25500 PE-1414D RIVERWALK
OL
S P O K A N E C O U N T Y
DIVISION OF ENGINEERING AND ROADS • A D[VISION OF THE PUBLIC WORKS DEPARTMENT
William A Johns, P.E., County Engineer Dennis M. Scott, P.E , Director
July 1, 1996
Todd Whipple, P.E.
Inland Pacific Engineering
Edward Dean
Dean Building Corporation
16720 N.E. 116th Street
Redmond, WA 98052
SUBJECT: P1414D - Riverwalk 5th Addition
Acceptance
Gentlemen:
We have conducted a general evaluation of your recent submittal for this project, and we find that this
submittal appears to meet the minimum standards of the Spokane County Standards for Road and Sewer
Construction(the "Standards"). We are, therefore, able to accept your approval of the plans and
calculations for this project.
We are enclosing a sepia copy of the plans, and a copy of the drainage calculations with the County's
acceptance stamp. The original construction plans and calculations aze on file at the Spokane County
Engineer's Office. In accordance with Section 5.02.D of the Standards, this acceptance is valid until
April 11, 1999. If the facilities are not constructed, you may request an extension of the acceptance for
an additional two years; the plans shall be revised at that time to reflect current standards, prior to
granting the extension.
Please note:
1. The County's acceptance of this submittal does not relieve the Sponsor or his agents from any
liability related to portions of the design that are not in conformance with the Standazds, or which do not
follow good engineering practice.
2. All permits and notifications necessary prior to construction are the responsibility of the project
Sponsor and/or his assigned agents.
3. The County Engineer's Office will not release the surety for construction engineering services
until all construction documentation and the certified Record Drawings have been submitted by the
Construction Engineer, and accepted by the County Engineer's Office.
1026 W. Broadway Ave. • Spokane, WA 99260-0170 •(509) 456-3600 FAX• (509) 324-3478 TDD: (509) 324-3166
Todd Whipple, P.E.
Edward Dean
Riverwalk 5th Addition
Acceptance
July 1, 1996
Page 2 of 2
4. As mentioned in the County Engineer's letter of May 16, 1996, the construction of Indiana
Avenue, from Barker Road to the easterly terminus in Riverwalk 2nd Addition, needs to be complete,
and established for maintenance by the County, prior to the Final Approval for these plats. This includes
all related and appurtenant work for drainage and landscaping.
If you have any questions, please contact Ed Parry at 456-3600. Thank you.
Very truly yours,
William A. Johns, P. E.
Spokane County Engineer
Edward J. Pazry, Jr., P.E.
Plan Review Engineer
encls: Plans (1 set) - sepia
Ca(culatioas
cc: project file
Pat Harper/Scott Englehard
Dave Berto
Permit Technician - Sylvia Lightfoot
reviewer (comments only)
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I STOR&RDRABLACE ANAL*SIS
OFFICI&L PUBI,IC DOCUMENT
' ORIGINAter .
' - _ SPOKANE CoA
UK
F
~F -con~s T a
44i PROJ~T'F:H DDITION
DATE ACCEPTED: ~'h~
' ACCEPTANCEEXPIRES: JI"
CONSTRUCTION DOCUMENTATION AND CERTIFIED
, RECORD DR.AWINGS ARE REQUiRED f'R!OR TO RELEASE
~ OF BOND FOR CORSTRUCTIOU ENG6NLERIPlG SERVICES
i' June 10, 1996
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~ Prenared Bv: .
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~ Inland Pacific Engineering .
~ 707 West 7''' Suite 200
Spokane, WA 99204
; (509)-458-6840
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DRAINAGE REPORT
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for _
, RIVERWALK -
5TH ADDITION
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NNE 10,1996
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Prepared by:
, I»land Pacific Engineering Company
707 West 7th Suite 200
' Spokane, WA 99204
' (509)458-6840 -
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A'i~~ ?'+N.' i M ]K'.. R~v
~he t~esign improveme,#s shown~ i'^~ this:set of platt; snd ~a,lcalat~u~ns eo~►fo~r~ ta-thes
F t
a A piica ble editio n s u f t~►e S p Q k a~~ C a u nty S t an6rc t s' f o r i t o adaa dS ewer Con s t w uc
and therySpokane County Giiidelineg #'or~S€orinwater N~aiiageiment..All}des_igri deviat~ons~`
' `;have,bee~t,app~rosyeil`by*the Spakaae Cvunty~EngineeI r. Approve these plai~s,. . + .
i~yM.v" yrYr , _ ijN•v.. _~•'Q}xM1n 1•
'v:£ •
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This report has been prepared by the staff of Inland Pacific Engineering CompAny under the direction
' of the undersigned professional engineer whose seal and signature appear hereon. This report
conforms to the applicable editions of the Spokane County Standards for Road and Sewer
Construction and the-Spokane County Guideline tormwate Management. ,
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EXPIRES 9/24/ ~
' Todd R. Whipple, P.E.
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~ PURPOSE
' The purpose of this report is to deternune the extent of storrn drainage facilities which will be
required to dispose of stormwater runoff created by the development of Riverwalk Sth Addition. _
The storm drainage facilities on this project will be designed to dispose of stormwater runofffor
t the 10-year storm event as required by Spokane County and The Guidelines for Stormwater
Manaeement. This development is within the Aquifer Sensitive Area and is subject to `208'
requirements.
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ANALYSIS METHODOLOGY
~ The Rational Method, which is recommended for basins Iess than ten acres in size, will be used to
deternune the peak discharges and runoffvolumes for the 10-year storm event. Bowstring
, calculations will be used to determine the volume of stormwater created by the 10-yeaz storm
event. The drainage analysis for this project will follow The Snokane Countv Guidelines for
Stormwater Manaizement.
' PROJECT DESCRIPTION
, Riverwalk P.U.D. 4th Addition is a 7.10 acre, 261ot sub-division, located in the S'/z of the SW
1/4 and Government Lots 5 and 6 of Section 8, T. 25 N., R. 45 EWM. Sheet 67 of the Soil
Survev of Spokane Countv. Washineton (copy attached) shows the soils types to be GgA,
' (Garrison gravelly loam, 0 to 5% slopes), GgB, (Garrison gravelly loam, 5 to 20% slopes), and
Rh (Riverwash).
~ PROJECT SOILS DESCRIPTION
' A brief description from the USDA -Soil Conservation Service, Soil Survev of Snokane Countv.
Washinston for each soil type follows.
' Garrison gravelly loam with 0 to 5 percent slopes (GgA) is a somewhat excessively drained
soil formed from a variety of igneous rock. Surface runoff is slow, and the hazard of water
erosion is slight to moderate. Spokane County Guidelines for Stormwater Manaeement has
, pre-approved this soil for drywell installation. The soil is suited for homesite development.
Garrison gravelly loam with 5 to 20 percent slopes (GgB) is similar in all characteristics to
~ GgA except this soil type has a surface layer thinner than GgA soil types. Garrison gravelly loam
with 5-20% slopes (GgB) soil types have runoff which is medium, and the hazard of erosion is
moderate. Spokane County Guidelines for Stormwater Manaeement has pre-approved this soil
, for drywell installation.
Riverwash (Rh) consists of gravel, cobblestones and stones, with very little finer material, found
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' on low bottoms along perennial and intermittent streams. The areas are flooded nearly every year
from runoff, and only serve to protect against channel cutting.
, DEVELOPED CONDTTION ' In the developed condition, the project can be divided into 7 basins, (A through G) by the crowns
and high points of the various road improvements, and the natural topography.. (See Basin Map,
, copy attached.)
BASIN AND STORMWATER DISPOSAL SUMMARY
! Basins A through F will be designed to dispose of stormwater created by the 10-year storm event.
The stormwater created by this event will be disposed of in ponds and Spokane County Standard
' drywells.
Basin A consists of portions of the road impervious areas on the south side of Riverwalk Lane,
, and the west side of 1Vrchielli Lane. This basin also includes half of lot 1, of lots 2 through 5,
block 3, and lots 1 and 2, block 4. The peak flow of 0.27 c.f.s. for sub-basin A1 will be disposed
of in intermediate Pond Ai, the peak flow of 0.54 c.f.s. will be disposed of in intemnediate Pond-
' A2, and the peak flow for sub-basin A3 of 0.87 c.f.s. will be disposed of in Pond A3, which has
one Type "B" drywell in sump condition.
~ Basin B consists of a portion of the road impervious area on the north side of Riverwalk Lane.
This basin also a section of lot 1, block 5 and of lots 1 through 7, block 6. The peak flow of 0.43
c.f.s. for sub-basin B1 will be disposed of in intermediate Pond B1, the peak flow of 0.46 c.f.s. in
, sub-basin B2 will be disposed of in intermediate Pond B2, and the peak flow of 0.74 c.f.s. for
sub-basin B3 will be disposed of Pond B3, which has one Type "B" drywell in sump condition.
, Basin C consists of portions of the road impervious area on the east side of Michielli Lane, and
the south side of Riverwalk Lane.This basin also includes half of lot 3, and all of lots 4 and 5,
, block 2. The peak flow of 0.58 c.f.s. will be disposed of in Pond C which one Type "A" drywell
in sump condition.
' Basin D consists of portions of the road impervious on the north side of Shannon Lane, and the
west side of Michielli Lane. This basin also includes half of lot 1, block 3, and a portion of one
future lot. The peak flow of 0.26 c.f.s. will be disposed of in Pond D with one Type "A" drywell.
, Basin E consists of a portion of the road impervious area on the south side of Shannon Lane.
This basin also includes half of lot 1, block 1. The peak flow of 0.15 c.f.s. will be disposed of in
, Pond E.
' Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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I Basin F consists of the northern section of lot 1, block 5, and lots 1 through 7, block 6, and all of
Tract C. The basin has been analyzed in the pre-developed and developed condition. The pre-
' developed condition assumes a"C" factor of 0.30, representing meadows and pastureland. The
peak flow was calculated to be 1.89 c.f.s.. In the developed condition, the northem section of lot
1, block 5 and lots 1 through 7, block 6 were assumed to be landscaped with lawn, in sandy soil
' rolling terrain, which reduces the "C" factor for that portion to 0.15.. The Tract C area falls
within the Spokane County Shoreline Program, and will remain undisturbed. The "C" factor for
that portion will remain 0.30. Using a weighted "C" factor, the peak flow for the devetoped
' condition was calculated to be 1.64 c.f.s.. The peak flow in the developed condition is [ower than
the peak flow from the pre-developed condition by 0.25 c.f.s..
' Basin G consists of the northern section of lots lthrough 3, block 7, and exsiting lots 1, block 3,
and lots 1 through 4, block 4 of Riverwalk 3rd Addition, and all of Tract A. The basin has been
analyzed in the pre-developed and developed condition. The pre-developed condition assumes a
' "C" factor of 0,30, representing meadows and pastureland. The peak flow was calculated to be
1.34 c.f.s. In the developed condition, the entire azea was assumed to be landscaped with lawn, in
sandy soil rolling terrain, which reduces the "C" factor to 0.15. The peak flow for the developed .
' condition was calculated to be 0.67 c.f.s.. The peak flow in the developed condition is lower than
the peak flow from the pre-developed condition by 0.67 c.f.s..
' Pond Al, Riverwalk 3rd Addition, was designed as part of the drainage plan for Riverwalk 3rd
Addition, but will be built as part of Sth Addition. It is located at the southwest end of Micheilli
~ Lane, and was designed as an intermediate pond to store `208' volume from the road impervious
area upstream. Pond A2, Riverwalk 3rd Addition, will store the storm volume. See the
calculations and Basin Map for Riverwalk 3rd Addition.
, Pond Bl, Riverwalk 3rd Addition was designed as part of the drainage plan for Riverwalk 3rd
Addition. It is located on the north side of Michielli Lane, and was designed as an intermediate
~ pond to store `208' volume from the road impervious area upstream. Pond B2, Riverwalk 3rd
Addition, will store the storm volume. See the calculations and Basin Map for Riverwalk 3rd
Addition. The north half of these lots aze included in Basin G calculations for Riverwalk Sth
, Addition.
STORMWATER CALCULATIONS
, The stormwater from the 7 basins will be dis osed of in '208' retention onds and S okan
P p p e
County drywells as shown on the plans and in the attached Bowstring Calculation sheets.
' Table 1 lists the totai and u ' npernous areas and the "C" factor for the Time of Concentration and
Peak Flow catculations.
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, Inland Pacific Engineering, Inc. Riverwallc P.U.D. Sth Addition - Drainage
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~ Table 2
summanzes the retention volumesrequued for each basin as calculated by the Bowstnng
, Calculations, as well as the depth, area, perimeter and volume provided.
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•,t `',S~h t7:x ^%ic~N~,\v::•:""'.::,M1..io{%r:t:;.,t. ..:a:.>,•v~ 2':':.kj~ttv;.~:,•::r;':L. 'h
k
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. . . n.. ti,
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,S . : '2 j•• ~i h';2• ~°d^~~ h\
. . :a, d r +d
. :.~l~,YY iFl+x:,•, ..`.y'i."6~r' .
, BASIN TOTAL TOTAL IMP. AREA # LOTS DU/GA "C"
AREA (S.F.) AREA (AC.) (S.F.)
' A1 15,483 _ 0.36 4068 1.0 2.78 0.25
A2 21,259 0.49 3319 2.5 5.10 0.40
, A3 34,133 0.78 3994 3.0 3.85 0.35
A 70,875 1.63 11,381 6.5 5.65 0.40
, Bl 10,034 0.23 1955 1,5 6.52 0.60
B2 10,764 0.25 2088 1,5 6.00 0.60
' B3 28,474 0.65 5699 3,0 4.62 0.40
B 49,268 1.13 9742 6.0 5.31 0.40
' C 15,609 0.36 4884 2.5 6.9 0.60
' D 9281 0.21 3125 1.0 4.76 0.40
E 5135 0.12 2090 0.5 4.17 0.40
' F 86,355 1.98 - - - 0.26
G 60,927 1.40 - - - 0.15
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Inland Pacific Engineering, Inc. Rivenvalk P.U.D. Sth Addition - Drainage
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' `208 RETENTION VOLUME CALCULATIONS
''208' retention volumes were calculated using the following formula:
Volume (cu. ft.) _ (depth)(area) + (slope area)(perimeter)
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•.y ..~a•+k ti.t r..<xa 3';`•'~ ;7•......l.:.t. y> S'S% • 3';
~4.5•.,., ~C w~y:ow+oa c,,~ oQ~.{t .v~~f~.~`. ; ry ~ N.:..,..:.:.~;i 4.L.
~ry: ta o ~ tttx ~.n.a,.~ ~k}k•:..v. ~'~'v.i,tha`~.......: ..,..v A,F..~ ' ~`#.r.,x..^ cv,n}a:{ ~yY r.4, y.4 T f~`..;
~3~4oti~~~°t;, R%:,~ctY 'i; ~~5,~'+ +'Si;; M . ~~47.ir.S •..:h.,+ . :.~...~"a!. . <
' BASIN POND AREA PERI- DEPTH 1208' `208' TOTAL PEAK DW
(S.F.) METER (FT.) REQ'D. PROV. VOL. FLOW
' (L.F.) (C.F.) (C.F.) PROV. (C.F.S.)
(C.F.)
' A1 A1 300 80 .5 170 180 180 0.27 -
A2 A2 234 62 .5 138 140 140 0.54 -
, A3 A3 350 78 .7 166 204 302 0.87 -
' A - - - 474 524 622 1.58 "B"
Bl Bl 132 46 .5 81 83 83 0.43 -
~ B2 B2 144 48 .5 87 90 90 0.46 -
B3 B3 416 84 .5 237 240 240 0.74 -
' B - - - - 406 413 413 1.07 "B"
C C 360 92 .5 204 215 ' 215 0.58 "A"
' D D 230 66 .5 130 140 140 0.26 "A"
' E I E I 140 I 48 I •7 I 87 I 88 I 134 ( 0.15 I -
Notes: Typical sideslopes are 3:1 maximum. .
, Ponds A1, A2, B 1 and B2 are intermediate `208' Ponds designed to handle the upstream
impervious areas only. 1
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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~ CURB INLET AND GRATE INLET CALCULATI
ONS
' It is necessary to check the adequacy of curb inlets provided to divert the flows &om the gutter to the retention
ponds. The Curb Iniet Calculation Sheet included in this report (see calculation sheet, copy attached) shows the
' required lengths of curb openings. As shown on the calculation sheet, various ponds have different curb inlet
requirements. Therefore, the required curb openings have been provided according to the tabulated results. All
curb inlets shall be standard 4' openings, unless otherwise noted.
' It is also necessary to check the capacity of grate uilets on continuous grade. The Grate Calculation - Continuous
Grade worksheets have been included. The calculations have been completed in accordance with Fiaure 15 of
' Snokane Countv Guidelines for Stormwater Manaaement. (See calculation sheets, copy attached.)
