66 a ♦601[6 C rip1v.RD C .ACOt• 0 • 0 .•NSICALC 0 •[011.1 ' 6 vINGO 0 •600051• 11/0 610 - va.SO$ a .CRJCLCS r '.1.1116 • C •.Oars 0 6a11.111610N , 'C .*61661 0 6666 0 •111151 r ••00011.1 a 5aLLCILL c/r .•116.62 - 61.56 0 1/1616• C 5a00IJ. • 6 5*LLCtl1. 0/0 a 6CS116J5 0 •l5Jt a •aoee• a NON/600060• •to C .0►■ILLION C vl5*aMJ 0 5aoeslll 0 ■511.06. C 6•62611106 - C •earls• r ••*111.0 C 1,6065 C 6*LLD000 C vaou0•0 D 6[95aD0 ' 0 .INSOT. ! 6.0650011165 C 6•LLSO(RG • 0 .5000 D 6[51,•1. • VINT • 0 6.01.[1GM _ 0 ••11SO6 o .a9a1M a '6605.611 0 .INt. off C •6055656 0 .8ILVSCI C va6tl11M • •6[511061.[ 8 •1111x1 • -.*OSSOleT$ C •••.•661 c .••e1uM. CLIV Loam C 6[0111• P A V$1,601 [ .AGES • 0 • .•LONG • 0 SWSTR6TVN - •666011 . 0 vto1.• '0 vmsaea 0 6.1.001.6 - • C .*5651 C •6[060.1• ' 0 .I.OMT C' •5605106 0 .*106!3 C v*01CC 0 -6000 SID .18*101 ' C '6AGO.TI6[ 0 6.636 • 6 .*0711• C v000. 3e8•63S10M.L D •61066$ •/0 6660•0 • •ASST[*0 ' ' ' • 0 ••RNA C •C156IUc C •VIIG[llC C SAM* • C 56 0 r • • V[RS,11 C .IS61L •0 66M*7O6• ' C .*1.TERS$O• 0 .•666 ' 6 •601[6. • a 66.6100 teat " O .&$!C 0 .ALTI - 0 V6RVSe SAG •e vs ' 0 .1.616 •Iv60 ' ' c 1.116116611 0 SILUv e _ 665* a vt$ • • .1661.1.. C' 'em 1*6• • • .15MT1 C .tier '0 .16111[ : C 6611561111 C .LLVs1.1E 0 1 I vaSOVC2 C • 0 •151• ' ! •*11[[66• e 0 _ vasi*1.L000 '0 6615[0 to C vitae C •*11LUCC • 0 . 00.11116' C • 6[1111.1.1 0 •/ETU?Sla. 0 55/55 O ••60115*• • 6111266 • '• •1sT• a' .1W• ' I' 6*N.[TON C 6.6(60 - C vas611C 'C vlsl.eu. - - &It VII c •••••c0•N C .6111C a .6111112. 0 -•.61T06 • r- VIV[S '0 •.113661 - 0 ■AMPOD 0 51LIN[- 1'- • '661* e • 61.'1 • e • •*1T*G*P ` 0 ISLE' e 5aUCLU51 ' C 661.1 ' W VISE% 0 '•*111116 " O 6.11.6.11 a .W.mam .IA- 0 •VtTC•CO ' - • •C - VI/Cal-00 0 •*0661. • - 0 •6651.CC - 0 .auC,MNSV ILL[ - ' C. .'6260 IT V IIC*001.1 ' - r '551*w 'A. 0 • '' 0 • .•• •`- a 'VII a .6.1.6. • • C 1 .•1•60• `.• C ■.1100 • ..r*s 0 61511 0 'LICE - O, . ' 6*I•LE•1t 0 •aN[T1• • 0 6[• ' - 1. • ..101.t I 61.6 C •*141.11.6 • 'x• a SWILL• • C•.66TCM • 6 .100 •e .0511 - e •*7A•* • ` D 6111$ - 0 6611CM. stove C '61[0.•3 - :'.}'''' • D ' vat• C •61611•.6 C 6AN11ACOt1 -• 0 'vEACIC M •10006 • 't 600[.■•1[0. ' '• 0 6A1cA10• .- 0 .*6006' >'• • O 66.60 ' - •' '61[62 `' S 6016111 • .• • •166.62 • ■•5061! C 6CCONT• 0 • .tec ' C 60.600•♦ ' • e 5*IU911 , " O ...see ' - o 66609' 0 . ".IC1C•r '" - C 501.16.1 "` - • .•It11 ' 0 65113(•. 0061510 • e vet, • `.IC*1$C - • •• 80•4 • • ••t 0 ' .*11.11[1. a - 624* C' ••166156. Div..- 0 •.CC C 6•6110.* 0 . 0r0.0C11 • 666. *1.6. ' • • VIC*SSW[ '- • 1 •OLC5T6" C *dilate 0 SVOSImatu. • 566* •*J• 'C '.IC6TON 6 • 5.151• • .0111014 • .*O.1.. SC005C0 • 0 616Ol IT .161160 0 •.a.aa '- 8 .*l..MU • C iu051511111• 6660*.. COOL. .- ' t! •ICTO■ -• • '-i' •'' 60611[• • 'Raise. ' • .5.566 • O KL65CC 0 66[19014 • 0 •..!•It C •x161 " • •*0211.0 '- a 621.041 _ - • •ICTOS.ILLt • •611• C vase - 0 •*.1 0 T(LOL6M. • •1C7051 0 •0.6621 • .62(66 • .•.►11111• - • .61.5• • • .ICU C •.T•I•c • C .*6[61[1.0 11 • ems, 6 e 621.36 • .105 C •.1*I•t. 096 N60' C .*661..55 C .6001.610 • • • 621.6• • VIO•u01 r 0 6.1.1.2. G•• •66[61.6 • 5 AMMO 0 vts* • C •100162 c 040 5/66111. 65[11* D Ill• O t 0 v10,14 ti .0.111(• C .*6055• el 56.11 • • •'Cm*0110 0 •7[6115 • • • •ONA E 51.055*. TILL • C •••TUS •- C 6[11.1.65 C 616011[3 a •09.6!2 ' ' 0 WOSIR*/V. • ••6.6:. • O 626.0.15 0 670.6 • C •01.56*. a 66.1111* • 0 • 6t*.6105 C 'ICI* 0 •00.111[3 C .a1.C*m C •••Otl1. C 626!1• o •1611665 C Gott a .6LCOTt 8 .5006• a 6212216 0 •160 0 .61.11.6 • ..1.01111.1.16 a NOT • 62.1[6 C 616115 8 •011 0 •aLOCCC • C 5600•!L. C 66111.0 0 6161110 0 605566 • P 561.0t6 0 5*e6 e 6256013 0 611. D VULCAN C 561.00 0 6.56.61.E 0 6[1111..1 0 611..1 • 61«6$ D ••1.0000 C/O •0•e5•• C _ veNu. 0 VILLA I •*611 a vast/PONT • • - vas. 5.01603 0 615111 a 611.6• 660.6 • •*•.SIC•" 'C ••►011011 0 •a6. 5091563. C i I VENDOORT 0 rILLtG.tl•• C r •*1080119 . 0 06•1620. Clay •e OCLI66 C •ILL• 0 embalm. 0 •ALES a suSSIDAIur 1101[5: 160 NTO60LOCIC SOIL 6601.01 SUCN •3 arc IS01CITIS 1116 0.•INIC#1110.•1«60 SITU•Tt0$. . • ' «00161553 55065. e.C.. 610.061 %UlsIvatu .' TO • 161C1676 SOIL 1[66[1 D11*31 SOUND IN SOIL 11109 1.66[15. (210-V1-TR•55, Second Ed., June 1986) A•41 Exhibit A-1, continued: Hydrologic soil groups for United States•soils 11•a s1m IMGS. C ••V1(CaM - 0 •0610 - C •(1T(*MOTi. c •10611' a 0*a1N!0. 616611 .6UOUIC 0 •CL°. C O(IZEL D •ICwIla C ammo S6.OIWGS. C •pl•I[• ; O .MLLE' C •t0t•108 - • •IC$U. O 0.41.6t0 ••6US[OM e/O •fLlIMGIOM 0 .1..61.6 0 •ICEONQOPT O 'maw S.aI.GS. COOL C ra*tOoa • D/O •ellww• . a r C ,rICRCNODUG O •/D 106,11.600 •0/0 .6U.S 0 •gvtas C/O •ICCP.SMew a 86•8.8. GeaviuLT ai0 •a O .IL1560110 . C .CT0001N 0 IIICIfTT C $1105011 a..r$slONa1. •CL4$C*etc . a .MaCa.• 0 UICCw. . 0 •60016( D •aVtO1T �0/0 0 . C •1161•0 ,.0 ..IFICE.:111, C 0.•0[01 CIO •6.61(1 0 .(115/00 0 •00611! , 0 VICRS•URG 0 OaeNOCR a •8o1.a o • 0CLLS8111.E • 0 •MaQTpl C .•ICU., C 0108 D vas . C •[L.108 a rwIC'D. . C 8106860 a • •u$•• e •n.00L 0. 1/1101 . . c ■.1611.11 0 rt01N C wasSING e D 1111..106 0 80(411.[. w./0 WIOTSO[ a •6•.ICC • 0 '(LSI .•O 8!(61010G1 - 0 811M C rasa 0 ravCu. , 0 0511(0 . 0 •U15a10lllt a 0161..80 c 'as•TCM • , a ••TOCM 0 .(.'•1.0 .a 80(11(0 .. . .• •1(06611 0 ra1CO a .6)16.0 _ CID •twl . .O, ..(el[10ILle• • ,,e . •,81!10 - 0 ra1D. 0/9 061008 _ .0 'Cows. DualotO C A•11t(LING 0 0166(.(0 .. •ms[I! 0 'at0tC0 O •1.8.1(16 C • 11 . 0• uIGGICTOM e r61N611PM 0 .aTN(S0000 a, '[.0601 -;C 8.(100(1 . „C •1610. - a •esOtNGtO•i a 04T00t080 C •t.DaMt. Da•t.to 0 .00(T$T001( , .0 0tlOw . .a 011810GtOM. •1.7 C Ka 0 8(1:00010 0, omiC808810 . 0 01 , 0 1VO$TO*TU0 - _ -.6650 C • 818011 0 ••010001 •C -0IL0.6Na. . C 861 4101 . e .C•tM(0000 O. •85000• C •W I I.MaNG - .O• to l Leua .,, 0 •a5NOUG*L a CC . C '!81.0018 , et 80!0060!.• C •,I1.OU0T00 e .a$NI(*ae - CIO • 80lllt .. a 05OGI0,56 -C •010.1.1 0 ',ILO/ C 11111.1.• -. • . . D. ; • OO C •e.'0 . C• 801.5TOCR •.0 ••ILCO! o 06$1046 e •ta•010K a .0(•[10 0 •.'01010 11. 0• •ILCOISON C 'Fascism - 0 818.1011. C. •11106 :C 0Wtt1[8DIC(• .• .0 .81 ,C• 0•SROle C 0(5E0 -0 •t•8ta - .0 ..HISOCS1wG WILOCat O . •63.0 0 'COIL[ . ,, C •C008CI . „ , S 7.180Il1LL • •01L0(SNISS , . C , 0611.16 . a •1811(0 ,•10 •t1C0w0(f, C, 0•111 a elsOCC0 a . .ass11... 0 0(01.1100 , .0 8510! , C ,rII1 (e • C •011000011 a ,t ••Tae _ C •18(•11 • 0 .ts►IL .. 0. 0«nc NOOSE C: •,1.0011 C •6!6.1• c emit . m •'(S', , ,..0 yv$tte 5101E 0. '•81100000 • 0 •616111• ... a .10.60 „ . , •C :•(5/• . 0 • •NIT[ Sews' - .0. ••n( ■LTCN*005 . C 0100016 •- ..8111.1' . .0: 80IT(C*0 : 0 .811.1? 'aTCNLV4 • , - e alto . • •110 ,• ,ei •,u•t/ccl0w ).,.0 •11.MItt..•. . •. C/o . r•1C8110G - • 0 •(10106 0 .et1.•C , •D 3.UM/TUV0 •. • -•ILM01I 0 •41(06110. O . •180••115 - ;,a II ,•1s.•C• c ,•811 y, ,....0 •rILSC1 , C 'ait•C881Ow 0 . 05e110LCNtC D SI101TaaTU. •.M11(/1$00 0. -•wILU$0N., . • 0 80 160(( - ._ • 8111$ , . . C . .(5151 ,>C -08IT(1000 • O• ,.1LItNS O . •OTC/N•W = 0 •18RS.1LL1• . . •10 . OtSTt000I , , D :.0110011 0. '•ILL ,010 5OTte10vN • •[(.a - O . •t5Te11•T . C 80111011.11 C. 81 , C 'ATM/14L[ O •([0000 C . •E1111*1E ;. c. ..01Itc1008 •0 ye1Ll6CT - a . ••111.5 1• . • .etIaTCwe ,.. • •••TCaO• • ..., C 801100088* -0 -•ILLactW1tt • , . C ••11105 OIOGl••-r•_ ., • 01C4 , t •($!C011* , . t: • ,881 0 -,r1 - 0 8810 7,--.••. •, • • .(06186.(1. o .[111 . . C .VNI , .0 .,.1LLa.(TTt . 0 06118.6• -.4.a.1 0 , Demagog •- C V1$T(IV11Lt • , •. • •NIT(0a0 „ 0 _Vt1100t1T1. leer C leaf - • ottilt .. . . O .11)0006 ,• •_,.• D •N1T(f(a0 • •,. O •.e1116WCM D •OT*OUS 0 '(IIIOT ti;• C•0 0(510010 • 0 umisgoITee „ C, '.01 C .611(1*. • • •[le(* . .. o •(l/06018. ; C f ewltl•OCt , . O el11a00 • •e*SOM --• C .[I056CW C $61181.■$Lt6LI . BN1TISS000••._ • C 01111111 . . •/D ■6!$001• 0 0[104601 co K511801* C 0Nlt(5•U0G C. •)1.1.0111 - C •6/581101112+ .-• O •(106al7(• C •15* _ D vI1T(100 I O •/LNO 0 .6T/ _ a. O 011• O 8(1)1.800 . .- Ile 8.11($1001 0 •1L1ta•s • .aftCN C •01060 . .. c 811,80•( --.• c �wmlitt0aw • _•IIL w larsic 5 '61111 C . C •[1.860. 'CT O 0(1)80011.6.0 0 881 .0 e$LLl•s508 C .•u•6T - • 8[t8.a.. . . • • •es,o. - , D . •MII(8010 . 6 I0111160180/T C 061101CC 10001.000110- 8115,00110 9. • 48011(8000 C•O •i1L16•510:M, C 1114110616 " - 0 8C156101G C •Cs1,04116• • •v1TI8000. 600 .ILLI*01,01ILt C •611608511 • -' • . 001115 • 05104.518,. • O 0/10?L00D10 - 811418.. e/0 •LUCID*« 0 . 0e15.aU0/) . 0 .Clv.o01. _ • •Mtft•eIGMI C WILLIS . C 'aUCNULa - S/O 8tI1$!0/[L1 C 0(1110.1. TWIN • 80111/6 O e1l1.11108 C •'auCNUL6. O 05I1181.e, . . . 0 s1t/6CC . 801710410 • C •1110. COCCI' , 6 _ 051 052,5l0wl 'tI$CSOCC C 8(5t5N01t 0 •MI)lt7 . 0 • •I110..0•LE 0 W OCO.a 0 •1100• 0 Ks1T000 C •MITLOCI a •lt10•rtsOC r. c 0auC006 • 811.•c• .. a 0[110110 5 61111.•8 0 811100060 e a •auCOWD* • a 8111! • •1•T•I1l( a 0011.(! _ , C , 0111001 D 156111(1 0 8(1C8 0 •(5 1'(60 0 0011180( 0 011.18000 • 668 • r(ICN. 0laY5ll7 • •(50100 C •1111101 a 'IL.s 0 8610(606 0 511IST0a7U.. 0[10000 . 5 '011$00 0 allot* C .6111100 a 04•101f0 •(t& O .01)11(• a 014.8IMGT0N O •aU10 C 8[1[00. a 0[10(01/1510 C 00110611 C 0104001 0 a1016C • '1000E0. 00.1010 8(1w1! C 800/•6/ C 810118108 0 'apogee a '61.60. 0.61.1(0 - C .tfo(!. 18/610(0 • 000160 0 •11.065 ( ••••• C v11CML•00 • •(10001. 0 .0001(0 C •11.0 1NT 0 f •'�'- •aU1acw - •/O •ELC081 e wen*. C mew 0 .I11w1•t • • w01(5: 180 Mt0a0*DGIC SOIL 600054 1860 AS e/C IN0,IC•IC$ 18e 06.10(0/880Sa3000 1ITU*T10M. • 00010151$ 10008. C.4.. OtOIOC• 185.10610. 110[0 TO a 18ICIIIC, SOIL 1e•/C$ 10.18 FOUND 100 1011 .a. L(G100. A-42 (210•V1-TR•55. Second Ed.. June 1986) Exhibit A-1T continued: Hydrologic soil groups for United States soils WILSON 0 •lSM•NO C •CODS C•OS% 0 r•NOOSC D .tee.. a •ILSONGULCM 0 •ISMOONC a W000St•t 0 .TCCtN• a • C •ILSONTILLC 0 •ISNLTLU C •OCOSTICLO C •TONING • TCLJaCC ' a WILS00 a WISNtaw 0 •000110( 0 •T118148 a •LLLO.Dam 0 •ILST C vI$Ntam. DOAINLO C • 0 W•sOCtING C/O TEL LO.MQUNO e •ILTON a vlscav C .000100 0 Rama a TCLLOvOOCC •a •Iwtba C •IS(t Plat 0 .000STOCC CID a .tLLO•STON1 0 WI C •ISNtR 0/0 TIOCIDSTOwv C BairitP a rely C WINCNLS?CR • •tSitR C WOOD TELL 0 aerl• 0 TEmaSSt! - C •INCNUCC C •ITSCCC BID •000•ILLC D 1e.0 a VemCC C WINO OITCO • •tTCWCLS 0 11000.aa0 a a(PI• C TeNLO e •INOCOaT 0 aItMaN 0 v00018ES1 C 0 ieoose - a WINDER a/o •TTNEE C •OOPUS 0 RICO C •CON•• a WINOS•• 0 •ITwfROCC •/D •OOLD80 C RISC C meOPiN a IONaL WITtteRELL 0 •OOLSe• a RIPE 0 memINGTOm • wI wMaw a •ITNC'S C VOOLS1aLF 0 RIPE. NOOto•TLL• C TeruO a •IMOICUECC a WITT a •OOLSTCO a .FT•-' _° •esu. a W1NOmILI a vITTEN 0 •COWSOCCET P SW&W 0 • N - e WINDSOR a WI•tSNelgOG a •OOSLOT C TaCOt1 a •CTULL a WtwoTwoOST C WITZ(L o •ODStea C Taco _'• C •IGO a - vINO.MIStLE C WWII C w011 TaNaNa C •1000 a WIMD•NISTLE. wimp' a NIXON a ■OPD(N C Tgsaaa C TLIG C ' MOT a aoCClt• C yowl 0 WaTwE C •001 -C WI INT a •OD• 0 •ow?C• 0 • TaNOLa 'P TOCMUN C •INeG a wODCN 0 • •C•lCm6N 0 'away 0 ,TaCIE? •C •INCot C •OOSCO• C •oRPOTDNE C 'TalNaa - ' a TOOEO a • •INSTTI a •OOS(Ov. aaatNeo P •OO1 C Wadi 0 TOOT C •INC•ADa C WO•,LT a RAMC. GNiVELLT a maxims 0 TONUat 0 WINF•LL a •OLCO C .00La.o C maws 0 •OCaTO _ 0 •INPIELO a WOLCOTT P/o WORLT• O '•a&UTai ✓ ' a TOCOML 0 WING 0 ' •OL*•LE 0 •01.SE' C ,aLtLace a •O(UT a •INGaTC a a .DaL!. DRaINED C WO.00( a 11.1.E • - C TOLLaBDLle 0 •INKP 5/0 •0.• 0 •OPSMa. D 1 a TOLD . .I WINGINA. .0 WOLF •01Nt C •0111114 C •aINtS a TOLOGO 0 WING•ille 0 tOLPCK[e a •D•t/tt• a ••aN•C P yTOaa• 0 •INIFatO C NOIP(SDN C ■Ow1NING 0 `•*NNILL C 'TOmOmT t P WING a •OLPCSOM. •C1 0 .C•rrar 0 •aal0 a ••ONGCS 0 WT•KLL o NOLPf• C •CRTN6N. Saw, • •a.SaT 0 TOWN& 0 mimALeN•N C •OLPw(N • •0.0C• C mama a :Mara 0 .INCLIN•N. •et 0 'O1. C ••aMGelL 0 'duce 0 ,•EW• •C •INCLCa 0 •OLLARO C ■.a-GO a •aNI(C 0 -TOac1DNN 0 11NLe0 0 •CLLCN1 0 Ma 0 mamlION a TOactaee. 'C •INLO 0 •OLOt a ••POa, 0 0 TO•cVILLC 0 •INN C •OLWE•IN( • ••ENCOE C •aP a COST C •I.Prte•GO a •0•6C( C usemmar C •a.oa, a TosT. OR•I.tO C . t •INmeCONNE C 000 a ' .tM .a C •acne a ••ouo , 5 D Wtmmtecooe C WOO. O•e.•alm C .•IG.I C •aOuI.a 0 TOUG3 a •ImrFNUCC• a v00. •ST C W.IGM/.•N C eaOUlNa. ORaINCO C '•OUGa. .LaND• � 0 •INMeSNi(x a 1000 RIVER 0 •SIGN118080 C •a•CO 0 SUe11SaT um mimmeft 0 • v0o08ttc • ••lGmTS•ILLt 0 Ta(OLe• C .TOUJ•• 0 .I..SS000 0 WDDDOINC a 001GMt0000 P roils 0 TOU.a• C 6114106 1 0 .000051001 C I •UCDNI a ••ta..ONt• C I TOUNGITAN _`e WINDMa 0 W000SURa C I mull/ • T•l•.IONCT. STONY 0 I`TOUNGStaN• •E1 , C 41NO0S•1 • WODOIU•T 0 •u. t•T 0 .ales 0 I •Oua•.e 0 •IMOP(E 0 000000CI a .uNJ(T a •auCO C 1"T0011.c0( •Y •Ivl0ct O •00070'0 O OWNSTdI 0 TaawaNNaN a I'TOTINP• I. 0 viola!To C •000LtA CM a avow° C T•UPO• 0 I •.0SS C •INSPCCT a • N 000a11 C •tmSTtN • T6WOIN 0 I TWT••.at. tint O WINST l I •000NUDS1 C . •ORT80000 C Ta•NEE a I TSIDOse "- _ C WONT 0 W0001N C ••6LUSING 0 ••alt• a I 'TU'PIDI a •IMTt•PICIO 6/0 .0001NG?QN 8/0 •TaNEO►Tt 0 •NON a I TTU•UI• • •INICONavIN 0 60°01M•ILIC 0 •T.6.1 C R 6Ge. • 1 •U•a e .INTL•IDGC I .0001NTILLt• C . •.6.0 a •Pa'• C I TuaO 0 •INC(US C OU•IMEO ',mama a 'caret NOLLO• a I TuION - D .INT(SS8000 C •000L••N 0 avail C •CaTCS NQLLO•. C I TuLee 0 81MLLLSE7 C •000L1te C •TCOLO C IOaNT suasme•wum• 1; 0 WINVN.00 • •0001.• a mire 0 STON• I TuNOUT C 'RULE, a WOOOITN 0 •Tt•St 0 NOLLO.. C I •U•. 0 •TNTON C W IL P ',Ulm a ID•.• SUSSTDa1U. I TV/Out 0 •INTOwta a WOODNENC a •Tt.ILLC C Testel NDLLO•. C I TUNAS 0 WINO C WOODNDNI C gild% 0 STOW• I IAA, 0 mime 0 v0005651 0 .•(Iva. a •eICES MOLLO•. C I tam• a •tOta a •00000C1 C TWIG" a NONS1ONT I taCa E WtOKe C •OODWOT 0 •■■•• P •CRIES NOLLOW. 00• C I t•CN•OIaS a TIP? 0 •000.0.. C •YCRL 0 NOLLON. C I taCN.•T c _ •ISCO• 0 SALINE. I .•N* 1St 0 COOOL, I taco D WISE C .00Dao.. C War. 0 •t•lON C I ta000 •/E r WtSLN•r a OCC•S10NALt• ••.•TALC C TCC•OSS • I taDWaa D •ISPLat o Plcooco C TIOIICa a i taus• a NOTES: 1.O N•oaOLOGIC SOIL GUDUPS W./Cm as sec NDIC•Tts TMC 0S•INCO/UmO.6iNtO Sllua?JON. NODIPISOS SNOWN.,L.G.. 88000CE S1.ISCS•CU.. OMPM• CO • SOCCIPIC•SOIL 1(51(5 (await POUND IN SOIL M•P LLGLND. (210•V1-TR-35. Second Ed., June 19861 a-i:•; • � • Exhibit A=1, continued: Hydrologic•soil groups for United States soils taGG C tOMH[o 0 I . -. •l•HRL •y C l0l• • C I . - .. • • l•Tq • a IOL•O C 1 -• . t•l0• .,C tOLT•• . C I ,a . lair[ • 2 t 001 CFOI . •taLCO .:• ZOO1. SIT• . C .I - L laL94 .. 0 SUOSTOatur. I . laLL• • zc a• 0 I , Za.OU• 0 ZOB.•a SI• , • ( . t•.SCaw 0 tO•E0 D I Z 0 Jun .co a •• last 0 /WELT . C I . .. • z•wZIS 0 , Zu1ar . 0 I - . 1aHeS•ILLI C ZILCH 0 I . taw60 ,. 0 , :unsay .. 0 I . Z•o• C tlr•r. ODOTCITtt, „CIOI , •2•o•I• T. .2w000 .• I .�_,,.•. 1101 _ c t Ir.•L T -. C I , ., • .. . 1•110r ILL/. C .zWIDE LL C : I _.1•U -C •tur$aLs C I ,.` tavaI - 0 !tart O I :r, - • • •Z•OCO ; C 111.ICM e , 1 . _•Za•a.TE • 2101CC[0 - , C I I•2( 0 .:.Ir►CL •.C I s .. .s•.. .!Cal[ _0 t.INGLE -,• tee a •ZT000E e 1 , Zee. 0 ZTNC 0 I :<', v,.., ZCC•MTOr C :vitro 0 I .. .. . ZECO•O _ e LTMe•a o I - .. •/Ms.Z1• . '_C 'ZVMe•a. TILL C , I - ZCELUOT 0 . IUOS T••T4.ms I ...Mitts C 1TDLJ• • 0 . I • • r , •WOOD „c ATM. 0 I • I:. ' SCIIO1GHT a :v22I ' •, 0 I „ , I ZC'lL .; e Z•2ZUG , 0 I - - _ 1 . Zcr ,C I ,,t. _ , LIMDa .0 . 1 _ - .ZIw1 C I • _ZIMITM .. I .. ZINIeo e t . :zew02 e I _ .1CMOO ` e 1- . woe i• C I 1__ fitO•Cw,' ' ' • .. I } .. zeoNa • _ I Zc9cl• . a 4•. 1 .., ` .. r 1COwar C ,.r I . _•tc"My 0 <, 0 ,..c I .. _ , .L'.... 1 • . t[00 D I ttn - e I _ . e 1 _ . • ., ZI••OCl C. I . • •. .I1• e' I r t10•Tl D ,� a ,•, • zseGewluss D .- . I. ' iseci[O C I. - , LIONS TO a ,; I. <' <;••• t11.60UT _ D I _ - w tllL•w V - I . 5 • 11L1•• • 00•1•42 C I. . _ • ZILLION 0 I; . 211.1..•1••• . e I. ,,,,..• .. tIN$erra• • I ZINCe 0 I_ �' , ZING C I. - , ZINZCa S I - LIN2[o. SaIINe••• C _ ZION . C I • Cleo 0 I . 1 1 OOt L • gip I /ID.. 0 .5 • I ,... , Lila a I. .. 111T•u . C I. loan C I _ ``++ ZOITI 0 I (y /DC 0 I ... 11.., tOCST• 0 I roles: 1.0 H•OOOLOCIC SO IL Ge0Ua1 %UCH•.•S Di('INDIC•TIs +M5 DO•iNt0IUa-0.•INtC StIU*TIDM. • .00lrllas SHOWN. C-...G.• OIOYOC• SUSSTG•TVH. .[.[• TO • tai CI,IC SOIL SCOICS 0•15I •OVNO IN %O11'•40 LCGINO. A-44 (210-VI•TR-55, Second Ed., June 1986) Appendix B Standard Notes for Construction Plans Guidelines for Stormwater Management Spokane County Public Works Appendix B Standard Notes for Construction Plans 'The following standard notes are to be included in a road and drainage plan set, for privately sponsored developments. These notes are applicable to bath public and private roads. • 1) All work and materials shall be in conformance with the "SPOKANE COUNTY STANDARDS FOR ROAD AND SEWER CONSTRUCTION" 1995,and as amended. t r 2) Locations of existing'utilities shown in The plans are approximate. The Contractor shall be responsible for locating all underground utilities. Any conflicting utilities shall be relocated prior -• to construction'of road and drainage facilities. • - - ' 3) ' The Contractor is required to have a complete set of the approved road and drainage'plans on the • job site whenever construction is.in-progress: . • . q 4) If the Contractor discovers any discrepancies between the plans and existing conditions 'encountered,the Contractor shall icrunndiately notify'the Design-Engineer and the Spokane-County Engineer's Office. 5) Far Construction-of drywells; install filter fabric'(Amoco 4545 or-approved equivalent)between the drywell barrel-and'the washed drainrocL and l ctweeaithe washed•drairirock and the native soils. 6) Prior to site construction, the Contractor is responsible for locating underground utilities. Call the underground utility location service at 456-8000 before you dig. ,Supplemental Notes_When Applicable 7) For any curb grades less than 0.8% (0.008 ft/R), a Washington State-licensed Professional Land Surveyor shall verify that the curb forms are at the grades noted an the approved plans, prior to placement of curb material. The Contractor is responsible for arranging and coordinating work with the Professional Land Surveyor. 8) The Contractor shall employ a licensed surveyor to verify that the cross-gutter forms are at the correct plane grade prior to concrete placement. The cross-gutters shall be constructed prior to • paving,and the pavement shall then match the edge of concrete gutter. Use note#9 wherever GPA swales are used: 9) The floor of a Grassed Percolation Area(GPA) swale includes the level portion of the floor of the swale, and the sideslopcs of the swale up to the GPA overflow elevation or top of dryweU. The soil located in the floor of the GPA swalc shall be a medium to well-draining material, with a minimum ' infiltration rate of 0.5 inches per hour. The Engineer shall provide a written statement which verifies that all GPA swales conform to this requirement. This written statement shall be submitted to the Spokane County Engineer's Office prior to installing finished landscaping/sod and prior to final acceptance. The swale floor material shall be installed to a native soil stratum which also meets or exceeds this minimum percolation rate of 0.5 inches per hour. Notes ER] through ER4 are to be includectin'the plan set when erosion control facilities are required or incorporated into the plans. - ER1) An Erosion/Sedimentation Control (ESC) plan is required for this project. implementation of the ESC plan, and construction,maintenance,and upgrading of the ES,C facilities are the responsibility of the Developer until all construction is completed sand accepted by Spokane County,or until vegetation is established throughout the site,and accepted by Spokane County,whichever is later. . - - • • . - ER2) Approval of the ESC plan does not constitute approval of any of the proposed road, storm drainage,grading or-utility design elements shown on the ESC,plan. . , . ER3) The erosion/sedimentation control measures shown, are the minimum requiremen ts for the anticipated site conditions. The Contractor shall inspect and maintain these ESC measures daily, and_shall,mthitain and upgrade these measures as necessary topre'vexit sediment-ladenwater from either flowing off the site, or into new/existing storm drainage.facilities, such as drywells, culverts, or gravel galleries. . ER4) The..Colitractor/Peveloperis responsibLe..for.installng Rcicktc,cinstruction-Entries at any and all locations used to enter or exit the project site. ERS), Geotextlle„fapric,is:to„lie,place,cra.stlie rims.,of cirywells,,catcli basins:and inlets until.such time the . vegetationontkie.site,is Fstablisi;ed.and.,tbe threat of sediment,dLposition,into.the drainage system is mitigated. •, - - =v• ' - • J'. :- c . - • -;.•, • ‘' .. . • • • • . • •••• • • • Appendix ./ •. .. :moo•::dl..y:•9 y,:k»..„'iv+a•-. vv - .. 1 .... Examples Guidelines for Stormwater Management Spokane County Public Works Appendix C Examples Contents Appendix C.1 Time of Concentration - Example Appendix C.2 Lot Plan - Example Appendix C.3 Bypass Flow Calculations - Example Appendix C.4 Water Budget Calculations - Examples Sheet 1 of 2 Runoff Volume, month-by-month Sheet 2 of 2 Evaporative Pond Performance, month-by-month Appendix C.5 Sinking Fund Reserve Account - Example 000000. 11■1111= / Contributing off-site basin limits Project Limits • a Grassed Percolation - Area or Receiving Drainage Facility Calculating Time of Concentration (Ta) Example of Tc routes • Tajo)=Time of concentration, considering 10-yr storm event. On-site basin area only. too) = Time of concentration, considering 50-yr storm event. On-site plus off-site contributing basin area. The time of concentration for the 10-yr storm event is less than the time of concentration for the 50-yr storm event, as shown in the exhibit. Runoff characteristics need to be calculated for both events, and a comparison made, and the receiving drainage facility needs to be designed to accommodate the greatest rate of runoff generated. • Time of Concentration Example • Guidelines for Stormwater Management - 010Q Appendix C.1 Addendum, February 1998 SP C 't1Y Appendix C.2 Lot Plan Example 4. CURB DROP -.. • ''' --. SPOKANE CO. STANDARD CUL-DE-SAC -.... ............ TYPE 'Er DRYWELL WITH STA. 0+75.06 5 ,r's:' . ELEV.=2078.60 s. --..., , TYPE 3 METAL FRAME & .••••" ‘‘, i i I GRATE. GRATE ELEV.=2077.85 , -- i / Bean Elev. = 278.35 -e. . 1....... ...„.7.22.:2. L. CI kr? . . o• , in . POND 1131-rom . L.I.,.0 o...... :-.." - / ...: EL-.."1/.=2077.35 ..... 4i:), ./ . 1r 40 719.72. -•Z''. ' z-t''' ' 7 ....: .. 72. '2 rtk N.• ii .- . ••tr -;.,-k- . DRAINAGE *.ii•Y EASEMENT .**"...(b .,-**\• .. .." \..• - I • • .••••• . . . 1 " . 1 .. a .. . . I , I . , - ...- •- -.-. .... . • . . . . . c -- • . ., -...;,..2-....A- —\ 1 . _ ...... • . .. . ■ ., • . o . — -..--.1 . r. •'.7 4 I . . • . 0 ' a. 4tC1-E759_, 4'-' ail • •I■ --, "2 i • . • . , , ..:„f> • • • WI • - - v) •• • ., ,• _. • . . -4.S 9/24/ • 61 • cr. - 1.,.,. . . • .. . , . . . • _ .. , • tg I • - • . . - . - .. .. -, • 1 . • ... . . . „. . .,..„ • ., - • I -80.02' ' - • • . . - - . . • • • . . , . IX FrJV • SCALE: 1"=20' . Exartple - , • /' •• ,. • ..-. ....• - •• ...1 ...) . • • '..*N -*-- • LOT 4, BLOCK 3 . . - Plat Name . • DATE: 1 1 /18/93 1 - - - . • .. . - • . „ . .. . .-. . , .4.° 00 .0„,,,... ......., ,.......444. • '• . - Contributing area,off-cito subbasin(D) Z; • Project Site Boundary(tubber, Developed Basin Limits of runoff I - \ • \ • .0) • " 4 . • TO \• \;4, • Pi cfr . • \ -•vP 11111111146p ft . NN, - . se 4,...-:...... . \-1,_ . .;,,,_ •-?:e.--). - •' 40p,-.2:1; r „.. \ 1-21‘ -`14" P.17:4Fir,y'A.e-•:; •-. ■•:;:::::K. ' .'..*:.''-.• -.1".-5;f17.442--jfirl,%':1*. if..7" .. , . .! ' - : . '"!:'‘..9:1.V Z-,,,,,W.. ..,:4-vAlp .... ...L:s",, '--;.-', .::::::::•:. Detention Pond . -, „.• . ,"` ., i..,:-..".: _:4,.:,;e••••,..4.,--;*2:-.:?-..f . '" •--4;,-..-- AI"•••••••• . 4013 , . -''''"1" ilt-',..1.6=-'"•••••-irl...•rit•-•••••.-..,.....r ; 4.-„•,..,, ,•(,, .........., " - •. • _s% •-t-444;,-t-.: 4":"-'="- -....'71•;""--•'- ----Mir (‘ -. . i '.- -r-1".•.1 ...11.0. - /....,, c(a - : , • ;II ti.•-...• -1, e Bypass Area(B1) \rii,.. , .. ./... .... . -. P• 7•,••', '•-• ;..- - • . :.■ • - :.-. . -• '. -• ..--:- •■--- / 9 % . , • •• • .. litv ,. •-•-... . . . . • -• - .' • .. The site discharges into the natural channel under pre-developed conditions. To compute the 1.1,allnwable discharge rate(Q „,)out of the detention pond, the following ps are to be taken: ., 1. Compute the pre-developed runoff rote, Qw: The pie-developed runoff is generated from the . project site limits (subbasin E)and the contributing off-site area(subbasin D). The runoff from these two arms under pre-developbil conditions is equal to Q . 2. Compute the runoff from the bypass's=(subbasin B1),Qb".: This subbasin will not direct runoff into the detention , but is part of thedeveloproent-limits: This value is computecitnder developed conditions. The bypass area drains to the same basin as the detention pond outfall. 3. Compute the allowable release rate out of the detention pond,Qgb,,,,: . . Bypass Flows for Detention Design . . pie , Guidelines for StonnwafeT Management - . . OH Appendix C.3 Addendum, February 1998 SParkiff.CaNri .. . _ . • , ' -iiIR: 748E2RN512• • • ci a a-*4 eJ IU • - t • 0 A 4 14 A lii F3 Ft Ft Ali RI F1 . I. coododeiclacicoci I . ; ' • ;; - ..-- zoo...p..0,0e.. usisicesssastess a . . A u 1 ° = g 1 * - i tie 1 Zi"RA i liViF..kizilEji ...-'' mg.)1111 pep::!Lei PE a' "el = c z c gas -8:213t-43588-8 e. = 73 4 uti • a,0 -I rd..--aciaiciddcici.zol > Iii- •D• a. _ 0 . 15 w • m 02212158104482 .1. , E . . , . - oo•- wirgr.:444...:d 0 0 7 I ill .•,, i . • ' e ; IT) .2 CP a C! 0 a C!CI CP CP C!C!C! ' • > .' ■ _ I.' 1 F„, . =0 c - .: ". .' t• , • 1., -• .* -1, u••sg•:.s5o la-d 8 1 1^6 P6.1 8 E 811-11- ;•--rc c c. , - . . ' 4 2 11 " ,.:cei-• , - -.. .& ;Pl. •• CL t" * • .../• i M ,.111"411113BBEIEI8eir•taii 4 . . :-. 441.. cicsciacicicid;-' • IA , • - * IA P: - ■• '7 a 5 ". ': • 'r, • - •, • . C el 11 SI !!la-,I'..."-in—"Ell2 • 1111M .... 5 . I 1 I 1.5- o lei- Id ad lid Igs Id idol 14.d la - '2 CD • ' .4 ' ' '- '' ■ - -r- -;* - , • I i t..-.- CL. ',IP .-. - Z - ' - • , ct ■ _ '-. • • ...- .. ., z c.e a, o 0 0 9 is.a p.ct - - -- ussa 2111112311322 • • . t5 . • ..a _4888 286kr8-82C '''81 l• .I. Pi 4;..• 4 .■w.0 0 m ..0101 ■0. ... 0 - • - _ .. I ti 1 ad E 2 ,2 • :...... -.-.... I i If-1 III- ..- - -.... r.,.., .,......:domi. rdoll el a ' Iligi /ill 1 • , . 1 . 2 • - P11,1 , I •. ,. . 1411 l'ii'.1111,1 , _- • 1 11 Li Li e e s \ , 4t Water Budget .4 • Example Calculations ( 1 Guidelines for Stormwater Management • A110'0 Appendix C.4 Addendum, February 1998 SP:WE aX.KIY Sheet 1 of 2 ' .. • " . . . •- . . .... . ............ • ON ..... 7,,,,,,,,tio,. i,... fe-- ..---;::- •, ■A "VEA...«.te.":- . ..- .e.,2 • ••• • :',-• • • . •c:::.::: .. - . .......... . 21 g. • ••. ' I!n" v..°li 3!..!1!!=1"';ii"2 3 S!!::ji g I',3 ii i 3 Fi • :-...•,...::::::: . . :: . ,. ,. 4,•••61.4„ . • ii"' sgE5E gii:;:: . •.•. .;iiiizi 7.2i.f.E.," ,..„..„.:.:.:. ,.„-....,:-• ••-•:.-_ i.. • •••.' ::•:&_,,_•iir: -. Ai /11111111111 11111111E111 . lig ..,.. . : vriia.• . reeves. Ire.... , eq....2z ,......* n. Fil„'Is.Z.,..• . • ...". ..;19 11:-:;:-.11„ei.-51 lizo,..11Ret-a- .-.es ea . 1...WI■...-0 . II%CO Z Igor.-- • • : • .. t, .-....c4i-.• .. . - •-...• ., -, . . .,. F. •4.?.;t: : . eci .4.egnear.1..zazat •cici•jokisin:Asini• OO la V •'.' .• I sr: •...,'. -..' .- • .. ., • , • .. • t ig .i.•. ' .).'. • ' • CS ja:Aeliavig282222,1 a 00 o cr:eser000 0 .fo.lrisc ;o " ,.:31113.s. :, •■.• .. : . '.:-.3T1.11511. ...;•... _-..tl t. :-,.,i.,••.,, '':. c. .._ • , • ...,.. lo..reni f•r**71.9•41114 .....,...V r.; • - tii,k; • -.., , - 4.,b. ■p.. ............. ;;;; .... •.rlt.p.•.....01 4 ro.... l'..:? W•„/.. -. ...:.he" .In....'4'. W::$14 ,*n elle.re........-N ...e.e. . . .. •,_ ° •$ --:..dt , .i ' 1.4/" , '4711•7471, IX 'i--q?',.... .4 -...- • .--1::it F.6.12.. . - • ,:::,11:..i 1 v 1.1C.:,::11• , ... : ! 66•■ ..." 4 2..".- • ... .... ...- ..; . . . • '..::::::-: F.,:- ....•., •32"-i-,-•:-.''-.;.,•.41- ..... :.;,4.... ! , . x4 :41 ..wii"-4. .-. .-;,,,,s...:.• .:--z- i ,1,- . r, . r ........ ...., ... • foSlii:intii; W,0:- -.."Igg';Z: '--. ';'•41ZZ. l'W•g I e.C.....12 2 Er.‘a tg el C.....IA 2 , . • '4."1-4: :11-P..; ■..: Oa; 4 • . $ r,.:4-:.' g to:. ...2.;,;4,r:, :,.. I,:: ,,,.;;;,„•„„,,,,_,r.•,.,4;,-,,,,;„. ,., ..- •_, _ III'.'•••... ..101.1115 ■••... " ,L . , U , titlk Ft,i a: .P..... ..ki:gi, '. • ' '? • , -_ . fi:::::,,,,,,,• in"; :-.:i;.;:ii,figt-!. •... .,. . .; -.... • ... ... -n..-..6:...... ,„; ..; 14 ,,,i-. ...1, ."..'': ;,/..-;=.,.., --:• ....... • .: . , . 1 .. : i ....1,....... ..•:•1.7,,-.:.;' . .4' 4! . , ( '‘. - . !. A: , ; , , .. • •■■■nt .k.0 0 *0 n $., . ...,.... ....--, 019 .,.! : . ....,,,, I • '_:: -7 .4. • . f.i .. -7-.'...::::•.... • ..:::a. ..' .4 : 132.1 ''. te-:"".-iti a a.a a a.a a a a Ce d'is:a a alielfif s ci•;;T.a 5 0... :j ri vi■••t. .•-•cli n••■0 0,* " . ...14 5 • -- . • ' ..- ..... :7."- 7, ;ir:.:.:•:a:S••.S41;.,.......... .• -:-.-.. c....c• .:=,,.-1 .. ••!: - 4. -- 1 .• -. -. -..1•? ,!= ..m.:::::;. :, ..•.),.., •.....,..- :...• .,-..,. 7... ^"- -. 1 7i .. g . . A 3 '•'--1.* • • tri- •its 00 o 000 0 o 000 issammmannggis ssimmcmccgos o n ::.=;,..-_, • • ' v.-. -:..-.:w.-7,:r'17,7,,,...', ry--:,..-.. .:■. .r.w.-. 4 ... ......,.. :.. . , Rija• . .„ . ...-.. •4. , ..., ‘:. , • :r.:: ._..!"..:::::::. .-. .1 * • .. :::. ..............,..,..,,....... *.' '..:::•.,,,. ....,,t,,,• ."--,4...5 1.4. .S. • V it.‘..1•:;F:;16,1', .4. •-4". ..' ... • It:.ii.,::.i.,,,iL4;i11:1;',: .-riii:1•'2 r.s'Its,'''fan- 2 2.2 2 2 tr;2 2 2 g 2 2 rt i(22 2 2 a,a ng a : • .-6.z..-el . : ni o 0 .4.- 1'....'.'.,,,---..211:RI::. '..-...;.3,-u•-• -,-,,•-•P--- '‘''' --. • • ., ...• • ,,,,-..- ,.2.2.2.•.....-:. .. _.:. ,::::.„,,,ig,....,;., ....s2,2?..••.- , .,... .2., - • .::F727:-"12mto-„2=-:,-.,61:s.,...., .,;.;::.-- -4...L.1........ .._ , :. ".-2.7.22222 -it :.:T°41.1..F ... a III : !F.?, :E..-- !z-,:!!!!! F.41.1 .....::. .... . “.4 ; .... .! - - : F • -...,1 .15 41:iii:"::::::X.:::... poi,-. . . •••• , . . . , • „„ .: :41,,;;;;;;;52.2,:.2.:-...,!,--::•-• . : , . . -: • - .7.: • , .z ....„„..,.„,„„ _ ,:... . .... - •• _ 8 . .. . , ... •. • 4.)..::::-.1ai::::i...iii• , •' --•-• • ,....-: ." .8.:,,- stnex......2.•-gs.• 8....20.rizzczn".6;,-. . ;-. . •••. t . ::::-•-•,.17::,:ir.=:, .; . • WI F4 el o o o.-44# •t1 . ..0 OO!..on Pil 5 . . .• , .., ,, •-.:44:Iiiervir -ig:4- • . , - . ; .:i.:. . _ . 1... • : ... 7-......V.W.244::::::!.1.1.1? • . • "' . . . - , a.:••• -.-7r-:rigiiitii: : •• - • , •,...i• ma 16.,, • 4 ' • • 116.4.' .4, .:.:”.4.: •Mtit. ;;;;.44::: • -,.',7 .:•. .-• .. : fl r; . : . • • • • . .. - V& 1•.:''. , I,trill.- f' :71.0.2;2... f. .--.. 1§. IFigitIlSgiS" IligIllig2S SO:8 , '. -Ali:. , : ....:.i.l." ' • , : - • - t; • . li . • . . . -. - • • . • • . • .. . - • • Water Budget .: - . Example Calculations..,, . . . . .. Guidelines for Stonnwater Management • ... -., . .. \ 1 11 .6 .., . . _ . • 11 • . .. Appendix C.4 ,:- .•• . • - Addendum, Februily 1998 SPWIsTf.ar.KIY • Sheet 2 of 2. _ - • • I) I Appendix C.5 Sinking Fund Reserve Account Calculations for • Operation & Maintenance Costs plus Replacement Costs Example Calculations to Determine Annual Cost per Lot Annual Operation and Maintenance Costs O&M= $ 770.00 Present Value of Storm Pipe System, PV $143,980 Assume 50% replacement of Pipes in 20 yrs, PV/2 $ 71,990 Future Value of pipes to replace in 20 years, FV FV=PV/2(F/P, 4%, n =20) assume inflation=4%, n=20 FV= $71,990 (2.1911)= $157,740.00 Annual Set-aside for future replacement of pipes, A A= $157,740(A/F,6%, n= 20) assume conservative investment, interest = 6% A= $157,740(0.0272) = $4,290.00 Total Charges per Lot Total Annual Charge=(O&M) + (A) 160 lots Total Annual Charge=$ 770.00 + Annual Charge/lot =(Annual Costs)+ $4,290.00 (annual set-aside amount, A) Annual Charge/lot= S 5,060.00/160 lots Annual ChargeJlot= S 31.63 Note: F/P, A/F factors are from interest tables • • Spokane County Public Works Appendix Sediment Yield Guidelines for Stormwater Management Spokane County Public Works Appendix D Estimating Sediment Yield: Flaxman Method - Elliot Flaxman published this equation which was derived from empirical data in areas where the terrain afforded a close relationship between erosion and sediment yield, and that gully and channel erosion were not significant contributors. °'S =-86.07 - 5.30 03 + 7.33�y os os+ 10.79 °s °s Y (Xt) ' h2) - 1.63(X;} ' (X4) + 0.92(X5) where: Y= sediment yield in tons per square mile/year X1 = (P/7)/1.43 with PIT expressed as percent P = average annual precipitation, inches T=average annual temperature, degrees F J X2=average slope of the watershed, in percent X3=percentage of particles coarser than 1.0 mm in the surface 2 inches of soil divided by 72, - expressed as percent X4 = percent of clay in the surface 2 inches of soil plus 100 if the pH of the soil is greater than 7, and 100 minus the percent of clay if the pH is equal to or less than 7. X5 =the 50 percent chance peak discharge in cubic feet per second per square mile(i.e. 2- yr storm event). For use of this equation, on site field samples need to be collected and tested to determine the variables X3 and X4. Guidelines for Stormwater Management Spokane County,February 1998 Appendix E Seed Mixtures Guidelines for Stormwater Management Spokane County Public Works Dryland Grass Seed Mix Grass Seed: Provide fresh, clean, new-crop seed complying with tolerance of purity and germination established by the Official Seed Analysis of North America. Provide seed mixture composed of grass species and percentages as follows: 10 percent Elka Perrenial Rye 20 percent Durar Hard Fescue 45 percent Covar Sheep/Fescue 15 percent Reubens Canadian Bluegrass Provide mixture composed of grass seed and fertilizer in percentages as follows: Grass Seed: 90 lbs. per acre Fertilizer: 16-16-16 timed release composition, 300 lbs. per acre • All seeding of slopes shall be done in accordance with the WSDOT Standard Specifications, Sec. 8-01. • Spokane County Public Works February 1998 Appendix F Easement Exhibits Lot Plan Requirements Guidelines for Stormwater Management Spokane County Public Works Drainage Easement Exhibits • Exhibit Requirements Spokane County Public Works, November 1997 • Plan to be drawn to scale with north arrow • Document Size: 8 '/z" x 11" or Legal • Margins: 1" or greater all four sides • Items to Include in Exhibit: Entire easement limits, surrounding property lines, nearby street names, lot and block numbers of affected parcels and adjacent parcels, plat name(s). Appendix G Inspection Agreement Form Guidelines for Stormwater Management Spokane County Public Works • SPECIAL INSPECTION AGREEMENT . Project Title Project Address • S T -R* Project Owner Project Number Pursuant to the conditions of the approved Design Deviation, the above-referenced project requires special inspection of: {Insert brief description of drainage facility: i.e.type,size,etc.) The stormwater system is being built on this site to control stormwater runoff resulting from the development of this parcel. The purpose of this special inspection is to insure that the drainage facilities are constructed in substantial conformance with the Accepted plans, and that the facilities will function as intended. • PART I. GENERAL CONDITIONS Definitions: • Special Inspector: A Professional Engineer licensed in the State of Washington, and his authorized agents, hired by the Owner, to provide quality control testing and inspection services. Owner: The person or company sponsoring the project Contractor: The person or company hired by the Owner to construct the facilities. Accepted Plans: Civil plans for the above referenced project, prepared, stamped, and approved by a Washington Licensed Engineer, which have been reviewed by the Division of Engineering and Roads and accepted for construction. Special Inspection Agreement page: 1 Spokane County Project No. Design Engineer: The Engineer of Record for the design of the stormwater control plans. This Engineer must be a Professional Engineer licensed in the State of Washington. rf _ General Conditions • The.Owner, Contractor,:and_Special Inspectoj are:to'perform their respective duties in a . :, cooperative manner, to insure that the drainage facilities are constructed in accordance with the Accepted Plans. This Agreement shall be signed by the responsible parties, the Contractor, Owner and Special Inspector, prior to issuance of a building permit. . .1., t. . .. • ... . .... .. - . ., < . .-, . • _ '..a. .. +.. „AJ s. ..f • Special Inspection Agreement page: 2 Spokane County Project No. • PART 2. SPECIFIC REQUIREMENTS FOR THE CONTRACTOR: 1. The Contractor shall provide the Special Inspector two working days.notice prior to performing any construction activity that will require inspection by the Special Inspector. 2. Activities that will require inspection include, but will not be limited to: . a) Excavation of drainage pond areas, conveyance ditches, berms,and any other earthwork. b) Placement of fill for drainage areas. , c) Placement of manholes, catch basins,gravity or pressure-line storm drainage piping, poured-in-place drainage structures.,gravel drainfields, pumping systems, storm water ponds and disposal facilities,etc. d) ' Finish grading; insiallaiion of'soddirii-seeding, landscaping,and irrigation systems; final cleanup. e) "" Other items, as listed in"Exhibit A." 3. The Contractor is responsible for reviewing the approved plans for additional activities that'require inspection by the Special Inspector. 4. . The Contractor shall correct any deficiencies in the work,as noted by the Special Inspector, in a timely fashion. - _ - 5. - The Contractor-shall notify the Owner,the-Special Inspector, Spokane County Development' Services(a representative of the County Engineer),and the Design Engineer immediately of any unexpected site conditions. Unexpected site conditions are those that would prevent the construction of the improvements as designed, or which would adversely affect the performance of the drainage facilities. Spokane County Develbprnent Services can be reached at 456=3600. 6. The Contractor shall read and understand the Owner's and Special Inspector's portions of this Agreement. -- CONTRACTOR ADDRESS: - PHONE NUMBER: DATE: BY: (Print Name) (Authorized Signature) Please copy and retain for your records Special Inspection Agreement page: 3 Spokane County Project No. • I_ PART 2. SPECIFIC REQUIREMENTS (Cont) . i FOR THE*OWNER: . r • . 1. The Owner agrees to employ a Professional Engineer, licensed in the State of Washington, prior to construction,for the purpose of being a Special Inspector of the construction activities for the stormwater drainage accepted for Construction. 2. For coordination purposes,the Owner shall provide the Contractor the name and phone number of the Special Inspector; and the Owner shall provide the Special Inspector the name and phone'number of the Contractor. 3. The Owner shall aid the Special Inspector in being present on the site'when required. The Owner shall also aid the Special Inspector in submitting final reports,testing data,and Record Drawings to the Spokane County Division of Engineering and Roads. • . • • - 4- The Owner,shall help to facilitate the correction of any deficient 5 aspects`of the stormwater drainage rystem •5:- The.Owner shall read and understand the Cantractor's•andSpecial Inspector's portions of this • qty 6. The Owner acknowledges that he/she will not receive a Certificate.of Occupancy until deficient aspects of the construction are corrected,and the Record Drawings are accepted by the Spokane County Division of Engineering and,RoadS.., OWNER ADDRESS: PHONE NUMBER • •'• • DATE: . -• •• . .._ • (Print-Name) (Autho'rized Signature) - . Please copy and retain for your records • • 1 • Special Inspection Agreement Page: 4 Spokane County Project No. • • I PART 2. SPECIFIC REQUIREMENTS (Cont.) FOR THE SPECIAL INSPECTOR: 1. The Special Inspector shall perform job site inspection,materials testing and quality control services to an extent that the drainage facilities associated with the project will function: a) in accordance with the applicable Spokane County Codes and regulations; b)as intended in the design; c)in conformance with the Design Deviation Conditions associated with this project, if any; and d)as shown in the Accepted Plans. ' 2. The Special Inspector must be licensed as a Professional Engineer in the State of Washington. 3. The Special Inspector has the responsibility of being present on the site when he/she is notified by the Contractor that work will be performed that requires inspection. 4. The-SPecial Inspector shall log into the Inspection•Record Card each time that he/she performs inspection work'on the site. - 5. The Special Inspector shall use the Accepted Plans, as defined above, for overseeing the construction of the drainage facilities.- 6. Examples of inspection duties include,but are not limited to: a) Durintexcavation and construction of pond areas,ditches, Berms,etc.: i) Note significant changes in soil or presence of groundwater. • ii) Confirm: . • . • - _ - •., . • • • - a), _ --Elevations of ponds, berms,conveyance ditches. b) Side slopes:grades and embankment stability.. c) Dimensions of ponds, berms,and ditches. . • d) Horizontal locations of improvements. • e) Pond liner materials and installation piocedrires, if used. f) Soil compaction. g) Elevations and dimensions of drainage structures. • iii) Perform testing of fill material for gradation and compaction.' b) Perform testing of cadent concrete for compressive strength, slump,and air entrainment. c) Inspect the placement of reinforcing steel in cement concrete structures. d) Inspection of the placement of gravity or pressure-pipe stormwater lines. Inspect pipe • material, size, length,grade, construction methods. Special Inspection Agreement page: 5 Spokane County Project No. • e) Observe the placement of sod, seed, landscaping,and irrigation systems. Ensure that these items meet specifications, and that they do not interfere with or harm the stormwater control system. • • • . ; f) See Exhibit 'A','Which is attached: • 7. Often, the Special Inspector will need to perform inspection duties beyond the minimum . requirements set forth on the plans or listed herein. It is recommended that WSDOT Specifications be used where specificationsare not expressly given. •• : ,• . 8. The.Special:Inspector shall notify the Contractor, Owner,-the Design Ewineer, Spokane County Division of Builciin,gand•Planning,and.Spokane County Development Engineering Services (a representative of the County Engineer) immediately, if unexpected conditions.are encountered that would prevent the proper construction of the improvements,or that would negatively affect the operation of the,drainage fiicilities. • - . • 9. Any modifications to the Aazeined.Plans must be submitted to the Design.Engineer_for approval, prior to construction of the modifications. .• • - 10. Copies of all routinereports,sjkall be submitted by theSpecial.Inspector to both Spokane County Development Engineering Services (a representative of the County Engineer)and the Division of Building and Planning on a weekly basis. 11. Prior to the issuance of a C.ertificate of Ocarpancy for this project: • a) The Special Inspector shall•submit-Um:x=6mi reports,lab reports,and.Record Drawings. The Record Drawings shall be stamped and signed by the Special Inspector,with a statement on theplaas that.the.constructed improvements are in substantial.conformance with the Accepted Plans. b) The Owner, Contractor and Special Inspector shall acquire written acceptance of the Record Drawings and inspection reports from the County Engineer: 12. The Special Inspector shall.read and.understazui the Cori:tractor's and Owner's portions of this Agreement. ,. .• •. SPECIAL INSPECTION FIRM: ••• • •• • • • -- • • •— ADDRESS: PHONE NUMBER: DATE: - • SPECIAL INSPECTOR: - (1Y01.Name) .. s.• . SPECIAL INSPECTOR- • . . (Authorized Signature) • • - WASHINGTON PROFESSIONAL ENGINEERS LICENSE NO. : Please copy and retain for your records \ Special inspection Agreement page: 6 Spokane County Project No. • • PART 2. SPECIFIC REQUIREMENTS (Cont.) Exhibit `A' Additional items which require inspection for this project are listed below. (To be Completed by Spokane County Engineer's Office) Special Inspection Agreement page: 7 Spokane County Project No. Appendix H Civil Site Plan Requirements - Checklist Guidelines for Stormwater Management Spokane County Public Works SPOKANE COUNTY ENGINEERING DEPT. MINIMUM REQUIREMENTS CHECKLIST Project : County Reviewer: The following is a-Iist.of,minimum standard Items used in reviewing plans for building permits. Without these minimum requirements the Spokane County Engineers Department is not able to perform a review of the project. The project will be returned to the applicant or held*without further review until the minimum items have been submitted. O RECitiRED er THLS PROJECT ❑ NOT APC,LCABLE TO T165 PROJECT _ .. , 0 An agreement to pay: fees must be received before review. ofrthe plans will continue. It is an agreement between=an•interested party (owner,agent, etc.)and.Spokane County to reimburse the County for costs accrued in reviewing the plans. • ' • ❑O All plans submitted to•this department are required by state law-to have a Professional.Engineer's stamp. The Professional Engineer's=stamp must-include the,currentfseal and=expiration:date;as well as the dated Engineer's,signature. The Engineer must be currently registered in the State of,Washington.; ❑❑ North Arrow must appear on the plans., r. ,. :.u. ❑❑ An appropriate engineering scale-is-required forthe plans. -- ,•- ' - 0 00-kbenchmarkliitisi be shown on the plans. A benchmark Is a physical-mark or object used*as'a reference for elevations. This'point must be left undisturbed by construction. • 00 Road names must appear on the plans. 00 Right.of..Way.dimensions,from centerline of.adjacent.roads to property lines.must appear-on the O•Property line dimensions of the entire parcel•must be shown, not just the portion.being constructed. . 00 Provide contours or sufficient spot elevations to check site grades. One-percent is the minimum requirement without special,construction requirements by a licensed engineer. .� 00 Land required to be set-aside for future acquisition,by the County,,for future,nght-of-way needs,to.be shown on the site plan. Required 208 swale areas must be outside of set-aside area. 00208' Calculations:for the site°are' required for runoff'of asphaltic surfaoesqpavement, roofs, etc.) within the-AquiferiSensitive Area.'Show the quantity of'asphaltic area, volume required,and provided, swale area required'and pmvided'.f• ; . • - - - - ❑O Provide a copy of roof detail sheet or state construction of roof. Metal roofs do not have to go to a swale, while asphaltic or built-up roofing is required to be handled by a swale: If-HVAC equi.pment,is proposed to be located on the roof then the roof area needs to be included ins ale ihiculations unless the HVAC unit is sealed and self contained. O 00 Show a typical section of a swale.The swale must be sodded and side slopes should not be steeper than 2:1 for up to 12" in depth. For swales with greater depths use 3:1. The top of the swale should be a minimum 2' above the drywall lid. 00 Provide bottom of swale elevations. ❑O Provide details of Spokane County Type A and/or B drywells. • - 00 Provide drywell grate elevations. Guidelines for Storniwater Management Spokane County, February 1998 ❑❑ A Spokane County Type 4 drywell lid is required for drywells. Specify on the drawings this type of lid. • DO Certain locations within Spokane County Require special testing to determine suitability of soil for drainage. Provide a detailed soil/site report from a licensed geotechnical firm. Report must include soil logs to 20 feet in depth or bedrock, indication of ground water.and infiltration tests. .f ❑❑ Calculations for all grates, pipes, inlets, ditches, etc., must be submitted. ❑❑ A Landscape Plan is required to ensure swale areas are not conflicting with landscaping. OO A traffic circulation plan is required for this project. This plan may be incorporated into the site plan. unless specifically requested to be separate. 00 All traveled surfaces are,requiretl to be paved unless a paving<waiver has been granted.. OO A letter from SCAPCA isrequired for projects requesting,a pavement.waiver. The letter is obtained by this department after a written request is received from the applicant. A-pavement waiver is required when a portion of a site is not paved when otherwise required to do so. 00 All parcels must be aggregated. If impossible, a reciprocal use agreement is required for this project. It is an agreement between the owners of two or more parcels granting reciprocal iuse'between the properties. Situations that may require-this•agreement•include: ingress/egress, parking-or drainage across•property Clines: °-This.agreement asja`lager•document between the parties invotved::: :For-more information, contact your land use attorney. - • 0-Approach-pemII are required-on all:new approaches,'as well as all approachesthatwill be altered Approach permrts"will be•available after final approval oftthe'site/drainage plan. . OD`Complete rioadta:nd drainage piaiis'are'required for'irtiproveinerits to the itiaduray: 'Mylars with=the• developers signature will be required before the plans are approved bbSpokane'County.:w:.--. • DO A bond or some other form of financial:.surety approved by-Spokane:4County:;isL required. •-To expedite,your request for,;a,:building permit-the.,County, has,3 pre-approved4bond formats. „If you,cttoose• to use a different format, a member•of the County's legal-steff-witJ,heve-to review the language; This will likely result in delaying the permit review process. The amount of the bond will be calculated by the l• County after the first submittal. " • ' r.:4„'•; :` : ❑O`A property deed is'required if'the applicaiitrdecides'toprocsed with a'Road'impiiovement District Agreement. This is an agreement to not protest the formation of a Road Improvement District. This document is'required:irirlieu<of making necessary roadway:improvements: A:deed?is also•necessaty'•if.•right-oi;wayris-required. _ ._• - This list is not inclusive of all of the• requirements needed Or •will'fulfillment of these minimum requirernerrts autos iafi'cally result apprval-from'this=department. e = . This checklist•is•smeant to help•expedite the;review- process by.assuring' that-minimum:items "are available. ' The County .welcomes cornmentstconceming this checktist;.to:assure that it is fulfilling its purpose- helping the review process be more efficient. Please direct all-comments in-witting to: Development Engineering Services • • .. < 1026_W..Broadway Ave. . . . ;r.:Y . Spokane WA 99266-0170 • - - _ • • Guidelines for Stormwater Management Spokane County. February 1 998 v Appendix I Geotechnical Site Evaluation Requirements Guidelines for Stormwater Management Spokane County Public Works • APPENDIX I CONTENTS: APPENDIX 1-1: STORM DRAINAGE GuthELINESFOR SITE CHARACTERIZATION APPENDIX 1-2: SITE INVESTIGATION FLOW CHART APPENDIX.1-3: REQUIRED mkiimUM'PER*Aigury FOR USE WITH STANDARD DRYWELL PRACTICE AND - -; • - DERIVATION OF MINIMUM "Kr VALVE - - • -- • • .• .10 APPENDIX 1-4.1: APPLICABILITY'OF IN-PLACE TEST METHODS . _ . APPENDIX STANDARD Fok ESTIMATING FIELD PERMEABILITY OF SOIL IN-PLACE USING BOREHOLE METHODS APPENDIX 14.3: : STANDARD FOR ESTIMATING FIELD' PERMEABILITY OF SOIL IN-PI:ACE-USING . TEST..PIT METHODS . APPENDIX 1-4.4: - STANDARD FOR ESTIMATING SURFACE • INFILTRATION RATE USING SINGLE-RING INFITROMETIER METHODS • . . . . APPENDIX 1-4.5: STANDARD FOR ESTIMATING OUTFLOW . RATE FROM A DRYWELL UNDER FULL SCALE, CONSTANT HEAD CONDITIONS. APPENDIX 1-5: REFERENCES APPENDIX I-1 STORM DRAINAG •ESIGN G sIELINE '0 • SITE : RA RIZATION Geotechnical site characterization should be conducted to demonstrate the site's general suitability for on-site storm water disposal. The scope of the investigation should consist of the following elements 1.0 Review the "Soil Survey of Spokane County, Washington", to identify mapped soil units and their boundaries relative to theproject site area Sites mapped within Garrison, Springdale, or Ellen sail-units may not require in-place testing. Acceptance for storm chlinage disposal using standard drywell practice for these areas may be based on index testing to verify soil group classification. 2.0 Review applicable geologic maps of the site area, to identify any site conditions that can impact,the use,of storrn,drainage disposal systems. This may include, outcrops, borrow pits, or existing ground water conditions 3.0 Siie exitlorations shouiciconsiit of a ininithum Otihree exploratory test pits or borings on the site and specifically in the planned disposal area. The explorations should-extend-at least 5 ft below the bottom'of the proposed disposal facility 4.0 Samples recovered from the site exploration workmay be tested to assess grada- tional characteristics to help veiifithe soil classification for coniparison with he mapped soil unit - 5.0 Include a limited surface reconnaissance of surrounding properties, particularly in the down-grathent ground,water flow direction, to assess potential impact of: additional ground water - 6.0 Perform in-place testing to estimate the permeability of the site soils. 7.0 Providez summary report, describing the results of the work Include a vicinity 'map, an exploration site plan, and laboratory test results. Include information regarding the depth to groundwater,andthe presence of any limiting layers which may control ground water flow Consider feakbility and limitations for on-site • rdisposal. Include information on how the field permeability testing was performed and the assumptions made for determining the recommended infiltration rate The report shall be prepareclunder the direction of a licensed professional engineer and "apPropnately.sigried and sealed , • • N a) T • ve 10 , Cr . o, ai �, c =y m c3 - , 10 • 2 THE I ) - & B. / v) a •v c _m b d .E c y 19 g � C to O ra co 0 p. O 1. C.) 0 d Dr y • y-d O ••R" to y C1 C Q c -_-° = 5 c C m C �. co a _ y c a, to C pEj a) TA a) .�. p 0 E o 3 CU iv c y Cr C U o E a c.s. , - . ° ° E 0 ea a' a. a) N. E c .u) U •:--: 41 • C o p• - yE ' m V. co O . Z•• V m L. 5_ • •c 1�C.•d Z - c0 d u a o. ° `o can v m. 1.7). cr• . ev .. • w r Q ZO ,_ ` Z 1" ° W a Z �. _ Cr °' a I-, y • •C - >- .. °. �. > >- r3 D Z C_ C 1-4 C - -� N _ :z:: 1 • cn G. C .5) co o c v 0 o C N > m y V N I0 C y l' Q)� ..� O• -a1.1 N IN 2-- yID a c • 'yea _ a, > 0 0 D • Q) v,'C. ; •° C• y >. H =°- �, V d E ti; c y W Z ► C `' Z _- C ' E p to a) co a) d -0 a N H H C c go O cn V7 C. a) 0 •fl. - efl in. u rn o ri ° C ° O o a d C a�i c- o d E ° a - ' ° 0 . a c • �o ao dN p a h r0 e0 V 0) ° en e0 y . G ID • a, .•H .ro ? _ o c v 0 Ti -3 'E ea e9 a > o d Q E n3 0. ¢ o in W c c c, ~ ; o �, W to W in • APPENDIX 1-3 REQUIRED MINIMUM PERMEABILITY FOR USE WITH STANDARD DRYWELL PRACTICE AND DERIVATION OF MINIMUM PERMEA., BILITY ("K") VALUE • . - . Spokane County Standard Type"A" or Type"B"-cfrywellsIlischarging•at as,surned,rates of 0.3 CFS and 1.0 CFS are allowed in soil groups other than Springdale; Gani:son, Bonner, Hagen, Bong, Phoebe, and Marble provided the other conditions in section 4 under Standard Drywell Practice are met, an the soil surrounding the drywell has a minimum permeability of 2.5 X 10.2 cm/s when tested ilaccOrcianee with the field procedures outlined in this appendix. • This minimum required value is based upon modeling the drywell as a reverse well and applying an equation presented in USBR Test Procedure 7300-89 that relates outflow rate, • ( from an injection well under constant head conditions to soil permeability and other well geometric properties. • The derivation of this rate is presented on the following page of this appendix. • , r Please note that permeability"K" is.used in-the-context of Darcy's'Equation that describes flo.;/.fthrouei poro.iis media: • .• Q=K * A -- • Where Q=Flow Rate in units of Volurne/Time Tameability in units Of Length/Time • _ i =Hydratilic Gradient in units of Length/Length - V - A=Cross sectional area of flow in units of Length Squared • Also please note the difference between permeability"K" as described above and the soil infiltratiori'rate . Within the context of this appendix, infiltration rate " is used to indicate a volume flow rate moving across a surface boundary having an area"A" (ie: - CFS./ square foot). 2.5X104 CM/SEC THRESHOLD PERMEABILITY CRITERIA DERIVATION Basis for 2.5E-2 cm/sec minimum permeability criteria for standard drywells. Reference: "Performing Field Permeability Testing by the Well Permeameter Method" USBR Procedure 7300-89. Given: Wetted perimeter of Type B standard drywell.with 10 foot bore depth is about • 600 square feet, (per Spokane County calculation circa 1992). • USBR Equation for Condition 1 (thickness of unsaturated strata greater than 3H, where H . is the height of the water in the cirywell).-The design equation is : . pi- - k = (L,n(= _ r 1 ) 22t -•r . . _,-L - . ,••• s. . • The design equation is solved for the permeability(k)required for a constant inflow(q) of 1 CFS. Geometric parameters required include H and r. A standard Type B drywell installation,with an-inverted conicaLenv,elope-of drainage gravel provides approximately • 600SE,of,sideslope-infiltrAition area.; Amequivalent cylindrical surface,-haying aside area of 600SF and a 10 ft. depth, would require an effective radius (r) of about„9:-5.1L. Using these parameters,.theminimumrequired k for q= 1 CFS is; therefore: ' • • • „. • 14il 10)2 1.0 10 10 2 N, 9.5 K.— (LA[— (--) •1] .1/10/9.5 2n(10)2 93 93 10/93 - • • • =7.8 x 10;4frsec =2.4 x 104 crtilsec - • APPENDIX.I-4.1 , _ RECOMMENDED FIELD PERMEABILITY TEST PROCEDURES APPLICABILITY OF TEST METHODS I-4.2 Spokane County Public Works Department Standard for Estimating Field • Permeability of Soil-In-Place Using Borehole Methods •`� Test method is applicable for determining permeabilities for use in the design of standard'andinan-standard systems utiliang,drywells::Note: Design deviation required for all non-standard subsurface disposal systems. • I-4.3 Spokane County Public Works Department Standard for Estimating Field Permeability of Soil-In-Place Test Pit-Methods Test method'is applicable for determining permeabilities for use in the design of non-standard, alternative subsurface disposal systems incorporating such features as subsurface trenches, subsurface galleries, low-profile drywells, etc. Note: Design deviation required for all non-standard subsurface disposal systems. I=4:4---'Spokane'County Public Works-Departnient•Standard for:Estimating Surfite; ..-Irifil tration:Rie-andtFieldPernieabilityRate Using Single-Ring Intiltrometer= • Test method-is applieablefor estimating infiltration-and permeability rates for.::. ' surficial soils in conjunction with non-standard, subsurface disposal systems . incorporating infiltration ponds. Note: Design deviation required for all non- standard subsurface4isposal systems.,.. :. I-4.5 Spokane County Public,Work Department Standard for Estimating Outflow Rate From A Drywell Under Full-Scale, Constant Head Conditions - Test method is applicable for confirmation of design outflow rates for newly installed standard and noii-standard drywells. • APPENDIX I-4.2 SPOKANE COUNTY PUBLIC WORKS DEPARTMENT STANDARD FOR ESTIMATING FIELD PERMEABILITY OF SOIL-IN-PLACE USING BOREHOLE METHODS (February 6, 1996) 1) Using a hollow-stem`auget, advance a 6-inch-diameter or greater borehole to a depth of 2-to 5'feet below the anticipated elevation of the proposed drainage structure. Use care not to contaminate the sides-of the hole with'Snes. 2) Install a slotted pipe or well-screen into the hole having a minimum diameter of 2-inches and a minimum 20%'open area through the hollow-stein portion'of the auger-string. Install the pipe as nearly as is practical to'the bottom of the hole. Wrapping the pipe with a highly porous;non-woven , geotextile fabric is an allowable pr et` ice. 3) During auger removal, install a gravel-pack of uniform, clean, dry, pervious fine gravel around the slotted pipe. Omission of this step is an allowable practice. However, calculations for permeability must be based upon the original diameter of the borehole, therefore omission of the gravel pack is not recommended. 4) Introduce clean water near the bottom of the hole through the slotted pipe using an in-line, commercially available, flow meter. Prior to the test, field check the accuracy of the flow meter using a suitable container of known volume (ie: 5 gallon bucket, etcetera). 5) Raise the water level in the hole until a level consistent with the operating head anticipated in the proposed drainage structure is achieved. Based upon the soil permeability, the subsurface soil profile, and the water supply system available, head levels lower than those anticipated in the drainage structure are permitted. 6) Adjust the flow rate as needed to maintain the constant head level in the hole. Minimum required test time is I hour. 7) Monitor and record the flow rate required to maintain the constant-head level at appropriate intervals. In no case shall the interval exceed 10 minutes in length. 8) Continue maintaining the constant head until a stabilized flow rate has been achieved. Consider the flow rate stable when the incremental flow rate required to maintain the head does not vary by more than about 5%between increments. The intent of this section is to achieve a relatively steady-state flow condition between the minimum 1 hour test time and a maximum test time of 1+1/2 hours. At the discretion of the on-site engineer or engineering technician, the test may be extended beyond the 1+1/2 hour maximum. )) Upon completion of the constant-head period, discontinue flow, and monitor the head level drop in the borehole at appropriate intervals over at least a 30 minute falling-head period. Page 1 of 2 • Spokane County Borehole Permeability Test Standard: Page 2 of 2 (February 6, 1996) " 10) Compute the permeability for the constant head portion of the test using methods outlined in the following: United States Bureau of Reclamation procedure 73000-89: Performing Field Permeability Testing By The Well Permeameter Method. And USER Procedure 7305-89: Field Permeability Test (Shallow-Well Permeameter Method). Note: Utilize stabilized flow rates observed near the end of the constant-head,period•in the permeability calculations. , 1 l) At a minimum the test report shall include-a description of the equipment used to conduct the test (including type of flow meter used and the results of the on-site, flow meter accuracy check); difficulties encountered during drilling and testing, a subsurface.log.of the,soils encountered; depth and diameter of the bore-hole; type of gravel-pack used (including•visual description); type,of slotted.pipe used, raw data for both constant&falling.head.periods_including flow meter readings, incremental flow rates and observed head levels; and calculations showing how the_reported permeability rates were computed. • • • . 'i.�'• c .- -. .- -. a ..,... .:. ._ 2 -• • • • • • APPENDIX I-4.3 SPOKANE COUNTY PUBLIC WORKS DEPARTMENT STANDARD FOR ESTIMATING FIELD PERMEABILITY OF SOIL-IN-PLACE USING TEST PIT METHODS (February 6, 1996) • • • ' i 9• _ 1) Excavate a rectangular test pit having approximate dimensions•of 2 feet in width•atid 4 feet in length. Extend the pit until it's bottom elevation is approximately 2'feet`to 5 feet below the bottom elevation of the proposed drainage structure. As much as is practical, excavate the pit to neat-line dimensions, andkeep it free of surface slotigh; organics; and other deleterious material. 2) 'L ne the walls and bottom of the pit with a:highly porous, non-woven; geotextile fabric. •Install=a vertical,PVC observation Pipe in the pit. Then bacl ill the pit with a clean,`uniform;'pervious, fine gravel:or a clean,'uniforin;pervious; open-graded coarse'giavel.'Note t}iat omission of the:PVC observation pipe and perviousgravel'backfill`is3an allowable practice: _ 3) Introduce clean water into the test pit using•an in-line, commercially available, flow meter. Prior to the test, field check the accuracy of the flow meter using a suitable container of known volume(ie: 5 gallon bucket, 55 gallon barrel, etcetera). • 4) Raise the water level in the pit until a level consistent with the operating head anticipated in the proposed drainage structure is achieved. Based upon the soil permeability, the subsurface soil profile, and the water supply system available, head levels lower than those anticipated in the drainage structure are permitted. 5) Adjust the flow rate as needed to maintain the constant head level in the pit. Minimum required test time is 2 hours. • 6) Monitor and record the flow rate required to maintain the constant-head level at appropriate intervals. In no case shall the interval exceed 15 minutes in length. 7) Continue maintaining the constant head until a stabilized flow rate has been achieved. Consider the flow rate stable when the incremental flow rate required to maintain the head does not vary by more than about 5% between increments. The intent of this section is to achieve a relatively steady-state flow condition between the minimum 2 hour test time and a maximum test time of 2+1/2 hours. At the discretion of the on-site engineer or engineering technician, the test may be extended beyond the 2+1/2 hour maximum. Yes, it is a 2 hour minimum for the pit method. • 8) Upon completion of the constant-head period, discontinue flow, and monitor the head level drop in • the borehole at appropriate intervals over at least a 30 minute falling-head period. Page 1 of 2 Spokane County Permeability Standard(Test Pit Method): Page 2 of 2 •• • (February 6, 1996) 9) Compute the permeability for the constant head portion of the test using methods outlined in the following: United States Bureau of Reclamation Procedure 73000-89: Performing Field Permeability Testing By The Well Permeameter Method. And USBR Procedure 7305-89: Field Permeability Test (Shallow-Well Permeameter Method). Note: Utilize stabilized flow rates observed near the end of the constant-head,,period.in the permeability.,calculations. See section 13.3 of USBR Procedure 7300-89 for test.pit method. _ ' 10)At a minimum the test report shall,include adescription of the.equipment used.to.conduct.the test (including type•of flow meter used and the results of the on-site, flow Meter accuracy check); difficulties encountered during excavation.arnd testing•,a,subsurface soil log of the test pit; test pit dimensions; color photographs or color,rcproductions winkthe excavation a_nd.sod ty_pest,� 11.. 1.• • ! th constant LPL ng encountered• a of fabnc.li:uri and%or vel backfill used• raw,dath'foz bo head periods inc udinglflo m_eter readings i .. .�.en l .s,a: n t.= _.,. w, r utcremtntal flow rates and observed head levels; and calculations showing how the repotted permeability rates were computed. • �' • APPENDIX I-4.4 • SPOKANE COUNTY PUBLIC WORKS DEPARTMENT STANDARD FOR ESTIMATING SURFACE INFILTRATION RATE AND FIELD PERMEABILITY OF SOIL-IN-PLACE USING OPEN, SINGLE-JUNG, I o TROMETER METHODS . (February 6, 1996) 1). Drive,jack, or hand-advance a short section of steel.or PVC pipe having a minimum inside diameter of approximately.-12 inches, and a beveled leading edge into-the soil surface to a depth of about 8 inches. If after installation the surface of the soil surrounding the-wall of the ring shows signs of excessive disturbance such as'enxtensive,cracking_or heaving, reset the ring at another location using methods that will minimize_the'disturbance.:`If_the surface.of the soil is only slightly.,ditrubed, tamp the soil surrounding the inside-and outside'.wall.of the ring until it is as firm as'it.was-prior to disturbance. 2) Introduce clean'waterinto the ring using an in-line, commercially available, flow meter."Prior to the • ".•test;field-check the accuracy of the flow meter using a suitable container of known volume (ie: 5 gallon-bucket, etcetera). Usesome form of splash-guard or diffuser apparatussuch arahighly• porous, non-woven;.geotextile fabric-or a sheet of thin aluminum plate to prevent erosion,of the surface of the soil during filling and testing. s. 3) Raise the water level in the ring until a head-level of at least 6 inches above the soil surface is achieved. 4) Adjust the flow rate as needed to maintain the constant head level in the ring. Minimum required test time is 2 hours. 5) Monitor and record the flow rate required to maintain the constant-head level at appropriate intervals. In no case shall the interval exceed 10 minutes in length. 6) Continue maintaining the constant head until a stabilized flow rate has been achieved. Consider the flow rate stable when the incremental flow rate required to maintain the head does not vary by more than about 5%between increments. The intent of this section is to achieve a relatively steady-state flow condition between the minimum 2 hour test time and a maximum test time of 2+1/2 hours. At the discretion of the on-site engineer or engineering technician, the test may be extended beyond the 2+1/2 hour maximum. 