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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~ APPENDIX
Developed condition 1-6
~ Peak Flow and Bowstring 7- 21
Curb Inlet calculations 22 -23
Soils Map 24
' Basin Map ' 25
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Inland Pacific Engineering, Inc. Riverwallc P.U.D. Sth Addition - Drainage
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°a- BOWSTRING METHOO PROJECT: Riverwalk Sih Addftion
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: A1
BASIN: A1 1QYear Desfgn Storm DESIGNER: S. Murphy
~Tot. Area 0.36 Acres DATE: 6110196
ImP• Area 4068 SF
C = 0.25
ti u,g„ vE " Time Increment (min) 5
CASE 1 Time of Conc. (min) 6.60
Outfiow (Cfs)
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70 ft. Overtand Flow &
Design Year Flow 10
Ct = 0.15 Area (acres) 0.36
Impervtous Area (sq ft) 4068
L = 70 ft. •
;C Factor 0.25
n= 0.40 208' Volume Provided 180
S= 0.020 Area C 0.090
>;,~.~•~~r
Tc = 3.58 min., by Equation 3-2 of Guidelines
Time Time Inc. Irttens. Q Devel. Vol.ln Vol.Out Storage
.z;::.,,•~,„~: ,
196 R. Gutter flow (min) (sec ) (inlhr) (cts) (cu ft) (cu ft) (cu ft)
;•x • _
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Z1 = 50.0 For 72 6.60 396 2.75 0.25 131 396 -265
22 = 3.5 Type B =1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.29 115 300 -185
.a: yz S= 0.008 ',;;~a~?•••••3: 10 600 2.24 0.20 148 600 -452
15 900 1.77 0.16 165 900 -735
d= 0.093 ft. 20 1200 1.45 0.13 174 1200 -1026
ZS 1500 1.21 0.11 178 1500 -1322
A R Q Tc Tc total 1 Qc 30 1800 1.04 0.09 181 1800 -1619
~~:th~;i 35 2100 0.91 0.08 183 2100 -1917
0.23 0.05 0.25 3.02 6.60 2.75 0.25 40 2400 0.82 0.07 187 2400 -2213
z45 2700 0 74 0.07 189 2700 -2511
Qpeak for Case 1= 0.25 cfs 50 3000 0.68 0.06 192 3000 -2808
55 3300 0.64 0.06 198 .3300 ~102
60 3600 0.61 0.05 ZOS 3600 -3395
CASE 2 65 3900 0.60 0.05 218 3900 -3682
70 4200 0.58 0.05 226 4200 -3974
Case 2 assumes a Time of Concentration less than 5 mfnutes so that the ~ u~;
75 4500 0.56 0.05 234 4500 -4266
peak flow =.90(3.18)(Imp. Area) = 0.27 cis 80 4800 0 53 0.05 235 4800 -4565
: •~~,..z..
85 5100 0.52 0.05 245 5100 -4855
. z;.
90 5400 0.50 0.05 249 5400 -5151
So, the Peak flow for the Basin (s the greater of the two flows, K??r'•: 95 5700 0.49 0.04 257 5700 5443
0.27 cfs ::Y € 100 6000 0.48 0.04 265 6000 -5735
208' DRAINAGE POND CALCULATIONS
Required'208' Storage Votume
=lmpervious Area x.5 in / 12 INft 170 cu ft
z....
208' storage volurtse Proviaed 180 cu ft
~ DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
~ .u Ma)dmum Storage Required by Bowstring -185 cu ft
Number and Type of Drywells Required 0 Single
. 1 Double
BOWSTRING METHOD PROJECT: Riverv+ratk 5tfi Add'dion
PEAK FLOW CALCULATION PROJECT Riverwalk 5th Addition DE7ENTION BAS1N DESIGN BASIN: A2
BASIN: A2 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 0.49 Acres DATE: 6/6/96
fmp. Area 3319 SF
C = 0.40
Time Increment (min) 5
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CASE 1 4; w:;~~xc Tme of Conc. (min) 6.55
z•;,~..t;rMa;
;~:iz. N~ Outilow (Cfs) 1
70 ft. Overlartd Flow :Design Year Flow 10
z Area (acr+es) 0.49
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Ct = 0.15 impervious Area (sq ft) 3319 •
L = 70 ft.
,a 'C' Factot
i°% 0.4
n= 0.40 '208' Volume Provlded 140
S= 0.020 ~Area • C 0.196
Tc = 3.58 min., bY Equation 3-2 of GuideGnes
„a
~ }~«t Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
198 ft. Gutter ftow „W:;. ~ (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
z~?1k~w
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Z1 = 50.0 ForZ2 6.55 ^393 2.76 0.54 285 393 -108
Z2 = 3.5 Type B=1.0 „4;
n = 0.016 Rolled = 3.5
~•K 5 300 3.18 0.62 251 300 -49
S = 0.005
10 600 2.24 0.44 322 600 -278
15 900 1.77 0.35 359 900 -541
d= 0.135 ft. ~~20 1200 1.45 0.28 379 1200 -821
":25 1500 1.21 0.24 387 1500 -1113
;.w•
A R Q Tc Tc total I Qc w=rz 30 1800 7,04 0,20 394 1800 -1406
= ~ • ` ;
35 2100 0.91 0.18 398 2100 -1702
0.49 0.07 0.54 2.97 6 55 2 76 0.54 ;~~~`~Z}~~ ~ 40 2400 0.82 0.16 407 2400 -1993
45 2700 0.74 0.15 411 2700 -2289
Qpeak for Case 1= 0.54 cfs
50 3000 0.68 0.13 418 3000 -2582
55 3300 0.64 0.13 431 3300 -2869
60 3600 0.61 0,12 446 3600 -3154
CASE 2 0 4200 0.58 0.11 4493 4200 -3707
Case 2 assumes a Time oi Concentration less than 5 minutes so that the 75 4500 0.56 0.11 509 4500 .3991
Peak flow =.90(3.18)(ImP• Area) 0.22 cfs
= `~z::^• <.,?v:~.
80 4800 0.53 0.10 513 4800 4287
g,,.,~:•,,:,,
85 5100 0.52 0.10 533 5100 -4567
90 5400 0.50 0.10 542 5400 -4858 ,
So, the Peak flow for the Basin is the greater of the two fiows, ;a~c"~zK"n 95 5700 0.49 0,10 560 5700 -5140
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0.54 cfs ~>100 6000 0.48 0.09 577 6000
it,~ ;;z;;izz'r•`i`.' -5473
zz~ ~ax>~x
~;•=t~~;~ ZOS' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervfous Area x.5 in / 12 iNft 138 eu ft
208' Storage Volume Provfded 140 cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
, Ma)dmum Storage Required by Bowstring -49 cu ft
Number and T of D Ils R uired
$~~yPe rywe eq 0 Single
1 Doubie
Sub BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCUTATION PROJECT Riverwalk Sth Addition ~1' DETENTION BASIN DESIGN BASIN: A3
BASIN: A3 ~ 10-Year Oesign Storm DESIGNER: S. Murphy
Tot. Area 0.78 Acres 'gK~:~ DATE: 6/6/96
Imp. Area 3994 SF
C = 0.35 yM1.zz.~~r„
Time IncremeM (min) 5
of Cona (min) 5.00
CASE 1
• ; ~Outflow (cfs) 1
70 ft. Overland Flow Design Year Flow 10
~~:'?z:iqrea (eCfes) 0.78
~ ,'~~x....
Ct = 0.15 ImpeMous Area (sq ft) 3994
L= 70 ft. 3N si;~r> 'C' Factor 0.35
n= 0.40 '208' Volurrse Provided 2a4
S= 0.020 Ar¢a ' C 0.273
Tc = 3.58 min., by EquaUon 3-2 oi Guidetines
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
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88 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu R) (cu ft)
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Z1 = 50.0 For Z2 5.00 300 3.18 0.87 349 300 49
Z2 = 3.5 Type B =1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.87 349 300 49
S= 0.005 10 600 2.24 0.61 429 600 -171
15 soo 177 0.48 asa soo -416
d= 0.161 ft. 20 1200 1.45 0.40 515 1200 -685
25 1500 1.21 0.33 529 1500 -971
A R Q Tc Tc total I Qc ;:;~30 1800 1.04 0.28 540 1800 -1260
a..
zzi.i:~:;, a~ 35 2100 0.91 0.25 547 2100 -1553
-
.w
0.69 ' 0.08 0 87 1.17 5.00 3.18 0.87 40 2400 0.82 0.72 560 2400 -1840
45 2700 0.74 0.20 566 2700 -2134
. «.:r: x..,,
S0 3000 0.68 0.19 576
Qpeak for Cese 1= 0.87 Cfs 3000 -2424
i.
55 3300 0.64 0.17 594 3300 -2706
~".~a,M1r`.60 3600 0.61 0.17 616 3600 -2984
CASE 2 ;z,"~, ~•a•~ 65 3900 0.60 0.16 656 3900 -3244
`~~~tk~ 70 4200 0.58 0.16 681 4200 ~519
Case 2 assumes a Time of ConcenUation less than 5 minutes so that the 75 4500 0.56 0.15 704 4500 -3796
peak flow =.90(3.18)(Imp. Area) = 0.26 cfs IM80 4800 0.53 0.14 709 4800 -4091
85 5100 0.52 0.14 738 5100 -4362
M~s'i 90 5400 0.50 0.14 751 5400 -4649
So, the Peak ftow for the Basin is the greater of the two flows, 95 5700 0.49 0.13 776 5700 4924
0.87 Cfs 100 6000 0.48 0.13 800 6000 a200
i; • .`'~"z.::ii~:z
208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft 166 cu ft
208' Storage Volume Provided 204 cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
Ma)dmum Storage Requlred by Bawstring 49 cu ft
~~M~~.~Ks;=: •
Number and Type oi Drywells Required 0 Single
1 Doubie
BOWSTRING METHOD PROJECT: Rivenralk Sth Addftion
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: A
BASIN: A 1QYear Design Storm DESIGNER: S. Murphy
Tot. Area 1.63 Acres DATE: 6110N96
Imp. Area 11381 SF
C = 0.40 a?.tt:~ .,.xk
Time Increment (min) 5
•~~i., ~
CASE 1 'Z~ Time of Conc. (min) 8.64
Outflow (cfs) 1
70 ft. Ovetland Flow -0; Design Year Flow 10
Area Ct = 0.15 mpervaous Area (sq ft) 11387
L= 70 ft. ~`:~.z;~. ;C Factor 0.4
n= 0.40 208' Votume Provided
S = 0.020
Area • C 0.652
Tc = 3.58 min., by Equation 3-2 of Guidelines
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
482 ft Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 Fof Z2
::~z.z~.....,..~
. 8.64 518 2.42 1.58 1096 -----518 -----578
72 = 3.5 Type B=1.0
n= 0.016 Rolied = 3.5 ~ %~;~5 300 3.18 2.07 833 300 533
S= 0.007 10 600 2.24 1.46 1134 600 534
zi~~a5tzv3'i:;~.
15 900 1.77 1.15 1242 900 342
d= 0.193 ft. '.zt~•~^:•.•,•3~ 20 1200 1.45 0.95 1301 1200 101
a ~ 25 1500 1.21 0.79 1322 1500 -178
A R Q Tc Tc total I Qc ;?'x~ 30 1800 1.04 0.68 1340 1800 -460
.';z~ 35 2100 0.91 0.59 1351 2100 -749
;
1.00 0.10 1.58 5.06 8.64 2.42 1.58 40 2400 0.82 0.53 1377 2400 -1023
45 2700 0.74 0.48 1388 2700 -1312
`Y
Qpeak for Case 1= 1.58 cfs 50 3000 0.68 0.44 1408 3000 -1592
55 3300 0.64 0.42 1451 3300 -1849
60 3600 0.61 0.40 1502 3600 -2098
CASE 2 65 3900 0.60 0.39 1595 3900 -7305
x 70 4200 0.56 0.38 1655 4200 -2545
Case 2 assumes a Tfine of Concentration less than 5 minutes so that the ~k'~~ »'~~Z; 75 4500 0.56 0.37 1707 4500 -2793
peak flaw =.90(3.18)(Imp. Area) = 0.75 cfs r ~~80 4800 0.53 0.35 1720 4800 -3080
85 5100 0.52 0.34 1789 5100 -3311
90 5400 0.50 0.33 1818 5400 3582
• "k .,t`t`~Y` k
So, the Peak Bow for the Basin is the greater of the two flows, ".95 5700 0.49 0.32 1877 5700 -3823
1.58 cis 100 6000 0.48 0.31 1933 6000 -4067
k 2Z
208' DRAINAGE POND CALCULATIONS
%
;M i Required'208' Storage Volume
Impervfous Area x.5 in / 12 INft 474 cu ft
;~1I101
.ar,,'r
208' Storage Volume Provided cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
Maximum Storage Required by Bowstring 578 cu ft
Number and Type of Drywetis Required 0 Single ,
1 DouWe
BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addftion DETENTION BASIN DESIGN BASIN: 61
BASIN: 61 10-Year Design Stortn DESIGNER: S. Murphy
Tot. Area 0.23 Acres DATE: 616196
Imp. Area 1955 SF ~
;zs:;,wN•
C = 0.60 ~.,~......e.
Time IncremeM (min) 5
r
CASE 1 E . < Time oi Conc. (min) 5.33
.;rz Outfl
•r,"zzi:: .".ow cfs 1
70 ft. Overlartd Flow r,,\,j.W?;~~x Design Year Flow 10
Area (acres) 0.23
Ct = 0.15 Impervious Area (sq ft) 1955
L= 70 ft. C Factor 0.6
n= 0.40 208' Volume Provided 83
S= 0.020 Area C 0.138
Tc = 3.58 min., by Equation 3-2 of Guidelines
~ Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
110 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
M M;~:;,~~,$
-
Z1 = 50.0 For 72 ;k kr, - 5.33 320 3.09 0.43 183 320 -137
7-2 = 3.5 Type 8 =1.0 n= 0.016 Rolled = 3.5 5 300 3.18 0.44 176 300 -124
10 600 2.24 0.31 219 600 -381
S = 0.005
~t x 15 900 1.77 0.24 246 900 ~54
d= 0.124 ft. ZO 1200 1.45 0.20 262 1200 -938
"25 1500 1.21 0.17 269 1500 -1231
..A R Q Tc Tc total I Qc ;;x~~~ x 30 1800 1.04 0.14 274 1800 -1526
. t
= ' } ? 35 2100 0.91 0.13 277 2100 -1823
.
:
0.41 0.06 0.43 1.75 5.33 3.09 0.43 :a; : 40 2400 0.82 0.11 284 2400 -2116
~ 45 2700 0.74 0.10 287 2700 -2413
Qpeak for Case 1= 0.43 cfs 50 3000 0.68 0.09 292 3000 -2708
55 3300 0.64 0.09 301 3300 -2999
Wz;
, k~,..,,,,.. .
:zr~ziz:i 60 3600 0.61 0.08 312 3600 -3288
CASE 2 4a $65 3900 0.60 0.08 332 3900 -3568
;,,vx..;a i?s 70 4200 0.58 0.08 345 4200 -3855
Case 2 assumes a Time of ConceMration less than 5 minutes so that the ~M~M" Z: 75 4500 0.56 0 08 356 4500 -4144
peak flow =.90(3.18)(Imp. Area) = 0.13 cfs ti,-z,' x:>?~>z~z' 80 4800 0.53 0.07 359 4800 4441
85 5100 0.52 0.07 374 5100 ~726
:zz:, gp 5400 0.50 0.07 380 5400 -5020
95 5700 0.49 0.07 393 5700 -5307
...;So, the Peak flow for the Basin is the greater of the two flows, %
0.43 Cfs : 100 6000 0.48 0.07 405 6000 -5595
::i::
~'''`•~C,.,~:',•.,~`
•~208' DRAINAGE POND CALCULATIONS
Required '2a8' Stotage Volume
Impervious Area x.5 in / 12 INft 81 cu ft
208' Stora9e Volume Provided 83 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Storage Required by Bowstring -124 cu ft
x~w rkz~~ . .
~.:x~~; ; Number and Type oi Drywells Required 0 Single .
1 Double
BOWSTRING METHOD PROJECT: Riverwralk Sth AddiHon
PEAK FLOW CALCULATION PROJECT Rivervralk Sth Addrtlon DETENTION BASIN DESIGN BASIN: B2
BASIN: 62 10-Year Design StoRn DESIGNER: S. Murphy
Tot. Area 0 25 Acres ~N~.,DATE: 616196
Imp. Area 2088 SF "
C = 0.60
Time Incxement (min) 5
CASE 1 Time of Conc. (min) 5.46
...Outflow (cis) 1
70 ft. Overiand Flow Desfgn Year Flow 10
:w~ar:, .•a
Area (acres) 0.25
Ct = 0.15 ImpeMous Area (sq ft) 2088
L= 70 ft. 'C Factor 0.6
n= 0.40 '208' Volume Provided 90
S= 0.020 Area' C 0.150
*'ari'~~'a ;
'
Tc = 3.58 min., bY Equation 3-2 of Guidelines
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
120 ft. Gutter flow (min) (sec) CiNhr) (cfs) (cu ft) (cu ft) (cu ft)
z;' ~`zzr;: ~~c'`
's,~::z;~~:~~
Z1 = 50.0 For72 5.46 327 3.06 0.46 201 327 -126
Z2 = 3.5 Type B=1.0 n= 0 016 Rolled = 3.5 M-k:5 300 3.18 0 48 192 300 -106
S= 0.005 10 600 2.24 0.34 239 600 -361
15 900 1.77 0.27 269 900 -631
d= 0.127 ft. Zz~ 20 1200 1.45 0.22 285 1200 -915
25 1500 1.21 0.18 292 1500 -1208
~.z:zz.z.:r~
A R Q Tc Tc total I Qc .~`:~`'.".'.'30 1800 1.04 0.16 298 1800 -1502
kuy~ ~ 35 2100 0.91 0.14 302 2100 -1798
w.