7) Upon completion of the constant-head period, discontinue flow, and monitor the head level drop in • the ring at appropriate intervals over at least a 30 minute falling-head period. Page 1 of 2 - Spokane County Single-Ring Infiltrometer Test Standard: Page 2 of 2 -- (February 6, 1996) • • • 8) Compute the surfaCe infiltration rate using the equation:-I Q/A Where I.is the surface infiltration rate, Q is the flow rate required to maintain the constant head, and A is the surface area of the soil inside the infiltrometer ring. Use stabilized flow rates observed near the end of the constant-head period to compute the rate. 9) Compute the permeability rate using the following equation: K=(Q *L)/(A * H) Where Q is the flow rate required to maintain the'constant head,Lis the length of soil-column contained within the ring,.A is-the area:ofthe ring, and Histhe headievel.measured from the-base ofthe.ring to the free water:surfac.e: This.equation is based tiponinformation presented in=the U:S. Bureau of.. - Reclamation'Drainage Manual section 34::Ring Permeameter Test. Use stabilized flowlates -observed-nearthe end.of the.constant head period-to compute the rate. . . • • 10) At a minimum the test report shall include a description of the equipment used to conduct the test -(icluding type of flow meter used.andthecresults:of the on-site, flow meter ac.curacy.,check);-a subsuiface.log vf the soils encountered (if test was conducted in the bottom-of a test-pitY;,difficulties encOunterecilduringltesting;lawciata for both constant.and fallinghead.petiocis including.flow:meter readings; incremental flow rates,.and obkrved head-levelszand calculations showing how the.,. ; infiltration and permeability rates were computed. k 3 • k '1 •- • . ' . • . , , '? • • ' ' • . . • • ' •-• - • \ I • • APPENDIX I-4.5 SPOKANE COUNTY PUBLIC WORKS DEPARTMENT STANDARD FOR ESTIMATING OUTFLOW RATE FROM A DRYWELL UNDER FULL-SCALE, CONSTANT HEAD CONDITIONS • (February 6, 1996) 1) Inspect the drywell and make a thorough report of its condition. At a minimum include information on any silt build-up; if there is any standing water in the drywell; whether it is interconnected to other drywells or catch basins by pipes; the overall depth of the drywell from finished grate elevation to bottom; the distance from finished grate elevation to the invert elevation of any interconnecting pipes; the length of the active barrel section. The active barrel section is defined as the length of ported sections from the bottom of the drywell up to the elevation of the base of the solid cone section. Include additional information as is applicable(ie: age of the drywell, if it appears to have been heavily impacted by unusual factors such as construction practices, etcetera). 2) Introduce clean water into the drywell using a calibrated, in-line commercially available flow meter. 3) Raise the water level in the drywell until it reaches the top of the active barrel section and then maintain it at that elevation. In the case of drywells interconnected by pipes, raise the water level to the invert elevation of the connecting pipe, or use an expandable pipe plug to seal the connecting pipe. 4) Adjust the flow rate as needed to maintain the constant head level in the hole. -Minimum required test time is 1 hour. Test time begins after the water level in the drywall has reached the top of the active barrel section, or the invert elevation of any interconnecting pipes. • 5) Monitor the flow rate required to maintain the constant head level in the drywell at appropriate intervals. In no case shall the interval exceed 10 minutes in length. 6) Continue maintaining the constant head level in the drywell until a stabilized flow rate has been achieved. Consider the flow rate stable when the incremental flow rate required to maintain the head does not vary by more than 5%between increments. The intent of this section is to achieve a relatively steady-state flow condition between the minimum 1 hour test time and a maximum test time of 2 hours. At the discretion of the on-site engineer or engineering technician, the test may be extended beyond the 2 hour maximum. 7) Upon completion of the constant head period, discontinue flow and monitor the head level drop in the drywell at appropriate intervals for a 30 minute falling head period. 8) Report test data in a format which includes time of day, flow meter readings, incremental flow rates, observed head levels and water depths in the drywell, and total flow volumes. • Page 1of1 APPENDIX I-5 REFERENCES: • 1) USBR 7300-89: Performing Field Permeability Testing by the Well Permeameter Method 2) USBR 7305-89: Field Permeability Test(Shallow-Well Permeameter Method) 3) USBR: Drainage Manual, Chapter 3 -Field& Laboratory Procedures • • • • Appendix J _ • Climatological Data Monthly Average Guidelines for Stormwater Management Spokane County Public Works I Appendix J Average Monthly Precipitation & Evaporation Data • Spokane Airport & Airway Heights, State of Washington Data Source: National Oceanic and Atmospheric Administration (NOAA) December 1997 • ■ Average Monthly Average Monthly Pan Month Precipitation (inches) Evaporation (inches): ..- January 2.05 . 0.61 February_ 1.57 1.11 March • 1.38- ` 2.28 April 1.11 4.45 - May 1.37 6.69 June 1.27 • - 8.14 July 0.50 10.70 August . 0.60 .9.42 •September ' ,0.80 . 5.90 October 1.22 2.58' November .. .. ... . 2 02 . 0.92. December. 2.22 .0.51 Annual Sum 2 16.11:,_ . . ..53.31 •. Guidelines for Stormwater Management Spokane County.February 1998 References Applicable to Addendum: Feb. 1998 . - • (1) ASCE (1995). "Hydraulic Design of Flood Control Channels." ASCE Publication 0-7844- 0067-9/95 (2) Brater, Ernest F. and Horace William King (1982). "Handbook of Hydraulics." McGraw-Hill Book Company,New Yoik:N.Y. (3) Federal Highway Administration, Office of Engineering (1965). "Hydraulic Charts for Selection of Htghway.Culverts."HEC-5. Reprinted 1977. • (4) French, Richard Hi.(1985): "Open-Channel Hydraulics." McGraw-1-01,,-Inc., New-York, - N.Y. (5) Maynard, T. Stephen (1989). "Riprap Design:" Journal of Hydraadic Frrgineerirrg,�ASCE, Vol. 115, No. 7, July 1989, pp 937 = 949.. • • . . . . .. _ . (6) Schaefer, Melvin G., (198?). "Selection'of Riprap."•Paper by Washington Dept. of Ecology, Dam Safety Section • .. _ .. (7) Shafai-Bajestan,Mahmood.and Maurice•L.`Albertson (1993). "Riprap Criteria:Below Pipe Outlet." Journal of Hyodraulic;Engineering,ASCE, Vol: 119,No.-2, February 1993,.,pp:181-199. r .t (8) Water Pollution Control F•deration-(WPGF) and the American-Society of Civil Engineers (ASCE) (1970). "Design and Construction of Sanitary and•Siorm•Sewers:".=WPCF vanal of Practice No. 9, ASCE_Manual of•Practice No.37..rFifth Priatirig 1982.- . f . .... ' (9) Water Environment Federation (WEF) and the American Society of Civil Engineers (ASCE) (1992) "Design and Construction of Urban Stormwater Management Systems." ASCE Manual of Practice No. 77, WEF Manual of Practice FD-20. Guidelines for Stormwater Management Spokane County: February 1998 . • , V Index 2/21393 . . . . . . ,-----, . Index Word I Page • -leY 5-19 •..--.•- moisture condition(AMC) 3.8,3.11 Aquifer Sensitive Ares(ASA) 15-1,5-4,5-18.5-19 . . As-Suitt,(Record Drawings) 12.6,2-0,3-12 • • •.... .beam' map,sub-basin .2-3,2-4,2.7,2-1D 3-7,38,426,5-16 Best Management Practices,13MPs 38 Bowstring 15-7,56,5-12,5 V . . .. 135,36 . ■ -• i exchange 156,5-18 characteristic velocity i420 • • . 11.4,2-4,3.7,3.8 ._ . concept drainage plan • 4242-7,24 v:• - . . . control stnicture 433 • cover -over pipe 46 - • • . • _ . 12-1,43,4-4,4-7,4-8,48,4-27 - . • - • 4.1,42 .. .. Curve NuMber,CN 33,3.4 ,.. ,3.8 • _ . Design Divtation- - 11-2, 1-3,1-4 2.2,2-6,2-7,3-7,34 • • '•. storm lase'atom event' •- - ;• ,detention ponds 11-4,2-1,2-4,2-7,3-5,34,34 4-15,4-23,421,4-25,5-12,543,5-14,5-15 tkrirrKinidient 11-3,2-6,2-7 - downstnsern,dcrionstniarn analysis 11-1,2-4,2-5.2-7,3-4,422,427 drainage plan,Drainage Report 11.1,2-1,2-3,2-4,2.6,3.6,3.8,4-27,4-23 &week 11-3,36,415,425,53,54,56,56,5-15,5-16 .,. _ . , 1-4,1-5,2-1,2-4.2-7,34,311,5-19 - • overflow see-overtiow' • -•, dramPleef 14'33 „-- - • '• ,(oho see sediment) r2-3,2-4,424,425,425 '• 1 11-4,2-4,38,34.3-10,3-11 . fence,fenced 11-4,1.5,3.5,4-2o,4- ,5-19 ll . iter,Biter blanket 26,429,4-30 Ficonan Method 1312,426 11-1,2-4.2-6,24,2-10,2-11 freeboard 11-6,426,5-19 34 113,2-3,25,2-6,36,34,3-11,430 • •11111,ffilldin2 Plan 3.5,3.7 i• •- -•percolation arte,GPA 11-4,2-4,2-5,3-7,5-1,5-2 56,5-6,5-7,5-18,5-19 12-1,4-1,4-2 11.3,245,2-6,34,38,311,426 headwater 144,410 hydraulic grebe line(HGL) 44-27,4-2s hydraulic imp -144,477.4-2e.4.zi nrittrWliPh '2-4,34,310,3.11„4-213,422,4-23,5-7 impervious 33,38,3-10,51,5-2 infillnition 1-3,1-4,2-4,24,24,2-11,36,3-7.34 311,426,5-1,5.18 liner,kning kned _*5,34 iot plan 2-4 maintenance.maintenance access 1-3,1-4,14 2-8,36,3-12,4-20,433,6-19 Altanning equation b.1,44.46,414,428 ••''-• Rational Mahal --( Impact 12-13 through 2-8,36 • ••.II •••• 11-2,25,24 2-7,36,426 .i _. seperater 1433 .• • _41,4.2 422 .. • 3.6.415,4-20,4-3),5-4,56 V pervious 33,34,310 pipe anchors 14-27 ( precipitation 8-10,5.4 i Rational Method 3-1,5-112,5.11 Record Drawings,(As-Bulls) p.6,243-12 • rimer, 14-219,4-29,433 • Index 2120156 index Word I Pace . SCS,Sal Canservetion'Servioe - 125;32„38;3-10,415;4-26 . . .- • - -" sedamrent • • -- 1312 - - . . . . . 0,. • sinfori8•tund 11.4 .- - • site chersstion:site study - 5,24 . • . - - snow,snowmelt_• • 10.311 . • SEendard•N es . • . t-3,•3-1,3 - - - atorn"event,design storm 2 35,,34,38,310,5.1,5-18 _.- . . = s+rbbeain - • rase.-besin-- suberitical flow • - .147;48,410.427 .. • • Submittal Cheelaiet - - . 123.•• .. __. . • sup m:ttics!flow• • 148;47;415,4-27 .. . . • • t'cne of oonaenbition -.._ t2.4..31.32,37,5-7.56,5.15 . - .__ _-. _ Tit-55 a-2.3.5_ : "_. .. • arse . • - I1-4,1-5,38,5-19. . -. .. - -' .. . trash rseta•-. - 27 . . _..._ .. ._ _ _ water budget-- - . .. • 13a.3-1o,3.11_.. - —. _ . _ weir 1430 . . . . . . • ..._ . . .. . . - . webs al• . . • P-4,2-7,3 7. . . .. . . . . . . .r: ■ ;08 INDIVIDUAL LOT PLAN GUIDELINES 1. - Show location of easements on the lot. Include dimensions of drainage easement and swale bottom dimensions from lot lines. Include a description of the lot legal description such as Lot Block , NAME OF SUBDIVISION OR SHORT PLAT. The bottom elevation of the swale is also required. • The station for any curb drops or sidewalk inlets should be shown on the plan drawing. If a drywell is included in •the=- swale it :should show the type Of drywell, frame • and grate type, elevation' of the grate, and centerline station and offset to the drywell. • 2. If there is no swale on the lot but there is a drainage ditch, the ditch should be shown on- the plan drawing. . The ditch flow line grades should be shown. along with any easement for the ditch with • dimensions from-property lines. ' 3. - All lot plans should- show a north: arrow, scale, street name of adjacent street, curb and sidewalk if applicable 'or edge of asphalt paving if thereiis no•curb:. .The .lot •dimensions should also be shown along with the building setback line with dimension from the front • property lines •shown. 4 . Any easements such as power line%) easements which prohibit building under them •should be shown on. the•-plan .drawing. Any other easements which-could interfere.with.buildings-=should also be shown. Any existing buildings should be shown.•�'. i A' ... . . 5. With -eachplan drawing there Sshould ,be. submitted a typical ' . section- drawing --of Fa : cut.t:through the -swale-- or' ditch -which best describes how-the- swale and/orr ditch would look as constructed from a side view. The typical section should:.show the curb and/or =sid'ewal'k if applicable or edgeof asphalt paving in relation to the swa-le. 'The section ..should' -also show -side-•.slopes, -vertical distance from swale bottom to top of back slope of swale or ditch, grate of the drywell, and normal gutter line, and any applicable note or other information which would describe the proper construction of the swale and/or ditch , concrete apron,' street righttof-way line, and grass sod or seeding if approved on the construction plans. 6. ' The "lot plan and' attached' section -sheets -shall be on ;8. 1/2" x 11" • paper. and. should be sealed, signed-.and dated by the engineer in a location outside of the lot boundaries.: 7 . The scale of the drawing should be such that the lot is depicted as large as possible and still be able to show the curb line of the • street. The interior of•:the: lot• should-,be as free as -possible of notes' and writing to allow the-builder room to draw in his proposed house and driveway location.' An example of a acceptable 208 lot plan is attached for use as a guide in preparing your drawings. NOTE: YOU SHOULD NOT BEGIN LOT PLAN DRAW NGS UNTIL YOU ARE CERTAIN THE SWALE AREAS ARE CORRECT AND YOU HAVE EASEMENTS WHICH ARE kPPROVED. PROJECT # PROJECT NAME. DATE CHECKLIST FOR USE IN PREPARING 08 LOT DRAWINGS, h • PLOT PLAN • • • 1. • I have -drawn the lot plan on 8 1/-2" x 11" paper to a * large enough scale to make- the lot :as large as possible • ' and still be-•-•able - to . .show the curb ..line . and the • • necessary notes and certification -stamp. ' • 2 . `I have- shown *tIie lot,- .block, -and subdivision description for the lot or tract/short'.plat #: • 3 . I have shown the drainage easement dimensions •in relation to property lines or corners. 4 . I have shown the bottom of swale dimensions in . relation ' to property lines or. corners.-. . - . 5. 1-'have,-shown the bottom:-elevation of .the. swale. . 6. I have shown the location ..of-:any.. curb, sidewalk -or. edge of asphalt line as applicable. • • 7. I 'have shown. the' name of~.the:street .adjacent to the lot being._drawn.. F. . .:n . . . 8. I 'have..shown--the."station and zany invert:.elevation of any f -.curb .dropfon drops that:.empty: into .:the swale ,. 9. I have shown the type of drywell;. :fr-:ame.;and ;grate -type, elevation of the grate, and centerline station and offset =r . of .'the :.dryweil. a. . • a_ __: . `_ 10. I °have shown any required ditches,:•••their-_ easements on the .drawing.,.that ditch' f low linergrade. and-required.-rip.rap, , etc. 11. ' I have shown a north arrow, scale, lot dimensions, and • building .-setback -lines w-ith , proper-_dimension•.: ' .I have.°shown any easements,:.which could,.affect any future building :locations and- '.I-:_ have shown.-. any -existing 13. I i have sealed•,:.•signed- and dated; :each:.drawing . . that is - - ' ;being "submitted*:for review "and.-in rappropriate location. : - �.. • • - - ATTACHED SECTION DRAWING- 1.4. I have•-.shownithe 'curb •and/or::sidewalk :ors edge -of- asphalt t• - ' in relation to the. swale, sides slope,- vertical :distance from the bottom of. the= swa'le to thet.'top- :of -,back-.slope, ,grate and normal flow line of the curb or edge of asphalt". : 15. - I have shown the concrete- apron,, street R.O.W. line, and • grass- sod -or seeding.:.if -approved and any applicable • • notes or -other information which may , be -necessary to ' . describe. proper construction. - - - • • Appendix K Erosion and Sediment Control BMP Manual Guidelines for Stormwater Management Spokane County Public Works ■ Ir L /py1�1/Sq.1I I I IIF Sou Spokane County Erosion and Sediment Control BMP Manual , Spokane County Public Works Division of Utilities \ i Preface: The Spokane County Erosion and Sediment Control BMP Manual consists of a copy of Chapter 5. Volume Il (The Technical Manual) of the Stormwater Management Manual for the Puget Sound Basin. The Best Management Practices (BMPs) described in this manual are nationally recognized and may be used in different regions of the country to prevent or reduce erosion and sedimentation caused by land disturbing activities. As Spokane County implements the Erosion and Sediment Control Guidelines and more information is learned about each of the BMPs presented in this manual, recommendations will periodically be made to possibly delete those BMPs that don't work and include new BMPs that do work. The intent of the BMP Manual is to provide an example of available BMPs which property owners can choose from to help meet the requirements of the Erosion and Sediment Control guidelines. Use of BMPs from this manual is at the discretion of the property owner, permit applicant, or their agent. It is not the intent of the BMP Manual to limit any innovative or creative effort to effectively control erosion and sedimentation. In those instances where appropriate BMPs are not in the BMP Manual, experimental management practices can be considered. Experimental management practices are encouraged as a means of solving problems in a manner not addressed by the BMP Manual, in an effort to improve erosion control technology and meet the purpose and intent of the Erosion and Sediment Control guidelines. • • • • CHAPTER II—S STANDARDS AND SPECIFICATIONS FOR BEST MANAGEMENT PRACTICES FOR EROSION AND SEDIMENT CONTROL • TABLE OF CONTENTS II-5.1 INTRODUCTION 1 • 11-5.2 STANDARDS AND SPECIFICATIONS FOR COVER PRACTICES 1 II-5.3 TEMPORARY COVER PRACTICES 2 II-5.3.1 BMP £1.10: TEMPORARY SEEDING OF STRIPPED AREAS 2 11-5.3.2 BMP--E1.15: MULCHING AND MATTING 5 • I1-5.3.3 BMP El'.20: CLEAR PLASTIC COVERING 12 I1-5.4 PERMANENT COVER PRACTICES • • • 14 I1-5.4.1 ' BMP 'E1.25: PRESERVING' NATURAL VEGETATION - - 14 11-5.4.2 BMP E1.30: BUFFER -ZONES - 18 II-5.4-.3 BMP E1-::35:- PERMANENT SEEDING -AND • ` • - • PLANTING i- • - • - - .20 II-5.4 .4. BMP £1.40: SODDING ' - - -. 24 1I-5.4.5 BMP E1.45: TOPSOILING • .. 26 AI 1I-5.5 STANDARDS AND SPECIFICATIONS FOR STRUCTURAL AND - .BIOMECHANICAL PRACTICES - ' -28 • I1-5.6 STRUCTURAL EROSION CONTROL BMPS 30 ' II-5.6.1 BMP E2=.10: STABILIZED'CONSTRUCTION I.. ENTRANCE AND- TIRE WASH • - • •30 - II-5.6.2 BMP £2:15: CONSTRUCTION •ROAD • STABILIZATION • ' ` . • . 32 • II-5.6.3 BMP E2.20: DUST 'CONTROL '34 1I-5.7.4. BMP- E2.25: PIPE SLOPE-DRAINS • - 35 II=S.'6':5- '$MP• E2'.,30: SUBSURFACE -DRAINS - • --38 • II-5.7.6 BMP• E2.35: • SURFACE ROUGHENING Al 1I-S.7.7 BMP E2.40': GRADIENT TERRACES - - 45 II-5.7.8 BMP £2.45: BIOENGINEERED PROTECTION. OF • - VERY STEEP SLOPES'.. ,- 7.'- . --Oil'8= - 1I-5.7.9 BMP•'E2.510°:1 '•LEVEL` SPREADER' : - 51 II-5.7.10 BMP £2.55: INTERCEPTOR DIKE-AND SWALE ••54 - 11-5.7.11 B(P: E2.60 = CHECK' DAMS` - . ' • •58 II=S 7.12 'BMP E2-.'70 c".-OUTLET PROTECTION - .61• 1I-5.7.13 BMP E2.75: RIPRAP - ' 62 II-5:7-.14 BMPt E2•:•B O: VEGETATIVE-STREAMBANK STABILIZATION- - . - ' ""64 1I-5.7.15 BMP E2.85:- BIOENGINEERING METHODS OF` - - •• STREAXMNK•STABILIZATION ' 68 I1-5.7.16 BMP E2.90: STRUCTURAL STREAMBANK= - STABILIZATION' ' 72 1I-5.8 SEDIMENT RETENTION . 74 c :1-5. 8. 1 BMP £3.10: FILTER FENCE 74 II-5. 8.2 BMP E3.15 STRAW BALE BARRIER 79 I 11-5.8.3 BMP £3.20: BRUSH BARRIER • 83 I1-5. 8.4 BMP E3.25: GRAVEL FILTER BERM 85 II-5.8.5 BMP £3.30: STORM DRAIN INLET PROTECTION. . . . 87 STORXWATER lOUUAGE?ENT MANUAL FOR 'THE PUGET SOUND BASIN II-S.3 TEKPOSART COVER PRACTICES j1-5.3,1 SNP E1.10: Teuoorary Seedinc of Stritted Areas; { � • Coda: 41:1 Symbol: • pefinitiosj The establishment•of a temporary vegetative cover on disturbed •areas by -. seeding with appropriate`rapidly growing annual plants: • • . • ra¢ • • To provide temporary soil stabilization by planting grasses and legumes to areas which would remain bare for more than 7 days where permanent cover is not necessary or appropriate. - . . . . .... . conditions Where • - Ann : ' ' • • Permanents structures arm'to'•bet.installed or extensive. ri=grading of , .'the'area-'•will'occur..prior-•to the'establishment of permanent:vegetation. • • • Areas which will not be subjected to heavy wear by construction traffic.. .. . ... . .. • -- Areas sloping{up to 10% for -100 'feet:orlless'- (wher.•temrperary seeding' is. the only BMP used • : - �ldvantaaes:a . .. - - - • '' =This is a relatively-•inexpefsive form of erosion control bu't lihoUld only. be ' used on sites awaiting permanent planting or grading. Those lite. should hive/, permanent measures used (see BAP E1.35, Permanent Seeding and Planting). , 4l • Vegetation will not only prevent erosion from occurring, but will also trap sediment in runoff from other parts of the site. ' • Temporary seeding offers fairly rapid protection. to -exiposed.-s=eas:= Din . antaoes/Problems :'_ • • Temporary seeding is only viable when there is a sufficient window in time for plants to grow and establish cover. During -the7eStablishment"-period"the bare soil should be protected with mulch (see BMP E1.15) and/or. clear plastic covering (see Btu Z1.20). . • If sown on subsoil, growth will be poor unless•'heavily 'fertilized and limed. Because over-fertilization can cause pollution of stosmwater runoff, other practices such as mulching (BMP E1.15) alone may be .more appropriate. The potential for over-fertilization is an even worse problem in or near aquatic systems. • Once seeded, areas cannot be used for heavy traffic. • • May require regular irrigation to flourish. Regular irrigation is not encouraged because of the expense and the potential for erosion in areas that are not regularly inspected. The use of low maintenance native • species should be encouraged, and planting should be timed to minimize the need for irrigation. Plaun ' c Consideration. Sheet erosion, caused by the impact of rain on bare soil, is the source of most fine( c particles in sediment. To reduce this sediment load in runoff, the soil surface • 11-5-2 FEE ARY, STORMWATER MANAGE1 NT 'MANUAL FOR THE PUGET SOUND BASIN • itself should be protected. The most efficient and economical means of controlling sheet and rill erosion is to establish vegetative cover. Annual plants which sprout rapidly and survive' far only one groving-season are suitable for establishing temporary vegetative cover. Temporary seeding'is effective when•combined with construction phasing no bare areas'of the site are "imised•at all times. Temporary seeding may prevent costly maintenance operations on other erosion control systems. For example, sediment basin clean-outs will be reduced if the: drainage area of the basin is seeded where grading and construction are not taking place. Perimeter-dikes will' be more effective if not choked•with sediment. Temporary` seeding-is-essential to preserve the integrity of earthen Structures used to control`Sediment, -inch as dikes, 'diversions, 'ant the banks and dams Of Sediment basins. Proper seedbed preparation and the use of quality seed are important in this practice just as in permanent seeding. Failure to carefully follow sound agronomic recommendations will often result in an inadequate stand of vegetation that provides little or no erosion control. • Design C iter's • • Time of Planting - Planting should preferably be done between April 1 and June 30, and September 1 through October 31. If planting is done in the months of July and August, irrigation may be required. If planting is done between November 1 and March 31, mulching shall be required immediately after planting. If seeding is done during the summer months, irrigation of some sort will probably be necessary. • Site Preparation - Before seeding, install needed surface runoff control measures such as gradient terraces, interceptor dike/swales, level spreaders, and sediment basins. • Seedbed Preparation - The seedbed should be firm with a fairly fine surface. Perform all cultural operations across or at right angles to the slope. See BMW £1.45, Topsoiling, and BHP E2.35, Surface Roughening for more information on seedbed preparation. A minimum of 2-4 inches of tilled topsoil is required. • Fertilization - as per suppliers and/or Soil Conservation Service recommendations. Developments adjacent to water bodies must use non- phosphorus fertilizer. • • Seeding - seeding mixtures will vary depending on the exact location, soil type, slope, etc. Information on mixes may be obtained from local suppliers, the Washington State Department of Transportation, or the Soil Conservation Service. However, approval to use any particular 'mix must be obtained from the local government. The following seed mix is supplied as guidance. Proportions Percent Percent 1? DV Wei-ht Purity Gem. 'nation Redtop (.orostis ba) 10% 92 90 Annual Rye (Lolium mult.' lorum) 40% 98 90 Chewings Fescue 40% 97 BO (Pestuca rubre eoT utata) White Dutch Clover (Trifolium..rerene) 10% • 96 90 • •fydro-seeding" applications with approved seed-mulch-fertilizer mixtures may also be used. • II-D_ FEBRUARY, STORKWATER MANAGENENT MANUAL FOR THE PUGET -SOUND BASIN. Maintenance • • _ . . . • •• • • •• • - . -•( . • , • • Seeding should be-supplied with adequate moisture. Supply water et needed, especially. in--abnormally or,dry weather_or on adverse sites:. Water application rates. shou/d.be„.contro//ed toprevent .runoff. . . • ;Re-seeding- - Areas- which fail, to establish veqetative_cover adequate, to prevent erosion shall be re7seeded as soon as such areas are identified.-.... • Al] temporary erosion• asifeedimeSt Contribijneaiures should be. reloved.withis„ 30 days after final site •tabi/iiation is achieved or after the temporary bm:061 are,no7longer needed. Trapped .ediment_must-be .removed_or.stabilized. on site. Disturbed soil areaa.resultinsfrom,removil ihouid,be permanently stabilized. . • . • • • • , • . . . • •.‘, • o<t• ••• • . • • • . . • .• • • • • * . • • • V"! -7** :4 • . •". - F ••! - • 0 • . • • . - . .v• rr • • • • ; • • • II- -4 • FEBRUARY; - . STORidiRTER MANAGEMENT MANUAL FOR THE PUCET SOUND BASIN 1I-5.3.2 BXP E1,15: Mulching and !�a*_ting Code: (:!I Symbol: --,--- pefinition Application of plant residues or other suitable materials to the soil surface. .- purpose To provide immediate protection to exposed soils during the period of short • construction delays, or over winter months through the application of plant .: _ residues, or other suitable material, to aripoied Soil areas. . Mulchee•also enhance plant establishment by conserving moisture and moderating soil temperatures. Mulch helps hold'fertilizer, .seed, and topsoil in place. in the presence of wind, rain, and runoff and maintains moisture near the soil Surface. Conditions where Practjee Applies , • • In areas which have been seeded either for temporary or permnent-'cover, ,. • mulching should immediately follow seeding. • Areas which cannot be seeded because of the season, or are otherwise unfavorable for plant growth. • • Areas which have been seeded as specified in:Temporary Seeding, (BHP E1.10) . •., • In an area of greater than 2:1 slope, mulching 'ahould immediately follow seeding. . - Ldvarftaaee• ` • Mulching' offers isiitant protection te,expossd areas. . . • Mtilehe■ °conserve moisture and reduce the' aged for irrigation. 1;. • Neither mulching nor matting require removal• ,seeds can,grow_through them • . • unlike' plastic- coverin s. ' , - = pioadvantacee/Problems ' - • Care must be taken to apply_ mulch at the .specified thickness, •and. on steep slope. mulch:must- be -suppler ted with betting. . . . . • ' Thick.mulchies-can reduce the soil .temperature, delaying seed ge tnation. • Mulches` 'such as 'stray, which are often applied t.o.,areas after grading, must then be removed' and either composted or landfilled.. Straw .is hollow, .so it can actually draw water into the -ground below .it if .the straw ii:'at ,an angle. . . Planning Considerations 7ulches are applied to 'the soil surface to conserve a desirable soil property`or to • promote plant growth. A surface mulch is one.of the most effective means of controlling runoff and erosion on disturbed land (see Figure 11-5.1 for i comparison of pollutant loading reductions for various mulches). • ^-, Yulches can increase the infiltration rate of the soil, reduce soil moisture• )Loss by evaporation, prevent crusting and sealing of _the .soil surface, modify . -oil temperatures, and provide a suitable microclimate for -seed germination. - . • )rgdnic mulelh 'materials, such as straw, wood chips, bark, and`good fiber, have'been 11-5-5 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN . • found to be the most effective. • A variety of nets and mats have been developed for erosion control in recent years, r,,' and these are also used as mulches, particularly in critical areas such as waterways. They may be used to hold other mulches to the soil surface. The choice of materials for mulching will be based on the type of soil to be protected; site Conditions, season, and economics. It is especially important to - mulch liberally in mid-summer and prior to winter, and on cut slopes and southern -• slope exposures. Table II-5.1 gives a comparison of costs based on 1988 figures. _ Oroanic Mu h sA • tr - Straw is'the mulch m aw ost: commonly'used in. conjunction with seeding. - Its use Is recommended where immediate protection'is desired 'anepreferably where the need ' for protection will be lees than 3 months. The..straw should come from.,wheat or . oats, and maybe spread by hand or machine. 1f-the straw. is not clean, weed growth, can occur': ' Straw can be windblown and must be-anchored dawn: Common anchoring_, ; methods ass': �� . 1. Crimping, disking, rolling or punching into the soil; " . , 2. Covering-With 'netting; •3. Spraying with a chemical or fiber binder (tackifier);, and,. - - . .. _ . 4. Keeping moist. Natural precipitation can often prey/de sufficient moisture. (2) Corn Stars -'These•?should .be'shredded into -4`to 6=ia`'ch lengths. Stalks decompose slowly and are resistant to windblow. , Wood chips - suitable for areas that will not be closely mowed, and around ornamental plantings. Chips decompose slowly and do not require tacking. They:must lip be treated with 12 pounds nitrogen per ton to prevent nutrient deficiency in p'lante. ` Chips can be a very inexpensive mulch if, they 'are,,obtained..from, trees cleareon the - site. However, both wood and`bark chips 'tend to-waa?i-down slope d• ,• s of more than 6 percent and create problems by clogging.,,inlet .grates etc...and; are ;therefore.not . preferred for use in thbie•-areas:'-- 7-' .. ` • Bark Chibei: Shredded kB=rk •By=p3roducts Of timber processing. ....pied in landscaped plantings. Bark is also a suitable mulch for areas planted tc-grasses and net closely mowed; may be applied by hand or mechanically. Bark is not.usually toxic to . grasses or legumes, and additional nitrogen fertiliser is not required: "-• ' "-' '• Wood Fibber -,Used in hydro-seeding operations',. applied as'part- of ithe slurry.. ..,These short cellulose fibers do not require tacking, al`though 'e tacking agent or soil binders are sometimes used with .wood fiber., , The longer. the .fiber length,..the better the wood' fibet'will work in erosion 'control•: This 'form of iaulcki does an provide sufficient-protection to erodible soils to bs ,used_ alone.during..the• severe heat .of summer or for- late fall siedings. Wood fiber'hydro-seed -slurries- may be.,used tot tack strive mulch. This combination treatment is well`-suited for-'steep. 'slopes,.and• critical''areas,-'and severe climate conditions. • • • - There are other organic materials which make excellent mulches bu`t' 'are only available -locally or seasonally. Creative use m e of these , aterials can reduce costs. . Manure Mulches M =. anure mulches should_be well-aged and'are not recommended for use near waterbodies. Chemical Mulches and Soil Binders . . The use of synthetic, spray-on'materials (except tacking ,egents used with hydro - . seeding) is not recommended. A major problem with their use is the creation -of � . impervious surfaces and, possibly, adverse effects on water quality. Research has `' . •. II-5-6 FEBRUARY 1992 - • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN shown that they can cause more erosion when used than dove bare exposed soil. Nets and Mats - Used alone, netting does not retain soil moisture or modify soil temperature. It stabilizes the soil surface while grasses are being established, and is useful in grassed waterways and on slopes. Light netting may also be used to hold other mulches in place. Its relatively high cost makes it most suitable for small sites. . The most critical aspect of installing nets and mats is obtaining firm, continuous contact between the material 'and the-soil. Without such contact, the material is useless and erosion occurs. It is important to use an adequate number of staples and to roll the material after laying it to ensure that the soil is protected. Table II-S.1 Summary of Estimated Service Lives and Costs 1988 Base - Horner, January, 1990 • + F�eimewA Cact .,• Esssromad Service Mat loved) . • feehnigt,ei Life(mmdts) (6 m v hs serrue) ' Str w(4'Var.) • : • 3 :3,200 • ' • • Stiaw 1125 Tract - . 3 - 2,300 - Straw(4 T/ac) e 6 • ,2,400 . stissasiranidthod. Y - fait' link:seeded i ' u lute that-a -6 - .3.700 •Ei:celsior, : r . y, 6 13.600 • Woven•suiw blanket + - • 6 . . s , .4,100 - G.]. Svmbette fiber blanket '• 6_ . .. 3.300. - • Wood f i b e r,mo th _6.- . .1:300- - . • �° wood fiber maldi;- 6 1.900 • ' . '(125 Thc)with .c . ' < a;adafu (S0 plrat). •Eeroliaeri seeded. . • ' .1. Wood fiber midi 6 2300 (125 Vac)with _____ (90'Wm). . fertilized.seeded' . Wood fiber mold 6 2.300 (125 Vac)with add8er(120 OM). htrnlit:ed.std,. - Cheitiical'attent ' . 6 2,100 Plttstsc iheetint; • -- 6 ' 2,300 Detect • 6 'c 42,00 sediment t i m pond , Non4ze7ned pond > 6 c 7,500 , a The estimated coat of mom amen it was and is lased as hydro-seeding (sppmtttoauly S500racrs). 1 11-5-7 FEBRUARY, 1 STORMWATER MANAGEMENT 'MANUAL FOR TBE' PUGET 'SOUND BASIN Figure 1V-5.1 Mean TSS and Overall Pollutant Loading_Reductions of Slope Treatments Relative to Controls ` "'frort' Horner, January,. 1990 • _ s - ® TSS Reduction . ,. Overall pollutam • loading reduction 100 — ..1 VINMEMP .: w� .. , r,. .?:.' .. • . .• +:• ri: � � •• 0 , v -V . ter.• . ' om. '. Straw Straw' Straw Straw Jute Excel- Woven Syn-';.,:'Wotid� �WQod Wood Wood Chentic- Filter (4 (1.25 (4 (2.75 sior Straw thet+c Fiber•».Frier Fiber Fiber at Fabric -20 -fr T/ac) Vac)c'"T/ac) 'Jlac)` " • ",_ ..."`. °: 'Fi3 ell`s;;(:1,±_•.. (;1*`- (1 (1.5 ' Fence . M,F,S M,F,S+ .. ,-'T/ac)` 'T/ac), 'Vac) 7/ac) y • • '•F,S: T F, T.F.S T,F$ �'z -40 ♦ - •a; -11987- (1988• : •• . - 88) 89) —I— • -50 — Slope Treatmer*i ' }• ., •. -• -Figure 3r Mcan•TSS and Overall-Pollutant taading.Reductions -O-- • .. • of Slope•TJLatments,Relative to Commis • { l. I II-5-8 FEBRUARY, 1992 • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN % lesion Criteria • . Site Preparation - Same as Temporary Seeding. • Mulch Materials, Application Rates, and Specifications - See Table 1I-5.2. • Erosion blankets_ (nets and mats) 'may be used on level areas, on slopes up to 50 ,percent, and in waterways. Where :oil is highly erodible, nets 'shall only be-uied in connection-with an organic mulch such as straw and wood fiber. Jute net shall be heavy, uniform cloth woven of single jute yarn which if 36 to 48 inches'•wide shall weigh an average of 1.2 lbs./linear yard. It must be so applied that``it is in complete contact with the soil. If it is not, erosion 'will occur-beneath it. Netting shall be securely anchored to the soil with No. 11 gauge wire`staples at least :6 inches long, with an overlap of three inches. • • 'Excels'ior blankets are considered protective mulches and may be used alone on erodible, soils and during all..times, of year. _ . _. 