0.43 0.06 0.46 1.87 5.46 3.06 0 46 :.,2~; ~40 2400 0.82 0.12 309 2400 -2091
x~q5 2700 0.74 0.11 312 2700 -2388
Qpeak for Case 1= 0.46 cfs 50 3000 0.68 0.10 317 3000 -2683
55 3300 0.64 0.10 327 3300 -2973
60 3600 0.61 0.09 340 3600 -3260
~,•.zc~?~,~.~'.'~',
CASE 2 <<„} 65 3900 0.60 0.09 361 3900 ~539
~~,i~ µ70 4200 0.58 0.09 375 4200 -3825
Case 2 assumes a Time of ConceMration less than 5 minutes so that the 75 4500 0.56 0.08 387 4500 -4113
peak flow =.90(3.18)(Imp. Area) = 0.14 cfs , i~ 80 4800 0.53 • 008 390 4800 -4410
85 5100 0.52 0.08 406 5100 -4694
`::zi. 90 5400 0.50 0.08 413 5400 -4987
So, the Peak flow for the Basin is the greater of Me Mro flows, 95 5700 0.49 0.07 427 5700 -5273
0.46 cfs 100 6000 0.48 0.07 440 6000 -5560
'w~?~?~"`' 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft 87 cu ft
208' Storage Volume Provided 90 cu ft
~k,
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
~z;.s;;^;z ,
~::z:i,~g,r?a~; Ma)dmum Storage Required by Bowstring -108 cu ft
~
Number and Type of Drywells Required 0 Singte
1 Double
~BOWSTRING METHOD PROJECT: Rivetwalk Sth Addftion
PEAK FLOW CALCULATION PROJECT Riverrvalk Sth Addftion ~.•3~~"w~r DETENTION BASIN DESIGN BASIN: B3
BASIN: 63 10-Year Deslgn Stortn DESIGNER: S. Murphy
Tot. Area 0.65 Acres DATE: 616196
•z,tz
Imp. Area 5699 SF wh}~~ „~„;kµ
C = 0.40
Time Inaement (min) 5
'z•n:a.::.z~'~.;'~
CASE 1 ~t~~~~~'~•~~2~ Time of Conc. (min) 6.15
:z4i: wtx
~~ffi~zz Outftow (CfS) 1
70 ft. Overland Flow v?,Design Year Flow 10
k A~a (BLr~. ) 0.65
.2.. Y`..v..`x.
Ct = 0.15 ~z;.y Impervfous Area (sq ft) 5699
L= 70 ft. 'C Factor 0.4
n= 0.40 a '208' Volume Provided 240
< ~z"k* S= 0.020 Area C 0.260
Tc = 3.58 min., by Equation 3-2 oi Guidelines
Time Time Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
185 ft. Gutter flow (min) (sec) (tNhr) (cfs) (cu ft) (cu ft) (cu ft)
:~~~"::z~--------
,,,,,..,~.,ry.
21 = 50.0 For Z2 6.15 369 2.86 0.74 367 369 -2
7-2 = 3.5 Type B= 1.0 i i';; iz :;;;w
n= 0.016 Roiled = 3.5 x~:~~~r~ 5 300 3.18 0 83 332 300 32
NIµiw
S= 0.005 10 600 2.24 0.58 422 600 -178
`~r".'"z~ %j: 15 900 1.77 0.46 472 900 -428
d= 0.152 ft. 20 1200 1.45 0.38 500 1200 •700
ii•o';%~zaru
~25 1500 1.21 0.31 511 1500 -989
' A R Q Tc Tc total I Qc 30 1800 1.04 0.27 521 1800 -1279
`:c:::~:~=::-~•; 35 2100 0.91 0.24 527 2100 -1573
0.62 0.08 0.74 2.56 6.15 2.86 0.74k 40 2400 0.82 0.21 538 2400 -1862
45 2700 0.74 0.19 544 2700 -2156
Qpeak for Case 1= 0.74 cfs tz i; :z~~.;;z~•~ 50 3000 0.68 0.18 553 3000 -2447
55 3300 0.64 0.17 570 3300 -2730
Fkk
60 3600 0.61 0.16 591 3600 -3009
CASE 2 65 3900 0.60 0.16 628 3900 -3272
70 4200 0.58 0.15 652 4200 -3548
Case 2 assumes a Time of ConceMratlon less than 5 minutes so that the 75 4500 0.56 0.15 673 4500 -3827
80 4800 0.53 0.14 679 4800 -4121
peak flow =.90(3.18)(Imp. Area) = 0.37 cfs .
85 5100 0.52 0.14 706 5100 -4394
90 5400 0 50 0.13 718 5400 -4682
So, the Peak 8ow for the Basin is the greater of the tvw ftows, ~ z4z,~i 95 5700 0.49 0.13 742 5700 -4958
0.74 cfs Zk.... 100 6000 0.48 0.12 764 6000 -5236
r~„n~;;.;~~
k zi-,' 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 INft 237 cu ft
a a?~
208' Storage Volume Provided 240 cu ft
2'`` 2':2S DRYWELL REQUIREMENTS-10YEAR DESIGN STOR
`ra;` ri.42`
Ma)dmum Storage Required by Bowstring 32 cu ft
Number and Type of Drywells Required 0 Single
»1 Double
;xt."...r.....>
~ ~ ~i ~ ~ ~ ~ ~ ~ii--- w ~ ~ ~ ~ ~ ~ ~ ~ ~ ~;:,~t~' BOWSTRING METHOD PRQIECT: Rivervvalk Sth AddiUon
;r...:~Wli PEAK FLOW CALCULATION PROJECT: Riverwalk 5th Addition Z~DETEIVTION BASIN DESIGN BASIN: B
BASIN• B ~ 10-Year Design Storm DESIGNER: S. Murohy
ToL Area 1.13 Acres „~.M,x;aDATE: 616/96
Imp. Area 9742 SF
C = 0.40
Time IncremeM (min) 5
CASE 1 `;wTime of Cone. (min) 8.~
Outflow (cfs) 1
~ 70 ft. Overland Flow 2..~,kk:z<z k:. Design Year Flow 10
.':x:z:.~t ` Area (atres) 1.13
Ct = 0.15 z~z.~=~x: Impervious Area (sq ft) 9742
L= 70 R ; 'C Factor 0.4
n = 0.40 '208' Volume Provided
S. 0.020 ~~Area' C 0.452
x:kz
z
Tc = 3.58 min., by Equatlon 3-2 0! Guidelines
;a~ y~; Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
415 R GuCer flow :~;~:~^t'~' " (min) (sec) (NhO (cfs) (cu ft) (cu ft) (cu ft)
c_aa~a1.07
21 - 50.0 FOi Z2 8.99 540 2.37 775 540 235
72 e 3.5 Type B= 1.0 % n~ 0.016 Rolled = 3.5 5 300 3.18 1.44 578 300 278
a
S. 0.005 10 600 2.24 1.01 793 600 193
z,xu~z•~a~ zi~ 15 900 1.77 0.80 867 900 -33
d= 0.167 ft. Vz.",ez~~'z~i~ : 20 1200 1.45 0.66 907 1200 -293
V25 1500 1.21 0.55 921 1500 -579
t.~z?:<'% ~
A R Q Tc Tc total I Qc ~$N~ 30 1800 1.04 0.47 932 1800 ~68
- 35 2100 0.91 0.41 939 2100 -1161
0.74 0.08 0.95 5.41 8.99 2.37 1.07 U, 40 2400 0.82 0.37 958 2400 -1442
~ti~~?w 45 2700 0.74 0.33 964 2700 -1736
Qpeak for Case 1 1.07 cfs f~~~• , 50 3000 0.68 0.31 978 3000 -2022
o z.~=::
~~~~M55 3300 0.64 029 1006 3300 -2292
r, w~,~` 60 3600 0.61 028 1043 3600 -2557
~r„t~.,t 65 3900 0.60 027 1107 3900 -2793
CASE 2 z ;'r^c;,~ ~ti~•.,.`~".~a:
70 4200 0.58 0.26 1149 4200 -1051
75 4500 0.56 0.25 1185 4500 ~315
Case 2 essumes a Time of Coneentratlon less than 5 minutes so tfiat the
peakflOw=.90(3.18)Qmp.Af08)~ 0.64 CfS ,:z•,~ ~.,'~••••~;.80 4800 0.53 024 1194 4800 -3606
.zr85 5100 0.52 0.24 1242 5100 -3858
1 k -gp 5400 0.50 0.23 1262 5400 -4138
~
95 5700 0.49 022 1303 5700 4397
So, the Peak flow fw ft Basin ts the greater oi the two ftows,
1.07 cfs k2 ~`zr"~; 100 6000 0.48 0.22 1342 6000 -4658
~
:ki:i.i^:`•::^aict
i208' DRAINAGE POND CALCULATIONS
~xx~z~:zhi Required'208' Sborage Volume
i;a~'.~'z;~;;,` = Impervfous Area x.5 in / 12 iNR 406 cu ft
nm208' Storage Votume Provlded eu ft
tx :xa
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
~=n~n;, Maxlmum Storage Requlred by Bowstring 278 cu ft
Number and Type af Drywells Required 0 Single
1 Double
~
~ ~ ~ ~ ~ ~ ~ ~ A ~ ~ ~ ~■~1 ~ ~ ~ ~ ~ ~ ~
BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT Rivervralk 5th Addition DETENTION BASIN DESIGN BASIN: C
BASIN: C 10-Year Design Stortn DESIGNER: B. Howard
~~•~x;~,%ii~ DATE: 616/96
Tot. Area 0.36 Acres
: ,
Imp. Area 4884 SF
C = 0.60
Time IncremeM (min) 5
CASE 1_ "-z~,;~~ o~~ tConc. (min) 6.89
0.3
100 ft. OveAand Flow Design Year Flow 10
Area (acres) 0.36
Ct = 0.15 Impervious Area (sq ft) 4884
.C' Factor
L = 100 ft. ;.;~.:%z.~ 0.6
n= 0 40 :'208' Volume Provided 215
S= 0.020 Area ' C 0216
Tc = 4.44 min., bY Equation 3-2 of Guidelines Y.
Time Time inc. Intens. Q Devef. Vol.ln Vol.Out Storage
) (sec ~ ) Nhr) (cfs) (cu ft) (cu ft) (cu ft)
x ` ~mfn
196 ft. Gutter flow ~
~~zzr:~:~~~~
"r 6.89 414 2.70 0.58 323 124 199
Z1 = 50.0 Fof Z2 2 x
Z2= 3.5 Type8=1.0 ;
n= 0.016 Rolled = 3.5 ; z rz :~w>r;~~ 5 300 3.18 0.69 276 90 186
S= 0.008 10 600 2.24 0.48 358 1 8 0 178
M;;~;;~2 ~ 15 soo 1.77 0.38 398 270 12s
d= 0.128 ft. ZO 1200 1.45 0.31 420 360 60
25 1500 1.21 0.26 429 450 -21
A R Q Tc Tc total I Qc 30 1800 1•04 0•22 436 540 "104
35 2100 0.91 0.20 440 630 -190
0.44 0 06 0.58 2.46 6 89 2.70 0.58 40 2400 0.82 0.18 450 720 -270
45 2700 0.74 0.16 454 810 -356
Qpeak for Case 1 0.58 cfs 50 3000 0.68 0.15 461 900 -439
55 3300 0.64 0.14 476 990 -514
60 3600 0.61 0.13 493 1080 -587
CASE 2 65 3900 0.60 0.13 524 1170 -G16
70 4200 0.58 0.13 544 1260 -716
~
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.12 561 1350 -789
peak flow =.90(3.18)(Imp. Area) = 0.32 cfs 80 4800 0.53 0.11 566 1440 -874
85 5100 0.52 0.11 589 1530 -941
i'',x',x,,,,z~`.z: z"a
90 5400 0.50 0.11 598 1620 -1072
z~:: 95 5700 0.49 0.11 618 1710 -1092
So, the Peak flow for the Basin is the greater of the two flows,
0.58 cfs 100 6000 0.48 0.10 637 1800 -1163
? zc 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft 204 cu ft
ZOS' Storage Volume Provided 215 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
Ma)dmum Storage Required by Bovvstring 199 cu ft
Number and Type of Drywells Required 1 Single
N, ~ 0 Double
BOWSTRING METHOD PROJECT: Rivervvalk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Additlon DETENTION BASIN DESIGN BASIN: D
BASIN: D ~"~,`H..., 10-Year Design Storm DESIGNER: B. Howard
Tot. Area 0.21 Acres ` DATE: 6l10r96
Imp. Area 3125 SF
C = 0.40
Time Increment (min) 5
CASE 1
Time of Cortc. (min) 5.18
Outflow (cfs) 0.3
70 ft. Overlartd Flow Design Year Flow 10
~zi: ; ~~~;',Area (acres) 0.21
; ~zz,ta
Ct = 0.15 "~x;Impervious Area (sq ft) 3125
L= 70 ft. 'C' Factor 0.4
~.n= 0.40 '208' Volume Provided 140
S= 0.020 ~z ,..;..:r::: Area " C 0.084
~z
Tc = 3.58 min., by Equation 3-2 of Guidelines
Tme Time Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
135 ft. Gutter 8ow (min) (sec) (inRir) (cfs) (cu ft) (cu ft) (cu ft)
:z
;
:M. i.~.:...
Z1 = 50.0 For 72 .z 5.18 311 3.13 0.26 110 93 16
7-2 = 3.5 Type B= 1.0 ;,,,.,:iz;i. .
~;?zz;: ,zii,z•i°i
n= 0.016 Rolled = 3.5 5 300 3.18 0.27 107 90 17
S= 0.016 10 600 2.24 0.19 133 180 -47
?,::~z
:~i: "ia~`K.~,"" 15 900 177 0.15 150 270 -120
d= 0.083 ft. 20 1200 1.45 0.12 159 360 -201
u~;.. •
25 1500 1.21 0.10 163 450 -287
A R Q Tc Tc total I Qc 30 1800 1.04 0.09 166 540 -374
35 2100 0.91 0.08 169 630 1361
0.18 0.04 0.26 1.60 5.18 3.13 0.26 40 2400 0.82 0.07 173 720 -547
45 2700 0.74 0.06 174 810 -636
Qpeak for Case 1= 0.26 cfs 50 3000 0.68 0.06 177 900 -723
55 3300 0.64 0.05 183 990 -807
60 3600 0.61 0.05 190 1080 -090
<:z~
CASE 2 65 3900 0.60 0.05 202 1170 -968
~
70 4200 0.58 0.05 210 1260 -1050
Case 2 assumes a Time oi Concentration less than 5 minutes so that the 75 4500 0.56 0.05 217 1350 -1133
zc......:::..::....
peak flow =.90(3.18)(Imp. Area) = 0.21 cis ~~~~zx;':;;;z•;w 80 4800 0.53 0.04 218 1440 -1222
85 5100 0.52 0.04 227 1530 -1303
gp 5400 0.50 0.04 231 1620 -1389
So, the Peak flow for the Basin is the greater oi the two 8ows, 95 5700 0.49 0.04 239 1710 -1471
0.26 cfs 100 6000 0.48 0.04 246 1800 -1554
h....} .
208' ORAINAGE POND CALCULATIONS
~~•Requfred'208' Storage Volume
Impervious Area x.5 in / 12 iNft 130 cu ft
208' Storage Volume Provided 140 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
~ •;z~,sw;i^
Naximum Storage Required by Bowstring 17 cu ft
i•ix:i:;.zs•••••
Number and Type of Orywells Required 1 Single ,
0 Double
BOWSTRING METHOD PROJECT: Riverwalk 5th Add'Rlon
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Adddion DETENTION BASIN DESIGN BASIN: E
BASIN: E 10-Year Design Stortn DESIGNER: B. Hovrard
Tot. Area 0.12 DATE: 616196
Imp. Area 2090 SF
C = 0.40 r , ` . a~zwi
v,,,,:: ~ Time Increment (min) 5
Time of Conc. (min) 5.00
~
CASE 1
„m~-` Out(low (cfs) 0
60 ft. Overtand Flow Design Year Flaw 10
Area (acres) 0.12
Ct = 0.15 Impervious Area (sq ft) 2090
L= 60ft. „~:::„;-~~M ;z~'CFactor 0.4
n= 0.40 ~~:-~~;'208' Volume Provided 88
w•x:
S= 0.020 Area . C 0.048
K~.~•.,,..,r.
~ ~ zzic~x:
Tc = 3.27 min., by Equation 3-2 of Guidelines
Time Time Inc. IMens. Q Devel. Vol.ln Vol.Out Starage
mfn sec iNhr cfs cu ft cu ft) (cu ft
100 ft. Gutter flrnnr ( ) ( ) ~ ) ~ ) ( ) ( )
Z1 = 50.0 For Z2 :.,`'Y'`M'."•:~:'"'`~ ~ 5.00 300 3.18 0.15 61 0 61
Z2 = 3.5 Type B=1.0
n= 0.016 Rolled = 3.5 • 5 300 3.18 0.15 61 0 61
S= 0.016 10 600 2.24 0.11 75 0 75
15 soo 1.77 0.08 as o as
d= 0.068 ft. ~~~`:.::~20 1200 1.45 0.07 91 0 91
MW"~'25 1500 1.21 0.06 93 0 93
A R Q Tc Tc total I Qc ~I{z' 30 1800 1.04 0.05 95 0 95
~`jk`:2:.~i2A.r2
35 2100 0.91 0.04 ~ 0 96
0.12 0.03 0.15 1.35 5.00 3.18 0.15 ~~F0 J.' 40 2400 0.82 0.04 98 0 98
45 2700 0.74 0.04 100 0 100
Q peak for Case 1= 0.15 cfs 50 3000 0.68 0.03 101 0 101
55 3300 0.64 0.03 105 0 105
60 3600 0.61 0.03 108 0 108
CASE 2 65 3900 0.60 0.03 115 0 115
70 4200 0.58 0.03 120 0 120
Case 2 assumes a Time oi Concentration less than 5 minutes so that the 75 4500 0.56 0.03 124 0 124
peak flow =.90(3.18)(Imp. Area) = 0.14 cfs gv;~;„ << 80 4800 0.53 0.03 125 0 125
";'Z' ;.85 5100 0.52 0.02 130 0 130
90 5400 0.50 0.02 132 0 132
So, the Peak tlow for the Basin is the 9reater of the two flows, 95 5700 0.49 0.02 136 0 136
0.15 cfs 100 6000 0.48 0.02 141 0 141
' w.:
~ ~ 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
M, = Impervious Area x.5 tn / 12 INft 87 cu ft
208' Storage Volume Provided 88 cu ft
%::::::;:za;~ x~ DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
~.?z~.a;
w"Maximum Storage Required by Bowstring 130 cu ft
:~i;a*M
x Number and TYPe of DMMeIis Re9uired 0 Sin9le
r.::i:zx~ .
„n^~ , } ERR Double
BOWSTRING METHOD PROJECT: Riverwalk 5th AddiNon
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth Addition -40"• DETENTION BASIN DESIGN BASIN: Pre-dev F
BASIN: Pre-dev F 10-Year Design Stortn DESIGNER: B. Hovrard
WN DATE: 6096
Tot. Area 1.98 Acres
Imp. Area 0 SF =
C = 0.30
vr~r`~•.; Time Increment (min) 5
CASE 1 Time of Conc. (min) 5.00
~g;<~:•~ `~z`'` Outflow (CfS) 1
150 ft. Overland Flaw Des(gn Year Flow 10
~klArea (acres) 1.98
Ct = 0.15 Impervious Area (sq ft) 0
~~..a• i: ; 0 3
L = 150 ft. 'C' Factor
n = 0.40 '208' Volume Provided
S= 0.040 0.594
Tc = 4.60 min., by Equation 3-2 of Guidelines
Time Time Inc. IMens Q Devel. Vol.in Vol.Out Storage
..,,...;.:;;x.
0 ft. Gutter flow % (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft)
}x .
5.00 300 3.18 1.89 759 300 459
Z1 = 50.0 For 7-2
7-2 = 3.5 Type B= 1.0
S 300 3.18 1.89 759 300 459
n= 0.016 Rolled = 3.5
S = 0.005 10 600 2.24 1.33 934 600 334
15 soo 1.77 1.05 1053 soo 153
d= 0.206 ft. 20 1200 1.45 0.86 1121 1200 -79
25 1500 1.21 0.72 1151 1500 -349
A R Q Tc Tc total I Qc 30 1800 1.04 0.62 1175 1800 -625
35 2100 0.91 0.54 1190 2100 -910
.m « .1.14 0.10 1.64 0.00 5.00 3.18 1.89 40 2400 0.82 0.49 1219 2400 -1181
%
,~'z~.•'}"='r„`. z"; 45 2700 0.74 0.44 1232 2700 -1468
xtzzw:x.
.
Qpeak for Case 1 1.89 cfs 50 3000 0.68 0 40 1253 3000 -1747
;i,,,.~ii:
z;; 55 3300 0.64 0.38 1293 3300 -2007
60 3600 0.61 0.36 1341 3600 -2259
CASE 2 65 3900 0.60 0.36 1426 3900 -2474
70 4200 0.58 0.34 1482 4200 -2718
Case 2 assumes a Time oi Concentration less than 5 minutes so that the 75 4500 0.56 0.33 1531 4500 -2969
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0 53 0.31 1543 4800 -3257
85 5100 0.52 0.31 1607 5100 -3493
90 5400 0.50 0.30 1634 5400 -3766
So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.29 1689 5700 -4011
1.89 cfs 100 6000 0.48 0.29 1740 6000 4260
z¢z. ` %
~ .,...t :
~2 ~„z•~~"~ 208' DRAINAGE POND CALCULATIONS
Required'2a8' Storage Vofume
z~ = Impervious Area x.5 fn / 12 iNft 0 cu ft
r'at::z,; ;z~„
zzizx
ZW Storage Votume Provfded cu ft
~`•i;;...,.•,az. .
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
r,,~r~~~ Maximum Storage Requfred by Bowstring 459 cu ft
Number and Type of Drywells Required 0 Single ,
1 Double
~BOWSTRINGMETHOD PROJECT: RlvervralkSthAdd~ion
st:i,
PEAK FLOW CALCULATION PROJECT Rivervvaik 5th Addftion DETENTION BASIN DESIGN BASIN: Developed F
BASIN: Developed F 10-Year Desi9n Storm DESIGNER: B. Hovrard
~
Tot. Area 1.98 Acres 0 ,a.~~-~ DATE: 6/6/96
Imp. Area 0 SF
C = 0.26
Time IncremeM (min) 5
CASE 1 Time of Conc. (min) 5.00
Outflow (cfs) 1
p n Year Flow 10
150 ft. Overland Flow ~9
'z Area (acres) 1.98
Ct = 0.15 Impervious Area (sq ft) 0
r•~.:~.~
L= 150 ft. 'C Factor 0.26
n= 0.40 208' Volume Provided 0
S= 0.040 Area • C 0.515
;3;K'" • ry:r~; :z. ~"~az
Tc = 4.60 min., by Equation 32 of Guidelirtes Time Time Inc. Intens. Q Devel. Vol.ln Vof.Out Storage
,z~:;w:z. • • ~
0 ft. Gutter flow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft)
:zr~;3:z-a:.
r
Z1 = 50.0 For 72 5.00 300 3.18 1.64 658 300 358
Z2 = 3.5 Type B =1.0
n= 0.016 Rolled = 3.5 ;~~„~r~z 5 300 3.18 1.64 658 300 358
S= 0.005 ?i~z:10 600 2.24 1.15 810 600 210
15 900 1.77 0.91 913 900 13
d= 0.206 ft. 20 1 200 1.45 0.75 972 1200 -228
25 1500 1.21 0.62 998 1500 -502
a 30 1800 1.04 0.54 1018 1840 -782
A R Q Tc Tc tatal I Qc
"i~i: <r.
35 2100 0.91 0.47 1032 2100 -1068
- _ - ` `
1.14 0.10 1.64 0.00 5.00 3.18 1.64 40 2400 0.82 0.42 1056 2400 -1344
45 2700 0.74 0.38 1067 2700 -1633
;~;.;:z„:d:{i:• 50 3000 0.68 0.35 1086 3000 -1914
Qpeak for Case 1= 1.64 cfs
55 3300 0.64 0.33 1121 3300 -2179
60 3600 0 61 0.31 1163 3600 -2437
CASE 2 65 3900 0.60 • 0.31 1236 3900 -2664
Tra,;• 70 4200 0.58 . 0.30 1285 4200 -2915
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.29 1327 4500 -3173
peak (low =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.27 1337 4800 -3463
'n"Izi..a 85 5100 0.52 0.27 1393 5100 -3707
90 5400 0.50 0.26 1416 5400 -3984
~ •`~N~ :.`So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.25 1464 5700 -4236
1.64 cis in,.~ ~~z ? 100 6000 0.48 0.25 1508 6000 -4492
~ ii
,r rz;zz~.:a
208' DRAINAGE POND CALCULATIONS
Required'208' Stora9e Volume
Impervious Area x 5 in / 12 iNft 0 cu ft•
izi;i~.?:~ 2Q8' Storage Volume Provided 0 cu ft
;i;;,..
~~;a:a
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
Maximum Storage Required by BauvsMng 358 cu ft
Number and Type of Drywells Required 0 Single
1 Double
r BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk Sth AddiUon DETENTION BASIN DESIGN BASIN: Pre-dev G
BASIN: Pre-dev G 10-Year Deslgn Storm DESIGNER: B. Howard
Tot. Area 1.40 Ac:res DATE: 616196
Imp. Area 0 SF
C = 0.30
Time Increment (min) 5
CASE 1 Time of Conc. (min) 5.00
Outflow (cfs) 1
~110 R. Overfand Flow ~.x Design Year Flow 10
;i ~A Area (acres) 1.4
Ct = 0.15 Impervious Area (sq ft) 0
L = 110 ft. 'C Fador 0.3
n= 0.40 z~.r M. Volume Provided
Area C 0.420
•
S = 0.040 t~
Tc = 3.82 min., by Equation 3-2 of Guidelines
Time Time tnc. Intens. Q Devel. Vo1.ln Vol.Out Storage
0 ft. Gutter 8ow (min) (sec) (in/hr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For Z2 5.00 300 3.18 1.34 537 300 237
Z2 = 3.5 Type B= 1.0 ` a.,,.••.,x
n= 0.016 Rolled = 3.5 5 300 3.18 1.34 537 300 237
~"`'"i:.~~~• ~
$ = 0.005 10 600 2.24 0.94 660 600 60
15 900 177 0.74 745 900 -155
20 1200 1.45 0.61 793 1200 -407
d = 0.191 ft.
25 1500 1.21 0.51 814 1500 -686
A R Q Tc Tc total I Qc 30 1800 1.04 0.44 831 1800 -969
35 2100 0.91 0.38 842 2100 -1258
- ~ z
0.98 0.10 1.34 0.00 5.00 3.18 1.34 40 2400 0.82 0.34 862 2400 -1538
45 2700 0.74 0.31 871 2700 -1829
Qpeak for Case 1= 1.34 cfs r~i 50 3000 0.68 0.29 886 3000 -2114
55 3300 0.64 0.27 914 3300 -2386
~ 60 3600 0 61 0.26 948 3600 -2652
CASE 2 65 3900 0.60 0.25 1009 3900 -2891
70 4200 0.58 0.24 1048 4200 -3152
75 4500 0.56 0.24 1082 4500 -3418
Case 2 assumes a Time oi Concentration less than 5 mtnutes so that the
peak flow =.90(3.1 S)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.22 1091 4800 -3709
85 5100 0.52 0.22 1136 5100 -3964
90 5400 0.50 0.21 1155 5400 -4245
So, the Peak Row for the Basin is the 9reater of the two flows, 95 5700 0.49 0.21 1194 5700 -4506
• ~:~zz::r„zz::c
1.34 Cfs 100 6000 0.48 0.20 1230 6000 -4770
208' DRAINAGE POND CALCULATIONS
Required 208' Storage Volume
Impervious Area x.5 in / 12 iNft 0 cu ft
:
208' Storage Volume Provided cu R
ii:~:i`:~
' ; DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
Maximum Storage Required by BawsMng 237 cu ft
Number and Type of Drywells Requfred 0 Single
1 Double
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ r ~ ~ ~ ~ ~ ~
BOWSTRING METHOD PROJECT: Rivervralk Sth AddiUon
PEAK FLOW CALCULATION PROJECT Rivervralk 5th Addftion z~~DETENTION BASIN DESIGN BASIN: Developed G
BASIN: Develoa~ G 10-Year Desisn Storm DESIGNER: B. Howard
Tot. Area 1.40 Acres DATE: 616/96
Imp. Area 0 SF
C= 0.15
Time IncremeM (min) 5
Time of Conc. (min) 5.00
CASE 1^ Outfiow (cfs) 1
110 ft. OveAand Flow ' *"Design Year Flow 10
2h"~x`:zw~,~ Area (acres) 1.4
x<i;:i : i
Ct = 0.15 Impervious Area (sq ft) 0
L= 110 ft. 'C Factor 0.15
Volume Provided 0
n= 0/~.4,~YV 0/~ , rt 44~'208' Area • C
tk4 ~ Q.2~~
S ~ ~.V 4,:.`.
`Y~,~b:..
,
,
Tc = 3.82 min., by Equation 3-2 of Guidelines
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
~~;z,;:.k...: •z
0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
~:e'
Z1 = 50.0 For 7-2 5.00 300 3.18 0.67 268 300 -32
72 = 3.5 Type B= 1.0
r'~•r.~~~;; ;:`sh
n = 0.016 Rolled 3.5 5 300 3.18 0.67 268 300 -32
S= 0.005 10 600 2.24 0.47 330 600 -270
' 4.
;.15 300 1.77 0.37 372 900 -528
d= 0.147 ft. 20 1200 1.45 0.30 396 1200 -804
>~c ~25 1500 1.21 0.25 407 1500 -1093
A R Q Tc Tc total I Qc 30 1800 1.04 0.22 415 1800 -1385
- "~~35 2100 0.91 0.19 421 2100 -1679
- •,;,.~~~;.~`:i:,`~.
0.58 0.07 0.67 0.00 5.00 3.18 0.67-x~ 40 2400 0.82 017 431 2400 -1969
46 2700 0 74 0.16 435 2700
50 3000 0.68 0.14 443 3000 -2557
Qpeak for Cese 1 0.67 cfs -2265
55 3300 0.64 0.13 457 3300 -2843
60 3600 0.61 0.13 474 3600 ~126
CASE 2 65 3900 0.60 0.13 504 3900 ~
70 4200 0.58 0.12 524 4200 -3676
Case 2 assumes a Time of ConceMration less tthan 5 minutes so that the 75 4500 0.56 0.12 541 4500 -3959
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.11 546 4800 -4254
~$'"85 5100 0.52 0.11 568 5100 -4532
90 5400 0 50 0.11 578 5400 -4872
So, the Peak fiow for the Basin is the greater of the two flows, 95 5700 0.49 0.10 597 5700 -5103
0.67 c(s '%100 6000 0.48 0.10 615 6000 -5385
x4~~~L
208' ORAINAGE POND CALCULATIONS
Requlred'208' Storage Volume
ImPervious Area x.5 in /12 iNft 0 cu ft
208' Storage Volume Provlded 0 cu ft
,
DRYWELL REQUIREMENTS -10 YEAR DESIGN STOR
Ma)dmum Storage Required by Bowstring -32 cu ft
Number and Type of Drywells Required 0 Single
~ 1 Double
,
' .
~
~
~
CURB INLET CALCULATIONS
,
1
1
1
1 ~
1 ,
1 1
1 _ .
1 .
1
1
1
~ r ~ - i~ w■■~ i r■■r r~■~ ~ ~ ~ ~ ~ ~w ~ ~ ~ ~
208' pand Calcula#ians
Froject: RivervvaEk 5th Additivn
Date. 01-Apr-96
Designer: S. Murphy
Upstream Carryover Accumul. Pond '208'
'209 Curh Inlet Imper. Storage Storage Storage Typel Starage Carryover .
Sub-Basin Statian R!L Area ReReq't Req't aize Provided Downstream
A1 43f73 R 4068 169.5 163.5 1 Qx3O 150,0
A2 41 +72 R 3319 138.3 138.3 13x18 140.3
A3 40+85 R 3994 166.4 166.4 1425 204.3
B 1 43+88 R 1955 81.5 81.5 11x12 83.3
B2 42+70 L 2088 87.0 87.0 12x12 90.0
133 40+85 L 5699 237.5 237.5 16x28 240.0
CURB INLET CALCULATIONS
Curb Inlet Depression = 2 in.
Standard Curb Inlet Length = 4 ft.