4 • • See'Pigure :II=5'.2 for orientation of •netting and•matting. Maintenance' • Mulched areas- Should be checked periodically, especially ,following severe stozms, when damaged areas of mulch or tie-down material should be repaired. •' All temporary erosion and sediment control measures :shall be removed within 30 days �after' final site stabilization is achieved or after the temporary HMPB are -norlongerrneeded. Trapped sediment shall be removed or stabilized on site. Disturbed--4611-areas resulting..from removal shall be permanently stabilized. • ✓Reference.;- 1 ,5 Horner,' Richard R. , Juno Guedry and••Michael H. Kortenhof,, Imt r• . $.nc the Coat E ect'v refs o , :,hw- Cons -, e • d Po - , Co o , ' Washington "State Dept. of Transportation, WA-RD 200.1, January,' 1990... • • •v • . II- - FEBRUARY, 1" STORMWATER MANAGEMENT MANUAL' FOR THE PUGET. SOUND BASIN • Table II-5.2 Guide to Mulch Materials, Rates and Uses Mulch Quality Application Rates . Depth of •. 7,• . - Material Standards Application Remarks' • /1000 ft?. /acre _ Gravel,Gravel, . . ..Washed, . .• • 9yds' 3 incliei Excellent-mulch - slag. or � - 11" • for short elopes crushed size w a.. -and•"around woody • stone • ornamentals:_. Use . ,, :where subjeet to foot traffic. • 4pgzox. _2000 .1bs/ Hay or Air dried, 75-400,: 11,-2/ , . Minimum of Use where .the straw ' free from Tbs. or . tone 2•inches mulching effect is unwanted 2-3 bales. or to be maintained... . seeds & 90-120 for >3 months. • Is ' coarse bales .subje_ct to..wind material blowing unless, kept moist or r :.•. . ..tacked.•down. Most common:i widely e a . usedy;muleliing , .mater . Can,be uied in critical erosion areas.. ,, M Wood Dyed green 25 - 30 1000- I� ,used. one fiber should no t•' lbi. 1500 ' �' ;critieil a�rets,,, cellulose - ..contain =" r: lbs. double;tAe 'normal (partially gro++th. .. 1 _ 1-".• _ s• application rate. digested inhibiting Apply wood factors. w/hydromulcher. No fibers) tie-down required. Packaged in 100 lb. bags. 'AII mulches will provide won demo of(1)ssosioo eaottd.()miaow • caadersau,(3)weal coajol.end(4)wduaieo of soil erasing. • II-5-10 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN •• . . • . ' - Figure 11-5.2 Orientation of Netting and Matting - ., ...,. •., . .-......11.-.1...-_-,,.:•. Shallow ... -,,......z--_,.-.-..-/•-.•.-.:•,:......-.•..-.. . . . Slope _.:-.Ii; 7,.-:-;;;-Zr....--".:1:-1. 1 ';.;:"..:!!!::: . : . ... . * ;•7.---.•:-.Z...-::::::::::•::::;...-:::•!?::!;:•:::.--.-•:::::rp.,• • . - • 44•; f47)..-.:•: ".•:•:::::..7:::::::!.:2! . -::111:.1,1:•., .". : .*i:;;;::;;;;;;;T;1-; On shallow slopes, strips . z : : :,..7.-.14-..1z4;:yfir.:1:::::-.;: --44:--;:i."4:4r ":".^1:41.:: • i1=7:7F-=::: .• of netting may be aopl led ........... .--:-.7.,-.•.:::::::::: ::::_:::::::: ................................................:•:___-, -acres.5 •the slope .i-7=:-......-...:-....-.:4-......:7,......-...-,..6.2.-.--:-.-:::::]:;•:::::::.-.7.:::: -----.• ___=•L:::.4-.-..----..c.,-/..t..z....-....-.-4....-41::::-.....:::-...r.,,;;.=..- — (Slopes up to 1:1) . • - --" :7.,-71--7-4r.-:./F4.-..714..-..:47.::4:::::::.______: • „........0 .--•••:--•••• ::-.::.-:::::::=:::.. . kn. •---$1?•:--- -7/..,-,F.-....„--;:.---------- • . 12--_-_. = . :-...•-...:-:-.'....:•-•:-.:.---- --... --":•_•:••••,.••-.,-----47-••"•::•=1:7----- -- . - - . 4 . 4:..._.?.i.:Z.11 r./141::.: •? .1 I -r----Mli .._. •--.:tet?.4-'••:::•:::.--•,---------.... . • ' . --,vel- lir -',-.-.•.=;;;;:p....147.-.7..:::_-=:E.-=_-.:::-.:-.._ -Liu .-.--:,::=-=.7..=7---._=____--. ... . . -, -4insigliEgt 1751 .," , ...., • . .• - . . . _ , :-:-..-..-.•. -t•-•.•• ,, :. -- . .. Where there•'-•it'•a berth'at '-the-,top •of the slope, • ' Berm- '•- • •11 ... - • bring the netting over the berm and anchor it i -- —gni=-=-- • behind the berm. . -. ::•y-• • • ..11,1--- iii.. ...- ..•:,...--.:-/" .(i.--,.,.. Steep ...1.1.-. 7*-::-•-.--ifiViit;,;: -...-,i-. •.,... 2.-...L. r; ..:..:.-.,.. 4-,-:-Fiiiiii,..•. - L. " -'s.1 • - •-. Slope :.7=-.T..F...7y...:-.,.:,,,-,-; :iF.,, ::: ••-/..--,:-...7i,.,2.- . , ...=-.:•-.;,-.4,-,..._-,.,,,::.:::?;::::::::.L-..,_-_-:.:.21nr.:.• . . •••.-- -...--..::.•:,..".`•4r_.,:-::::--...,:::•:•::.=-..-===..• zijigi.,..,.w...,,..,........=- . . -.-_--,--_-_....... . F •..,., .-- 4.:::ii:.:.:f -- -----------. On steep slopes, apply ....:.:.,7..:?.....-.-7,-,,,,,:::;•.:•.:.:., :::::::,.....z .___- • • , •..-.„..-31-:,-.F.,..;,,,,.............,..:.::,:„....--_-_. • .•:-.-....-=.4.----.-..;.:•.;:i:.:7;F.t z.i.:44-::::.;.;;.===.!—•; strips of parallel • . :::+i.F :::,:.-,-:2:::::::=------ •-=--_--=...-- • :::.-zzs.,;; : to the direction of flow -__ — -!!...-::::.•::::::-.i.-:;;F::::::!..,....... .._..-. •_ .....-=•---•-1 II -,..-.-Z.,:.?-7:;:::::::":::::::::,_:.,........ _??-- : and anchor securely. - - -k,'41- 1 _ ,*-7z.i..F..7z•Tz•:::::::;;•- -- - (Slopes greater .. --r: ,,, ...........:*::„..., - , . . , .... '' . • - -7%--=ii i 1- --::::-:::: . ,.,., --•_., - ..- ...,:.• --Ttlit..=_.....-....;zi:.._ .. . .. , -. . • ...7.. :.. -=:• :.- r- , . -. , , • . ' '1;ggifigNilligg • s' (4!', • ::i■''i'.'•..1-••A -A .. .7....17. nommINM Bring_netting, down to a level area, before . • .t, .. .t. t 3... ..: L ••L- .• . terminatino the installatioT..n. Turn the • -lir .--...,_.-. end• under 6--"...and-.staple ,at-,,,12"- intervals. • . 6". ..-- ,.. ,-- •-•>.-----: - -12" ■-7. _ -'•-:ilir'S••'"-7- Ditch ...•.„..:.-.....:-:.-f..i..l:..I-i:i:.--.".-:..4•:•'.-'/.....-•::,-::-._,,•' :,1:•:.•,:.::i::1:-1:•::;:"f:1:-._-i--=•K--,••..:! • • ,::,•-••.:.:•...7...-.-.,..-,..-•-,,,,...-_, ..,F.-.,,,,:::::::::::::-T.7„.: . . .:=z.:::•.......-....-..-.•?...--...-:-.-. .. - z.,.::i..;:::•:::::,::::%-.. .-..:•- in ditches, a pp 1 y netting , ...-z--......-:-.:-.:---.-••••.-:::.---- •■-•-•-•--•-•-•••I.....::';::••::::::.--....: '..'•:....'iL4,7::::::::::•,...../....::"...;::=■-• •••;;■;i::i::::::::•::::: !'. parallel 1 1 e 1 '-'•-to the direction —:-.---:-.".•-----c---..--7.-:-.=::.-: :E:: :.: :=_- : . ; . .. --;•-•-•••••••••••••••:-.7.-:-.------i•P:c:-•:-::-.,:— , of flow.- • Use check slots ..-.. .•-- ...1.-•--.:---- .;.-....:•.:-.:-.:— --..•-..-,ove.-4:-...-..-..-4-...--....-;-..:r::••:::-.=:— • ---..-:".-:-.:-.•":..-.:•-•.--------x,;-.1....zz..-7.-. -....- every' 15 feet. Do not . • --....:,.. . .-..... .1...t.!- --:;;;;si:.:.....:::— -.. • • • •=--=*:,.'..'.-'.:-*''z.-V■z.?'.-:.--':----li-•::.:':::::::.---::---.. join strips in the center :%C44644$?1.-4;re "IE::::-1:=%=::------ -- nf the'-di tch. - •-•• 41.:-- t-:::- -0 ri--.- 1111 =-7,0",:lezi.N....w. ,-;:.;:isi;;• — • ., L,„L. ....;—...._–,=_—_,....,01.1;.• ,..._„/ --.a._ ... .0,- -i.- - • . --rii 1 C. - m.-- . . . . • • ....: , :. - .. . • FEBRUARY, 992 • STORMWATER MANAGEMENT MANUAL FOR THE PTGET SOUND BASIN ;I-5.3.3 BIM E7,.20: Clear Plastic- Covering •• Code: 0 Symbol: --E-- >'J Definition, The covering with clear plastic sheeting-.of bare areal which need mediate protection from erosion..,..;. - . - -.- , , . Purpose To provide immediate temporary eroaon:.protection to 'alopee•and disturbed areas that cannot be covered by;mulching.,_;;in particular during• the''specified' seeding periods or as otherwise required 'by the local•governmmeft-. "''Clear• plastic is 'also_used ;to protect disturbed areas which must .-be.:covered ..during abort';periods of inactivity to meet November 1-March 31 cover requirements. -Because •of' many disadvantages clear plastic covering is the least•preferred :covering AMP.. - Conditions Where Practice Applies •, . , ; • Disturbed areas which require immediate erosion protection. • Areas seeded during the time period from November 1 to March 1. •(Note: Plantings at this-time:;require •clear plastic covering-.for germination and protection :from.heavy rains. • . Advantages '4 s. • Clear plastic covering is a good method of protecting bari,,areas which need immediate cover and for winter plantings. : ;=_- . `, 1 . • May be quickly and easily placed. " Di sadvantaaesiproblems '. . •• • :1 -JD : • ...':• ' .:1 M•:.-'r,•,�•. •':''Y,•� ' .:.�a Y. .•:.! ?�V,c, • There car_be...problems.with vandals and-�maintenance 4:_ .. 1' c .•,ARC aa• ;A' •tr • The sheeting.'wil•lzresuklt in rapid, 100.%-runoff .which'"may,'cauie serious erosion problems and/or flooding at the base slopee:.-urloas the:-runoff is properly intercepted and safely conveyed by a call ctiag_dra n This is strictly a temporary measure, so permanent stabilization-is still required. • it is relatively expensive. . • ••' v and anchored. • The Mast c` map;''blow away it , is not adequately, o erlappae - ' • Ultraviolet-•:and4;:possibly visible light can came .soMe'types•of plastic to Decome:�brittle-and easily torn. • Plastic must be disposed of at)e landfill•• it is:,not easily degradable in the environment. 7:: °: •='4,-.°:,f; • If i plastic pis left on.too long:'•during the'spring••.it,_.can. severely burn any vegetation-that has .grown under•`it; d_uring;••cooler:periods. ` Design Criteria , - +, • Clear plastic sheeting shall'•have'.a• minimum_thickness; of 6'mil and-meet the requirements of WSDOT/APWA Section ,9-14:.5: ,.• , • • Covering shall be installed and maintained :tightly in .place by using sandbags or tires on ropes with a maximum 10 foot':giid spacing.:in all directions. All ; seams shall be taped or weighted down full length:and there shall be at least•(\, 1 to 2 foot overlap of all seams. Seams should then be rolled and staked or • . II-5-12 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE'. PUGET SOUND BASIN tied. ;• • Covering shall be installed immediately on areas seeded between November 1 to March 1, and remain until vegetation is firmly established. • When the covering is used on unseeded slopes, it shall be left in place until the next seeding period. • Sheeting should be toed in at the top of the slope to prevent surface flow beneath the plastic. • Sheeting should be removed as soon as is possible once vegetation is well grown to prevent burning the vegetation through the plastic sheeting, which acts as a greenhouse. Maintenance • Check regularly .for rips and places where the plastic may be dislodged. Contact between the,plastic-and the ground-should always be maintained. Any air bubbles found should be removed immediately or the plastic may rip during the next windy period. Re-anchor or replace the plastic as 'necessary- All temporary erosion and sediment control measures shall be removed,within 30 days after final site stabilization is achieved or after the temporary B2es are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • • i a • 1• - • • , • y 22-5-13 FEBRUARY, 1992 STORXWATER MANAGEMENT MANUAL FOR THE PUGET' SOUND' BASIN II-5.4 PERMANENT COVER PRACTICES ZI=5.4:2 BMP rl. 5:• Preserving Natural Veaetation • • Code: 0 - Symbol: —�— 'efirnition Minimizing exposed' soils and consequent erosion by clearing only where construction will occur. Purpose • ' To reduce erosion by preserving natural vegetation wherever practicable. Condition Where Practice ADelies . • • Natural :vegetation should ,be`preserved on steep slopes, •near perennial and Intermittent watercourses-or swales; and on building sites iii wooded areas. • As:•required .by local governments. ' • • Advantaaee.', - • . • • . - • • Preserving natural. vegetation -will: "'' • - • • • • Help reduce soil erosion. • Beautify an area. • Save money on landscaping costs. / . • Provide areas for wildlife. • Possibly increase the value of the land. • Provide buffers and screens against noise. • Moderate temperature changes and provide shade and cover habitat for surface waters and land. This is especially important where detention ponds drain to salmonid-bearing streams. Increases in water temperature tend to lower the dissolved oxygen available for aquatic life. Disadvantaaes/Problems • Saving individual trees can be difficult, and older trees may become a safety hazard. Cottonwood and alder trees are especially prone to blowdown. Plannino Considerations New development often takes place on tracts of forested land. In fact, building sites are often selected because of the presence of mature trees. However, unless sufficient care is taken and planning done, .in the interval between buying the property and completing construction much of this resource is likely to be destroyed. The property owner is ultimately responsible for protecting as many trees as possible, with their understory and groundcover. This responsibility is usually exercised by agents--the planners, designers and contractors. It takes 20 to 30 years for newly planted trees to provide the benefits for which we value trees so highly. • Desian Criteria . • Natural vegetation can be preserved in natural clumps or as individual trees, shr- and vines. I1-5-14 • FEBRUARY. 1992 STOR2{W'ATER MANAGEMENT MANUAL••FOR TEE PUGET SOUND BASIN The preservation of individual plants is more difficult because equipment is generally used to remove unvinted vegetation.. The points to -remember_when attempting to save individual plants are: : • Is the plant worth saving? Consider the location, species, size, age, vigor, and the work involved. Local•governments may also have ordinances to save natural vegetation and trees. • Is the -tree or shrub • desirable:plant?. .Is it shallow-rooted, do the 'roots seek water, or are insects and .disease a problem? Shallow-rooted plants can cause problems in the establishment. of lawns or ornamental plants. Water-seeking roots can block sewer and tile lines. Insects and diseases can make.the plant undesirable. This is especially true with aphid on alder and maple. • Old"'and/or •large plants do not-generally adapt to changes in environment • as readily as young plants of the same species. Usually, it is best to • leave trees which are less than 40 years of age. Some of the hardwoods (Red"alder,:'Cherry,r-etc. ) mature :at approximately•-50 years of-cage. After maturity they rapidly decline in vigor. Conifers, after 40 years of age, 'may-becomeia safety:hazard dueZt6 the -possibility•,ofa.breakage or•-blowdown, +aespecially-where construction'has''left-only.Lafew scattered trees in an area that was formerly'dense woods: y'iihile-old='large trees--•are sometimes desirable, the problem of later removal should be considered. Again, • local governments.-may.°have•requirements'to=preserve;older; 'larger specimen • trees'. rIVEis:expensive-tó-cut 'ar:.large treee,and-to':remove.'the tree and • stump'from'a!devel'oped.-area:a Thinning=eome`-branches,from trees can provide avenuescfor wind and-henceblessen;the •'sail'''effect. • = Clearly flag ,or :markarea■ around trees that',are •tol be:saved. It is • • -=pre•ferable(to keepiground disturbance away'fromj'the -trees.at least as far • o - ut-'as°the =dripline. i ...y. ,_ . • . • *4 - • • Plantsmnsed`protection from;'three>kindwof injuries:"3 ••_ ='7,:1 L. _ .. . .rte. yv _T.. . • . : ' • Construction-Eau:sment,—:This injury cane be above'or- below..the ground level: '-aDamage'resulte'-from'scarting,v'cuttingiof roots, and.compaction of ' theksoir Such injuries"can be prevented:by roping or fencing a buffer zone around plants to be saved prior to construction (Figure II-5.3. ) . • Grade Changes -- Changing the natural ground level will alter;lgrades_.:which affect the plant's ability to obtain the necessary air, water, and • • thinerala:'-' Minor• •f-ills usually do .not!cause problems- although._•sensitivity betweeespecies does. vary. Cedars'=are- more sensitive. Trees .can tolerate fill of 6 inches or less. For shrubs and other plants the fill should be less. When there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be done by placing a layer of gravel and a tile system over the roots before the fill is made. A tile system protects a tree from a raised grade. The tile system should be laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered with small stones to allow air to circulate over the root area (see Figure II- 5.3) . • Lowering the natural ground level can seriously damage trees and shrubs. The highest percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be necessary to terrace the immediate area around the plants to be saved. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants can also be preserved by leaving them on an undisturbed, gently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside the dripline of the plant (Figure 11-5.3) . 1Y-5-15 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL. FOR- THE PUGET SOUND BASIN . . ' . • ' EitclOrmitione ,.. Protect trees and other plants when excavating for tile, - -wAter, land sewer lines; Where possible,. the trenches should be routed around trees and large shrubs: >,:When this is not ii,best.to tunnel under them. This can be done with hand tools or with power augers. .: , , - • • - Tf it is not ;possible to route the .trench•around p/apts to be saved, then the following should be observed: .4f . - . Cut ascfew roots as -possible, . When you have to cut,-- . • Cut clean:, .-Paint cut.,root ends with .a wood,dreaeing like asphalt - • . base...paint:. . - , ... . -,,:. . . ,,, ,.- e, • . , . . . . • - . i.. 4Backfill the trench,as%soon as -possible. . .- . . . . , •,: _ - . 7.?.: Tunnel beneath root systems as close to the center of --: --, .. - .-4,the. main trunk tovreservemost of the important,feeder _ - , . :roots:, -.• -• ., :T,,i. . :1,1. - ,..;•,-- . . . • •• ,::-. ' .. ;,s _ •;.; , . , .,.: ei-e_;-: ..,--,.-.,,, „:.: ., -•„>,,,? $..... . !-E-.:.- 4. •• - .: •'..:..-::... ku--,:: •-• ,J. •-• . • Some:.problemw.that _Can,-be ,encisunteredocith a- fewl;specific .t.reeivare: -- !.4: , -- .- •1,,..`-- 3 .:•,..,,z•.-..,;,:. •,:c.." • :.•;,,;--.. i,i ,,,,I, .i...:.•• • :-;'-,.- f.-.. ..4t. ": . " •-. ... Maplei. D0gwood;, ,Red.alderi Westerntemlock, Westernrids;cedar and Douglas • . .,- ;.,.. fir.,•.do;-..not readily:Adjust:tcchanges;:in.environment-AndIspecial care . - .- 4i . -:,,-.0hould.7.beiptaken_to-zprotecttheee,!trees:- .4'• •*-•-",- :7F:4- :* . ..•At •.::.b. .=0 •,..:.—....1'5 .•s,..: .....:.4. Z.'t.t. ,Orrrz;•:7.,:, •r..:-.. :..!. ;4.. 1,;;;;•;7,`-.•'...4: /..: . F.,1 11.'.."1: e. • .:. ....4.. t ..:1, The:tipover-:hAzardt,,of,,,Pacifinuailver.,,fir419-;hightfwhile that -mf Western • - , :.. -hemlock-,in.moderate, - TheT,dangeviof:tipover.increases where;dense stands . , -have...,been.k,-.thinnedoOther,LApeciesk,Aunless4theytareGonshallow, wet soils underf20 .inchews4oep)1ievaslA7lowb.tipover hazardw; -:•:. :::-... ,,. • cottonwoods,:.msplA4 anct;willhwiwhsvw,lwaterreeeking rnot.. . These can ,- • -::4, , --- causewtroubletiiinsewer lines,:and filteryfields. On..theuother hand, they s, thrive in high moisture conditions that Other -treemowould -succumb to. (., ' I • Thinning operations. In pure.,..orp:mixed:etands•of-Crand,„fir, Pagific silver • fir, Noble fir, Sitka spruce, Western red cedar, Western hemlock, Pacific • si..“logwoodi•-and7Reds.a/der •can-;cause.yseriows:AieeAee.2pcoblims ::Disease can ... becocmaelitablishedl:throiagn,damaged;./Imbs4...trunki,F.:rbiiiiiivAnd freshly cut . -.1stumps Diseaseckand-mmakened...trees- are -alsolsusceptible to insect ' •••• •• !":, attack: - .. ..„" ,...,: . •.. ...... ....„: :.,:,.. /.... .';,7,f;"''.A, ...,.,': 1...7 .•--*:Y:. ...:i' ':,,,,-,::dr.:■ -: .f.'; 't .r Mainten•nce;-- ,.. :-.• -,z . . .-;.---2--. : ;-.: :-. -....7,..t -, •-., . -t-,...-:, • - :L. ..,.; ".6..t.:• .-.:.: ., ...4-Inspeet:- flagged .areas regularly -to make„Aure,.flagging.:hat hot teen removed. If • :`:•`:• •.: tree roots have-,been• exposed i or..inlured, re-cover and/or_ Asa/ them. --.: • :••:-.- ••.L. :.,••... _: ?' ,...,_,.,•"-- `••: - ,-,... ,... ..-. .:,t, ..,;'-F ....: ' .: *,'•• . a".' ! ' ! ' • .• •. . . . . " • — ... ., '. .. .. •.'. • ' — • • • . . . . • - • . • ' . . . . - . • . • . . . ** - : ' • . .- - ._ .• • 4 ' . . . . . -,-,•: •.. .. tO: ' • . •;,. . . • , - .:. . • . ' ,... _ . •. . .: ' • • '•• — . . . • , .. . . . -. .• . • • * ' ... , ..• , . - • • :., - • . . .. • -• I . . .. . • . k f , 1 • . ..-. .. • • . _ . . . . • . Z-5-16 • FEBRUARY, 1992 • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.3 Preserving Natural Vegetation r A f1 r. 4ti w4 I 1 . r / 1 . i r r %. . +ti :�. •r.. I. _I7 1 r ,-5, •'� 17C • . • • ' . • lam. comotito 7 far wow.with- ��, ,' Satfoa - le and dav4. .•.45, Cl/and aea`'' -1/4: ----....7....--A. -t-ii.....-__,..... - _,._ 4,111621a . Drio . . Woo r..Nking rood war clog J • Pilo.liras. individual Plants • ,•-.;: Potential Problems - " •• -1 . • /�1 ( `'o,� °' �• 1•v #•, Na. ? •) -• .V •-r16,41,I - - . • • • Loast•smnes--• .., v ,.. . . • . • Drain Tiles " Dry Well' _ 1, "Vertical tilos" Soil Fill • 5 �+„ , � A r" " i. Ism •Q 41.0 :,I• %... � 1 � VOF'. ). � „ j -gloom Original-gio Dripliri. // 1 __--- `' Minh/re of 1 1 Rttoining .roll -=r-- • P!e• gtodr = ;• �ptor MOt or heal rwoid .$:.,.:,.. Ond soi I II—S-11 FEBRUARY, 2992 STORMwATBR MANAGEMENT MANUAL FOR THE PUGET -SOUND BASIN 1I-5.4-2 BMP E1.30: duffer Zones Code: 4:11 Symbol: •-- " peti ,i,tio and Purpose An undisturbed area or strip of natural vegetation or an established suitable planting that will provide a living filter to reduce soil erosion and runoff velocities. , Conditions Wher 'Prsct - e-'ApDiiee • • Natural buffer zones are used along streams and other bodies of water that need protection from erosion and sedimentation. -vegetative buffer -zones• can be used to proteat'netural.awa/es and incorporated. into •natural landscaping of an area. • Advaageq • y • ; • Buffer zones•-ptovide critical habitat adjecent. to streams and wetlands, as well as assistin.•controllingzerosion, especially on unstable Steep slopes. Buffers along streams and other water bodies also provide wildlife -corridors, a protected area•where .wildfife' can move from.-one place to--another: • Act as a visibility -and noise screen. ' ' - Disadvantage's/Problems • Extensive buffers will increase development coats. pesi.gn Criterjo • • Preserving natural vegetation or plantings in clumps, blocks, or strips is generally the easiedt and out successful method. . _ • • • Leave all unstible' steep'slopes in natural vegetation. • • Fence or flag cleariiq limits Yanda.keep all equipment;?acid.construction debris out of the nateral_areas. t,,.;. :. • • Xeep all eicivationsi outside ,the dripline of trees:and; shrubs. • Do not push-:debris=orllixtra soil=into the buffer =eine'Jarea'because it will cause damage from burying and smothering. • • vegetative buffer zones for streams, lakes or other waterways should be a minimum of 100 feet wide on each side with increases subject to other on-site sensitive conditions, existing vegetative conditions and erosion hazard potential (see Table I1-5.3 for setback guidelines) . • • • • 1I-5-18 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Table II-5.3 Minimum 'Recortmended Guidelines for Undisturbed Vegetative Setbacks From Wetlands, Streams, Lakes and Other Sensitive/Critical Areas: (Expressed in feet from 'ordinary high water mark'. ) 1 Wetlands2 Category I High intensity 300 feet Low intensity 200 feet Category II High intensity 200 feet Low intensity 100 feet Category III High intensity 100 feet Low intensity 50 feet Category IV High intensity 50 feet Low intensity 25 feet • ,Streams: To be completed at a later date. akes: To be completed at a later date. • • • The term ordinary high water mark' means the line on the shore established by the fluctuations of water and indicated by physical characteristics such as a clear, natural line impressed on the bank; shelving; changes in the character of soil destruction on terrestrial vegetation, or the presence of litter and debris; or other appropriate means that consider the characteristics of the surrounding area. _/ Source: Model Wetlands Protection Ordinance, Dept. of Ecology, September, 1990. Note: These buffer ranges have been established to reflect the impact of intense land uses on wetland functions and values. The ratings system (Categories I-IV) are based on the Puget Sound Wetlands Rating System as set out in the same document. Poor, fair, good and excellent conditions refers to percent coverage and growing condition of vegetation. • Erosion hazard ratings are based on the percent slope and hydrologic soil group of bare ground, as defined by the SCS. NOTE: If ground cover is improved through reseeding reduce recommendations to next level within the same category except for excellent rating which is minimum specification. Maintenance • Inspect the area frequently to make sure flagging remains in place and the area remains undisturbed. • • 1I-5-19 FEBRUARY, 1492 • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN I1-5.4.3 BKP 51.35: Permanen• Seeding and Planting Code: C) Symbol: —».-- pefinition The establishment of perennial vegetative cover on disturbed areas. Purpose To establish permanent vegetation (such as grasses, legumes and trees and shrubs) as rapidly as possible to prevent soil erosion by wind or water, and to improve wildlife habitat and site aesthetics. To provide pollutant filtration (biofiltration) in vegetation-lined channels and to establish constructed wetlands as required (see BMSP RW.10 in Chapter 111-4 and RV.05 in Chapter I1I-6) . Conditions ilhere Practice At►alies • Graded, final graded or cleared areas where permanent vegetative cover is needed to stabilize the soil. • Areas which will not be brought to final grade for a year or more. • vegetation-lined channels. • Retention or detention ponds as required. ,Adv ntpoee • Well established grass and ground covers can give an aesthetically pleasing, finished look to a development. • Once established, the vegetation will serve to prevent erosion and retard the velocity of runoff. pisadvantaa m P oblewis • vegetation and mulch cannot prevent soil slippage and erosion if soil is not inherently stable. • Coarse, high grasses that are not mowed can create a fire hazard in some locales. Very short mowed grass, however, provides less stability and sediment filtering capacity. • Grass planted to the edge of a watercourse may encourage fertilizing and mowing near the water's edge and increase nutrient and pesticide contamination. • May require regular irrigation to establish and maintain. Planning Considerations Vegetation controls erosion by reducing the velocity and the volume of overland flow and protecting the bare soil surface from raindrop impact. Areas which must be stabilized after the land has been disturbed require vegetative cover. The most common and economical means of establishing this cover is by seeding grasses and legumes. Advantages of seeding over other means of establishing plants include the small initial establishment cost, the wide variety of, grasses and legumes available, low labor requirement, and ease of establishment in difficult areas. • ::-E-20 :EBRUARY, .992 STORMWATER MANAGEMENT MANUAL TOR THE PUGET SOUND BASIN Consider the microclimate(r) within the development area. Low areas may be frost sockets and require hardier vegetation since cold air tends to sink and flow towards Plow spots. South-facing slopes may be more difficult to re-vegetate because they tend to be sunnier and drier. Disadvantages which must be dealt with are the potential for erosion during the establishment stage, a need to reseed areas that fail to establish, limited periods during the year suitable for seeding, and a need for water and appropriate climatic conditions during germination. There are so many variables in plant growth that an end product cannot be guaranteed. much can be done in the planning stages to increase the chances for successful seeding. Selection of the right plant materials for the site, good seedbed preparation, timing, and conscientious maintenance are important. Whenever possible, native species of plants should be used for landscaping. These plants are already adapted to the locale and survivability should be higher than with exotic species. - Native species are also less likely to require irrigation, which can be a large maintenance burden and is neither cost-effective nor ecologically sound. If non-native plant species are used, they should be tolerant of a large range of growing conditions and as low-maintenance as possible. pesia7 Criteria • Vegetation cannot be expected to supply An erosion control cover and prevent slippage on a Boil that is not stable due to its texture, structure, water movement, or excessive slope. • Seeding should be done immediately after final shaping, except during the period of November 1 through March 1, when the site should be protected by mulching or plastic covering until the next seeding period. • Permanent vegetation may be in the form of grass-type growth by seeding or sodding, or it may be trees or shrubs, or a combination of these. Establishing this cover may require 'the use of supplemental materials, such as mulch or jute netting (see SNP E1.15) . • Site Preparation: Install needed surface runoff control measures such as gradient terraces, berms, dikes, level spreaders, waterways, and sediment • basins prior to seeding or planting. • Seedina Grasses and leoumes: Seedbed Preparation -- If infertile or coarse textured subsoil will be exposed during land shaping, it is best to stockpile topsoil and respread it over the finished slope at a minimum 2 to 6-inch depth and roll it to provide a firm seedbed. If construction fills have left soil exposed with a loose, rough, or irregular surface, smooth with blade and roll. If cuts or construction equipment have left a tightly compacted surface, break with chisel plow or other suitable implement. Perform all cultural operations across or at right angles to the slope (contoured), such as with cat tracks on the final pass. The seedbed should be firm with a fairly fins surface. • Soil Amendments: Rates will depend on site characteristics and soil, but as a guide, apply lime at the rate of 100 pounds per 1,000 square feet. Apply actual nitrogen at the rate of 1-2 pounds per 1,000 sq. feet, phosphoric acid at the rate of 1.5 pounds per 1,00D sq. feet, and potassium at the rate of 1.5 pounds per 1,000 sq. feet. Work in lime and other nutrients to a depth of a minimum of 4 inches with suitable equipment. Scatter amendments uniformly and work into the soil during seedbed preparation. • Seeding: Apply an appropriate mixture to the prepared seedbed at a rate of 120 lbs/acre. (Seed mixture may be varied by the local government to take account of local conditions) . 11-5-21 FEBRUARY, IF77- • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Urban Annlicatioi: • Portions Percent Name pY Height Purity Gemination Kentucky Bluegrass • 30% 85 80 Creeping Red Fescue 40% 98 90 Perennial Rye 30% 95 90 Rural Arm 'cation: Kentucky Bluegrass (20A 15% 85 80 .rater►si.s) Tall Fescue (Festuc, 40% 95 90 prundincea) Perennial Rye (j.olium perenne) 30% 95 90 Chewings Fescue 15% 95 90 • Cover the seed with topsoil or mulch no deeper than h inch. It is better to work topsoil into the upper soil layer rather than spread a layer of it directly onto the top of the native soil. 'Hydro-seeding' applications with approved seed-mulch-fertilizer mixtures may also be used. tie lands deed Mixtures: For newly created wetlands, a wetlands specialist should design plantings to provide the best chance of success. As a guide apply the following mixture at a rate of 60 lbs/acre, and/or additional tubers for cattail, bulrush, slough sedge, as required by the local government. See Chapter 111-4, Volume III for more information on constructed wetlands. 1` to not under any circumstances use introduced, invasive plants like reed canarygrass (goal iris prundi.aacea) or purple loosestrife (jrvthrum salicaria) . Using plants such as these will cause many more problems than they will ever solve. Proportions Percent flame wejaht Purity Germination Red Top Charoesti.e albs) 30% 92 80 Birdsfoat Trefoil 30% 90 80 -(yotus corniculatus) Creeping Red Fescue 40% 98 90 Tree and Sh b Planting B Bides their erosion and sediment control values, .treed and shrubs also provide natural beauty and wildlife benefits. When used for the latter, they are usually more effective when planted in clumps or blocks. These procedures should be followed: 1. Trees and shrubs will do best in topsoil. If no topsoil is available, they •can be established in subsoil with proper amendment. If trees and shrubs are to be planted in subsoil, particular attention should be paid to amending the soil with generous amounts of organic matter. Mulches should also be used. 2. Good quality planting stock should be used. Normally one or two-year old deciduous seedlings, and three or four-year old coniferous transplants, when properly produced and handled are adequate. Stock should be kept - cool and moist from time of receipt and planted as soon as possible. II-5-22 FEBRUARY, 1992. . • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 3. Competing vegetation, if significant, should be pulled out of the area where the plant or plants are to be placed. Maintenance Inspect seeded areas for failure and make necessary repairs and reseed immediately. Conduct or follow-up survey after one year and replace failed plants where necessary. • If vegetative cover is inadequate to prevent rill erosion, overseed and fertilize in accordance with soil test results. • If a stand has lees than 40% cover, reevaluate choice of plant materials and quantities of lime and fertilizer. Re-establish the stand following seedbed preparation and seeding recommendations, omitting lime and fertilizer in the absence of soil test results. If the season prevents resowing, mulch or jute netting is an effective temporary cover. • • • I1-5-23 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN IT-5.4.4 BHP E1.40: sodding Code: (::, Symbol: — � Definition Stabilizing fine-graded disturbed areas by establishing permanent_grass stands with sod. Puri-acme To establish permanent turf for immediate erosion protection or to stabilize drainageways where concentrated overland flow will occur. Condit'on: Where Practice Atralies • Disturbed areas which require immediate vegetative cover. • Waterways carrying intermittent flow, where immediate stabilization or aesthetics are factors and other locations which are particularly suited to stabilization with sod. Advantages • Sod will give immediate protection. • Sod gives an immediate vegetative cover, which is both effective in checking erosion and is aesthetically pleasing. • Good sod has a high density of growth which is superior in protection to a • recently seeded area. • • Sod can be placed at any time of the year provided that soil moisture is �. adequate and the ground is not frozen. pisadva taae#JProblems • Sod is expensive. • Sod is heavy and handling costs are high. • Good quality sod, free from weed species, may be difficult to obtain'. • If laid in an unfavorable season, midaummer irrigation may be required. This also applies to very droughty sandy soils. • Grass species in the sod may not be suitable for site conditions. • If mowing is required, do not use grass sod. on slopes steeper than 3:1 (use minimum maintenance ground covers). • If not anchored or drained properly, sod will 'roll up' in grassed waterways. pea'an Criteria • Shape and smooth the surface to final grade in accordance with the approved grading plan. • Use of topsoil shall be in accordance with the requirements of Topsoiling (BMP E1.50) . • Add lime to reach a soil pH value of 6.5 (based on soil tests) . • Fertilize according to a soil test or in the absence of a test use available i\ I -5-44 EBRUAR7, 1- - STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN nitrogen, phosphorus and potash as prescribed for permanent seeding. Use fertilizers that are not highly soluble. • Work lime and fertilizer into the soil 1 to 2 inches deep and smooth the surface. • • Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely in place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least 12 inches. Staple if on steep slopes. • •• Roll the sodded area and irrigate. • • When sodding is carried out in alternating strips, or other patterns, seed the areas between the sod immediately after sodding. • Sod should be free of weeds and be of uniform thickness (Approx. 