Upstream 10-Yr. Gutter Roughnes Reciprocal Depth Length
Basin or Curb Inlet Impervious Peak Flow Slope Coeff. Cross slope of Flow Required
Sub-Basin Station R/L Area c.f.s. S n Z ZJn d* Qa/La"" QI(Qa/La) Remarics
A1 43+73 R 4068 0.27 0.0090 0.0160 50 3125 0.09 0.062 4.35 Need - 1 4' Inlet
A2 41+72 R 3319 0.54 0.0052 0.0160 50 3125 0.13 0.089 6.05 Need - 1 4' Inlet
A3 40+85 R 3994 0.87 Sump Condition
61 43+88 R 1955 0.43 0.0052 0.0160 50 3125 0.12 0.082 5.25 Need - 1 5' Inlet
62 42+70 L 2088 0.46 0.0052 0.0160 50 3125 0.12 0.084 5.47 Need - 1 5' Inlet
63 40+85 L 5699 0.74 Sump Condition
C 44+48 R 4884 0.58 Sump Condition
D 20+42 L 3125 0.24 0.0160 0.0160 50 3125 0.08 0.055 4.73 Need - 1 4' Inlet
E 20+05 R 2090 0.15 0.0160 0.0160 50 3125 0.07 0.083 1.81 Need - 1 4' Inlet
* Calculated per Figure 18 of Guidelines
Calculated per Figure 16 of Guidelines '
A 4 foot curb drop with,a 6" gutter has a capacity of 4.0 cfs in sump condition
~ .
a
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~ GOUNTY, WASHI
NGTC?h! _ SHEET IVUMBER 67
R 44 E ~ R 45 E
(Jvrns sheet 58)
67
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7
' INLAND PACIFIC ENGINEERING, INC.
'
'
'
1
~
~
~
'
tLL V,~1
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w cn j
I ' STORM DRAINAGE ANA Z~q W
Z,,,,
RECE1VED for °w'
'
az v O
MAY 14 1996 ¢ o(r o
, SPOKANE COUNTY ENGINE~VERWALK LL Z O~~ _
5TH ADDITION° a a ~ ~
' tn Q. cn .
~
, April 11, 1996
,
1
,
Preoared Bv:
' Inland Paci ic Engineerin
f g
707 West 7* Suite 200
' Spokane, WA 99204
(509)-458-6840
1
'
1
' ~that the requirements noted above are the minimum requirements necessary to pecform a cursory review oF the project
. jthat additional inforqiation should be included with this submittal as necessary.
frstand that this submittal will be checked for completeness prior to review, and that it will be returned for further information
.
is found to be incomplete. ~`U~~~ C~,
6-~►
. understand that this submittal will not be accepted foc review (and placed on the review (tst) until all required information has
been submitted. Form completed by the respon4ble Engineer: T~ ~ ~U-M rPL15
Company: ~ ~11~3~~ ~~GIFIC. ~~-Ll1.~C~'~11.~~ •
Address: UC- . ScuT157 2-410 C-PC19MJ5, aCI 2.014
Zip code
Date: 4 FQR SPOKANE COUNTY USE OIYLY
SUBMITTAL: Accepted for review.
X Recurned for submittal of the following:
GENERAL iTEM f{ :
S
'ROJECT DESIGN ff : _ c
RESUBMITTAL ITEM /t: ' -
Form returaed ro: 7000~''~`",~°~
Company:
Address:
Date:
By; Spokane County Pclblic Works Development Services
,
Uckp1atv1.01May95 2 , •
SPOKANE COUNTY INTERIM ROAD & DRAYNAGE
r SUBMITTAL CHECKLXST
.
PROJECT N `1 'rJSS I DATE: I-o
t
PROIECT NAME: 'RtvEIW"K 51U AbDl TIOIL)
PROJfiCT SPONSOR: DEA"- TF! N
PROlECT ENGINEER: ItortA w14LPpLE TELY 45S"~
(Road & Drainage Plans) 'T~ A,~- M~ S 1~ '~~j4 ~
PROJECT SURVEYOR: TF1
~ ~ O
(Plat)
PLEASE PROVIDE A RESPONSE TO EACH OF THE FOLLOWIIVG ITEMS.
GENERAL ITEMS
vaUrvo11NIA❑ l. A signed "AGREEi41EiVT TO PAY FEES" form has been submitted to Spokane County along with any
applicable plat fees, prior to any pre-design/presubmittal meeting
vaUr~oOnrA❑ 2. I have a copy of, and have ceviewed the taost recent conditions of approval and any E[S/MDNS requirements
and conditions of approval have been incocporated in this plan submittal.
S PROJECT DESIGN
Yauno11r+rA❑ 1. I have completed a minimum of one Pre-design meeting with Spokane County Development Engineering
Services Engineers where agreement was reached on drainage design approach.
v.12HoOruA13 2. I have included the results of any geotechnica( testing that is required by the design approach to verify design
parameters.
Ya19r+oOn,A❑ 3. I have included any required pavemant design calculations on new Public roadways as required by the
"SPOKANE CO[JIVTY STANDARDS FOR ROAD AND SEWER CONSTRUCT'ION", latest edition.
,r.QN,13ru,❑ 4. The ro 1d and drainage plans comply with the"STANDARD ROAD PLAN" requirements for plan, profile, and
typical cross section elements conwined in"SPOKANE COIJN'I'X STANDARDS FOR ROAD AND SEWER
CONSTRUCTION" latest edition ezcept as allowed through approved design deviations.
r.BKoOH~A13 5. 'Ihe dcainage repoct incorporates the m'inisnum requirements for a storm drainage analysis as noted in the GSM
and othec items which aze appropciate [b'demonstrate that the design meets all requirements of the Spokane
County Guidelines for Stormwater Management ezcept as allowed through approved design deviations.
vnas.❑N/A❑ b. A com lete drainage basin map with tinie of concentration paths shown has been included with the detailed
hydrolog'y calculadons. Drainage basin map shows topograph, proposed drainage features, and correlates with
hydrology caiculations. .
vtsUNoOruAD 7. All applicable traffic signing requirements are met and have been incorporated in the plan submittal.
YaOkoOruAff" 8. I have included copies of all approved D_rSIGN DEVIATIONS which are required for this project.
relat'i.OwAll 9. The plans and drainage report are stamped, signed, and dated, and conta'ins, the aQplicable certification
statement.
rd12na0ru,❑ 10. I have included an adequate erosion control plan and applicable standard plan notes.
vdM.11N/A0 11. I have secured appcovals from all applicable outside agencies such as fire districts where appticable and 6ave
included proof of their approvals..
~"1E1r,o11N/A❑ 12. I have provided an acceptable means for perpetual mainteaance of street and dtainage facilities that is acceptable
to Spokane County and have secured and included copies of any required eazements. '
roE+voE1wA❑ 13. I have r:viewed the plans, calculations and other submittal data for completeness, accuracy and consisteacy and
have su )mitted two copies of plans and (1) bound drainage report. •
✓ 14. A 4ac-lwe4it A x
i1ckplatvl.01May95
uilderstand that the requirements noted above are the minimum requirements necessary to perform a cursory review of Uie project
plans, and that additional inforqiation should be included with this submittal as necessary.
i understand that this submittal will be checked for compleeeness prior ro review, and that it will be returned for further information
if it is found to be incomplete.
' _ understand that this submitta will not be accepted for review (and placed on the review list) until all required information has
been submitted. • .
Form completed by the respon4ble Engineer: TC) ,,L1~ ~41 PPL-6
Company: 11~I~IJD ~~GIFIL E'~'lell.J41 .
Address: ~~~WTG 240 ~ $P0 -1J 2.0dq
Date: 4 Zip code
: FUR SPOKANE COUNTY USE OM..Y
SUBMITTAL: Accepted for review.
Reiurned for submittal of the following:
GENERAL ITEM :
i
"ROJECT DESIGN l! :
c .
RESUBM[Z"I'AL ITEM b: -
,
Form retumed to: '
Company:
Address: R •
Date:
BY: Spokane Counry Public Works Development Services
,
.
,
Uckplatv l .0/May95 2
'QaucG ~b~.~rMO•
ipopftr"
'T~ ~sTooAy
144 v46W,
S Y O K A N E • C O U N`r Y
O+ACE oF Ti re Cwrrtr Erxoffwv • A DrvsioN oF n►e PuBLic Wowcs DFrAwnMFxr
ttonnW C: ITomwnn, P,E.. Crntn1y Enginec► Dennb M. 5catt P.B., Dlrecloi`
AGRCEMENT TO PAY FEES
L+1VCII+IEFR'9 ACRELr11iFN1' NUMBER c •
~ .
T'6b agreemmt betaeen Spokatu Connty and *N '
wlwee {nuteal in the proJect is O4Jl~CA. .
, . . `
is entcred into this Z~ day of ~~V*jn~f , 19 Thls agrewnetu i.v appliceble lo ihe prnject
known aa• VA344 L-K 5~1 A~t 7i ~ ,p~ Q[.2Q'S _ SPOK~ewt CO. .
That the indivlduals oud paAies iwmed herefn as having an interesi in iire atove dcacribcd properly or proJcct
agra to llie following:
l. Reimburse S[akaiu Couidy for projecl review atd insnectiou fees as specified in Clwpler
9.14 of the Spoicane CouMy Code. 'ffie feea will be based on aduaf salary casts incurred
by Spokane County for project revlews nnd / or irupeclions plus a!en peroertt
edministrative charge, and w+ll be billed tnonthly as accnied. Any billing amounts dtte;
inciuding em expeRSes iiicurred in the collecllon of an ovenlue accoum, must be paid
prtot to Ihe County's acxeptanoe of the pmject for (iling, lf a project ia epproved and/or
filed with a Ualance stiN owing, i1ze unpald balance ahall be paid within 30 day8 of Uu
invofce date.
2. TI►e undersigned agrees lhat Iheae feea on• due atd prnyable upon reccipl o( Ihe bi!ling es
speclfted above.
. 3. Aiiy invoicea noi pald widdn 30 deys of We invoice date will tre co».sfderod deltnquent,
" I( aay outatanding 6alance on qte account for thla projecl is not pafd wittfin 30 days oF
Ihe invoice dale, no furtlver reviews o( Ihe project docamtnts wlli be cornlucted untii lhe
entire accourtt balance is paid. Any batmioe at Ihe account for lhis projecl tmc patd
wtthln 65 days of lhe ittivoice date may reautl in legel adion or the lnitiation of othcr
colleelion proeedures, incluJing referral to a collectlon ageitcy. The Sponsoc will be
Uable for any and all expenses incurred by lhe Cwnty for ihe collectfon of ovadue
accounts.
4. The motrU►ly bllNng should be sent to the atterrtion of:
NAMB: MAAIC 64&4oGIC
UEAw "muSC.eY Co~*"J'r
ADDRESS: /6720 NC Ur.
crrv, srnzs: ROaw4 oN.e, _ wA
zIP conB. 91,~os2 ~
PHONE N: 2"W 66 9"661S
! utaltrslaial lhat foiluro co pay lliese fccs nay result in delay iu cwuidetiun ar approval of Uw proJoG or oUier
pvasible swnctioav.
❑ lf this fee agreement is comptecod by soutcone otGer than tlu Sponsor (i.e., the project
owner ot a psincipel in Ihe Cinn sponsoring the project), aucfi as the Engineer deaigning
the project, Ihrn wrillen euthorization from the Sporisor shecitlcully authoriztng lhe
Agent to ezeeute Hds Fee Agreesna~s~ched to tfi1s fec Agreateent.
v
SICNATURB By: -"'+-c ,14
. (PR1NT NAMB)
RETURN YELLOW COPI' TO 3P KAtVE COUNTY ENGItV¢RRS
rVv~.sMzWA.r« uMs
3026w. S,waa,.,q nve. - spolcanG WA 97260-0170 •(sa9) 456 _3uic► rnX• (509) 324•3478 ron• (so9) 374-3166
INLAND PACIFIC ENGINEERING - TRANSMITTAL
707 W. 7th Avenue, Sufte 200 Spokane, WA (509)458-6840 Fax (509)4588"
- TO: Spokane County Engineers Office DATE: May 14, 1996
~x .
1026 W. Broadway
Spokane, Wa. 99206-0170 ,>;t.P.E:?C. PROJECT#: 95569 -
.
. ATTENTION: Ed Parry, P.E. ,PF20JECT NAME:;Riverwalk 5th
~Addition
~~,r • vY~~,` PROJECT PE-1414-81 :`~ry, A~C~~V~;,~~,
}F~'~F 7 'rfCC ~ - ` '
Description: SPOKANE COUNTY ENGINEEA
❑ Xerox Prints ❑ Copy of Letter ■ Submittal Package
■ Original Drawing O Contract Documents ❑
❑ Work Authorization ❑ Report ❑
No. Copies Description
1 Submittal package and checklist required by Spokane County
2 sets (4 of 4) Street Plan and Profile Sheets
Purpose
■ Information O Review & Comments ❑ Per Your Request
O Written Approval ■ Signature & Return ❑
Remarks
Ed - At the request of our client, please accept and review the above mentioned
information as required under the recently adopted Sookane Countv Standards for
Road and Sewer Construction.
Please let me know of any additional requirements for final acceptance. If you have
any questions concerning the submittal package or its contents, feel free to contact
me at our office.
Signed:
,
'
~ DRAINAGE REPORT
' for
,
RIVERWALK
' STH ADDITION
1
. APRII.,11, 1996
'
Prepared by:.
' Inland Pacific Engineering Compcmy
707 West 7th Suite 200
' Spokane, WA 99204
(509) 458-6840
' This report has been prepazed by the staff of Inland Pacific Engineering Company under the direction
of the undersigned professional engineer whose seal and signature appear hereon. This report
' conforms to the applicable editions of the Spokane County Standards for Road and Sewer
Construction and the Spokane County Guidelines for Stormwater Management.
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~ EXWRES 9/24/ ~
, Todd R. Whipple, P.E.
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I PURPOSE
' The purpose of this report is to deternune the extent of storm drainage facilities which will be
required to dispose of stormwater runoff created by the development of Riverwalk Sth Addition.
The storm drainage facilities on this project will be designed to dispose of stormwater runofffor
, the 10-year storm event as required by Spokane County and The Guidelines for Stormwater
Manasement. This development is within the Aquifer Sensitive Area and is subject to `208'
requirements.
' ANALYSIS METHODOLOGY
' The Rational Method, which is recommended for basins less than ten acres in size, will be used to
' determine the peak discharges and runoff volumes for the 10-year storm event. Bowstring
, calculations will be used to deternune the volume of stormwater created by the 10-year storm
event. The drainage analysis for this project will follow The Snokane Countv Guidelines for
Stormwater Management.
' PROJECT DESCRIPTION
' Riverwalk P.U.D. 4th Addition is a 7.10 acre, 261ot sub-division, located in the S'/Z of the SW
1/4 and Government Lots 5 and 6 of Section 8, T. 25 N., R. 45 EWM. Sheet 67 of the Soil
Survev of Snokane Countv_ Washineton (copy attached) shows the soils types to be GgA,
' (Garrison gravelly loam, 0 to 5% slopes), GgB, (Garrison gravelly loam, 5 to 20% slopes), and
Rh (Riverwash).
' PROJECT SOILS DESCRIPTION
A brief description from the USDA -Soil Conservation Service, Soil Survev of Snokane Countv,
' Washineton for each soil type follows.
Garrison gravelly loam with 0 to 5 percent slopes (GgA) is a somewhat excessively drained
, soil formed from a variety of igneous rock. Surface runoff is slow, and the hazard of water
erosion is slight to moderate. Spokane County Guidelines for Stormwater Manaeement has
~ pre-approved this soil for drywell installation. The soil is suited for homesite development.
Garrison gravelly loam with 5 to 20 percent slopes (GgB) is similar in all characteristics to
, GgA except this soil type has a surface layer thinner than Gg.A soil types. Garrison gravelly loam
with 5-20% slopes (GgB) soil types have runoffwhich is medium, and the hazard of erosion is
moderate. Spokane County Guidelines for Stormwater Management has pre-approved this soil
' for drywell installation.
Riverwash (Rh) consists of gravel, cobblestones and stones, with very little finer material, found
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' on low bottoms along perennial and intermittent streams . The areas are flooded nearly every year
from runoff, and only serve to protect against channel cutting.
I DEVELOPED CONDITION
' In the developed condition, the project can be divided into 7 basins, (A through G) by the crowns
and high points of the various road improvements, and the natural topography.. (See Basin Map,
copy attached.)
, BASIN AND STORMWATER DISPOSAL SUMMARY
' Basins A through F will be designed to dispose of stormwater created by the 10-year storm event.
The stormwater created by this event will be disposed of in ponds and Spokane County Standard
' drywells.
Basin A consists of portions of the road unpernous areas on the south side of Riverwalk Lane,
' and the west side of Michielli Lane. This basin also includes half of lot 1, of lots 2 through 5,
block 3, and lots 1 and 2, block 4. The peak flow of 0.27 c.f.s. for sub-basin A1 will be disposed
of in intermediate Pond A1, the peak flow of 0.55 c.f.s. will be disposed of in intemnediate Pond
' A2, and the peak flow for sub-basin A3 of 0.85 c.f.s. will be disposed of in Pond A3, which has
one Type "B" drywell. in sump condition.
' Basin B consists of a portion of the road impervious area on the north side of Riverwalk Lane.
This basin also a section of lot 1, block 5 and of lots 1 through 7, block 6. The peak flow of 0.43
c.f.s. for sub-basin B1 will be disposed of in intermediate Pond B1, the peak flow of 0.46 c.f.s. in
sub-basin B2 will be disposed of in intermediate Pond B2, and the peak flow of 0.74 c.f.s. for
sub-basin B3 will be disposed of Pond B3, which has one Type "B" drywell in sump condition.
' Basin C consists of portions of the road impervious area on the east side of Michielli Lane, and
the south side of Riverwalk Lane.This basin also includes half of lot 3, and all of lots 4 and 5,
' block 2. The peak flow of 0.64 c.f.s. will be disposed of in Pond C which one Type "A" drywell
in sump condition.
Basin D consists of portions of the road impervious on the north side of Shannon Lane, and the
, west side of Michielli Lane. This basin also includes half of lot 1, block 3, and a portion of one
future lot. The peak flow of 0.21 c.f.s. will be disposed of in Pond D with one Type "A" drywell.
' Basin E consists of a portion of the road impervious area on the south side of Shannon Lane.
This basin also includes half of lot 1, block 1. The peak flow of 0.15 c.f.s. will be disposed of in
' Pond E.
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' Basin F consists of the northern section of lot 1, block 5, and lots 1 through 7, block 6, and all of
Tract C. The basin has been analyzed in the pre-developed and developed condition. The pre-
, developed condition assumes a"C" factor of 0.30, representing meadows and pastureland. The
peak flow was calculated to be 1.89 c.f.s.. In the developed condition, the northern section of lot
1, block 5 and lots 1 through 7, block 6 were assumed to be landscaped with lawn, in sandy soil
, rolling terrain, which reduces the "C" factor for that portion to 0.15.. The Tract C area falls
within the Spokane County Shoreline Program, and will remain undisturbed. The "C" factor for
that portion wiU remain 0.30. Using a weighted "C" factor, the peak flow for the developed
, condition was calculated to be 1.64 c.f.s.. The peak flow in the developed condition is lower than
the peak flow from the pre-developed condition by 0.25 c.f.s..
' Basin G consists of the northern section of lots lthrough 3, block 7, and exsiting lots 1, block 3,
and lots 1 through 4, block 4 of Riverwalk 3rd Addition, and all of Tract A. The basin has been
' analyzed in the pre-developed and developed condition. The pre-developed condition assumes a
"C" factor of 0.30, representing meadows and pastureland. The peak flow was calculated to be
1.34 c.f.s. In the developed condition, the entire area was assumed to be landscaped wnth lawn, in
, sandy soil rolling tetrain, which reduces the "C" factor to 0.15. The peak flow for the developed
condition was calculated to be 0.67 c.f.s.. The peak flow in the developed condition is lower than
the peak flow from the pre-developed condition by 0.67 c.f.s..
' Pond A1, Riverwalk 3rd Addition, was designed as part of the drainage plan for Riverwalk 3rd
Addition, but will be built as part of Sth Addition. It is located at the southwest end of Micheilli
' Lane, and was designed as an intermediate pond to store `208' volume from the road impervious
area upstream. Pond A2, Riverwalk 3rd Addition, will store the storm volume. See the
calculations and Basin Map for Riverwalk 3rd Addition.
, Pond B1, Riverwalk 3rd Addition was designed as part of the drainage plan for Riverwalk 3rd
Addition. It is located on the north side of Michielli Lane, and was designed as an intermediate
' pond to store `208' volume from the road impervious area upstream. Pond B2, Riverwalk 3rd
Addition, will store the storm volume. See the calculations and Basin Map for Riverwalk 3rd
' Addition. The north half of these lots are included in Basin G calculations for Riverwalk Sth
Addition.
'
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STORMWATER CALCULATIONS
' The stormwater from the 7 basins will be disposed of in '208' retention ponds and Spokane
County drywells as shown on the plans and in the attached Bowstring Calculation sheets.
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Inland Pacific Engincering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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, The stormwater from the 7 basins will be disposed of in '208' retention ponds and Spokane
County drywells as shown on the plans and in the attached Bowstring Calculation sheets.
Table 1 lists the total and impervious areas and the "C" factor for the Time of Concentration and
Peak Flow calculations.
' Table 2 summarizes the retention volumesrequired for each basin as calculated by the Bowstring
Calculations, as well as the depth, area, perimeter and volume provided.
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r.,,r,,.~ry , . . „ : . . . . .
~ ti~y2'4 . ..4n.f w~}JC> zs,x<a?:ar,.t>•.::>•. •y°.; z; +Cc~ s.r` \tic<^p,wh ,9' <.uq•,,
, ..'y .
t~xK>~ R , 5i, fi~ ' •p. j ~ 'y . .a.ti'i.iv rf}{>'.'5,~,~6k.,, f?~r~t:rtSs•1:s.. k Kt,. . ~ °y. ~.4 `~f ~j~
' , , . . . ~.S . . . s .
BASIN TOTAL TOTAL IlVIP. AREA # LOTS DU/GA "C"
' AREA (S.F.) AREA (AC.) (S.F.)
. A1 15,483 0.36 4068 1.0 2.78 0.25
' A2 21,259 0.49 3319 2.5 5.10 0.40
A3 34,133 0.78 3994 3.0 3.85 0.35
' A 70,875 1.63 11,381 6.5 5.65 0.40
Bl 10,034 0.23 1955 1.5 6.52 0.60
' B2 10,764 0.25 2088 1.5 6.00 0.60
' B3 28,470 0.65 5699 3.0 4.62 0.40
B 49,268 1.13 9742 6.0 5.31 0.40
' C 15,609 0.36 4884 2.5 6.9 0.60
D 9281 0.21 3125 1.0 4.76 0.40
' E 5135 0.12 2090 0.5 4.17 0.40
F 86,355 1.98 - - - 0.26
, G 60,927 1.40 - - - 0.15
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' `208 RETENTION VOLUME CALCULATIONS
''208' retention volumes were calculated using the following formula:
Volume (cu. ft.) _ (depth)(area) + (slope area)(perimeter)
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} ~ ~,~y'1,.,},~~~~?~r~k~~'~.+~1. . . ~k~' 4 . . . '~ir~~ S>}3~~~~~~~
' -
POND DEPTH AREA PERIlViETER VOL. REQ'D. VOL. PROV.
' A1 .5 300 80 170 180
A2 .5 234 62 138 140
' A3 .5 350 78 166 204
, Bl .5 132 46 81 83
B2 .5 144 48 87 90
B3 .5 416 84 237 240
C .5 360 92 204 215
' D .5 230 66 130 140
E .5 140 48 87 88
r
Notes: Typical sideslopes are 3:1 maximum.
' Ponds Al, A2, B 1 and B2 are intermediate `208' Ponds designed to handle the uPstream
impervious areas only.
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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, STORM VOLUME STORAGE
`208' storage is provided in the first .5' of depth in all ponds. Pond bottom elevations of intermediate ponds are
' set .5' below the flow line, and sized to contain the upstream `208' requirement only. Should there be an
overIlow, water will flow out of the lowest curb inlet in each intermediate pond to the next pond downstream.
' Pond bottom elevations of terminal ponds with drainage structures (located at the low point of a basin) are set .9'
below the flow line. This allows an additional.4' storage above the `208' storage.
' Pond A3 illustrates the storm volume storage above the .5' depth for `208' storage:
Total `208' storage required for Sub-basin A3 166.0 cubic feet
' Total `208' storage provided at .5' depth 204.3 cubic feet
Total Bowstring requirement for Basin A(See Sheet 8) 578.0 cubic feet
'`208' storage provided, Ponds A1, A2 &A3 474.0 cubic feet
Storm volume storage required 104.0 cubic feet
, Storage volume provided at 7 depth, Pond A3 302.3 cubic feet
`208' Storage provided 166.0 cubic feet
' Storm volume provided 136.3 cubic feet
Pond E also will store storm volume above the .5' depth reserved for `208' storage:
, Total `208' storage required for Basin E 87.0 cubic feet
Total `208' storage provided at .5' depth 88.0 cubic feet
' Total Bowstring requirement (See Sheet 18) 130.0 cubic feet
`208' storage provided, Pond E 87.0 cubic feet
' Storm volume storage required 43.0 cubic feet
Storage volume provided at 7 depth 133.5 cubic feet
'`208' Storage provided 87.0 cubic feet
Storm volume provided 46.5 cubic feet
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' CURB INLET AND GRATE INLET CALCULATIONS
' It is necessary to check the adequacy of curb inlets provided to divert the flows from the gutter to the retention
ponds. The Curb Inlet Calculation Sheet included in this report (see calculation sheet, copy attached) shows the
required lengths of curb openings. As shown on the calculation sheet, various ponds have different curb inlet
, requirements. Therefore, the required curb openings have been provided according to the tabulated results. All
curb inlets shaU be standard 4' openings, unless otherwise noted.
It is also necessary to check the capacity of grate inlets on continuous grade. The Grate Calculation - Continuous
Grade worksheets have been included. The calculations have been completed in accordance with Fieure 15 of
Snokane Countv Guidelines for Stormwater Manaeement. (See calculation sheets, copy attached.)
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Inland PaciSc Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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APPENDIX
' Developed condition 1-7
Peak Flow and Bowstring 8- 22
' Curb Inlet calculations 23 -24
. Soils Map 25
Basin Map 26
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' Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' PEAK FLOW AND BOWSTRING
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z :~p;*•:"~~;i BOWSTRING METHOD PROJECT: Riverwalk Sth Additfon
PEAK FLOW CALCULATION PROJECT Riverwalk 5th Add~ion t DETENTION BASIN DESIGN BASIN: A
BASIN: A z~ 10-Year Deslgn Stomi DESIGNER: S. Murphy
Tot. Area 1.63 Acres DATE: 4/1/96
Imp. Area 11381 SF
C = 0.40 ;~s ?
` ~
.~.:.z;
.z;
t~
Time IncremeM (mfn) 5
CASE 1 Time of Conc. (min) 8.59
Outtlow (cis) 1
70 ft. Overtand Flow Design Year Flow 10
Afea (BCreS) 1.63
Ct = 0.15 i~ '•~i Impervious Area (sq ft) 11381
L= 70 ft. 'C Factor 0.4
n= 0.40 .208' Volume Prwided 474
S= 0.020 Area ' C 0.652
Tc = 3.58 min., by Equatlon 3-2 of Guidelines
Time T1me Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
460 ft. Gutter flow ~ ~M; ~ (min) (sec) QNhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 Fot Z2 ?=4 8.59 515 2.43 1.58 1093 515 578
72 = 3.5 Type B= 1.0
300 3.18 2.07 833 300 533
n= 0.016 Rolled = 3.5 10 60
S = 0.006
0 2.24 1.46 1132 600 532
15 900 1.77 1.15 1241 900 341
d= 0.196 ft. ti•,~20 1200 1.45 0.95 1300 1200 100
25 1500 1.21 0.79 1322 1500 -178
A R Q TC TC totel I Qc 30 1800 1.04 0.68 1339 1800 -461
,x„"~~~ j;;;z 35 2100 0.91 0.59 1350 2100 -750
1.03 0.10 1.57 5.01 8.59 2.43 1.58 ~~`;•i 40 2400 0.82 0.53 1377 2400 -1023
~a.
45 2700 0.74 0.48 1387 2700 -1313
Qpeak for Case 1= 1.58 cfs 50 3000 0.68 0.44 1408 3000 -1592
55 3300 0.64 0.42 1450 3300 -1850
60 3600 0.61 0.40 1501 3600 -2099
C A S E 2 % 65 3900 0.60 0.39 1594 3900 -2306
i70 4200 0.58 0.38 1655 4200 -2545
Case 2 assumes a Time of Concentratlon less than 5 minutes so that the
•`,~;r~~ 75 4500 0.56 0.37 1707 4500 -2793
peak flow =.90(3.18)(Imp. Area) = 0.75 cfs
80 4800 0.53 0.35 1719 4800 ~081
a ;z ,a;>
85 5100 0.52 0.34 1789 5100 ~311
90 5400 0.50 0.33 1818 5400 -3582
So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.32 1877 5700 -3823
1.58 cis ;x.~'
100 6000 0.48 0.31 1933 6000 -4067
,.zz. ..a
M'
i a~r 'a,.~~,,
Y"'k M; 208' ORAINAGE POND CALCULATIONS
Required'208' Storage Volume
= Impervious Area x.5 in / 12 Wft 474 cu ft
NiH•~K\
208' Storage Volume Provided 474 cu ft
Xc
.,,..r,...
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
i~ AAa)dmum Storage Required by Bowstring 578 cu ft
M~; Mx ~
;x•• z~xa, ~
Number and Type of Drywells Required 0 Sin le
1 Doubte
. r'§~z;~ BOWSTRING METHOD PROJECT: Rivervralk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk 5th AddiUon ~DETENTION BASIN DESIGN BASIN: A1
BASIN: A1 ~~10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 0.36 Acres DATE: 4N/96
Imp. Area 4068 SF
C = 0.25 : ~
CASE 1 ~ Tirr~e Increment (min) 5
Time of Cortc. (min) 6.66
: ~ Outflow (cis) 1
u
70 ft. Overtand Flow Design Year Flow 10
Area (acres) 0.36
Ct = 0.15 ImpeMous Area (sq ft) 4068
L= 70 ft. 'C Fador 0.25
o.ao 'zos~ voiu~ P~dea Ieo
S= 0.020 Area C 0.090
Tc = 3.58 min., by Equatlon 3-2 of Guidelirses WIR
Time Time Inc. Intens. a Devel. Vol.ln Vol.Out Storage
200 ft. Gutter flow min sec r cfs cu ft cu ft cu R
( ) ( ) ~ ) ~ ) ( ) ( ) ~ )
Zt = 50.0 For 72 ~6.G6 400 2.74 0.25 ^ 132 400 -268
Z2 = 3.5 Type B= 1.0 t; ~
n= 0.016 Rolled = 3.5 5 300 3.18 0.29 115 300 -185
S= 0.008 10 600 2.24 0.20 148 600 -452
15 900 1.77 0.16 165 900 -735
d= 0.093 ft. 20 1200 1.45 0.13 174 1200 -1026
25 1500 1.21 0.11 178 1500 -1322
A R Q Tc Tc total I Qc :"""30 1800 1.04 0.09 181 1800 -1619
35 2100 0.91 0.08 183 2100 -1917
0.23 0.05 0.25 3.08 6 66 2.74 0.25 40 2400 0.82 0.07 187 2400 -2213
45 2700 0.74 0.07 189 2700 -2511
Qpeak for Case 1= 0.25 Cfs 50 3000 0.68 0.06 192 3000 4808 55 3300 0.64 0.06 198 3300 --3102
3600 0.61 0.05 245 3600 3395
CASE 2 65 3900 0.60 0.05 218 3900 -3682
70 4200 0.58 0.05 226 4200 -3974
Case 2 assumes a Tlme of Concentrra8on less than 5 minutes so that the 75 4500 0.56 0.05 234 4500 -4266
peak flow =.90(3.18)(Imp. Area) = 0.27 Cis 80 4800 0.53 0.05 235 4800 -4565
85 5100 0 52 0.05 245 5100 -4855
90 5400 0.50 0.05 249 5400 ti5151
So, the Peak flow for the Basin Is the greater of the two flows, 95 5700 0.49 0.04 257 5700 -5443
0.27 Cfs 100 6000 0.48 0.04 265 6000 -5735
208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft
170 cu ft
208' Storage Volume Provided 180 cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
Ma)dmum Storage Required by Bowstring -185 cu ft
Number and Type of Drywells Required 0 Single
~0
1 Double
t?"~"r BOWSTRING METHOD PROJECT: Rivervralk Sth AddiUon
PEAK FLOW CALCULATION PROJECT Riverwalk 5th Additlm DETENTION BASIN DESIGN BASIN: A2
BASIN: A2 10-Year Design Stortn DESIGNER: S. Murphy
Tot. Area 0.49 Acres DATE: 411/96
Imp. Area 3319 SF
C = 0.40
, Time Irtcrement (min) 5
CASE 1 Time of Cona (mtn) 6.42
Outflow (cfs) 1
70 ft. Overtand Flow , Design Year Flow 10
Ct = 0.15 Ampe (Mous Anea (sq ft) 33 9
L = 70 R. 'C' Factor 0.4
n= 0.40 ~208' Volume Provided 140
S = 0.020 -
; x~ •
,.,Area C 0.196
Tc = 3.58 min., by Equation 3-2 oi Guidelines
:;;.~;;N A Time Time Irtc. Intens. Q Devel. Vol.ln Vol.Out Storage
190 ft. Gutter (tow iz~- a; (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu R)
tz~
Z1 = 50.0 For Z2 ,r~ ~ 6.42 385 279 0.55 282 385 -103
Z2 = 3.5 Type B= 1.0 '
n= 0.016 Rolled = 3.5 ~ 5 300 3.18 0.62 251 300 -49 ~=a
x;v~z:za~a..