1 in. ) and should have a dense root mat for mechanical strength. • • 4Sa'ntenance • Inspect sodded areas regularly, especially after large storm events. Re-tack, re-sod, or re-seed as necessary. • • • • • • II- - FEBRUARY, 2- - STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN 11-5.4.5 BM? El.45: Topsoilinq Code: Q Symbol: --+��►r=- While not a permanent cover practice in itself, topsoiling has been included in this section because it is an integral component of preparing permanent cover to those areas where there is an unsuitable soil surface for plant growth. Use of in-situ or imported topsoil is always preferable to planting in subsoil. Definition Preserving and using topsoil to enhance final site stabilization with vegetation. Purpose To provide a suitable growth medium for final site stabilization with vegetation. Conditions Where Practjce Applies • Preservation or importation of topsoil is determined to be the most effective method of providing a suitable growth medium, and the slopes are less than 2:1. • Applicable to those areas with highly dense or impermeable soils or areas where planting is to be done in subsoil, where mulch and fertilizer alone would not provide a suitable growth medium. • Advantaaee • Topsoil stockpiling ensures that a good growth medium will be available for establishing plant cover on graded areas. It has a high organic matter cant.•• and friable consistency, water holding capacity and nutrient content. ( . • The stockpiles can. be used as noise and view baffles during construction. DisadvantaaeslProblemn • Stripping, stockpiling, and reapplying topsoil, or importing topsoil may not always be cost-effective. It may also create an erosion problem if improperly secured. • Unless carefully located, storage banks of topsoil may also obstruct site operations and therefore require double handling. • Topsoiling can delay seeding or sodding operations, increasing exposure time of denuded areas. • most topsoil contains some weed seeds. Plannin• Co,s 'derations Topsoil is the surface layer of the soil profile, generally characterized as being darker than the subsoil due to the presence of organic matter. Zt is the major zone of root development, carrying much of the nutrients available to plants, and supplying a large share of the water used by plants. Topsoiling is strongly recommended where ornamental plants or high-maintenance turf will be grown. Topsoiling is a required procedure when establishing vegetation on shallow soils, ant' soils of critically low pH (high acid) levels. If topsoiling is to be done, the following items should be considered: J . Whether an adequate volume of topsoil exists on the site. Topsoil should be,\ spread at a depth of 2-4 inches. More topsoil will be needed if the subsoil is 11-5-26 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN rocky. 2. Location of the topsoil stockpile so that it meets specifications and does not interfere with work on the site. 3. Allow sufficient time in scheduling for topsoil to be spread and banded prior to seeding, sodding, or planting. 4. Care must be take ,sot o o s .=o ' • ,e two so; s ave con rest ' - .textures. Sandy topsoil over clayey subsoil is a particularly poor combination, as water creeps along the junction between the soil layers and causes the topsoil to slough. S. If topsoil and subsoil are not properly bonded, water will not infiltrate the soil profile evenly and it will be difficult to establish vegetation. The best method to prevent a lack of bonding is to actually work the topsoil into the - layer below for a depth of at least 6 inches. • pesion Criteria • Field exploration of the site shall be made to determine if there is surface - soil of sufficient quantity and quality to justify stripping. Topsoil Shall be friable and loamy (loam, sandy loam, silt loam, sandy clay loam, clay loam) . Areas of natural ground water recharge should be avoided. • Stripping shall be confined to the immediate construction area. A 4 to 6 inch stripping depth is common, but depth may vary depending on the particular soil. All surface runoff control structures shall be in place prior to stripping. • Stockpiling of topsoil shill occur in the following manner: r a. Side slopes of the stockpile shall not exceed 2:1. b. An interceptor dike with gravel outlet and silt fence shall surround all topsoil stockpiles. c. Erosion control seeding or covering with clear plastic or other mulching materials (see BMPe E1.10, E1.20) of stockpiles shall 'be completed within 7 days of the formation of the stockpile. • Topsoil shall not be placed while in a frozen or muddy condition, when the subgrade is excessively wet, or when conditions exist that may otherwise be detrimental to proper grading or proposed sodding or seeding. • Previously established grades on the areas to be topsoiled shall be maintained according to the approved plan. Maintenance • Cover piles with clear plastic covering until needed. 11-5-27 FEBRUARY, 1992 • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5.5 STANDARDS AND SPECIFICATIONS FOR STKUCTCRAL AND BIOI CEANICAL 1 PRACTICES Structural and biomechanical control practices are used to either reduce erosion or retain sediment on the construction site. The BMPs in this section have been divided into two basic groups based on these characteristics. The standards and specifications of each BMP are presented in the same format used for nonstructural practices. Structural erosion control BMPs include measures for site stabilization (such as stabilized construction entrances), slope protection (such as pipe slope drains) and drainageway protection (such as level spreaders) . Sediment control BMPe include filter fences, berms, and sediment traps. Table I1-2.2 in Chapter II-2 gives the coding for these and all other BMPs in the volume. Structural control is more effective when combined with vegetative protection and appropriate grading practices as part of an Erosion and Sediment Control (ESC) Plan (see the supplemental guidelines on preparing an ESC plan). Control measures may be either permanent or temporary depending on whether they will remain in use after development is complete. Although temporary structures are emphasized in this section, they may be combined with permanent control facilities to provide protection of downstream properties during construction. Temporary ESC facilities provide siltation control, but downstream erosion protection must also be provided. Accordingly, the allowable discharge from development sites shall not exceed SD% of the pre-development peak flow for the 2-year, 24-hour storm. It is also important not to disturb areas of natural ground water discharge and/or retention. To accomplish this, a permanent detention pond may have to be constructed first with modifications allowing it to temporarily function as a sediment pond. Or, a control structure as specified in Chapter 1II-4 of the Runoff Control Volume may be required on the outlet of the sediment pond. The design of structural measures for erosion and sedimentation control is accomplished by carefully predetermining appropriate factors. The design storm, maximum drainage area, slope and other restrictions are noted for each BMP. The design criteria and limitations are important; if they are not observed, the simplest measures will fail and erosion control will not be achieved. In most ESC designs, especially for sites larger than 5 acres, several small • structures will function more effectively than a single large structure. For example, a combination of BMPs, such as filter fences, temporary dikes/swales, and several small sediment traps/ponds (depending on subbasin configuration) may be used as opposed to a single large sediment pond. Maintenance is also of critical importance for proper operation of structural BMPs and must be considered in their design. Maintenance requirements and frequency vary with each BMP and its performance criteria. At a minimum, the ESC plan shall require monthly maintenance, or following each runoff producing storm (whichever occurs more frequently) , for silt removal and proper operation of all ESC facilities. ESC facilities may have to be replaced or relocated depending on their performance under field conditions. The following factors should be considered when designing structural control measures: • Use material available on-site whenever possible. • Keep structures simple and take advantage of permanent facilities unless the. permanent structures are for infiltration. • Install the most important control structures first. X1-5-26 FEBRUARY, 1992 • STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN • Install BMPs correctly; visit the site dune and after storms to be sure that all structures are properly located, constructed, and functioning as designed. • Install control measures in sequences which minimize land disturbance. For example, install interceptor dikes/dm/ales and drainage trenches before seeding to avoid disturbing the seedbed. Avoid disturbing or removing existing vegetation whenever possible. • Do not block a natural drainageway. Make certain that all necessary permits have been obtained before starting any work in a wetland, stream, or other sensitive area. • Place control measures out of the way of construction operations. • Make field modifications where necessary with the approval of the local jurisdiction. • Provide access for 'maintenance. Although design and construction standards and specifications are presented in some detail, this section is not a substitute for training in hydraulic and construction engineering. The materials presented are guidelines to assist in the design of erosion control measures. The standards and specifications provided should not be considered rigid requirements except where statutory requirements are indicated. Where local experience has shown that an alternate design will work better, it may be used as long as it meets the requirements contained found in Chapter I-2 and is approved by the local government. Aeeivners are eneouraved to continuously seek out ew ma e e - so . , . ., .- ,. .s•o ;nd .e . . • • • • • • II- - FEBRUARY, 2-'- • STORl4WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-S.6 STRUCTURAL EROSION CONTROL B)Ps. .11-5.6.1 BHT E2.10: Stabilized Construction Entrance and Tire Wash Code: col Symbol: �� I Definition A temporary stone-stabilized pad located at points of vehicular ingress and egress on a construction site. Purpose To reduce the amount of mud, dirt, rocks, etc. transported onto public roads by motor vehicles or runoff by constructing a stabilized pad of rock spa/le at • entrances to construction sites and washing of tires during egress. Conditions Whe e Practice Applies • • Whenever traffic will be leaving a construction site •and moving directly onto a public road or other paved areas. Advantages • Mud on vehicle tires is significantly reduced which avoids hazards caused by depositing mud on the public roadway. • Sediment, which is otherwise contained on the construction site, does not enter stormwater runoff elsewhere. ,Planxun• _Considerations I� Construction entrances provide an area where mud can be removed from vehicle tires before they enter a public road. If the action of the vehicle traveling over the gravel pad is not sufficient to remove the majority of the mud, •then the tires must be washed before the vehicle enters a public road. If washing is used, provisions must be made to intercept the wash water and trap the sediment before it is carried off-site. Construction entrances should be used in conjunction with the stabilization of construction roads to reduce the amount of mud picked up by vehicles. It is important to note that this BMP will only be effective if sediment control is used throughout the rest of the construction site. • Desion Criteria • Material should be quarry spa//s (where feasible) , 4 inches to 8 inches size. • The rock pad shall be at least 12 inches thick and 100 feet in length for sites more than 1 acre; and may be reduced to 50 feet in length for sites less than 1 acre. • A filter fabric fence (see BMP E3.10) should be installed down-gradient from the construction entrance in order to contain any sediment-laden runoff from • the entrance. • Width shall be the full width of the vehicle ingress and egress area (minimum 20 feet) . • Additional rock should be added periodically to maintain proper function of pad. - • See Figure 1I-5.4 for details. • 11-5-30 FEBRUARY, 1992 STORXWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN • Tire washing should be done before the vehicle enters a paved street. washing should be done on an area covered with crushed rock and the wash water should be drained to a sediment retention facility such as a sediment trap or basin. • The volume of wash water produced by tire washing should be included when calculating the sediment trap or basin size. Maintenance • The entrance shall be maintained in a condition which will prevent tracking or flow of mud onto public rights-of-way. This may require periodic top dressing with 2-inch stone, as conditions demand, and repair and/or cleanout of any structures used to trap sediment. All materials spilled, dropped, washed, or tracked from vehicles onto roadways or into storm drains must be removed immediately. • All temporary erosion and sediment'control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BKPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. Figure II-5.4 Stabilized Construction Entrance 0 r s+a°°'ro S lop. -wn Cosa AFC, �* ;mo o role% `f • f°�4e°�r l ; e *?e y •l.i�i a •is ::% {�:Ods�.* Qe +�11:1s Iasi.►Nm�, �•�i / I�/s1��es►�•ay.a o� -.e/.1/sir Ie 1�l GIs 00 R = 25' min. :i��' �1'te�///.11 j,I��ii 4, ... •%1 •a 1 2 min. *iv, IS 4' to 8 quarry spells provide full width of ingress/egress area • II-5-31 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5:_6,2 BMP E2,_15: Construction Road Stabilization Code: E!.0 Symbol: pefinition The temporary stabilization with stone of access roads, subdivision roads, parking areas, and other on-site vehicle transportation routes immediately after grading. Purpose • To reduce erosion of temporary road beds by construction traffic during wet weather. • To reduce the erosion and therefore regrading of permanent road beds between the time of initial grading and final stabilization. Conditions Where Pr- e flies - • Wherever rock-base roads or parking areas are constructed, whether permanent or temporary, for use by construction traffic. • Note: Exceptions may be granted in areas with gravelly soils, such as the Everett series, as approved by the local government. Advantaoea • Efficiently constructed road stabilization 'not only reduces on-site erosion but can significantly speed on-site work; avoid instances of immobilized machinery. and delivery vehicles, and generally improve site efficiency and working ' conditions during adverse weather. � .. pisadvantaaee/Problems • Measures on temporary roads must be cheap not only to install but also to 'demolish if they interfere with the eventual surface treatment of the area. • Application of aggregate to construction roads may need to be made more than once during a construction period. _ Plannina Considerations Areas which are graded for construction vehicle transport and parking purposes are especially susceptible to erosion. The exposed soil surface is continually disturbed, leaving no opportunity for vegetative stabilization. Such areas also tend to collect and transport runoff waters along their surfaces. During vet weather, they often become muddy quagmires which generate significant quantities of sediment that may pollute nearby streams or be transported off-site on the wheels of construction vehicles. Dirt roads can become so unstable during wet weather that they are virtually unusable. Zmmediate stabilization of such areas with stone may cost money at the outset,it may actually save money in the long run by increasing the usefulness of the road during wet weather. Permanent roads and parking areas should be paved as soon as possible after grading. As an alternative, the early application of stone may solve potential erosion and stability problems and eliminate later regrading costs. Some of the stone will also probably remain in place for use as part of the final base course of the road. 11-5-32 FEBRUARY, inf- STORMWATER MANAGEMENT MANUAL FOR THE PUCET SOUND BASIN DeBiQn C 'teria • A 6-inch course of 2 to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or the completion of utility installation within the right-of-way. A 4-inch course of asphalt treated base (ATB) may be used in lieu of the crushed rock, or as advised by the local government. • Where feasible, alternative routes should be made for construction traffic; one for use in dry condition, the other for wet conditions which incorporate the measures listed below. • Temporary roads should follow the contour of the natural terrain to the maximum extent possible. Slope should not exceed 15 percent. Roadways should be carefully graded to drain transversely. Provide drainage swales on each side of the roadway in the case of a crowned section, or one side in the case of a super-elevated section. Drainage •wales shall be designed in accordance with the standards given in Chapter 11I-2. • Installed inlets shall be protected to prevent sediment-laden water entering the drain sewer system (see Section 11-5.8.5 on Storm Drain Inlet Protection BHP E3.30) . • Simple gravel berme without a trench can be used for less traveled roads. • Undisturbed buffer areas should be maintained at all stream crossings. • Areas adjacent to culvert crossings and steep slopes should be seeded and mulched and/or covered. • ' Dust control should be used when necessary (see BHP E2.20). Maintenance • Inspect stabilized areas regularly, especially after large storm events. Add crushed rock if necessary and restabilize any areas found to be eroding. • • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilised on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • • 11-533 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 11-5.6.3 BMP E .20: Duet Contra),. Code: (Pi) Symbol: — -- Definition Reducing surface and air movement of dust during land disturbing, demolition, and construction activities. purpose To prevent surface and air movement of dust from exposed soil surfaces. Conditie� ns Wh e P aetice Apoliee, • In areas (including roadways) subject to surface and air movement of dust where on-site and off-site damage is likely to occur if preventive measures are not taken. AdventaoeS • A decrease in the amount of dust in the air will decrease the potential for accidents and respiratory problems. Disadvantauee/Problems. • Use of water on-site to control dust emissions, particularly in areas where the soil is already compacted, can cause a runoff problem where there wasn't one. planning Considerations Construction activities inevitably result in the exposure and disturbance of Fugitive dust is emitted both during the activities (1.e. , excavation, demolition, vehicle traffic, human activity) and as a result of wind erosion over the exposed earth surfaces. Large quantities of dust are typically generated in •heavy' construction activities, such as road and street construction and subdivision, commercial and industrial development, which involve disturbance of significant areas of soil surface. Research at construction sites has established an average dust emission rate of 1.2 tons/acre/month for active construction. Earthmoving activities comprise the major source of construction dust emissions, but traffic and general disturbance of the soil also generate significant dust emissions. In planning for dust control, remember that the less soil is exposed at any one time, the less potential there will be for dust generation. Therefore, phasing a project and utilizing temporary stabilization practices upon the completion of grading can significantly reduce dust emissions. DesiCn Criteria • Minimize the period of soil exposure through use of temporary ground cover and other temporary stabilization practices (see Seeding and Mulching, BMPs E1.10 and E1.15). • Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud onto street, refer to Stabilized Construction Entrance (BHP E2.10) . • Spray exposed soil areas with approved dust palliative. Oil should not be used for dust suppression. Check with the local government to see which other dust palliatives may be used in the area. Maintenance • Respray area as necessary to keep dust to a minimum. 1I-5-34 FEBRUARY,- 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-S./.4 BHP E2.2S: Pine Slone Drains Code: Symbol: Definition A pipe extending from the top to the bottom of a cut or fill slope and discharging into a stabilized water course or a sediment trapping device or onto a stabilization area. Purnoee To carry concentrated runoff down steep slopes without causing gullies, channel erosion, or saturation of slide-prone soils. Conditions Where Practice Applies • • Where a temporary (or permanent) measure is needed for conveying runoff down a slope .without causing erosion. Advantages • Slope drains provide a potentially effective method of conveying water safely down steep slopes. Disadvantages/problems • • Care must be taken to correctly site drains and not underdesign them. Also, when clearing takes place .prior to installing these drains, care must be taken • to revegetate the entire easement area, otherwise erosion tends to occur beneath the pipeline, resulting in gully formation. Planninc Conside atinns • There is of ten a significant lag between the time a cut or fill slope is completed and the time a permanent drainage system can be installed. During this period, the slope is usually not stabilized and is particularly vulnerable to erosion. This situation also occurs on slope construction which is temporarily delayed before final grade is reached. Temporary slope drains can provide valuable protection of exposed slopes until permanent drainage structures can be installed. When used in conjunction with diversion dikes, temporary slope drains can be used to convey stormwater from the entire drainage area above a slope to the base of the slope without erosion. It is very important that these temporary structures be installed properly sinco their failure will often result in severe gully erosion. The entrance section must be securely entrenched, all connections must be watertight, and the conduit must be staked securely. Design Criteria • The capacity for temporary drains shall be sufficient to handle a 10-year, 24- hour peak flow. This may be computed using the conveyance design method in Chapter III-1 of the Runoff Control Volume. Permanent pipe slope drains shall be sized for the 25-year 24-hour peak flow. • The maximum drainage area allowed per pipe is ten acres. For larger areas, a rock-lined channel or more than one pipe shall be installed (see Volume III Chapter 11I-2). • The entrance shall consist of a standard flared end section for culverts 12 inches and larger with a minimum 6-inch metal toe plate to prevent runoff from undercutting the pipe inlet. The slope of the entrance shall be at least 3 percent (Figure 11-5.5) . • • 1I-5-35. FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN • • The soil around and under the pipe and entrance section shall be thoroughly compacted to prevent undercutting. • The flared inlet section shall be securely connected to the slope drain and have watertight connecting bands. • . Slope drain sections shall be securely fastened together and have gasketed watertight fittings, and be securely anchored into the soil. • Interceptor dikes shall be used to direct runoff into a slope drain. The height of the dike shall be at least 1 foot higher at all points than the top of the inlet pipe. • The area below the outlet must be stabilized with a riprap apron (see BMP E2.70, Outlet Protection, for the appropriate outlet material) . • If the pipe slope drain is conveying sediment-laden water, direct all flows into the sediment trapping facility. • Materials specifications for the type of pipe used shall be set by the local government. Maintenance • Check inlet and outlet points regularly, especially after heavy storms. The inlet should be free of undercutting, and no water should be going around the point of entry. If there are problems, the headwall should be reinforced with compacted earth or sand bags. The outlet point should be free of erosion and_ installed with appropriate outlet protection (see BMP E2.70) . • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • • I_ - FEBRUARY, 1" STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIL: Figure II-5.5 Pipe Slope Drains • Discharge into a stabilized � R; �Earn Dike • --•��''=t D watercourse or a sediment � � trapping oeve COT D a • stabilized area It / Corrugated metal ' or CPEP pipe •�,: Sfope.2.1 H 7 .l.4 % .O.t2' etxws 11111111111114 Slope 3%or tai ra Table lU steeper Rip rap per 2.6 !/ Depth of apron shall be Corrugated metal \ ��. ` min equal to pipe diameter or CPEP pipe �b Standard Sand Cutolt wan anemia,madam mum& Diameter (tor pipe 2 121 a•min.at less than 1•..slope 1 II-5-37 FEBRUARY, 1117— • STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN • II-5.6.S :)(P E2.30: Subsurface Drains Code: (ii) Symbol: pefiniti.on A perforated conduit such as a pipe, tubing, or tile installed beneath the ground to intercept and convey ground water. Purpose To provide a dewatering mechanism for draining excessively wet, sloping soils-- usually consisting of an underground perforated pipe that will intercept and convey ground water. Condit'_piis When Pr-etiee ,applies • Wherever excessive water must be removed from the soil. The soil must be deep and permeable enough to allow an effective system to be installed. Advantavee • Subsurface drains often provide the only practical method of stabilizing excessively wet, sloping soils.Disadvantages/Problems • Problems may be encountered with tree roots (see Maintenance). • Pipes cannot be located under heavy vehicle crossings. • planruino Cojjsiderat 'ons Subsurface drainage systems are of two types; relief drains and interceptor drains. Relief drains are used either to lover the water table in order to improve the growth of vegetation, or to remove surface water. They are installed along a slope and drain in the direction of the slope. They can be installed in a gridiron pattern, a herringbone pattern, or a random pattern (Figure 11-5.6). Interceptor drains are used to remove water as it seeps down a slope to prevent the soil from becoming saturated and subject to slippage. They are installed across a slope and drain to the side of the slope. They usually consist of a single pipe or series of single pipes instead of • patterned layout (Figure IT-S.7) . • peeion C toils • Subsurface drain shall be sized for the required capacity. The minimum diameter.for a subsurface drain shall be four inches. • The minimum velocity required to prevent silting is 1.4 ft./sec. The line shall be graded to achieve at least this velocity. • Filter material and fabric shall be used around all drains for proper bedding and filtration of fine materials. • The outlet of the subsurface drain shall empty into a sediment trap or pond. If free of sediment, it shall empty into a receiving channel, swale, or stable vegetated area adequately protected from erosion and undermining. • The strength and durability of the pipe shall meet the requirements of the in accordance with the manufacturer's specifications. C I2-5-38 FEa UARY, • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Construction Specifications • The trench shall be constructed on a continuous grade with no reverse grades or low spots. • soft or yielding soils under the drain shall be stabilized with gravel or other suitable material. • Deformed, warped, or otherwise unsuitable pipe shall not be used. • Filter material shall be placed as specified with at least 3 inches of material on all sides of the pipe. • Backfilling shall be done immediately after placement of the pipe. No sections of pipe shall remain uncovered overnight or during a rainstorm. Baekfill material shall be placed in the trench in such a manner that the drain pipe is not displaced or damaged. Maintenance • Subsurface drains shall be checked periodically to ensure that they are free- flowing and not clogged with sediment. • The outlet shall _be kept clean and free of debris. • Surface inlets shall be kept open and free of sediment and other debris. • Trees located too close to a subsurface drain often clog the system with their roots. If a drain becomes clogged, relocate the drain or remove the trees as a last report. Drain placement should.be planned to minimize this problem. • Where drains are crossed by.heavy vehicles, the line shall be checked to ensure that it is not crushed. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary EMPS are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • • • II- - . FEBRUARY, 1— STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN . . .. . , Figure II-5.6 Subsurface Drain Layout • RANDOM PATTERN ,, . . -r-•::-..}.,.. . ,. .-4t....,.....,-.... ,..-,..,-.. • . . MillaNNIMMIr w ,. Outlet f-ay..-414•&.. .. .c.:.::- • f,;...7..r......- HERRINGBONE PATTERN i.... ;,‘".•-''''';1;-• —'.1,... . . ‘', * - - *•—•' .. ,. .• ,, „:.... ,...,„„:1_,,- 9 „It, . ... ..,---.....-T.7---..„ .„...„,,,...... _ . . Outlet 1.c.t tr, •.....,.:4r....r•-• .ft, 1r,wl - 7...'.-14...-2 .. - ',,,77.)....... - Lateral . PARALLEL PATTERN -777----"-----."-.--. ...-...:.• .Ftf,..rar.:k.-40-"""i." Main :-'".7-•.,,, - - • •• -",e"---4.---•-•x2::;••••:*4-eso.r.7;-*-- :- ..,cr•Er. .:4•;.i.s.r...r.:•-,-,:. ..,,, ;T:::-. . -. :.......- ,-_ . • -•-• • ,. . , Outlet or -'---/ .., 71 - .1.,::••,- L. • . . 3/4" minus :.•,--dik '..01 1‘ Filter Fabric Gravel vo-1. • .4 .. . . TYPICAL SECTION •:fiia. :•• . -,,,,„,,,..„I•••,1;Ie/ flpi;.• . . O. • Water Table Before Drainage • Water Table Atter Drainage Interceptor Drain ---IMI,.1=0 OM OM .. .• • Seepage Area .,. ,..........,.. - -,:„•:,: •• • , ,— / • —z—zz ,"•:.'7;-:--:--.4;•. :-.... . - ..(.,,...:•• •• 7 ///7 /-/ • —/ / • - Grounowater F'ow Impermeable Layer Figure 1I-5.1 Effect of Subsurface Drain on Water Table II-5-40 FEBRUARY, 2.992 STORMWATER MANAGEMENT HA DAL FOR THE PUGET SOUND BASIN S.7.6 M� 2.35; Sur ace Rou henin Code: SR Symbol: �-,__. Definition Provision of a rough soil surface with horizontal depressions created by operating a tiller or other suitable equipment on the contour or by leaving slopes in a roughened condition by not fine grading them. Purpose To aid in establishment of vegetative cover, reduce runoff velocity, increase infiltration, and provide for sediment trapping. Conditions Where P artice Applies • All slopes steeper than 3:1, and greater than 5 vertical feet, require surface roughening; either stair-step grading, grooving, furrowing, or tracking if they are to be stabilized with vegetation. Advantacies • Surface roughening provides some instant erosion protection on bare soil while vegetative cover is being established. • It is an inexpensive and simple erosion control measure. Disadva,taaesJProblems • While this is a cheap and simple method of erosion control, it is of limited effectiveness in anything more than a moderate storm. Planrino Con ideretions Graded areas with smooth, hard surfaces give a false impression of 'finished grading' and a job well done. It is difficult to establish vegetation on such surfaces due to reduced water infiltration and the potential for erosion. Rough slope surfaces with uneven soil and rocks left in place may appear unattractive or unfinished at first, but they encourage water infiltration, speed the establishment of vegetation, and decrease runoff velocity. Rough, loose soil' surfaces give lime, fertilizer, and seed some natural coverage. Niches in the surface provide aicroclimates which generally provide a ,cooler and more favorable moisture level than hard flat surfaces; this aids seed germination. There are different methods for achieving, a roughened soil surface on a slope, and the selection of an appropriate method depends upon the type of slope. Roughening methods include stair-step grading, grooving, and tracking. Factors to be considered in choosing a method are slope steepness, moving requirements, and whether the slope is formed by cutting or filling. 1 . Disturbed areas which will not require moving may be stair-step graded, grooved, or left rough after filling. 