S= 0.005 10 600 224 0.44 321 600 -279
~g 15 900 1.77 0.35 358 900 S42
d= 0.136 R. ':MWN=' 20 1200 1.45 0.28 378 1200 -822
25 1500 1.21 0.24 387 1500 -1113
sa
A R Q Tc Tc tatal I Qc Z~jh~ ~ ;i 30 1800 1.04 0.20 394 1800 -1406
_=___aae __ev__ca aacaa~ao Qacaaa3a aacaaa~~ aaaa~aca aa.:aaeaa :~:::y~.' 35 2100 0.91 0.18 398 2100 '1702
~w`~;„f k. t'~ zz
0.49 0.07 0.55 2.84 6.42 2.79 0.55 f M:; ,W ~V= 40 2400 0.82 0.16 407 2400 -1993
45 2700 0.74 0.15 411 2700 -2289
Qpeak tor Case 1= 0.55 cfs 50 3000 0.68 0.13 417 3000 -2583
r 55 3300 0.64 0.13 430 3300 -2870
60 3600 0.61 0.12 446 3600 3154
CASE 2 65 3900 0.60 0.12 474 3900 -U26
70 4200 0.58 0.11 492 4200 3708
Case 2 assumes a Time of Conceniration less than 5 minutes so that the ~ 75 4500 0.56 0.11 508 4500 3992
peak flow =.90(3.18)(Imp. Area) = 0.22 cfs 80 4800 0.53 0.10 512 4800 -4288
zz'~`z^~,`,g``;z
~~85 5100 0.52 0.10 533 5100 ~567
e,~;~_ 90 5400 0.50 0.10 542 5400 -4858
..a„...,,.
So, the Peak tlow for the Basln !s the greater oi the two ttovvs, ~;w•~~ 95 5700 0.49 0.10 560 5700 5140
0.55 crs .100 sooo 0.48 0.09 sn sooo s423
208' DRAINAGE POND CALCULATIONS
Requlred'208' Storage Volume
Impervious Area x.5 in / 12 INft 138 cu ft
ZOS' Storage Volume Provtded 140 cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
Ma)dmum Storege Required by Bowsbing -49 cu ft
Number and Type of Dryweils Required 0 Single
1 Double
BOWSTRING METHOD PROJECT: Rlverwalk Sth Addbon
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth AddiUon DETENTION BASIN DESIGN BASIN: A3
BASIN: A3 1QYear Design Storm DESIGNER: S. Murphy
Tot. Area 0.78 Acre.s DATE: 4/1/96
Imp. Area 3994 SF
C = 0.35
Time Increment (min) 5
CASE 1 Time of Conc. (min) 5.29
' Outflow (cis) 1
70 ft. Overland Flaw ~~~~z~; ~ De.slgn Year Flaw 10
1~ Area (acres) 0.78
Ct = 0.15 ~~'.~~;~r ~ Impervrous Ar~ (sq ft) 3994
L= 70 R ?•"";r 'C Factor 0.35
n= 0.40 NN~N r208' Volume Provided 204
S= 0.020 ~;;a~::~..,•~~ Area' C 0.273
:xx a.
Tc = 3.58 min., by Equatlon 32 of Guidelirses
Time Time Inc. Intens. Q Devel. Vot.ln Vol.Out Storage
150 ft. Gutter flow (min) (sec) (inlhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For 72 5.29 =====317 3.10 0.85 361 ==317 ======43
7-2 = 3.5 Type B -1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.87 349 300 49
S•• 0.008 10 600 2.24 0.61 433 600 '167
`k : 15 900 177 0.48 487 900 '413
~c.. ;d= 0.148 R. 20 1200 1.45 0.40 518 1200 -682
; 25 1500 1.21 0.33 531 1500 -969
A R Q Tc Tc total I Qc z ' 30 1800 1.04 0.28 542 1800 -1258
1~ 35 2100 0.91 0.25 549 2100 -1551
0.58 0.07 0.65 1.71 5.29 3.10 0.85 40 2400 0.82 0.22 561 2400 -1839
M ~ C~ MM r~ ~q
wC M
'.2~'C2~:`.2Y~' x: `N G/W ~.74 O.ryV G .N7 G/ W 'G~.N
Qpeak ror case 1= 0.85 ors so 3000 0.68 0.19 sn 3000 -2423
55 3300 0.64 0.17 595 3300 '2705
60 3600 0.61 0.17 617 3600 -2983
cASEZ ss ssoo 0.60 0.16 657 ssoo -3243
r~:7~i;~•70 4200 0.58 0.16 682 4200 -3518
i;~ i • ~
Case 2 assumes a Time of ConcentraUon less than 5 minutes so that the 75 4500 0.56 0.15 704 4500 -3796
peak flow =.90(3.18)(Imp. Area) = 0.26 cis 80 4800 0.53 0.14 710 4800 -4090
85 5100 0.52 0.14 739 5100 -4361 90 5400 0.50 0.14 5400 -4648
%
So, the Peak flo~w for the Basin ts the greater of the two flows, ~M~:~ ~95 5700 0.49 0.13 7777 5700 -4923
0.85 cfs 100 6000 0.48 0.13 800 6000 5200
208' DRAINAGE POND CALCULATIONS
% Required 208' Storage Volume
Impervtous Area x.5 in / 12 INft 166 cu ft
~ 208' Stwage Volume Provided 204 cu ft
~~ii~,,,
kM' DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
;;~3~it':xza
Ma)dmum Storage Required by Bowstring 49 cu ft
Number and Type of Oryvvelis Requfred 0 Sirsgle
11,., t Double
BOWSTRING METHOO PROJECT. Rivervralk 5th AddiUon
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: B
BASIN: B 4::{~t~1QYear Design Storm DESIGNER: S. Murphy
vQ v~
Tot. Area 1.13 Acres DATE: 4/11 f96
Imp. Area 9742 SF ~'i~ w
C = 0.40
Time Irtcxement (min) 5
CASE 1 ~z Time oi Conc. (min) 9.10
t.z° z;z~za~•z Outflow (cfs) 1
70 ft. Overland Flow :c~,.i : Design Y~r Flow 10
tt;~ (acres)
Area
µ r'z K~ 1.13
Ct = 0.15 Impervious Area (sq ft) 9742
r.s........~c~'
L= 70 ft. a„....w.., u, 'C' Factor 0.4
n= 0.40 208' Volume Provided 406
S= 0.020 Area • C 0.452
z;,.„..
Tc = 3.58 min., by EquaUon 3-2 of Guidelines
Tirtse Time Inc. Intens. Q Deve1. Vo1.ln Vol.Out Stora e
~i : • 9
415 ft. Gutter flow (min) (sec) (infir) (cfs) (cu ft) (cu ft) (cu ft)
v.K
zi = 50.0 Forzs 9.10 sas 236 1.06 ns sas 233
Z2 = 3.5 Type B= 1.0
n= 0.016 Ralled = 3.5 5 300 3.18 1.44 578 300 278
S= 0:005 10 600 2.24 1.01 795 600 195
15 900 1.77 0.80 869 900 -31
d a 0.167 ft. ZO 1200 1.45 0.66 908 1200 -292
25 1500 1.21 0.55 922 1500 -578
A R Q Tc Tc total I Qc 30 1800 1.04 0.47 933 1800 -867
=aaa=aaa a~~-~z~~ 35 2100 0.91 0.41 940 2100 -1160
-
r . : z
0.74 0.08 0.93 5.52 9.10 2.36 1.06 40 2400 0.82 0.37 958 2400 -1442
~45 2700 0.74 0.33 965 2700 -1735
Qpeak for Case 1= 1.06 cfs iiai'; ,~z; ~ 50 3000 0.68 0.31 979 3000 -2021
55 3300 0.64 0.29 1008 3300 -2292
60 3600 0.61 0.28 1044 3600 -2556
CASE2 65 3900 0.60 0.27 1108 3900 -2792
70 4200 0.58 0.26 1150 4200 -3050
Case 2 essumes a Tirr►e of Coricentratton less than 5 minutes so that the 75 4500 0.56 0.25 1186 4500 -3314
peak fiow =.90(3.18)(Imp. Area) = 0.64 cfs 80 4800 0.53 0.24 1194 4800 3606
85 5100 0.52 0.24 1242 5100 -3858
90 5400 0.50 0.23 1262 5400 -4138
So, the Peak 8ow for the Basin is the greater of the two flows, 95 5700 0.49 0.22 1304 5700 -4396
1.06 Cfs 2^^~^~•^^~~~ 100 6000 0.48 0.22 1342 6000 -4658
208' ORAINAGE POND CALCULATIONS
Required'ZOB' Storage Volume
Impervious Area x.5 in 112 INR 406 cu ft
M w ~M.
r,.i 208' Storage Volume Provided 406 cu R
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Maximum Stota9e Re4ulred bY Bowsiri►19 278 cu ft
;;;;wL?~• Number and Type o( Drywells Required 0 Single
; ;a~ 1 Double
~i`. .w..,
BOWSTRING METHOD PROJECT: Rivennralk Sth AddiUon
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Additfon DETENTION BASIN DESIGN BASIN: B1
BASIN: B1 10-Year Design Stortn DESIGNER: S. Murphy
Tot. Area 0.23 Acres DATE: 4111/96
Imp. Area 1955 SF
C= 0.60
Time IncremeM (min) 5
CASE 1 Time of Canc. (min) 5.33
Outflow (cis) 1
70 ft. Overland Flow i Desi9n Year Fkow 10
Area (acres) 0.23
Ct a 0.15 2:zImPeMous Area (sq ft) 1955
L= 70 ft. 'C Factw 0.6
n a 0.40 "208 Volume Provided 83
S = 0.020
;.x;s, Area C 0.138
*ii:%~ .
Tc = 3.58 min., by Equatlon 32 of GufdeOnes
Time Time Inc. IMens. Q Devd. Vd.ln Vol.Out Storage
110 ft. Gutter flow (min) (sec) ONhr) (cis) (cu ft) (cu ft) (cu ft)
Zt = 50.0 For 7-2 5.33 320 3.09 0 43 183 320 -137
7-2 = 3.5 Type B=1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.44 176 300 -124
S= 0.005 10 600 2.24 0.31 219 600 -381
15 900 1.77 0.24 246 900 -6S4
d= 0.124 ft. ~z~"~~.'',•~i ~ ZO 1200 1.45 0.20 262 1200 -938
25 1500 1.21 0.17 269 1500 -1231
,z,„„a,: xxz,,.xz••
A R Q Tc Tc total I Qc ,;;?"~~"~a 30 1800 1.04 0.14 274 1800 -1526
;~~`r,,~µ:.~ 35 2100 0.91 0.13 277 2100 -1823
, ri~ .
0.41 0.06 0.43 1.75 5.33 3.09 0.43 40 2400 0.82 0.11 284 2400 -2116
45 2700 0.74 0.10 287 2700 -2413
Qpeak for Case 1= 0.43 cfs 50 3000 0.68 0.09 292 3000 -2708
55 3300 0.64 0.09 301 3300 -2999
60 3600 0.61 0.08 312 3600 -3288
CASE 2 65 3900 0.60 0.08 332 3900 3568
70 4200 0.58 0.08 345 4200 3855
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.08 356 4500 -4144
peak flow =.90(3.18)(Imp. Area) = 0.13 cis 80 4800 0.53 0.07 359 4800 4441
85 5100 0.52 0.07 374 5100 4726
90 5400 0.50 0.07 380 5400 5020
So, the Peak flow for tlie Basin ls the greater ot the two flows, 95 5700 0.49 0.07 393 5700 5307
0.43 cis 100 6000 0.48 0.07 405 6000 5595
NO
.y^ci N s
•.a*viz: • ,•it :
~~zM1«a?~ ~
i 208' DRAINAGE POND CALCULATIONS
Reyuired'208' Stwage Volume
Impervious Area x.5 in / 12 iNft 81 cu ft
:,i:.iw~ z: •
#'"•'~ii?;: ~ c`
208' Storage Volume Provided 83 cu R
ORYWELL REQUIREMENTS -10 YEAR DESIGN STORM
~Maximum Storage Required by Bowstring -124 cu ft
:iav uzz
Number and Type of Drywells Required 0 Single
1 Double
BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT RNerwalk Sth Addition M, DETENTION BASIN DESIGN BASIN: 82
BASIN: B2 x 10-Year Design Storm DESIGNER: S. Murpfiy
Tot. Area 0.25 Actes DATE: 4/11196
Imp. Area 2088 SF
C = 0.60
„zi 0 rk - Time Increment (min) 5
CASE t Time of Conc. (min) 5.46
Outflow(cfs) 1
70 ft. Overtand Flow Design Year Flow 10
Area (acres) 0.25
Ct = 0.15 ImPervious Area (S4 ft) 2088
,,z•`L= 70 ft. 'C' Fador 0.6
n= 0.40 208' Volume Provided 90
S a 0.020 3'- $ Area ' C 0.150
Tc = 3.58 min., by Equation 3-2 oi Guidelines ~ ~2.
Time Time Inc. IMens. Q Devel. Vol.In Vol.Out Storage
120 ft. Gutter eaw a. . ; (min) (sec) (iNhr) (ots) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For 72 5.46 327 3.06 0.46 201 327 -126
72 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 5 300 318 0.48 192 300 -108
S= 0.005 'WE m;'~ 10 600 2.24 0.34 239 600 -361
15 900 1.77 0.27 269 900 -631
d= 0.127 ft. 20 1200 1.45 0.22 285 1200 -915
25 1500 1.21 0.18 292 1500 -1208
A R Q Tc Tc total I Qc 30 1800 1.04 0.16 298 1800 -1502
35 2100 0.91 0.14 302 2100 -1798
0.43 0.06 0.46 1.87 5.46 3.06 0.46 40 2400 0.82 0.12 309 2400 -2091
45 2700 0.74 0.11 312 2700 -2388
Q k for Case 1= 0.46 cfs
pea 5C0C J 3~~00/~M/~ 0 0.6Q8~ 0.10 317 3~0~0/y0~ -26~83
\\h / 0.V`~ 0.10 ~ NW~J -yW~
`~~`a W ~
z.. 60 3600 0.61 0.09 340 3600 ~260
CASE 2 tiMsi.>~x~ .-~i,`c` 65 3900 0.60
, 0.09 361 3900 -3539
' z;;;•:•. e.:~ 70 4200 0.56 0.09 375 4200 -3825
trir.i:\ :2 ~```2
Case 2 assumes a Time of Concentratlon less than 5 mfnutes so that the 75 4500 0.56 0.08 387 4500 -4113
peak flow =.90(3.18)(Imp. Area) = 0.14 cfs >i:;:;~:;:i;i~ :
80 4800 0.53 0.08 390 4800 -4410
85 5100 0.52 0.08 406 5100 4694
90 5400 0.50 0.08 413 5400 -4987
~'a.: ',•.i~`~„~~? : »
So, the Peak flanr for the Basin Is the greater of tfie two flows, 95 5700 0.49 0.07 427 5700 -5273
0.46 cfs 100 6000 0.48 0.07 440 6000 5560
z: :z a~~E¢at
2C .2 ~2A`..
2v~208' DRAINAGE POND CALCULATIONS
Required 'ZOS' Storage Volume
Impervious Area x.5 in / 12 INft 87 cu ft
ZOS' Storage Volume Provided 90 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
±Ma)dmum Storage Required by Bwvstring -108 cu ft
Number and Type oi Drywells Required 0 Single
u;r •
\ ............:5" I DOUbl@
ETHOD PROJECT: Rivenralk Sth Addftlon
BOWSTRING M
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addftion DETENTION BASIN DESIGN BASIN: B3
SEEN,,
BASIN: 83 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 0.65 Acres ~ DATE: 4111f96
Imp. Area 5699 SF
C= 040 "
m?.~.
~ti,,,~,~ ~ Time Increment (m1n) 5
CASE 1 Time of Cona (min) 6.19
w,•
;.ix: ,i:.x_ Out(low (Cfs) 1
70 ft. Overland Flow ~Z;';;~, Design Year Flaw 10
w,k Area (acres) 0.65
Ct = 0.15 gk% µr Impervious Area (sq ft) 5699
L= 70 ft. 'C' Factor 0.4
n= 0.40 'Z08' Volume Providad 240
S= 0.020 Area ' C 0.260
Yi
Tc = 3.58 min., by Equafion 32 of Guidellnes
Time Time Inc. IMens. 0 Devel. Vol.ln Vol.Out Storage
~
185 ft. Gutter flow NOM;(min) (sec) ((Nhr) (cfs) (cu ft) (cu ft) (cu R)
i~z~~~~
~..,.,z.,,;
-
Zt = 50.0 For Z2 ~ 6.19 371 2.84 0.74 368 -----371 -3
7-2 = 3.5 TYPe B= 1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.83 332 300 32
S _ 0.005 i^•,~~~?