2. Stair-step grading is particularly appropriate in soils containing large amounts of soft rock. Each 'step' catches material which sloughs from above, and provides a level site where vegetation can become established. Stairs should be wide enough to work with standard earth moving equipment. 1 3. Areas which will be mowed (these areas should have slopes less steep than 3:1) may have small furrows left by disking, harrowing, raking, or seed-planting machinery operated on the contour. 11-5-41 FEBRUARY, 1932 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 4. It is important to avoid excessive compacting' of the soil surface when scarifying. Tracking with bulldozer treads is preferable to not roughening at all, but is not as effective as other forms of roughening, as the soil surface is severely compacted and runoff is increased. Design Criteria Graded areas with slopes greater than 3:1 but less than 2:1 should be roughened before seeding (Figures II-5.8a,b). This can be Accomplished in a variety of ways, including "track walking," or driving a crawler tractor up and down the slope, leaving a pattern of cleat imprints parallel to slope contours. Graded areas steeper than 2:1 should be stair-stepped with benches as shown in. Figure II-5.9. The stair-stepping will help vegetation become established and also trap soil eroded from the slopes above. Jiaintenance • Areas which are graded in this manner should be seeded as quickly as possible. • Regular inspections should be made of the area. If rills appear, they should be re—graded and re-seeded immediately. • • • II-5-42 FEBRUARY, 1992 STORK WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.8(a) Heavy Equipment Can Be Used To Mechanically Scarily Slopes undisturbed area ;vitt tread grooves of track perpendicular to dope direction I undisturbed vegetation (so diversion C �� m do=er treads create grooves V.%* — perpendicular to slope direction `" - 11Y V"\•••::*t .% G .� j.r. Figure II-5.8(b) Unvegetated Slopes Should be Temporarily Scarified to Minimize Runoff Velocities II-5-43 FEBRUARY, 1 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.9 Stair-Stepping Cut Slopes and Grooving Slopes tar, Debris from slope above . ---• is caught by steps _ •-'ll..n- „Alt 'l , 'mg Drainage -Alit ,I � °' �fJ I! :� ,ice- �i� i -� ! _ 40 W i- 50" 1_' , inliat .i.. • ------- IIl1_ "r �1r Water, soil , and fertilizer ' 1 _ - held by steps - plants iiii 1 — can become established on -.W• ,_ _ the steps. :u:1_ II;- •• Jt' i,=, —,=-_ 11 -&—_-_ stair Stepping Cut Slopes 1- it/l^�1 •.. • 1 I 1 ►tom. - : : ; I I Mill _ 1i „ ;, l l ! I I -:.:---1". 11---- . _ >e :$ 1 _ 1 i 1 i _ Grooving is cutting furrows 1111=--. „ _ 4 along the zontour of a slope. � ' 'I Irregularities in the soil -iii===NI A surface catch rainwater and l� provide some coverage of lime, fertilizer and seed. . ." IIG I:—i li Grooving Slopes ' II-5-44 FEBRUARY, 1992 Appendix K Erosion and Sediment Control BMP Manual Guidelines for Stormwater Management Spokane County Public Works • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN ZZ-5.7. 7 BMP E2.40: Gradient Terxacel; Code: Symbol: Definition An earth embankment or a ridge-and-channel constructed with suitable spacing and with an acceptable grade. Purpose To reduce erosion damage by intercepting surface runoff and conducting it to a stable outlet at a nonerosive velocity. (This standard covers the planning and design of gradient terraces and does not apply to diversions. ) Condit one Where Practice Avnlies • • Gradient terraces normally are limited to denuded land having a water erosion problem. They should not be constructed on deep sands or on soils that are too stony, steep, or shallow to permit practical and economical installation and maintenance. Gradient terraces may be used only where suitable outlets are or will be made available. Advantages • Gradient terraces lower the velocity of runoff, increase the distance of overland flow, and reduce effective hydraulic gradient. They also hold moisture and minimize sediment. J pisadvanta.es/Problems _ • May significantly increase cut and fill costs and cause sloughing if excessive water infiltrates soils. pes3.cm Criteria • The maximum spacing of gradient terraces should be determined by the following method: V.I. = xs + y Where: V.I. gi vertical interval in feet z M 0.8 for Washington' • land slope in feet per 100 feet y a soil and cover variable with values from 1.0 to 4.02 • The minimum constructed cross-section should meet the design dimensions. • The top of the constructed ridge should not be lower at any point than the design elevation plus the specified overfill for settlement. The opening at the outlet end of the terrace should have a cross section equal to that specified for the terrace channel. U.S. . Soil Conservation Service, National Engineering Handbook • • /Values of 'y• are influenced by foil erodibility and cover practices. 1 The lower values are applicable to erosive soils where little to no - residue is left on the surface. The higher value is applicable only to erosion-resistant soils where a large amount of residue (111 tons of straw/acre equivalent) is on the surface. 1I-5-45 FEBRUARY, 1992 • STOR?4WATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN • Channel Grade - Channel grades may be either uniform or variable with a maxim grade of 0.6 feet per 100 feet length. For short distances, terrace grades may be increased to improve alignment. The channel velocity should not exceed that which is nonerosive for the soil type with the planned treatment. • Outlet - All gradient terraces should have adequate outlets. Such an outlet may be a grassed waterway, vegetated area, or tile outlet. In all eases the outlet must convey runoff from the terrace or terrace system to a point where the outflow will not cause damage. Vegetative cover should be used in the outlet channel. • The design elevation of the water surface of the terrace should not be lower than the design elevation of the water surface in the outlet at their junction, when both are operating at design flow. Specifications • Vertical spacing determined by the above methods may be increased as much as 0.5 feet or 10 percent, whichever is greater, to provide better alignment or location, to avoid obstacles, to adjust for equipment size, or to reach a satisfactory outlet (Figure I1-5.10). • The drainage area above the top should not exceed the area that would be drained by a terrace of equal length with normal spacing. • Capacity - The terrace should have enough capacity to handle the peak runoff expected from a 2-year, 24-hour design storm without overtopping. • Cross-section - The terrace cross-section should be proportioned to fit the land slope. The ridge height should include a reasonable settlement factor. The ridge should have a minimum top width of 3 feet at the design height. The. " minimum cross-sectional area of the terrace channel should be 8 square feet for land slopes of 5 percent or less, 7 square feet for slopes from 5 to 8 percent, and 6 square feet for slopes steeper than 8 percent. The terrace can be constructed wide enough to be maintained using a small cat. Maintenance • Maintenance should be performed as needed. Terraces should be inspected regularly; at least once a year and after large storm events. • • • • • • • . - FEBRUARY, - - STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN . Figure II-5.10 Gradient Terraces tiope to adequate outlet *4r.y- 10' min. 0 mss* _ _ 1. y/ -• r �` A` 1/� _ ...„,,,, o 4 K411 1 ic.----- \ " . i et\-weiile - /P . I , . IA/Ilv . ei-- - scs / y. I . i i 1,.---W\ ' — -- — — — — — — — —--J Z I • • II-5-47 E.BRUAR7, STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5.7.B B!!P E2.45: Bioenaineered Protection of Very steep Sloped • Code: SSP Symbol: E-- - p Definition Steep slope protection using a combination of vegetative and mechanical measures. Purpose To stabilize steep banks. Conditions Where Practice AApliee, Slopes of steep grade, cut and fill banks, and unstable Soil conditions that cannot be stabilized using ordinary vegetative techniques. Adventaaee • Vegetation reduces sheet erosion on. slopes and impedes sediment at the toe of the slope. • Where soils are unstable and liable to slip due to wet conditions, utilization of soil moisture by vegetation can reduce the problem. • Shrubs and trees shelter slopes against the impact of rainstorms, and the humus formed by decaying leaves further helps to impede runoff. • Mechanical measures help to stabilize soil long enough to allow vegetation to , become established. �. pisadvantaoeB/Probleten • The planting of non-seeded material such as live willow brush is a specialized operation and cannot be highly mechanized or installed by unskilled labor. • The methods described are effective but require a complete knowledge of soil, hydrology, and other physical data to design measures that will adequately solve the problem. pesian C 'teria. The following bioengineering methods can be used atter slopes have been protected by diversion of runoff (covered in B!0? E2.55) or through the terracing of slopes (BMP E2.40). • Sod walls or retaining banks are used to stabilize terraces. Sod is piled by tilting it slightly toward the slope and should be backfilled with soil and compacted as they are built up. Sod walls can be as steep as 1:8 but should' not be higher than 5 feet (Figure II-5.111). • Timber rame et-b'1 zatiom is effective on gradients up to 1:1 and involves the following steps in construction: 1) Lay soil retarding frames of 2 x 4 in. vertical members and 1 x 4 in. horizontal members on slopes. Frames on slopes over 15 feet in length need to be anchored to slope to prevent buckling. 2) Attach 14 gauge galvanized tire wires for anchoring wire mesh. 3) Fill frames with moist topsoil and compact the soil. 4) Spread straw 6 inches deep over slope. 5) Cover straw with 14 gauge 4-inch mesh galvanized reinforced wire. 6) Secure wire mesh at least 6 feet back of top slope. 7) Plant ground.' cover plants through straw into topsoil (Figure I1-5.11b) . • Woven willow whips (Figure II-5.11c) may be used to form live barriers for immediate erosion control. Construction: 1) 3 foot poles are spaced at 5 foot 11-5-48 FE RUAR , STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN distances and driven into the slope to a depth of 2 feet. 2) 2 foot willow sticks are inserted between poles at one foot distances. 3) Live willow branches of 5 foot length are sunk to a depth of 1 inch and interwoven with poles and stocks. 4) Spaces between the woven 'fences' are filled with top- soil. Fences are generally arranged parallel to the slope or in a grid pattern diagonal to the direction of the slope. • perm Planting. 1) Excavate ditches from 3 to 5 feet apart along the slope and shape a berm on the downalope side. Construct ditches with 5 percent longitudinal slope. 2) Plant rooted cuttings on 3 foot centers and mulch. Suitable trees are willow, alder, birch, pine, and selected shrubs. In extremely dry situations, rooted cuttings can be planted in biodegradable plastic bags that are watered at the time of planting (Figure II-5.11d) . • Brush Lavers. 1) Prepare 3 foot 'niches* as shown. 2) Lay uprooted 5 foot live branches of willow or poplar at close spacing. 3) Starting at foot of slope, backfill lower ditch with excavated material from ditch above it. Operation should be carried out during dormant season (Figure II-5.11e) . Maintenance • Regardless of the stabilization method used, inspections should be made on a regular basis to make sure the system 'is functioning correctly. • Note: There are a number of manufacturers who provide prefabricated bioengineered devices for the protection of steep slopes. l • • • 1 • II-5-49 • FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN l '\ 1:2 maximum slope ..-.: .../ ' sod usually 18' x 72" . '% well•drained fill tamped in • place in layers ea sod is stacked Figure II-5.11(a) Sod Retaining Bank staked down 1"x 4" members 1"x 4" cross pieces with wire ties in place /=��w „f .! extend netting into trench and bury / ,, mow ..�=�i A,� topsoi in framework "141,1,-w/w%// ;;..r�� _��/ • i/i//i I-;;.-. Maw.„::.....tforfr .. --r:: -�, netting secured in place by wire ties r timber, frame. straw & netting Figure II-5.11(b) Timber Frame Stabilization - _ L ,s 6• push willow whips into 6' topsoi placed flush — ground and then inter- with top of 'brush' weave between posts• Figure II-5.11(c) Woven Willow Whips BERM PLANTING strip of sod well tamped SECTION I (baekfgl BRUSH LAYERS - - SECTION Figure II-5.11(d) Figure II-5.11(e) Berm Planting Brush Layers II-5-5D FEBRUARY, 1992 STORWATER MANAGEMENT MANUAL FOR TEE POGET SOUND BASIN 11-5.7.9 BM? E2.50: Level Screader, Code: (ii) Symbol: milmmilla pefition A temporary outlet for dikes and diversions consisting of an excavated depression constructed at zero grade across a slope. =lent e To convert concentrated runoff to sheet flow and release it onto areas stabilized by existing vegetation or an engineered filter strip. Condition Where Practice Anoliee • To be constructed on undisturbed areas that are stabilized by existing vegetation and where concentrated flows are anticipated to occur at 0 percent grade. Advantages • Level spreaders disperse the energy of concentrated flows, reducing erosion potential and encouraging sedimentation. Disadvantages/Problems • If the level spreader has any low points, flow tends to concentrate there. i This concentrated flow can create channels and cause erosion. If the spreader serves as an entrance to a water quality treatment system, short-circuiting of 1 - the forebay may happen and the system will be less effective in removing • sediment and particulate pollutants. Planninc Corsiderat 'one Interceptor dikes and svalea (IMP E2.55) call for a stable outlet for concentrated stormwater flows. The level spreader can be used for this purpose provided the runoff is relatively free of sediment. If properly constructed, the level spreader will significantly reduce the velocity of concentrated stormwater and spread it uniformly over a stable undisturbed area. Particular cars crust be taken during construction to ensure that the lower lip of the structure is 1.1)481. It there are any depressions in the lip, flow will tend to concentrate at these points and erosion will occur, resulting in failure of the outlet. Thin problem may be avoided by using a grade board or a gravel Zip over which the runoff must flow when exiting the spreader. Regular maintenance is essential for this practice. peslom C ' ris • The grads of the channel for the last 20 feet of the dike or interceptor entering the level spreader shall be less than or equal to 1 percent. The grade of the level spreader shall be 0 percent to ensure uniform spreading of storm runoff (Figure 1I-5.12) . • • A 6-inch high gravel berm placed across the level lip shall consist of washed - crushed rock, 2 to 4 inch or 3/4 inch to 1+ inch size. • The spreader length will be determined by estimating the flow expected from the 25-year, 24-hour design (Q), and selecting the appropriate length from the ` following table: 1I-5-51 FEBRUARY, 1992 • STORMWATER )SANAGEXENT MANUAL POR TEE PUGET SOUND' BASIN in CFS rli.n. Lencth in feet 0 - 0.1 15 0.1 - 0.2 20 0.2. - 0.3 30 0.3 - 0.4 40 • The width of the spreader should be at least 6 feet. • The depth of the spreader as measured from the lip should be at least 6 inches and it should be uniform across the entire length. • The slope of the undisturbed outlet should not exceed 6% percent. $aintenance • The spreader should be inspected after every runoff event to ensure that it is functioning correctly. The contractor should avoid the placement of any material on or prevent construction traffic across the structure. If the spreader is damaged by construction traffic, it shall be immediately repaired. t.. I - - - BRUARY, STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN J Figure II-5.12 Level Spreader `a 4\O Interceptor Berm Last 20'of Interceptor � not to exceed 1%Grade i ...... i\ 14'1/4.`-...,. ,,\ 4...7.......--__ -_--- ........_____ 21r* -,021---- ji5Alla - -- "/1".✓ Channel Grade 0% Stabilized Slope '" / •"- 6'Gravel Berm Spreader Undisturbed O)utlet /I r. 4-0":1110:--:7".. 1, t / �, ,1:/r,.%1,,r i'� ' 1'min , �� - _ _- �N_• 1 �,,. ,Q I �'�-■ 2.1 or hatter y t ii i// �'/d �` I 3' wnm. • I II-5-53 FEBRUARY, 1992 STORNWATER MANAGEMENT MANUAL FOR THE PUCET SOUND BASIN ,TI-5.7.10 BHP E2.55: Interceptor Dike and Swale Code: III) Symbol: • u Definition, A ridge of compacted soil or a swale with vegetative lining located at the top or base of a sloping disturbed area. Purpose To intercept storm runoff from drainage areas above unprotected slopes and direct it to a stabilized outlet. • • Conditions Where Practice Applies • • Where the volume and velocity of runoff from exposed or disturbed slopes must be reduced. When an interceptor dike/swale is placed above a disturbed slope, it reduces the volume of water reaching the disturbed area by intercepting runoff from above (Figures II-5.13a,b) . When it is placed horizontally across a disturbed slope, it reduces the velocity of runoff flowing down the slope by reducing the distance that the runoff can flow directly downhill. Advantages • This BHP provides a practical, inexpensive method to divert runoff from erosive situations. DisadvantaaenjProblems • None f lannino Considerations A temporary diversion dike or swale is intended to divert overland sheet flow to a stabilized outlet or a sediment trapping facility during establishment of permanent stabilization on a sloping disturbed area. When used at the top of • slope, the structure protects exposed slopes by keeping upland runoff away. When used at the base of a slope, the structure protects adjacent and downstream areas by diverting sediment-laden runoff to a sediment trapping facility. If the dike or swale is going to remain in place for longer than 15 days, it shall be stabilized with temporary or permanent vegetation. The slope behind the dike or awale is also an important consideration. The dike or &wale must have a positive grade to assure drainage, but it the slope is too great, precautions must be taken to prevent erosion due to high velocity of flow. This practice is considered an economical one because it uses material available on the site and can usually be constructed with equipment needed for site grading. The useful life of the practice can be extended by stabilizing• the dike or Swale with vegetation. peei,on Criterii • • Interceptor dikes !hell meet the following cr teria: Top Width 2 feet minimum. Height 18 inches minimum. Measured from upslope toe and at a compaction of . 90 percent ASTM D698 standard proctor. Side Slopes 2:1 or flatter. • • . 11-5-54 FEBRUARY, 1 STORMWATER MANAGEMENT MANUAL FOR THI PUGET SOUND BASIN Grade Topography dependent, except that dike shall be limited to grades between 0.5 and 1.0 percent. Horizontal Spacing of Interceptor Dikes Slopes <5% 300 feet Slopes 5-10% = 200 feet Slopes 10-40% = 100 feet Stabilization Slopes = <5% Seed and mulch applied within 5 days of dike construction (see BMP E1.10) . • Slopes 5-40% Dependent on runoff velocities and dike materials. Stabilization should be done immediately using either sod or riprap to avoid erosion. Outlet The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion shall occur at the outlet. Provide energy dissipation measures as necessary. Sediment-laden runoff must be released through a sediment trapping facility. Other Minimize construction traffic over temporary dikes. • Interceptor swales shall meet the fol. owing criteria: Bottom Width 2 feet minimum; the bottom • shall be level. • Depth 1 foot minimum. Side Slope 2:1 or flatter. Grade Maximum 5 percent, with positive drainage to a suitable outlet (such as a sediment trap). Stabilization Sated as per BMP E1.10 Temporary Seeding, or•E2.75 Riprap 12 inches thick pressed into the bank and extending • at least 8 inches vertical from the bottom. Swale Spacing Slope of disturbed area: <5% 300 feet • 5-10% 200 feet 10-40% = 100 feet Outlet • Level Spreader or Riprap to stabilized outlet/sedimentation pond. I1-5-- FEBRUARY, - - STORNKATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Maintens ce • • The measure should be inspected after every major storm and repairs made as necessary. Damage caused by construction traffic or other activity must be repaired before the end of each working day. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed.' Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • • • • • 11-5- - FEBR ARY. STORNWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.13(a) Temporary Interceptor Dikes Dike Mien!mmpaaed 9D%Standard Proctor t I I 4 ,, W rrtn. 1. flow F . �n l Interceptor Oae soavtg• to0'.200.Or 300'Ocoenting on grmIe • • 1 hedn. 1 K trot Lnlel 8nmen ROW or Ober eats or Rom TS E=oaseo Scope r /,/% 7f /- !/ ' /mil ins t t I 2 2 e tan.l Sorntq. 100.200.or 300' ,, Oepertelnq on Stops Figure II-5.13(b) Interceptor Swale II-5-57 FEBRUARY, 1992 , STORMIWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN • 11-5.7.11 BMP E2.60: Check Dams Code: (ii) Symbol: �'— ) • Definition Small dams constructed across a ewale or drainage ditch. Purpose To reduce the velocity of concentrated flows, reducing erosion of the Swale or ditch, and to slow water velocity to allow retention of sediments. Conditions Wbere Practice Applies • Where temporary channels or permanent channels are not yet vegetated, channel lining is infeasible and, therefore, velocity checks are required. • In small open channels which drain 10 acres or lass. No check dams may be placed in streams (unless approved by the State Departments of Fisheries or Wildlife as appropriate) . Other permits may also be necessary. • Check dams in association with sumps work more effectively at slowing flow and retaining sediment. Advantages • Check dame not only prevent gully erosion from occurring before vegetation is established, but also cause a high proportion of the sediment load in runoff settle out. • In some cases, if carefully located and designed, these check dams can remain as permanent installations with very minor regrading, etc. They may be left as either spillways, in which case accumulated sediment would be graded and seeded, or as check dams to precipitate further sediment coming off that site. • • ieadvanftaoes/Problems • Because of their temporary nature, many of these measures are unsightly, and they should be removed or converted to permanent check dams before dwelling units are rented or sold. • Removal may be a significant cost depending on the type of check dam installed. • Temporary check dams are only suitable for a limited drainage area. • Clogging by leaves in the fall may be a problem. Planning Considerations Check dams can be constructed of either stone, logs, or pea gravel filled sandbags. Log cheek dams may be more economical from the standpoint of material costs, since logs can often be salvaged from clearing operations. However, log check dams require more time and hand labor to install. Stone for check dams, on the other hand, must generally be purchased. However, this cost is offset somewhat by the ease of installation. • If stone check dams are used in grass-lined channels which will be mowed, care should be taken to remove all the stone from the channel when the dam is removed. This should include any stone which has washed downstream. Since log check dams are embedded in the soil, their removal will result in more disturbance of the soil than will removal of stone check dams. Consequently, extra care should be "taken to stabilize the area when log dams are used in permanent II-5-58 FEBRUARY, 1 STOR!(WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN ditches or svales. Design Criteria • Check dams can be constructed of either rock, pea-gravel filled bags or logs (Figures II-5.14a,b) . Provide a deep sump immediately upstream (see Figure II- 5.14c) . • The maximum spacing between the dams shall be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam (Figure II- 5.14c) . • Rock check dams shall be constructed of appropriately sized rock. The rock must be placed by hand or mechanical placement (no dumping of rock to form dam) to achieve complete coverage of the ditch or swale and to ensure that the center of the dam is lower than the edges. The rock used must be large enough to stay in place given the expected design flow through the channel. • Log check dame shall be constructed of 4 to 6-inch diameter logs. The logs shall be embedded into the soil at least 18 inches (Figure II-5.14a) . • In the case of grass-lined ditches and swales, check dams shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the Swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. jtajntenance • Check dams shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump depth. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary Sees are no longer needed. Trapped sediment shall be •removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • 1I-5-59 FEBRUARY, 1992 STORMWA'TER MANAGEMENT MANUAL FOR THE PUGET SOOND BAS IN Figure II-5.14 Check Dams • L'-6" Lasts - • . . - 'I likrn r nun.— .in WI E?iffiiraF".: t ...c... _____—■ 7 • . i " T' :.,t. -: . . • • la Ci 11/0111 5,1111/1511.1" 91 i i :: I- u - . . C . •• .. ...- . . ‘ • . i • • f . • ; : . 6 . 1— 1. ..,. 1 I . • . .... I ' Flo. .it .. a. _Loa Cheek Da . -.. I I 1 [ i• I ••■••■-- „w•• 1 •, • .• „ , ..* Tirti r5J-11 _i • ..- . -..... .-7,1,ev,.....-:.....-, _......-z-............-.0 --:.-7---„,,,-..=...... ......:,...00.4.,,,■:.,,,,. ---..../. .11-—- .--„,,,--y•-s.........- ...IN TAUB rt!'f..... .t."07••••••Wre 1,7.411.4.-Z:e•::-•••U.:.- M•0;1•.+• • 4 ars.."•■••••-•,::- ''"Zwr-tt7w.. • ../....-....... i . . NO SCALE (• - ' • 2"-Av 12.ock. _ IL, • up% ..-• •••...,11.. ..17 -::..,Alb.........•- flow a.,o ..-w,0-.... -" 24 .. -- ..-•••,... •.&,• -I .....•-...4...•.*a.,..............010•40.0..... .1-.0„..„:„ . ."...116,..•‘.•""••••, ......44•401.„4"..Z.....„-o.. , , ....„-...... ,iii„........•• ........... ..,,.....-- ....,,,„ • p. - .. . C,ee. Dar . . . . NO SCALE L.110 drums oudt Om mons A 6 a ...•::.:e.:, ..........:4...,,-,,, II*al uour summen _,-......tet.--,i,„7:;-..c.A■ . . ...,,_••,40.11,e....... , • '.,Net}.411.1;.1.• . A • 4,ten ..."...-.. .. L B -l'It'n, k:,.., lir, 9- ,--• ...:... 1.-- I .. . '. --.;,.." f.. : -t. -11 -,--or-itettsrae■ l .-.7.-*a.- •-•log, --1. ITY • ,1 ...-64:-..1,=-1-4; . • ,,- 411,09t.L.,...‘ I l, irs•'fil : ., s'...It. oof -of,' i . ,_... •"li A il, . . . . • , ( . . . • 4. • - C - 1 c. Spike' s, Between Chec_ Dame II-5-60 FEBRaW7-1772- STORMWATER MANAGEMENT MANUAL FOR TIM PUGET SOUND BASIN 11-S.7.12 BM? E2.70: Outlet ?rote-tion Code: (i) Symbol: MEM Definition Structurally lined aprons or other acceptable energy dissipating devices placed at the outlets or pipes or paved channel sections. Purpose To prevent scour at stormwater outlets, and to minimise the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. Condition where Practice APPiiea • Applicable to the outlets of all pipes, interceptor Swale outlets, and channel sections where the velocity of flow at the design capacity of the outlet will exceed the permissible velocity of the receiving channel or area. Advantages • Plunge pools which can develop without outlet protection may severely weaken the embankment and thus threaten its stability. • Protection can prevent scouring at a culvert mouth and thus prevent gully erosion which may gradually extend upstream. Disadvantages/Problems • Some types of structures may be unsightly. • Sediment removal may be difficult. Planning Considerations An outfall is defined as a concentrated discharge point which directs collected surface water flows into an open drainage feature, natural or manmade. These drainage features include ditches, channels, wales, closed depressions, wetlands, streams, rivers, ponds, lakes, or other open bodies of water. In nearly every case, the outfall will consist of a pipe discharging flows from a storm pipe system, a culvert, or • detention facility. Design Criteria See Sections 1II-2.3.4 and 2.3.5 in the Runoff Control Volume. • Jin•ntenance All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. Rock may need to be added if sediment builds up in the pore spaces of the outlet pad. II-5-61 FEBRUARY, 1992 • • STORMWATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN 11-5.7.3,E amP E2.75: ItiPra Code: (ii) symbol: Definition A permanent, erosion-resistant ground cover of large, loose, angular stone. Purpose To slow the velocity of concentrated runoff or to stabilize slopes with seepage problems and/or non-cohesive soils by placement of _large, loose, angular stone. Conditions Where Practice Amoiies • Soil-water interfaces, where the soil conditions, water turbulence, water velocity, and expected vegetative cover, are such that the soil may erode under the design flow conditions. Advantages • Riprap offers an easy-to-use method for decreasing water velocity and protecting slopes from erosion. It is simple to install and maintain. • Riprap provides some water quality benefits by increasing roughness and • decreasing the velocity'of the flow, inducing settling. Disadvantages/Problems • Riprap is more expensive than vegetated slopes. • Riprap does not provide the habitat enhancement that other vegetative Blues do. -fanning Considerations - Graded vs. Qnifoz R' .ran Riprap is classified as either graded or uniform. A sample of graded riprap would contain a mixture of atones which vary in sire from small to large. A sample of uniform riprap would .contain stones which are all fairly close in size. For most applications, graded riprap is preferred to uniform riprap. Graded riprap forms a flexible self-healing cover, while uniform riprap is more rigid and cannot withstand movement of the stones. Graded riprap is cheaper to install, requiring only that the stones be dumped so that they remain in a well-graded mass. band or mechanical placement of individual stones is limited to that necessary to achieve the proper thickness and line. Uniform riprap requires placement in • more or less uniform pattern, requiring more hand or mechanical labor. Riprap sizes can be designated by either the diameter or the weight of the stones. • It is often misleading to think of riprap in terms of diameter, since the stones should be rectangular instead of spherical. However, it is simpler to specify the diameter of an equivalent size of spherical stone. Table 11-5.4 below lists some typical stones by weight, spherical diameter and the corresponding rectangular dimensions. These atone sizes are based upon an assumed specific weight of 165 lbs./ft' pptt Desicn criteria, 1. Also see Table 1II-2.27, Rock Protection at Outfalls in the Runoff Control Volume. • 1I-5-62 FEBRUARY, 1992 • • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT • • Table II-5.4 Size of Riprap Stones Mean Spherical Rectangular Shape Weight (lbs) Diameter (ft) Length (ft) Width, Height (ft) 50 0.8 1.4 0.5 100 1.1 1.75 0.6 150 1.3 2.0 0.67 300 1.6 2.6 0.9 500 1.9 3.0 1.0 1000 2.2 3.7 1.25 1500 2.6 4.7 1.5 2000 2.75 5.4 1.8 4000 3.6 6.0 2.0 6000 4.0 • 6.9 2.3 8000 4.5 7.6 2.5 20000 6.1 10.0 3.3 Since graded riprap consists of a variety of stone sizes, a method is needed to specify the size range of the mixture of stone. This is done by specifying a diameter of stone •in mixture for which some percentage, by weight, will be smaller. For example, do refers to a mixture of stones in which 85 percent of the stone by weight would be smaller than the diameter specified. Most designs are based on d. In other words, the design is based on the median size of atone in the mixture. • J} Sequence of Construction Since riprap is used where erosion potential is high, construction must be sequenced so that the riprap is put .in place with the minimum possible delay. Disturbance of areas where riprap is to be placed should be undertaken only when final preparation and placement of the riprap can follow immediately behind the initial disturbance. Where riprap is used for outlet'protection, the riprap should be placed before or in conjunction with the construction of the pipe or channel so that it is in place when the pipe or channel begins to operate. • Maintenance • • Riprap coverings should be inspected on a regular basis and after every large storm event. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of- their intended function. All maintenance-and repair shall be conducted in accordance with an approved manual. ) ' II-5-63 FEBRUARY, 1992 STOR?SWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN • T1-5.7.14 BMP E2.B0: Vegetative Streambank Stabilization Code: 41) Symbol: Definition The use of vegetation to stabilize streambanks. Purpose To protect streambanks against erosion through vegetative means. Condition Where Pia • e :uml_.i,es • Applicable to water areas and all land uses. To be used to stabilize banks in swales, creeks, streams, and rivers as well as man-made ditches, canals and impoundments, including ponds and storage basins. • Advantages • Streambank vegetation can break wave action and the velocity of flood flows. • Roots and rhizomes stabilize streambanks. • The reduction of velocity can lead to the deposit of water-borne soil particles. - ' • Certain reeds and bulrushes have the capability of improving water quality by f,` absorbing certain pollutants such as heavy metals, detergents, phenols, and indole (1) . • Plants regenerate themselves and adapt to changing natural situations, thus• offering a distinct economic advantage over mechanical stabilization. • Wildlife and fisheries habitat is improved. Disadvanta•ee/ bless • Native plants may not be carried by regular nurseries and may need to be collected by hand, or obtained from specialty nurseries. Nurseries which carry these plants may require a long /sad time for large orders. • Flow retarding aspects of vegetated waterways need to be taken into account. Plarr.,w,1• Co,s '. rations A primary cause of stream channel erosion is the increased frequency of bank-full flows which often results from upstream development. Most natural stream channels . are formed with a bank-full capacity to pass the runoff from a storm with a 1.5 to 2-year recurrence interval. However, in a typical urbanizing watershed, stream channels may became subject to a .3 to 5-fold increase in the frequency of bank-full flows if stormwater runoff is not properly managed. As a result, stream channels that were once parabolic in shape and covered with vegetation may be transformed into wide rectangular channels with barren banks. In recent years, a number of structural measures have evolved to strengthen and protect the banks of rivers and streams. These methods, when employed correctly, Immediately ensure satisfactory protection of the banks. However, many such structures are expensive to build and to maintain. Without constant upkeep, they are exposed to progressive deterioration by natural agents. The materials used often prevent the reestablishment of native plants and animals, especially when the 11-5-64 FEBRUARY, 42 STORMWATER MANACEMEN7 MANUAL FOR TH£ PUGE2 SOUND BASIN DRAFT design is executed according to standard -Foss-sec tions which ignore natural variations of the stream system. Vary often these structural measures destroy the appearance of the site. Additionally, structural stabilization e-rd char'znelization can alter the hydrodynamics of a stream and only serve to transfer erosion potential and associated problems downstream. 2n contrast, the utilization of living plants instead of or in conjur etion with • structures has many advantages. The degree of protection, which may be low to start with incteaaes as the dents grow and spread. The repair and maintenance of structures is unnecessary where self-maintaining strew bank plants are established. The protection provided by natural vegetation is more reliable and effective when the cover consists of natural plant communities adapted to their site. • beeion Criteria • Design must be prepared based on criteria and input/review by a qualified fiaheriee biologist. - • Streambanke can be divided into 1) aquatic plant zones at the mean low-water level (MWL} ; 2 } reed bank zones covered at bankfull stage (BF) ; 3) lower riparian zones or open floodway zones naturally covered with willows and shrubbery plants (OF) ; 4) upper riparian areas or flood fringe areas that would naturally be covered with canopy-forming trees (FF) (see Figure I2-5.15a) . - • A at c cants are often conuidered weeds and a nuisance though they do slaw �.--- down streamflow and protect the streambed. Primary emphasis of streambank stabilization lies in the bankfull zone. • The reed bank zone forms a permeable obstacle, slowing down current waves ,by friction. Suitable plants can be found by consulting the guidelines found in Chapter 111-5. Their shoots, with a root clump, can be planted in pits at 1/2 to I a foot depth below water, or in a read roll au in Figure 11-5.15b. A trench 1-1/2 feet wide and deep is dug behind a row of stakes; wire netting is then 'stretched from both aide,' between uptight pl#nka; coarse gravel is dumped on this and covered with reed Clumps until the two edges of the netting can just be held together with wire. The upper edge of the roll should not be more than two inches above water level. Finally, the planks are taken out and gaps in the ditch are backfilled. • The lower riparian zone in the Puget Sound region has a nature/ growth of willow, alder, cottonwood, small espies, and various berries. These vegetative t} . can be reintroduced on denuded flaodplaims to stabilize the sail with their roots. In periods of high water, their upper branches reduce the speed of the current and thereby the erosive force of water. The most commonly used vegetative stabilizer for this zone is willow because of its capability to develop secondary roots on cut trunks and to throw up suckers. Willows are planted either as individual cuttings bound together in various forms or wired . together in -fascirses.• • `aucine. (Figure II-5.16a) have a diameter of 3 to 12 inches and contain bruenwocd and sticks and coarse gravel or rubble in the center tightly wound around. Packed faeoine-work (Figure 1I-5.16b) can be employed on out hanks. It consists of 1 foot layer. of branches covered with young, freshly Out shoots secured by stakes. The 'spacer between the shoots are filled with dirt and another layer is added on top, another technique is the use of willow , -\ mattresses (Figure I1-5.16c} made from 4 to 6 foot willow switches set into Et- inch trenches' held down by stakes that are braided or wired together. The entire mattress is lightly Covered with dirt. A variation of thin method le the brush-mesh technique which is designed to stabilize breached cut bank(' and to encourage the deposition of sediment (Figure I1-5.16d). It involves the following steps: I1-5- FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT { i • 1. Placement of poles at 10 foot distance. 2. Placement of large branches and brush facing the stream. 3. Setting cuttings of live willow branches between the brush vertically, and 4. Securing vertical 'willows with cuttings set diagonally facing the streamflow. • Slip banks of the lower riparian zone and tidal banks can be stabilized with grass (3) . First the bank needs to be graded to a maximum slope of 3:1. Topsoil should be conserved for reuse; lime (2 tons/acre) and fertilizer (1,000 lbs/acre of 10:10:10) should be applied. Coarse grass and beach grass should be planted at the water's edge to trap drift sand; and bermuda grass, suitable for periodic inundation, should occupy the face of the slope, followed by tall fescue on higher ground. Maintenance • Streambanks are always vulnerable to new damage. Repairs are needed periodically. Banks should be checked after every high-water event is over. Gaps in the vegetative cover should be fixed at once with new plants, and mulched if necessary. Fresh cuttings from other plants on the bank can be used, or they can be taken from mother-stock plantings if they are available. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as. needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accorda , ! I with an approved manual. References (1) Seibert, P. , jmoortance of Natural Vegetation for the .Pr- ection of the Banks of Streams, Rivers and Canal = : Freshwater. The Council of Europe. Manhattan Publishing Co. , New York, 1968. (2) U.S. Soil Conservation Service, jnterim Standards and Specifications for Veoetat've Tidal Bank Stabilization, College Park, Maryland, 1969. (3) Sch.iectl, Hugo, pioenoineerina for 3,and Reclamation and Conservation, University of Alberta Press, 1980. • 1I-5-66 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.15a Figure II-5.15b Streambank Vegetative Reed Roll Zones I MWL; OF 1r BF ul •••:-:7 • .. PAWL a` i'.,;s.::p ai/ Figure II-S.16a Figure II-5.16b Fascinee Packed Fascine-Work roils of shoots simiar BAW M to reed roll �� .ayc..: 7= -7 • •-'_ ,4 alternate layers of u i A. branches and dirt • Figure II-5.16c Figure II-5.16d Willow Mattress Brush-Mesh Protection eralded shoot= or win seolaina mat to bank /AWL Ml r�I�I► - w • • 1 down to refuse • II-5-67 FEBRUARY, 2992 ' STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 11-5.1.15 BKP Bioenaineerin Methods of Streambank Stabilization Code: Symbol: pefinition Methods of stabilizing streambanke through a combination of vegetative and mechanical means. Pur0ose To provide protection of critical sections of streambank where ordinary vegetative means of protection are not feasible or offer insufficient protection. Conditions Where Practice AmPliee • To be used in streams with swift flow where the flow/soil conditions exceed the stabilizing effect of purely vegetative channel protection. Advantaoee • Mechanical materials provide for interim and immediate stabilization until vegetation takes over. • Once established, vegetation can outlast mechanical structures and requires little maintenance while regenerating itself. • • Aesthetic benefits and wildlife habitat. i ' nisadvantemes/Problema • Slightly higher initial cost and need for professional advice. (It is recommended that the services of a qualified bioengineer be sought for this work) . • The methods described are effective but require a complete knowledge of soils, hydrology, and other physical data to design measures that will adequately solve the problem and stand up to the test of time. Deaion Criteria Streams in urban settings may carry an increase in runoff of such great magnitude that they cannot be maintained in a natural state. In these cases bioengineering methods can provide for stabilisation without complete visual degradation and they can provide higher effectiveness than purely mechanical techniques. This applies primarily to: 1) the reed bank zone (B!) and 2) the lower riparian zone (OF) (Figure II-5.17a) . The following techniques apply to the reed bank zone: Reed berme (Figure II-5.17b) , consisting of a combination of reeds and riprap, break wave action, and erosion of banks by currents. Banks should not exceed. a 2:1 slope. Riprap is placed to form a berm that extends beyond the surface at mean low-water level, separating the reed bed from the body of water. Willow -jetties (Figure II-5.17c) can be constructed at the water level to stabilize a cutbank by deflecting the current and by encouraging deposition of sediment. • Steps: 1. Dig ditches diagonally to direction of flow, and place fill to form berm • downstream from ditch. 1I-5-68 FEBRUARY, 1992 STOR?(WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT • 2. Set 2-foot willow branches (4 feet may be needed) at 45° angle and 3-inch spacing facing downstream. 3. Weigh down branches with riprap extending beyond water level. Willow eabions (Figure II-5.17d) can be used when a hard-edged effect is desired to deflect the eroding flow of water. Live willow branches, pointing downstream, are inserted through the wire mesh when the gabion is packed with stone and an addition of finer materials. Branches need to be long enough to extend through the gabion into the soil of the bank. They also should be placed at an angle back into the slope. Pilino revetment (Figure II-5.17e) with wire facings is especially suited for the stabilization of cutbanks with deep water. It involves the following steps: 1. Drive heavy timbers (8-12 inch diameter) on 6 to 8-foot centers along bank to be protected to point of refusal or one half length of pile below maximum scour. 2. Fasten heavy wire fencing to the post and if the etreambed is subject to scour, extend it horizontally on the streambed for a distance equal to the anticipated depth of scour and weight with concrete blocks. As scour occurs, this section will drop into place. 3. Pile brush on the bank side of the fence, and plant willow saplings on bank to encourage sediment deposits. In the }owes riparian zone (Figure II-5.17f) (open floodway) bank stabilization efforts should be concentrated on critical areas only. The stabilizing effect of -iprap can be supplemented with willows which will bind soil through their roots and screen the bank. Banks can be paved with stone (set in sand) . Willow cuttings in joints need to be long enough to extend to natural soil and should have 2 to 4 buds above surface. Willow branches in riprap should be installed simultaneously. Branches should extend 1 foot into the soil below stone and 111 feet above ground, pointing downstream. wow branch mat revetment (Figure II-5.17g) takes the following steps to install: 1. Grade slope to approximately 2:1 and excavate a 3 foot ditch at the toe of slope. 2. Lay live willow brush with butts upslope and anchor mat in the ditch below normal waterline by packing with large stones. 3. Drive 3-foot willow stakes 211 feet on center to hold down brush; connect stakes with No. 9 galvanized wire and cover brush slightly with dirt to encourage sprouting. Ha .ntenance • Costs vary according to local availability of labor. However, there are practically no maintenance costs for the vegetation once it is established, since it holds the banks 'naturally' as compared to concrete 'improvement' that constantly needs repairs. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. 1I-5-69 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT (l References • (1) USDA, Soil Conservation Service, Enaineerina Field Manual for con nervation Practices, 1969. (2) USDA, Soil Conservation Service, Firm P7,pnners Enaineera.na H-ndbook for the Uflver Hissseir�ni Region, Agricultural Handbook 157, 1953. (3) Schiectl, H. Bioenaineerina for Land Reclamation and Consery tion, University of Alberta Press, 1980. (4) Gray, Donald H. and Leiser, A.T, Biot chni al Slone Protection and Erosion Control„ Leiser Van Reinhold Inc. , 1982. • • • • • ZI-5-70 FEBRUARY. 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN dumped riprap berm OF... • > BFB. .. 'i 'J 111 © •ill/ ' ( _�!�:I+y - + MWL 2:1 max. Figure II-5.17a• Figure II-5.17b Reed Bank Zone (BF) Reed Berm and Lower Riparian Zone (OF) eroding bank.. MWLl d berm_i 1� IMIIIIII :;; note: branches extend ../7 sediment builds through gabion Otto soil behind jetties MLWL I plan --' 2,41:- , Figure II-5-17d ea _.`� Willow Gabion -4, J Figure II-S.17c Willow Jetty . ash - preferably willow -- i r, . ' sat'tion MWL Z bank b im.s..ar,e ' I hand placed rock J.1,77A • .. willow cuttings -r;:il .� tdrir.n to refusal at X o a o ice �0•fence and oono. bod ��bew.oil.depth so&ammo sand eft e*ri•i .bor*and aka scour Figure II-5.17e "1,��- - Piling Revetment ,.. a h *mod mak& ead maw.willow .brush mat revetment •P aratingis Plan "before" max grade 1:1% \ ■ J'.,.k.e-sift ail• .. 18"•Bt' %. `, " f hty out wales ' ' ,.......-•.f; pis*0 YC amass P.4% ;4bk 14:1:- beak ways t max. scour .• .r ,own wet and same n -•�,t with sae willow brush mat revetment _�� "after* i rock and willow branches . ....v‘ . Figure II-5.17f , -- - • is _ Willow Branches in Riprap ._J i Figure II-5.17g Willow Branch Mat Revetment II-5-71 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5.7.15 BHP E2.*90: Structural Streambank Stabilization Code: © Symbol: Definition Methods of stabilizing the banks and streams with permanent structures. Purpose To protect streambanke from the erosive forces of moving water, where vegetative or bioengineered methods are insufficient or infeasible. Conditions Where P.ract'ce flies • • Strsambank sections, where excessive erosion is anticipated because of highly erodible soils. Advantaoee - • Permanent structural measures are an effective method of preventing severe etreambank erosion. DisadvantaoeslProblems • Most types of structural stabilization do not offer any water quality benef,. except for the potential for reduced erosion and downstream siltation. pi.- fling Considerations • �• • Stream channel erosion problems vary widely in type and scale and there are many different structural stabilization techniques which have been employed with varying degrees of effectiveness. The purpose of this specification is merely to point out some of the practices which are available and to establish some broad guidelines for their selection and design. Such structures should be planned and designed in advance by a professional engineer licensed in the state of Washington. Many of the practices referenced here involve the use of manufactured products and should be designed and installed in accordance with manufacturer's specifications. Before selecting a structural stabilization technique, the designer should carefully evaluate the possibility of using vegetative stabilization (BAP E2.80) or bioengineering measures (IMP E2.85) to achieve the dssirsd .protection. Vegetative techniques are generally less costly and more compatible with natural stream characteristics, and, in Most instances, RPAs from the state Departments of Fisheries and Wildlife may require this method. pesion C it�ris. • Design must be prepared based on criteria and input/review from a qualified fisheries biologist. • • Since each reach of channel requiring protection is unique, measures for streambank protection shall be installed according to a plan and adapted to the specific site. Design shall be developed according to the following principles: • a. Bottom scour shall be controlled, by either natural or structural mean' before any permanent type of bank protection can be considered feaeibl!',, J See Chapter 11I-2, Volume III for channel design. • 1I-5-72 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT b. Stream requirements must be met. These include, but are not necessarily limited to, development limitations imposed by the local government's Sensitive Area Ordinance (if applicable) , the requirements of the Shoreline Management Act and permit requirements from State and Federal agencies such as a Hydraulic Project Approval (HPA, Washington Depts. of Fish and Wildlife) , Dam Safety (Washington Dept. of Ecology) , and Navigation, Shoreline and Section 101 and 404 permits for the Corps of Engineers. c. Special attention shall be given to maintaining and improving habitat for fish and wildlife. d. Structural measures must be effective for the design flow and be capable of withstanding greater flows without serious damage. • The following structural streambank stabilization measures may be considered: a. Ri,prrp - heavy angular stone placed on the streambank to provide armor protection against erosion. • b. Gabion - rectangular, pervious, semi-flexible rock-filled wire baskets which can be used to armor streambanks. • c. Reinforced Concrete - retaining walls or bulkheads used to armor eroding sections of streambank. d. POI/ Cribbing - retaining structure built of logs to protect atreambanks ' from erosion. (Log cribbing can have vegetation inserted between logs. ) e. Grid Pavers - modular concrete units with interspersed void areas which can be used to armor the streambank while maintaining porosity and allowing the establishment of vegetation. Maintenance • Inspections should be made regularly and after each large storm event. Repairs should be made as quickly as possible after the problem occurs. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. i • 11-5-73 FEBRUARY, 1992 • STORMWATER MANAGEMENT MANUAL FOR TES PUGET SOUND BASIN DRAFT :r 11-5.8 SEDIMENT RETENTION BMP E3.10: Filter Fence • Code: Q Symbol: '-' Definition A temporary sediment barrier consisting of a filter fabric 'stretched across and attached to supporting posts and entrenched. The filter fence is constructed of stakes and synthetic filter fabric with a rigid wire fence backing where necessary for support. • Purpose 1. To intercept and detain email amounts of sediment under sheet flow conditions from disturbed areas during construction operations in order to prevent sediment from leaving the site. 2. To decrease the velocity of sheet flows. Conditions Where Practice ••lies • Filter fences must be provided just upstream of the point(s) of discharge of runoff from a site, before the flow becomes concentrated. They may also be required: 1. Below disturbed areas where runoff may occur in the form of sheet and ri erosion; wherever runoff has the potential to impact downstream resource:' 2. Perpendicular to minor swales or ditch lines for contributing drainage areas up to one acre in size. Advantages • Downstream riparian areas will not be damaged by sediment deposits originating from the development. • Sediment will not cause damage to fish habitat. • D igadvantaaeslProbl.ems • Filter fences are ILA practical where large flows of water are involved, hence the need to restrict their use to drainage areas of one acre of less, and flow rates of less than 0.5 cfs. This flow should not be concentrated; it should be spread out over many linear feet of filter fabric fence. • Problems may arise from incorrect selection of pore size and/or improper installation. • Filter fences should not be constructed in streams or used in V-shaped ditches. They are not an adequate method of runoff control for anything deeper than sheet or overland flow. Planninsi Considerations Laboratory work at the Virginia Highway and Transportation Research Council has shown that silt fences can trap a much higher percentage of suspended sediments th? can straw bales. Silt fences are preferable to straw barriers in many cases. r . However, while the failure rate of silt fences is lower than that of straw barrier there are many instances locally in which silt fences have been improperly II-5-74 FEBRUARY, 1 9r3 STORK WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT installed. The installation methods outlined here can improve performance. Fabric Types: There are four types of material used for filter fabric fences; woven slit-film fabric, woven monofilament fabrics, woven composites (of differing materials) and non-woven heat-treated or needle punched fabrics. Slit-film fabrics are made from woven sheets of nonporous polymers. The sheets are very thin but are cut or slit in wider bands to form the threads which are then woven into the fabric. Since slit- film weaves use strands that are quite thin, the resulting woven fabric has little rigidity, and pore spaces are not uniform. Wire fencing must be used as a backing for this type of filter: fabric fence. While this type of fabric is generally cheapest and the most widely used, the additional costs of the wire fence installation must be figured in. Woven monofilament fabrics are made from uniform spun or extruded filaments which are then woven to form the fabric. They are usually thicker and thus more rigid than slit-film fabrics. The pores in monofilament fabrics are regularly spaced and • the increased rigidity offers more resistance to pore distortion. The material has a very low flow-through rate. Woven composites are similar in structure but use more than one fiber type. Non-woven fabrics are made by using either continuous filaments or short staple fibers. These fibers are then bonded together by various processes that can include a needling process that intertwines the fibers physically, or a thermal or chemical bonding operation that fuses adjacent fibers together. The resulting fabric has a random fiber orientation and may have a thickness that ranges from thick felt to a relatively thin fabric. King County Conservation District recently completed tests on 18 different types of filter fabrics. Their results have been incorporated into the design criteria. Design Criteria • Drainage area of 1 acre or less or in combination with sediment basin in a larger site. • Maximum slope steepness (normal (perpendicular) to fence line) 1:1. • Maximum sheet or overland flow path length to the fence 100 feet. • No concentrated flows greater than 0.5 ofs. • Selection of a filter fabric is based on soil conditions at the construction site (which affect the apparent opening size (ADS) fabric specification) and characteristics of the support fence (which affect the choice of tensile strength) . The designer shall specify a filter fabric that retains the soil found on the construction site yet will have openings large enough to permit drainage and prevent clogging. The larger the ADS number, the smaller the AOS site of the opening in the fabric. • The material used in a filter fabric fence must hive sufficient strength to withstand various stress conditions and it also must have the ability to allow passage of water while retaining soil particles. The ability to pass flow through must be balanced with the material's ability to trap sediments. The following criteria are recommended .for selection of the AOS: 1 1. Because of the properties of soils in the Puget Sound basin, field work must be done to determine the optimum ADS for filter fence installations. Because -of glaciation, many soils in this area contain both cobbles and II-5-75 FEBRUARY, 1992 STOR SHATER MANAGEMENT MA UA1 FDR TUE Po o= SDUND BASIN DRAFT fines. If an SCS ate dard soil descriptions ie used, (e.o. Alderwood gravelly sandy loam) the AOS specified will not be sufficient to trap the finer partic1ee of soil. Including gravels and larger sizes skews the results towards an ADS which is too seal] to capture suspended settleable solids and reduce TSS. Mosaofilametit and non-woven geotextiles must have a minimum ADS of 70 when mood in glacial soils. Composites and slit film fabrics meet be extra-atreFigth to perform similarly; in their ease the A0S 1 range may he from 4D-613. In areas where Mama ash is lentiful in the soil profile, a larger ADS will be necessary, or, fabric with an ADS of 7C ■hould be used for outwrash ■oily. 3. For all other soil types, the ADS should be determined by first passing soil through a 110 sieve (2.0 mm) . Based on the amount of the re aaits.ieg soil, by weight. which passes through a U.S. standard sieve !#o. 100, select the ADS to retain SS percent of the soil. where direct discharge to a stream, lake, or wetland will occur, then the ACS shall be no larger than Standard Sieve No. 100. Non-woven and regular strength slit fiat fabrics shall be supported with wire mesh. Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six =Tithe of expected usable construction life at a temperature range of 0•F. to 12.0*F. - Standard Wotan • In addition to the Technical information 'Report (see Chapter 1-3) required by the local government when preparing an erosion and sediment control plan, add the following notes to the Filter Fabric Fence Detail (Figure II-5.16) ! • e. The filter fabric shall be purchased in a continuous roll cut to the length cif'VJ the barrier to avoid use of joints. When joints are necessary, filter cloth shall be spliced together only at a support port, with a minimum 6 inch overlap, and both ends securely fastened to the post. b. Poste shall be spaced a maximum of 6 feet apart and driven securely into the ground a minimum of 30 inches (where physically possible) . c. A trench shall be excavated approximately 8 lathe■ wide and 12 inches deep along the line of .posts and upslope from the barrier. The trench shall be constructed to follow the contour. d. When slit film filter fabric is eased, a wire mesh support fence shall be fastened securely to the upslop+e side of the posts using heavy-duty wire staples at least 1 inch long, tie wires or hog rings. The wire shall extend into the trench a minimum of 4 inches and shall not extend more than 36 inches) above the original ground surface. e. Slit film filter fabric shall be wired to the fence, and 20 inches of the fabric shall extend into the trench. The fabric shall not extend mare than 36 inches above the original ground surface. Filter fabric awl not be stapled to existing trees. Other types of fabric may be stapled to the fence. f. When extra-strength or manafilament fabric and closer post spacing are used, the wire mesh asspport fence may be eliminated. In such a case, the filter fabric is stapled or wired directly to the poste with all other provisions of Standard Note me- applying. Extra care should be used when joining or overlapping these stiffer fabrics. g. Local governments may specify the use of properly compacted native material. i..�� . In many instance'', this may be the preferred alternative because the soil form: a more cailtinuoun contact with the trench below, and use of native materials II-5-7 - F$ERUARY, 1992 STORKWATER MANAGEMENT MANUAL FOR TEE FUGET SOUND BASIN DRAW • cute down on the number of trips that muRt be made on and off-Bite. If gravel is used instead, the trench °hall be backfilled with i-inch minimum diameter washed gravel. Care must be taken when using gravel to ensure goad contact between the fabric and the trench bottom to prevent undercutting. h. Filter fabric fences shall be removed when they have nerved their rueful purpose, but not before the up$lcpe area has been permanently stabilized. Retained sediment must be removed and properly disposed of, or mulched and seeded. Maintenance • Inspect immediately after each rainfall, and at least daily during prolonged rainfall. Repair as necessary. - • • Sediment must be removed when it reaches approximately one third the height of the fence, especially if heavy rains are expected. • Any sediment deposits remaining in place after the filter fence is no longer required shall be dressed to conform with the existing grade, prepared and seeded. • • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved ar after the temporary EMRs are no longer needed. Trapped sediment •hall be removed or stabilized on site. Disturbed soil area resulting from removal shall be permanently stabilised. \\ / References: (1 ) Rulzer. Louise, Conaa¢ex3�tj..on for Using Gecrtextiles in Silt Feace APPliCatierfe, Metro Technology Transfer Publication, Nov: , 1988. (2 ) Varney, Dick, AUtvaluation of eotert' ea n . '.iltez'_ Fabric FeTS PJ. Local _Soil°tcr_P1arenina and Engineering, Ring County Conservation District, Sept. . 1991. (3) Varney, Dick, personal communication, March 4, 1992. • • • • II-5-77 'FEBRUARY. 1992 STORt4WATER MANAGEKENT MANUAL FOR THE PUGET SOUND BASIN DRAFT • • Figure II-5.18 Filter Fabric Fence Detail Falter fabric inswrisl in continuous rolls: Use swiss or weirs rirops to attach fabric to writs Woo mesh support lanes for snit film tabrias n fl • • CV • • • ;;;;:;;;T:1?"-a. �a .i.z:r O �,.. u /AIUV/.11i ui Its" Y III/ Bury bottom of Mot matrisl 1 Lo ; 1 in II"by 12'bench , 1 a U I I 6. Max. ' 1 i by 2-weed posts,surmised bower bsr wr '— w otsiavalsnt Wits gnash support lanai tor filet frtn fabrics .... 4 tO Fiber talk& • rrrbsrisl O iii lV Nr c + P rvirib washed grovel 'jf b sica or compscosei ��,. N minim so&as dimmed by local Cowmni nt trey bantam of Mor wisbsrisl_.1 ■•.• tr.Min. in E'by 12'bsndi 2'by 2' wood posts.standard or Mew •""--".... w spisaisrtl --, • • 11-5-78 FEBRUARY, ]992 • STORNWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 11-5.8.2 BMP E3.15 Straw Bale Barrier Code: Q Symbol: Definition A temporary sediment barrier consisting of a row of entrenched and - anchored straw bales. Purpose 1. To intercept and detain small amounts of sediment from disturbed areas of limited extent to prevent sediment from leaving the site. 2. To decrease the velocity of sheet flows and low-to-moderate level channel flows. Conditions Where Practice Applies • Below disturbed areas subject to sheet and rill erosion. • Where the size of the drainage area is no greater than 1/4 acre per 100 feet of barrier length; the maximum slope length behind the barrier is 100 feet; and the maximum slope gradient behind the barrier is 50 percent (2:1) . • In minor swales or ditch lines where the maximum contributing drainage area is no greater than 2 acres. • Where effectiveness is required for' less than 3 months. • Under no circumstances should straw bale barriers be constructed in live streams or in swales where there is the possibility of a washout. Advantaoee • When properly used, straw bale barriers are an inexpensive method of sediment control. pieadvantaQesJProblems • Straw bale barriers are easy to misuse and can become contributors to a sediment problem instead of a solution. • It is difficult to tell if bales are securely seated and snug against each other. plannin• Considerations Based on observations made locally and in Virginia, Pennsylvania, Maryland, and other parts of the nation, straw bale barriers have not been as effective as many users had hoped they would be. There are three major reasons for such ineffectiveness. 3 . Improper use of straw bale barriers has been a major problem. Straw bale barriers have been used in streams and drainsgeways where high water velocities and volumes have- destroyed or impaired their effectiveness. 2. Improper placement and installation of the barriers, such as staking the bales directly to the ground with no soil seal or entrenchment, has allowed undercutting and end flow. This has resulted in additions to, rather than removal of, sediment from runoff waters. II-5-79 FEBRUARY, 1992 52ORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT • • 3. inadequate maintenance lowers the effectiveness of these barriers. For example, trapping efficiencies of carefully installed straw bale barriers on one project in Virginia dropped from 57 percent to 16 percent in one month due to lack of maintenance. There are serious questions about the continued use of straw bale barriers as they are presently installed and maintained. Averaging approximately $4.00 per linear foot, the thousands of straw bale barriers used annually represent sufficient expense that optimum installation procedures should be emphasized. If such procedures are carefully followed, straw bale barriers can be quite effective. Therefore, continued designation of straw bale barriers as a BMP will be contingent upon significant improvement in the installation and maintenance procedures applied to their use. Design Criteria • A formal design is not required. • • Sheet Flow Applications 2. Bales shall be placed in a single row, lengthwise on the contour, with ends of adjacent bales tiohtl y abutting one another. 2. All bales shall be. either wire-bound or string-tied. Straw bales shall be installed so that bindings are oriented around the sides rather than along the tops and bottoms of the bales in order to prevent deterioration of the bindings (Figure II-5.19) . 3. The barrier shall be entrenched and backfilled. A trench shall be excavated the width of a bale and the length of the proposed barrier to a • minimum depth of 4 inches. The trench must be deep enough to remove all grass and other material which might allow underfloor. After the bales are staked and chinked (filled by wedging) , the excavated soil shall be backf illed against the barrier. Backfill soil shall conform to the ground level on the downhill side and shall be built up to 4 inches against the uphill side of the barrier (Figure II-5.19). 4. Each bale shall be securely anchored by at least 2 stakes or re-bars driven through the bale. The first stake in each bale shall be driven toward the previously laid bale to force the bales together. Stakes or re-bars shall be driven deep enough into the ground to securely anchor the bales. Stakes should not extend above the bales but instead should be driven in flush with the top of the bale for safety reasons. 5. The gaps between the bales shall be chinked (filled by wedging) with straw to prevent water from escaping between the bales. Loose straw scattered over the area immediately uphill from a straw bale barrier tends to increase barrier efficiency. Wedging must be done carefully in order not to separate the bales. 6. Inspection shall be frequent and repair or replacement shall be made promptly as needed. 7. Straw bale barriers shall be removed when they have served their usefulness, but not before the upslope areas have been permanently stabilized. • Channel Flow Applications • 1. Bales shall be placed in a single row, lengthwise, oriented perpend'culaz- to the contour, with ends of adjacent bales tightly abutting one another. 11-5-80 FEBRUARY, 1992' STORl7WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure 1I-5.19 Cross-Section of a Properly Installed Straw Bale Barrier Stated and Entrenched Straw Bale Binning wire or ietne 1 I (` 1 Coeoacted Soil to I1 {1 Prevent Piping (� � Sediment LaOen Filtered Runoff �� I ` �� , l 4 . . Runoff • �� 1111'1LUW " •.4 • • ii"." 1\ I II 1 === === -elf=Uri=1lUi 1�„to- ='!11M11 ,II!°1-ti1l11.=lili' III U 1' 11i 11 2. The remaining steps for installing a straw bale barrier for sheet flow applications apply here, with the following addition. 3. The barrier shall be extended to such a length that the bottoms of the end bales are higher in elevation than the top of the lowest middle bale (Figure II-5.20) to assure that sediment-laden runoff will flow either , through or over the barrier but not around it. 'aintenanee • Straw bale barriers shall be inspected immediately after each runoff-producing rainfall and at least daily during prolonged rainfall. • Close attention shall be paid to the repair of- damaged bales, end runs, and undercutting beneath bales. • • Necessary repairs to barriers or replacement of bales shall be accomplished promptly. • Sediment deposits should be removed after each runoff-producing rainfall. They must be removed when the level of deposition reaches approximately one-half the height of the barrier. • Any sediment deposits remaining in place after the straw bale barrier is no longer required shall be dressed to conform to the existing grade, prepared and seeded. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BHPs are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. I ' II-5-81 FEBRUARY, 1992 STORMWATER MANAGEF2NT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.20 Proper Installation of a Straw Bale Barrier ? . Excavate the trench. 2 . Place and stake strew bales . M1L1l ,• ivo r1Q� � � .,y.1�4, � mill- y cl 4*- "L � wi dthe� w l(!: ✓ - , 1 • •-� 1': " • ,� , � �..I 11 rr:!_ ILL �1' — - . iii 1 • • 3. Wedge loose straw between 4. Backfill and compact the bales. • - 'excavated soil . CONSTRUCTION OF A STRAW BALE BARRIER • A • 1404; 111 `-� =//lid , >ta:ha+,94-4n ii;;:, Points A should be higher than point B PROPER PLACEMENT OF STRAW BALE BARRIER IN DRAINAGE WAY 1I-5-82 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT 11-5.8.3 B110 E3.20: Brush Barrier Code: BB Symbol: email" Definition A temporary sediment barrier constructed at the- perimeter of a disturbed area from residue materials available from cleaning and grubbing on-site. Pstrmoee To intercept and retain sediment from limited disturbed areas. Conditions Wh-re Pr.e+i a awl es • Below disturbed areas of less than one quarter acre that are subject to sheet and rill erosion, where enough residue material is available for construction of such a barrier. Note: This does not replace a sediment trap or pond. Advantages • Brush barriers can often be constructed using materials found on-site. Problems • None Planning Con- '•eratione Organic litter and spoil material from site clearing operations is usually burned or hauled away to be dumped elsewhere. Much of this material can be used effectively on the construction site itself. During clearing and grubbing operations, equipment can push or dump the mixture of limbs, small vegetation, and root mat along with minor amounts of soil and rock into windrows along the toe of a slope where erosion and accelerated runoff are expected. Anchoring • filter fabric over the berm enhances the filtration ability of the barrier. Because brush barriers are fairly stable and composed of natural materials, maintenance requirements are small. Material containing large amounts of wood chips should not be used because of the potential for leaching from the chips. Dee'an C term►, • Height 3 feet (minimum) to S feet (maximum) . • Width 5 feet at base (minimum) to 15 feet (maximum). • Filter fence anchored over the berm will enhance its filtration capacity. • Further design details are illustrated in Figure I1-5.21. • Maintenance • Brush barriers generally require little maintenance, unless there are very heavy deposits of sediment. Occasionally, tearing of the fabric may occur. • When the barrier is no longer needed the fabric can be removed to allow natural establishment of vegetation within the barrier. Over time the barrier will . rot. II-5-S3 FEBRUARY, 2992 STORI4WATER MANAGEMENT HANVAL FOR T'EZ PUGET SOUND BASIN • Figure II-5.21 Brush Barrier • filter fabric draped over • brush pile and secured i _�...--__ .,, �!�i' trench w/ compacted backAl , ..7. '7 .`� ter: __ ��: � � - i .17%".........�` .ii..ii i_ e � ��/i / ry . ,L • / _■//j - _ //. j O �+ r iii /!/ - ".. viii//i /� ♦�i •�� ice' �/ '4 7. -_.� /�I/I//��I �I rte•-� _� �sI/if �r �0. lam!'_ ��1 �� %%i.i 1�� anchor downhill edge of �A/,.. �*if brush barrier w/ twine _— ��w�-..•�iri �ye fastened to fabric & stakes �,. - o, ��_ ii- Vii∎ ��j�� - _-_ _+t��":r'_'�•�i iii. — i� i� ja ��i '7 .' ...*/ 07 MI. 44,40, min 3' high ' ,` • 6' x 6" (min.) trened, vegetative debris/brush piled along uphill edge of brush barrier uniformly in row to form barrier • • • II-5-84 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN 1I-5.B.4 Blip E3.25: Grave/ Filter Berm Code: Symbol: Gib Definition A gravel berm constructed on rights-of-way or traffic areas within a construction site. Purpose To retain sediment from traffic areas by using a filter berm of gravel or crushed rock. conditione Where Practice Ai,plies • Where a temporary measure is needed to retain sediment from rights-of-way or in traffic areas on construction sites. Advantages • Thie is a very efficient method of sediment removal. Disadvantages/Problems • This BMP is more expensive to install than are other MOB which use materials found on-site. Design Criteria Berm material shall be 4 to 3 inches in size, washed, well-graded gravel or crushed rock with less than 5 percent fines (Figure 1I-5.22) . • Spacing of berms: every 300 feet on slopes less than 5 percent every 200 feet on slopes between 5 and 10 percent every 100 feet on slopes greater than 10 percent • Berm dimensions: 1 foot high with 3:1 side slopes 8 linear feet per 1 cfe runoff based on the 10-year, 24-hour design storm. •J4a intenanee • Regular inspection is required; sediment shall be removed and filter material replaced as needed. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. 11-5-85 FEBRUARY, 1992 STORKWATER 2SANAGEKENT MANUAL FOR THE PUGE'3' SOtJWD HAS IN , Figure II-5.22 Gravel Filter Berm ,-/ ‘._,7-:„../t'7 / r----r---- "..... ...'.. --):"."..."'>'-' -..' .x..,...t..4 �� I .1.iI.,.a"r' i STORHWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN II-5. 8.5 BM? E3.30: Storm Drain Inlet Protection Code: 0 Symbol: Definition A sediment filter or an excavated impounding area around a storm drain, - drop inlet, or curb inlet. Pureose To prevent sediment from entering storm drainage systems prior to permanent stabilization of the disturbed area. Conditions where Pract'ce Applies • • Where storm drain inlets are to be made operational before permanent stabilization of the disturbed drainage area. Different types of structures are applicable to different conditions: a. Filter Fabric Fence - applicable where the inlet drains a relatively small (less than 1 acre) flat area (less than 5 percent elope) . (see Figure II- 5.23) . Do not place fabric under grate as the collected sediment may fall into the drain when the fabric is retrieved. This practice cannot easily be used where the area is paved because of the need for driving stakes to hold the material. b. Block and Gravel Filter - applicable where heavy flows (greater than 0.5 cfs) are expected (Figure I1-5.24) . c. Gravel and Wire Mesh Filter - applicable where flows greater than 0.5 cfs are expected and construction traffic may occur over the inlet (Figure II- 5.25). • ,Advantages • Inlet protection prevents sediment from entering the storm drain system and clogging it. Disadvantages/Probleme • Sediment removal may be difficult, especially under high flow conditions. plannino Considerations Storm severs which are made operational before their drainage area is stabilized can convey large amounts of sediment to natural drainageways. Zn cases of extreme sediment loading, the storm sever itself may clog and lose a major portion of its capacity. To avoid these problems, it is necessary to prevent sediment from entering the system at the inlets. • There are several types of inlet filters and traps which have different applications dependent upon site conditions and type of inlet. Other innovative techniques for accomplishing the same purpose are encouraged, but only after specific plans and details are submitted to and approved by the Plan Approving Authority of the local government (see Design Criteria for the description of a new method currently under development by Emcon Northwest) . Note that these various inlet protection devices are for drainage areas of )ess than one acre. Runoff from larger disturbed areas should be routed through a Temporary Sediment Trap or Pond (see EXPs E3.35, E3.40) . II-5-81 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT The best way to prevent sediment from entering the storm sever system is to stabilise the site as quickly as possible, preventing erosion and stopping sediment at its source. Design Cite is • • Grates and spaces of all inlets should be secured to prevent seepage of sediment-laden water. • All inlet protection measures should include sediment sumps of 1 to 2 feet in depth, with 2:1 side slopes (Figure II-5.23) . • Installation procedure for filter fabric fence: a. Place 2 inch by 2 inch wooden stakes around the perimeter of the inlet a maximum of 3 feet apart and drive them at least 8 inches into the ground. The stakes must be at least 3 feet long. b. Excavate a trench approximately 8 inches wide and 12 inches deep around the outside perimeter of the stakes. c. Staple the filter fabric (for materials and specifications, see BMP E3.10, Filter Fence) to wooden stakes so that 32 inches of the fabric extends out and can be formed into the trench. Use heavy-duty wire staples at least h inch in length. d. Backfill the trench with 3/4 inch or less washed gravel all the way • around. • Installation procedure for block and gravel filter: a. Place wire mesh over the drop inlet so that the wire extends a minimum of 1 foot beyond each side of the inlet structure. Use hardware cloth or comparable wire mesh with one-half inch openings. If more than one strip is necessary, overlap the strips. Place filter fabric over the wire mesh. b. Place concrete blocks lengthwise on their sides in a single row around the perimeter of the inlet, so that the open ends face outward, not upward. The ends of adjacent blocks should abut. The height of the barrier can be varied, depending on design needs, by stacking combinations of blocks that are 4 inches, 8 inches, and 12 inches wide. The row of blocks should be at least 12 inches but no greater than 24 inches high (Figure 11-5.24) . • c. Place wire mesh over the outside vertical face (open end) of the concrete blocks to prevent stone from being washed through the blocks. Use hardware cloth or comparable wire mesh with one half inch openings. d. Pile washed stone against the wire mesh to the top of the blocks. Use 3/4 to 3 inch gravel. • Installation procedure for gravel and wire mesh filter: a. Place wire mesh over the drop inlet so that the wire extends a minimum of 1 foot beyond each aide of the inlet structure. Use hardware cloth or comparable wire mesh with 1/2 inch openings. If more than one strip of mesh is necessary, overlap the strips. Place filter fabric over wire mesh. b. Extends the filter fence/wire mesh beyond the inlet opening at least t 18 inches on all sides. Place 3/4 to '3-inch gravel over the filter �• fabric/wire mesh. The depth of the gravel should be at least 12 inches II-5-88 FEBRUARY, 1992 • • STOR)4WATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT over the entire inlet opening (see Figure 1I-5.25) . Exoerinental Inlet Protection BHP: EMCON Northwest, Inc. has recently developed a catchbasin filter (patent pending) that prevents sediments and other contaminants from entering storm drainage systems. The catchbasin filter is inserted in the catchbasin just below the grating. The catchbasin filter is equipped with a sediment trap and up to three layers of a fiberglass filter material (see Figure 11-5.26) . This type of system may not be applicable in all catchbasins but would work well at construction sites, industrial facilities, service stations, marinas/boatyards, etc. During research and development of the catchbasin filter, EHOON Northwest, Inc. has found that particulates as small as 15 microns are retained by the filter. Additionally, high levels of particulate heavy metals, oil and grease and TSS have been removed at both industrial facilities and construction sites. The catchbasin filter is equipped with an overflow mechanism which allows it to pees peak flows up to 240 gallons per minute. Effective filtration can be accomplished at flows as high as 40 gallons per minute. For further information, contact John MacPherson at EMcON Northwest Inc. , (206) 485-5000. Please note that this information is presented for informational purposes only. While this technology appears to be an effective method of controlling some types of pollutants, Ecology is not in a position to confirm or deny its efficacy at this time. 3aintenance • For systems using filter fabric: inspections should be made on a regular basis, especially after large storm events. If the fabric becomes clogged, it should be replaced. Sediment should be removed when it reaches approximately one-half the height of the fence. If a sump is used, sediment should be removed when it fills approximately one half the depth of the hole. • For systems using stone filters: If the stone filter becomes clogged with sediment, the stones must be pulled away from the inlet and cleaned or replaced. Since cleaning of gravel at a construction site may be difficult, an alternative approach would be to use the clogged stone as fill and put fresh stone around the inlet. • • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. • • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPO are no longer needed. Trapped sediment shall be removed or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. I ' 11-5-B9 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-5.23 Filter Fabric Fence Inlet Filter Drop inlet with Grate Stakes P �! r. • fir• � 2 - tvd Fitter Fabric Stakes , Filter Fabric Runoff Water ,Washed Gravel with Sediment [fttered Water g Buried Filter � _-- !-- Fabric Z . 11-5-90 FEBRUARY, 1992 \1 STORKWATER MANAGE2lENT MANUAL FOR THE PUGET SOUND BASIN • Figure II-5.24 Block and Gravel Filter Wire Screen . - '_-, e''i�-''%? - Gravel Filter •;(M u it -.FI-11 11 :J' i,, --...�-�.ir!..111...•411:77.•__,, 1.s ��•.. q.p7# I,.. :•• •.ice•i i •11 ..-v as. ....;;;;;;;0; vurcps . .4. Ai 74 ir.tilkAr 4.40 044 elf raraNi1j%� • 7 Overflow Concrete Block Ire Screen Filtered Water Runoff Water :-;;;; ' with Sediment ,;'.� %" j'�.• � • : • STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN Figure II-S.25 Experimental Catchbaain Filter With Sediment Trap a S C �_ N.e. 9 . . . . T. Iii. . . w . ._ .. .. . . ...., Lt.. .. . .. r,.., .. . z ....E.' ` • m , CC o ..—..--. S u <+ 1.......1....... U G u:,:.:: ,; 1 a a. au so 4 0 / r. I o 1 1 • II V 1 . • C e e~ ; z 90 W V V) 1 • U) r Z 0 .. - _. ,. . . . D. NI II-5-92 . FEBRUARY, 1992 • , STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN • II-5.E.6 BM? E3.35: Sediment ''rap Code: c: E1:) Symbol: sir. Editor's Note: Based on comments that were received during the technical review period of the manual, BMPe E3.35 (Sediment Trap) and £3.40 (Sediment Pond) were revised and the use of the Universal Soil Loss Equation to calculate the sediment storage volume was dropped. Instead, volume calculations are to be based on one of the methods found in Volume III, Runoff Control, and a constant depth for 'sediment storage. It is important to understand that sizing is perhaps less important for these Blues (because of their temporary nature) than is constant maintenance. Inspections must be made and sediment removed regularly for either of these BMPe to function well. pefinition A small temporary ponding area, with a gravel outlet, formed by excavation and/or by constructing an earthen embankment. Purpose To collect and store sediment from sites cleared and/or graded during construction. It is intended for use on relatively small building areas, with no unusual drainage features, and projected quick build-out time. It should help in reducing silt-laden runoff. This silt-laden runoff clogs off-site conveyance systems and destroys habitat, particularly in streams. The trap is a temporary measure (with a design life of approximately 6 months) and is to be maintained until the site area is permanently protected against erosion by vegetation and/or structures. Conditions Where Pract'ce henlies • Proposed building sites where the tributary drainage area is less than 3 acres. Advsnteaee • Downstream riparian properties will not be damaged by sediment deposits originating from that development. • Sediment deposits downstream will not reduce the capacity of the stream channel. • Sediment will not cause the clogging of downstream impoundments and other facilities. pisadventaves/Problems, • Serves only limited areas. • • Sediment traps (and ponds, see MP £3.40) are only practically effective in removing sediment down to about the medium silt size fraction. Runoff with sediment of finer grades (fine silt and clay) will pass through untreated, emphasizing the need to control erosion•to the maximum extent first. P en:iinc Considerations, Sediment traps should be used only for small drainage areas. If the contributing drainage area is greater than 3 acres, refer to Sediment Ponds (see BMP E3.40), or subdivide the catchment area (see Figure II-S_27) . Sediment must be periodically removed from the trap. Plans shall detail how this II-5-93 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT "- sediment is to be disposed of, such as by use in fill areas on-site, or removal to an approved off-site dump. Sediment traps, along with other perimeter controls, shall be installed before any land disturbance takes place in the drainage area. Safe= See Section II-5.8.7, Sediment Ponds (8MP E3.40) . pesian Criteria The sediment trap may be formed completely by excavation or by construction of a compacted embankment. It shall have a 1.5 foot deep sump for sediment storage. The outlet shall be a weir/spillway section, with the area below the weir acting as a filter for sediment and the upper area as the overflow spillway depth. • See Figures 11-5.27 and 11-5.28 for details. • • The temporary sediment trap volume can be found by computing the detention volume required for the 2-year, 24-hour design storm using one of the approved methods found in Volume III, Chapter 1. Side slopes should not exceed 3:1. After determining the necessary volume, size the trap by adding an additional lA feet for sediment accumulation to the volume computed using the 2-year, 24- hour design storm. • 7o complete the design of the temporary sediment trap: a. Figures 11-5.28 and 1I-5.29 may be useful in designing the sediment trap. • • b. A 3:1 aspect ratio between the trap length and width of the trap is ,... • desirable. Length is defined as the average distance from the inlet to the outlet of the trap. This ratio is included in the computations for Figure 11-5.28 for the surface area at the interface between the settling zone and sediment storage volume. c. Determine the bottom and top surface area of the sediment storage volume • to be provided (see Figure 1I-5.29) using lA feet in depth for sediment storage and 3:1 side slope from the bottom of the trap. Note the trap bottom should be. level. d. Determine the total trap dimensions by adding the depth required for the 2-year, 24-hour design storm above the surface of the sediment storage volume, while not exceeding 3:1 side slopes (see Figure II-5.29). Maintenance • • The key to having a functional sediment trap is eon in al monitoring and regular maintenance. The size of the trap is less important to its effectiveness than is regular sediment removal. Sediment should be removed from the trap when it reaches approximately one foot in depth (assuming a 1A sediment accumulation depth). Regular inspections should be done and additional inspections made after each large runoff-producing storm. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary 8tbs(\ are no longer needed. Trapped sediment shall be removed or stabilized on permanently Disturbed soil areas resulting from removal shall be * nently stabilized. I1-5-94 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN J Figure 11-5.27 ESC Structural Practices \ 1 • L_____ `o 1 C • S u. t r at • \o e' • o • Sediment Trap\ O% i Drainage Area \ < 3Ac. • t • I or\► Ii `-�` / t Filter Fence �7/� S•olmmnt PonC Sediment Trap ,C!°/� Bettie < 10 Ac. Mca Drainage Area I 1 G/4e = 3 At. h ..— or Sir_, a .0, flitter '-: ::\„„..,..,.:7;:s"........ Filter Fabric Fence. i 1 ■ pock Protection N ralnage Area 51 Ac. Dulled • al�r \, GPE . �"--- $.1 "t9 Rt • 1__-.• 1 11-5-95 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN - Figure 11-5.28 Sediment Trap • Outflow channel is constructed by excavation 4' ruin. 1' overflow depth 1' depth of 2• •4' rock 2' setting pt 1?.:1,"-'i: . .5' sediment storage ——- i ....... Tt ." itl N "' 1' depth 'V-- 1 Ys washed gravel filter fabric fencing CROSS SECTION NO SCALE note: may be constructed by excavation or by building a berm • • _~ 6=- m overflow spillway "tea`'' -tee ;:�__ 6' mitimum width \._��.��C :.:iii- • w •3 yr_ /� �T� ..▪ :‘!":. ;;;::?.. -'.7:,...,�� nti_ _..,:z..., �-i�' ~ 4 1.5' sediment storage ,.==.cv".i r...=, _1/4.-i.."`i'.1,.-.„■ ..e:‘._-a..:-'-:'.,.h..„...,-,._.:.....Th..4,.,..-L.,"„-■■..:...',*--•a'.....'s� ��`�` 2' settling depth & 1' depth of 2' -4' rock 1' depth of I• - 1112" washed gravel SEDIMENT TRAP OUTLET NO SCALE I II-5-96 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN ' i II-5.B.7 BXP E3.40: Temporary Sediment Pond (or Bas n) griNgsgesszsex Code: SB Symbol: Editor's Note: Based on comments that were received during the technical review period of the manual, BMPe E3.35 (Sediment Trap) and E3.40 .(Sediment Pond) were revised and the use of the Universal Soil Loss Equation to calculate the sediment storage volume was omitted. Instead, volume calculations are to be based on one of the methods found in Volume III, Runoff Control, and a constant depth for sediment storage. It is important to understand that sizing is perhaps less important for these BMPs (because of their temporary nature) than is constant maintenance. Inspections must be made and sediment removed regularly for either of these BMPe to function well. pefinition A .temporary basin with a controlled stormwater release structure formed by constructing an embankment of compacted soil across a drainageway, or other suitable locations. Purpose • To collect and store sediment from sites cleared and/or graded during construction or for extended periods of time before reestablishment of permanent vegetation and/or construction of structures. It is intended to help prevent erosion on the site which results in silt-laden runoff. The basin is a temporary measure (with a ( design life less than 1 year) and is to be maintained until the site area is permanently protected against erosion. . Conditions' Where Practice Applies • Proposed construction sites where the tributary drainage is less than 10 acres. Safety Sediment traps and ponds must be installed only on sites where failure of the structure would not result in loss of life, damage to homes or buildings, or interruption of use or service of public roads or utilities. Also, sediment traps and ponds are attractive to children and can be very dangerous. Local ordinances regarding health and safety must be adhered to. If fencing of the pond is required, the type of fence and its location shall be shown on the ESC plan. AdvantBbes • Becaues of additional detention time, sediment ponds may be capable of trapping smaller sediment particles than traps. However, they are most effective when used in conjunction with other MP, such as seeding or mulching. pisedvan roes/Probleios, • Ponds may become an "attractive nuisance" and care must be taken to adhere to all safety practices. • Sediment ponds are only practically effective in removing sediment down to about the medium silt size fraction. Sediment-laden runoff with smaller size fractions (fine silt and clay) will pass through untreated emphasizing the need to control erosion to the maximum extent first. • • • 11-5-97 FEBRUARY, 1992 STORMWATER MANAGEMENT MANUAL FOR TFU: PUGET SOUND BASIN DRAFT P1&WIina Cons'•erations rf fectiveness Sediment basins are at best only 70-80 percent effective in trapping sediment which flows into them. Therefore, they should be used in conjunction with erosion control practices such as temporary seeding, mulching, diversion dikes, etc. to reduce the amount of sediment flowing into the basin. Sediment basins are most effective when designed with a series of chambers. .ocation To improve the effectiveness of the basin, it should be located so as to intercept the largest possible amount of runoff from the disturbed area. The best locations are generally low areas below disturbed areas. Drainage into the basin can be improved by the use of diversion dikes and ditches. The basin must not be located in a stream but should be located to trap sediment-laden runoff be ore It enters the stream. The basin should not be located where its failure would result in the loss of life or interruption of the use or service of public utilities or roads. Jful tin - Use Sediment basins may be designed as permanent structures to remain in place after construction is completed for use as stormwater detention ponds. Wherever these structures are to become permanent, or if they exceed the size limitations of the design criteria, they must be designed as.permanent ponds by a professional engineer licensed in the State of Washington. Permanent ponds are dealt with in Volume III, Runoff Control. pee ian Criteria The sediment pond may be formed by partial excavation and/or by construction of a compacted embankment. It may have one or more inflow points carrying polluted runoff. Baffles to spread the flow throughout the basin should be included (Figure 1I-5.30) . A securely anchored riser pipe is the principal discharge mechanism along with an emergency overflow spillway. The riser pipe shall be solid with two 1-inch diameter dewatering holes located at the top. of the sediment storage volume on opposite sides of the riser pipe as shown in Figure I1-5.30. Outlet protection is provided to reduce erosion at the pipe outlet. • The sediment pond volume is the sum of the sediment storage volume (3 feet in depth) plus a settling volume of not leas than 2 feet in depth. The sediment depth is computed based on the basin surface area required to settle out the design particle at the design inflow rate. Com utina she sett 'no zone volume: The settling zone volume may be approximated by assuming a 2 foot depth above the sediment storage volume and extending the 3:1 side slopes as necessary, or by computing the precise volume as outlined below. The maximum settling zone depth shall be 4 feet. a. Pond surface area • . The settling zone volume is determined by the pond surface area which is computed using the following equation: (SA) 1.2Q10 / Vaid Where Q10 se design inflow based on the peak discharge from a 10- year, 24-hour duration design storm event from the tributary drainage area as computed using the methods. described in Chapter II1-1 of Volume III, Runoff Control. II-5-9B FEBRUARY, 1992 - ) STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN DRAFT = the settling velocity of the design soil particle. The design particle chosen is medium silt (0.02 mm) (1) This has a settling velocity (V.1) of 0.00096 ft/sec. Note that for the relatively common sandy loam soils found in the Puget Sound basin, approximately 80 percent of the soil particles are larger than 0.02 mm. Thus, choosing a design particle size of 0.02 ma gives a theoretical trapping efficiency of approximately 80 percent. In practice, and for more finely textured soils, the trapping efficiency would be less. However, as a general rule, it will not be necessary to design for a particle of size less than 0.02 mm, especially since the surface area requirement increases dramatically for smaller particle sizes. For example, a design particle of 0.01 mm requires about three times the surface area of 0.02 mm. However, for sites with very finely textured soils, the local government may require a smaller design particle size than 0.02 mm. Note also that choosing a Vad of 0.00096 ft/sec equates to a surface area (SA) of 1250 sq. ft. per cfs of inflow. b. Settling depth (SD) should not be less than 2 feet and is also governed by the sediment storage volume surface area and relationship to the basin length (L). The basin length is defined as the average distance from the inlet to the outlet of the pond. The ratio of L/SD should be less than 200. The settling volume is therefore the surface area (SA) times the required settling depth. To complete hp lesion -f the sediment pond: Total sediment pond volume and dimension are determined as outlined below: a. Determine pond geometry for the sediment storage volume calculated above using 3 feet in depth and 3:1 aide slopes from the bottom of the basin. Note, the basin bottom is level. b. Extend the pond side slopes (at 3:1 max. ) as necessary to obtain the settling zone volume at 2 foot depth minimum or as determined above, 4 foot maximum. • ) 11-5-99 FEBRUARY, 1992 • STORHWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN {, r Figure 1I-5.29 Sedimentation Pond Baffles Fireerfotrnetl Lt I L2 . ■ we ettective.0101,1 of WW1 I?*Pt 4,(-- A• sUrtaee area at on.,«we^ __ _ _ tltlel]to west N - - ( / i L. ■snortat travel orstances t .... F ,t� *MUM Me WtIie iron+ Normal Pool I Vie, Inset to outlet . T II Aser is ptatssC \ Rner here Is in very Acne no bathe 000r'Canton.pestle is recurred Is rpuireo -� — -- BAFFLE L Normal Pool tt_ _ — YWe . t -' tnh w . 5 Reef I I t;AF F Li. Normal Pod In eel Case a is In2low L enconant to otace I borne so Mat Lt ■L2 • Elea snt 01 Sheen of orvwi000 alt r 8 ti t tb m r nser'nest e.tNlor Divincloo or gun. Depth Of water• { r' r I I � I1 I m basin when tutI I t 1 I ( • 3' Mau. ll I I I I H I I. ro � Posts 4 In Moore or 1'1�:1� 1�a !lY j 5.n uno rnrn.,fnu+.s wt at'east 3 ti into prouno t.J c Elevation DI I I basin bosom •• •+ B l i cente's I - II-5-100 FEBRUARY, 1992 • 1 STORMWATER MANACElENT MANUAL FOR THE PUCE? SOUND BASIN Figure II-5.30 Sediment Pond pond length z 3x pond width filter fabric fence -411111 1 inflow Not. �C,_ - _ oy .44iftr Q level bottom :lie p-__________ .. -4, , . perforated drain pipe' in taltmera Duvet pipe gravel-filled trench riser pipe' w/ weighted be • • Nov: $odirn•m dawatarinp may bs occorrroishsd with psrloratsd pipe in trench as shown sr wrtth a parforstad riser pips coveted with filar fabric and a prawl -cone. A control sovetus w+ay also ile req iwd:owl Conditions W1sne Psectioe ApOa* 1' spillway depth provide a rebar trash rack on riser 0 Y pth / pipes z 18 1' freeboard 6' . riser pipe, open at top "' emergency °yellow (principal spillway) spillway Crest delwatering outlets _— max 4' 4 .`�, ?7 filter fabric fence ? min. 2' settling depth outlet pipe sediment storage _ J 11:1 - •• .. , 3' maximum depth.- level grade tl''' perforated drain pipe in anti4 p collars gravel-filled trench for energy dissipating rock silt dewatering; trench weighted base to _ wrapped w/filter fabric prevent floatation full length Section A-A II-5-101 FEBRUARY, 1992 STORMdATER MANAGEMENT MANUAL FOR TEE PUGET SOUND BASIN DRAFT • d. Adjust the geometry of the basin to effectively combine the settling zone volume and sediment storage volumes while preserving the depth and side elope criteria. Provide baffles to prevent short-circuiting (see Figure II-5.30) . A 6:1 aspect ratio between the basin length and width of the pond is desirable. Maintenance • • Inspections should be made regularly, especially after large storm events. Sediment should be removed when it fills one half of the pond's total sediment storage area. The effectiveness of a sediment pond is based less on its size than on regular sediment removal. • All temporary and permanent erosion and sediment control practices shall be maintained and repaired as needed to assure continued.performance of their intended function. All maintenance and repair shall be conducted in accordance with an approved manual. • All temporary erosion and sediment control measures shall be removed within 30 days after final site stabilization is achieved or after the temporary BIPB are no longer needed. Trapped sediment shall be removed- or stabilized on site. Disturbed soil areas resulting from removal shall be permanently stabilized. • I II-5-l•2 FEBRUARY, 19-2 STORMWATER MANAGEMENT MANUAL DRAFT LIST OF PROPOSED BMP' s TO BE ADDED Slurry Pit • Purpose To provide an designated on-site location where all washwater from concrete trucks and cleaning of equipment will be concentrated. Conditions Where Practice Applies On projects where washing activities occur Design Criteria A designated washout area for concrete trucks and equipment needs to be clearly marked on construction sites. The area should be located where the concrete wash can harden, be broken up and then put into a dumpster. An alternate method would be to break up the harden concrete wash in the pit, making sure the largest pieces are six (6) inches or smaller, then fill in the pit after it is full or no longer needed. The designated location should not be located in the path of surface water runoff and should be located a minimum of 20 feet away and not directly upstream from any drainage facilities or receiving water. The slurry pit should be clearly posted upon entrahce to the site so operators are fully aware of the pit location Washout should never be allowed to get into storm drains, grassy swales, open ditches or onto soil or pavement where concentrated stormwater runoff occurs. When spray washing driveways or walkways to expose the aggregate, all washwater should be diverted or sprayed to the sides, not down the driveway towards downstream inlets. If washwater can not be diverted, protection against fine material at the inlet needs occur and material that settles out in the right-of-way needs to be removed after the washing is completed. 11-5-103 APRIL, 1996