10 600 2.24 0.58 423 600 -177
15 soo 1.n 0.46 472 soo ~zs
d~ 0.153 R. 20 1200 1.45 0.38 500 1200 -700
25 1500 1.21 0.31 512 1500 -988
A R Q Tc Tc total I Qc 30 1800 1.04 0.27 521 1800 •1279
===a===a c==acaaa caaeaaaa aaanaaa~ ma==ac~ aa~aanaa ~`,t~. $S 2100 0.91 0.24 527 2100 -1573
0.62 0.08 0.74 2.61 6.19 2.84 0.74 .'~z 40 2400 0.82 0.21 539 2400 -1861
45 2700 0.74 0.19 544 2700 -2156
Qpeak for Case 1= 0.74 cfs %50 3000 0.68 0.18 553 3000 -2447
55 3300 0.64 0.17 570 3300 -2730
60 3600 0.61 0.16 591 3600 -3009
CASE 2 65 3900 0.60 0.16 628 3900 -3272
70 4200 0.58 0.15 652 4200 -3548
%
Case 2 assumes a Time of Concentratian less than 5 minutes so that the
?~;e~• 75 4500 0.56 0.15 674 4500 -3826
peak flow =.90(3.18)(Imp. Area) = 0.37 cfs 80 4800 0.53 0.14 679 4800 -4121
;,:<'na,ih 85 5100 0.52 0.14 707 5100 -4393
90 5400 0.50 0.13 718 5400 -4682
xa ;
So, the Peak fbw for the Basin Is the greater of the two flows, 95 5700 0.49 0.13 742 5700 -4958
0.74 Cfs 100 6000 0.48 0.12 765 6000 -5235
i,~, ~
iixzili£~~
208' DRAINAGE POND CALCULATIONS
Required '208' Storage Volume
= Impervlous Area x.5 in / 12 INft 237 cu ft
~m
208' Storage Volume Provided 240 cu ft
..2\~
;„iz:;t; =a:;;:::;•......^'i'DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
~
~ Ma)dmum Storage Required by Bovvstring 32 cu ft
Number arsd Type of Drywelis Requlred 0 Single
t Double
R,1"BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: C
BASIN: C 1QYear Design StoRn DESIGNER: S. Murphy
Tot. Area 0.36 Acres DATE: 4/11l96
Imp. Area 4884 SF
C = 0.60 zz
CASE 1 ~nme Increment (min) 5
Time of Conc. (min) 5.79
Outflow (cfs) 0.3
70 ft. Overfand Flaw
Design Year Flow 10
ih ,s; •
Area (acres) 0 36
Ct = 0.15 ImpeMous Area (sq ft) 4884
xdc
L= 70 ft. "Z"~'^u'C Factot 0.6
n= 0.40 '208' Volume Provided 215
S= 0.020 Area ' C 0.216
`~.~.-"`.``.~~.`',x`~`.•.``,,; ;"~x .
Tc = 3.56 min., by EquaUon 3-2 ot Gufdelines
,
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
a.
180 ft. Gutter flaw (
~~~,x, mfn) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft)
`:2:~`.~~t.2; aaaaaca:a ca~aa~ea aa«.aaa: a~ae~e~~ aaa~~e~sa aa=ae_=:
Z1 = 50.0 For 7-2 347 2.96 0.64 297 104 ~r--- 193
~ Z2 = 3.5 Type B= 1.0
•
n= 0.016 Rolled = 3.5 z;;5 300 3.18 0.69 276 90 186
S= 0.008 10 600 2.24 0.48 347 180 167
~15 900 1.77 0.38 389 270 119
d= 0.133 ft. ~ZO 1200 1.45 0.31 413 360 53
25 1500 1.21 0.26 423 450 -27
A R Q Tc Tc total I Qc 30 1800 1.04 0.22 431 540 -109
35 2100 0.91 0.20 438 630 -184
0.47 0.07 ^ 0.64 2.20 5.79 2.96 0.64 % ~ 40 2400 0.82 0.18 446 720 -274
45 2700 0.74 0.16 450 810 lw
Qpeak for Case 1= 0.64 cfs 50 3000 0.68 0.15 458 900 -442
,~~,..~~.;•w 55 3300 0.64 0.14 473 990 -517
~..~.x 60 3600 0.61 0.13 490 1080 -590
CASE 2 65 3900 0.60 0.13 521 1170 -649
70 4200 0.58 0.13 541 1260 -719
Case 2 assumes a Time of Concentratfon less than 5 minutes so that the • 75 4500 0.56 0.12 559 1350 -791
peak flow =.90(3.18)(Imp. Area) = 0.32 cfs 80 4800 0.53 0.11 563 1440 -877
85 5400 0.50 0.11 596 1620 -1 0-944
` 90
24
So, the Peak flaw for the Basin Is tfie greater of the two flows, 95 5700 0.49 0.11 616 1710 -1094
0.64 cfs 100 6000 0.48 0.10 634 1800 -1166
. . i~ 4
% 208' DRAINAGE POND CALCULATIONS
,S Required 208' Storage Volume
Impervious Area x.5 in / 12 in/ft 204 cu ft
~ii ;,.'z:'\'z i;•;~
•g;
,r„z>, z., ~ 208' Storage Volume Provided 215 cu ft
zi.::,:<Z;i, ~
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Storage Required by Bowstring 193 cu R
k,mz~;; xc; Number and Type of Drywe[Is Required 1 Single
0 Double
BOWSTRING METHOD PROJECT: Rivenralk 5fh Additlon
PEAK FLOW CALCULATION PROJECT Rivervwalk 5th Additbn DETENTION BASIN DESIGN BASIN: D
BASIN: D 10-Year Deslgn Storm DESIGNER: S. Murphy
Tat. Area 0.21 Acres DATE: 4/11196
Imp. Area 3125 SF
C = 0.40
Time Increment (min) 5
CASE 1 f*Time of Conc. (min) 5.12
-}v,,-Outtlow (cfs) 0.3
70 ft. Overland Flow M Deslgn Year Flow 10
Area (acres) 0.21
3125
Ct = 0.15 ImPervfous Area (SQ ft)
L= 70 ft. W: i'C Factor 0.4
n= 0.40 208' Voiume Provlded 140
S= 0.020 a~:i,iz Area ' C 0.084
Tc = 3 58 min., by Equatfan 32 of Guidelines
Time Time Inc. Irttens. Q Devel. Vol.ln Vol.Out Storage
130 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 ForZ2 5.12 307 3.15 0.26 109 92 17
Z2 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 = 5 300 3.18 0 77 107 90 17
S a 0.016 :ti.......,.. ~ 10 600 2.24 0.119 133 180 47
15 900 177 0.15 149 270 -121
d= 0.083 ft. 20 1200 1.45 0.12 159 360 -201
25 1500 1.21 0.10 163 450 487
A R Q Tc Tc total I Qc 1~'~ 30 1800 1.04 0.09 166 540 -374
r:;'„'35 2100 0.91 0.08 169 630 -01
0.18 --------0.04 0.26 1.54 5.12 3.15 0.26 r;zi i*40 2400 0.82 0.07 173 720 S47
v;a~vzwtx`:;:~ 45 2700 0.74 0.06 174 810 -636
Q peak for Case 1~ • 0.26 cfs 50 3000 0.68 0.06 177 900 -723
•,.~~',~.;~}gg'~c; i;,„ 55 3300 0.64 0.05 183 990 -807
a,. 60 3600 0.61 0.05 190 1080 -890
CASE 2 z' 65 3900 0.60 0.05 202 1170 -968
Mii~
„Z;~::rsai;..;:t: 70 4200 0.58 0.05 210 1260 -1050
75 4500 0.56 0.05 217 1350 -1133
~~e oAC~oncentratlon less than 5 min 2es ~that the ~ ~ ~
~ 053 0.04 218 1440 1222
P~ flow 90(3.18)(mP• ) =
t~.:zx:e~.:z;i..i 85 5100 0.52 0.04 227 1530 -1303
-.:....::zv:.a~ ~i 90 5400 0.50 0.04 231 1620 -1389
So, the Peak fbw for the Basin is Uhe greater of the two 8ows, 95 5700 0.49 0.04 239 1710 -1471
0.26 cfs " ~.100 6000 0.48 0.04 246 1800 -1554
x?" 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft 130 cu ft
µ •z~x,.
: 208' Storage Volume Provided 140 cu ft
N 'r~~x: ;•xa
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Mwdmum StoraSe Re4uired bY Bowstrin9 17 cu ft
Number and Type of Orywells Required 1 Single
0 Double
` , .
BOWSTRING METHOD PROJECT: Rivervralk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverviralk Sth Addidon DETENTION BASIN DESIGN BASIN: E
BASIN: E 10-Year Design Stortn DESIGNER: S. Murphy
Tot. Area 0.12 DATE: 4/11/96
Imp. Area 2090 SF x~
C = 0.40 „~`x.~~
.xi ~tr
Time IncremeM (min) 5
CASE 1 Time of Conc. (min) 5.00
outflow (cis) 0
70 ft. Overfarxi Flow Design Year Fbw 10
Area (acres) 0.12
Ct = 0.15 Impervious Area (sq ft) 2090
L= 70 ft. r'C' Factor 0.4
n= 0.40 "208' Volume Provided 88
S= 0.020 Area • C 0.448
Tc = 3.58 mfn., by Equation 32 of Guidellnes
Time Time Iric. Irttens. Q Deuoel. Vol.tn Vol.Out Storage
100 ft. Gutter ftav zx`IkR(min) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft)
,
~••••,;:#;k~~` ___aava= ~vccv=a: e=aaa=aa a~~~~ca~~ ~ a_==== ==a
Z1 = 50.0 ForZ2 5.00 300 3.18 0.15 61 0 61
72 = 3.5 Type B= 1.0
,',bcaz:
n= 0.016 Rolled = 3.5 ~ 5 300 3.18 0.15 61 0 61
t;.;;'r. i
S= 0.016 10 600 224 0.11 75 0 75
` 15 900 1.77 0.08 85 0 85
d= 0.068 ft. ~`t t~ 20 1200 1.45 0.07 91 0 91
3
25 1500 1.21 0.06 93 0 93
A R Q Tc Tc total I Qc 30 1800 1.04 0.06 95 0 95
;i 35 2100 0.91 0.04 96 0 96
x=¢
' ~ ~::,~x;.
?i
0.12 0.03 0.7 5 1.35 5.00 3.18 0.15 I; 40 2400 0.82 0.04 98 0 98
45 2700 0.74 0.04 100 0 100
z:3'^ •3~3;~k~.,
Qpeak for Case 1= 0.15 cfs 50 3000 0.68 0.03 101 0 101
55 3300 0.64 0.03 105 0 105
i?gp 3600 0.61 0.03 108 0 108
~ ~;~e:t;•:.::,Y.
CASE 2 65 3900 0.60 0.03 115 0 115
70 4200 0.58 0.03 120 0 120
N~µ.~.....~.~:
Case 2 assumes a Time of Corcentration less than 5 minutes so that the 75 4500 0.56 0.03 124 0 124
pealc flow =.90(3.18)(Imp. Area) = 0.14 cfs 80 4800 0.53 0.03 125 0 125
85 5100 0.52 0.02 130 0 130
90 5400 0.50 0.02 7 32 0 132
So, the Peak flow for the Basin is the greater of the two flows, 95 5700 0.49 0.02 136 0 136
0.15 c i s 100 6000 0.48 0.02 141 0 141
.
208' ORAINAGE POND CALCULATIONS
vi4 v ~
Required'ZOS' Storage Volume
Impervious Area x.5 In / 12 INft 87 cu ft
208' Storage Volume Provided 88 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
MaAmum Storage Required by Bowshing 130 cu ft
r:•:a~~i~:~::
Number and Type of Drywells Required 0 Single
ERR Double
BOWSTRING METHOD PROJECT: Riverwalk Sth Addition
PEAK FLOW CALCULATION PROJECT Rivervralk Sth Addidon „x DETENTION BASIN DESIGN BASIN: Pre-dev F
BASIN: Pre-dev F 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.98 Acres DATE: 4/11/96
Imp. Area 0 SF
C = 0.30
Time Increment (min) 5
CASE 1 Time oi Conc. (min) 5.00
Outtiow (cis) 1
150 ft. Overhand Flow Design Year Flow 10
Area (acres) 1.98
Ct = 0.15 Imperv(ous Area (sq ft) 0
L= 150 ft. 'C' Factor 0.3
n= 0.40 '208' Vdume Provided 0
S= 0.040 Area • C 0.594
Tc = 4.60 mtn., by EquaUon 3-2 of Guidelines
Time Time Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
0 ft. Gutter fiow (min) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For 7-2 5.00 300 3.18 1.89 759 300 459
7-2 = 3.5 Type B= 1.0 N"'~
n = 0.016 Rolled = 3.5
5 300 3.18 1.89 759 300 459
S= 0.005 10 600 2.24 1.33 934 600 334
15 900 1.77 1.05 1053 900 153
d= 0.206 ft. ZO 1200 1.45 0.66 1121 1200 -79 .
25 1500 1.21 0.72 1151 1500 -349
A R Q Tc Tc total I Qc 30 1800 1.04 0.62 1175 1800 -625
35 2100 0.91 0.54 1190 2100 -910
1.14 0.10 1.64 0.00 5.00 3.18 1.89 40 2400 0.82 0.49 1219 2400 -1181
45 2700 0.74 0.44 1232 2700 -1468
Q k for Case 1= 1.89 cfs
P~ 50 3000 0.68 0.40 1253 3000 -1747
55 3300 0.64 0.38 1293 3300 -2007
60 3600 0.61 0.36 1341 3600 -2259
CASE 2 65 3900 0.60 0.36 1426 3900 -2474
10a." .Ir
70 4200 0.58 0.34 1482 4200 -2718
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.33 1531 4500 -2969
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.31 1543 4800 -3257
85 5100 0.52 0.31 1607 5100 -3493
~ii:xz :i: xK=Z? 90 5400 0.50 0.30 1634 5400 -3766
So, the Peak flow for the Basin is the greater of the Mro flows, 95 5700 0.49 0.29 1689 5700 -4011
1.89 cis 1-1-1k 100 6000 0.48 0.29 1740 6000 -4260
r,a
zM;~•,•;;~;w;
208' DRAINAGE POND CALCULATIONS
Requfred 'ZOS' Storage VoJume
Impervious Area x.5 in / 12 iNft 0 cu ft
' 208' Storage Vdume Provided 0 cu ft
:z:>
;x:•~ z;::a:,~'~;~
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Storage Requlred by Bowstring 459 cu ft
Number and Type of Drywells Requlred 0 Single
1 Double
~~t BOWSTRING METHOD PROJECT: Rivervvalk 5!h Add'Rion
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth Addition DETENTION BASIN DESIGN BASIN: Developed F
BASIN: Devebped F ~10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.98 Acres ~ DATE: M11/96
Imp. Ar~ 0 SF ~C = 0.26
'KM 'm Time Incxement (min) 5
CASE 1
Time of Conc. (m(n) 5.00
Outflow (cfs) 1
150 ft. Over~nd Flow N~~..
- Deslgn Y~r Ftaw 10
, Area (acres) 1.98
Ct = 0.15 Impervlous Area (sq ft) 0
M M 2~
L _ 150 s. 'cFaaor 0.26
n= 0.40 208' Volume Provided 0
S= 0.040 ; 2~~ k x k Area • C 0.515
} ' `~2h.2 i E22 i •
Tc = 4.60 min., by Equation 3-2 of Guidelines
Z:~: ~ Ttme Time Inc. Intens. Q Devei. Vol.ln Vol.Out Storage
0 ft. Gutter flow i ; ~ ' (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
:z
`r,`, i i Z;Nz~ i ' ' ====a- aa===°=_ °_-====aa ac=aca_ : acaa: a==
Z1 = 50.0 For Z2 M ~z; °5.00 300 3.18 1.64 658 300 358
72 = 3.5 Type B= 1.0 ;n= 0.016 Rolled = 3.5 5 300 3.18 1.64 658 300 358
S= 0.005 10 600 2.24 1.15 810 600 210
15 900 1.77 0.91 913 900 13
d= 0.206 ft. 20 1200 1.45 0.75 972 1 Z00 -728
~ 25 1500 1.21 0.62 998 1500 S02
A R Q Tc Tc total 1 Qc 30 1800 1.04 0.54 1018 1800 -782
; 35 2100 0.91 0.47 1032 2100 -1068
r.:';;,,~:~ :
1.14 0.10 1.64 0.00 5.00 3.18 40 2400 0.82 0.42 1056 2400 -1344
~45 2700 0.74 0.38 1067 2700 -1633
QP~k for Case 1= 1.64 cis ~
~~x.,„,.:„,~• 50 3000 0.68 0.35 1086 3000 -1914
„;w~ 55 3300 0.64 0.33 1121 3300 -2179
^,60 3600 0.61 0.31 1163 3fi00 -2437
CASE2 ~
65 3900 0.60 0.31 1236 3900 -2664
;ia~ n`~„~`~i~ 70 4200 0.58 0.30 1285 4200 -2915
Case 2 assumes a Time of CorscentraUon less than 5 minutes so that Use i:~?~`?ic:: 75 4500 0.56 0.29 1327 4500 -3173
,
.r.,..,...,..
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.27 1337 4800 -3463
85 5100 0.52 0.27 1393 5100 -3707
90 5400 0.50 0.26 1416 5400 -3984
~~:i::: cw zc
So, the Peak flow for the Basin is the greater of the two fbws, 95 5700 0.49 0.25 1464 5700 -4236
1.64 cfs 100 6000 0.48 0.25 1508 6000 -4492
208' ORAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervlous Area x.5 In / 12 tNft 0 cu ft
.x
208' Storage Volume ProNded 0 cu ft
Y~
po..~ .i
u.~~~ ~ DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Storage Required by Bawstring 358 cu ft
`,~~"kr Number and Type of Drywells Required 0 Single
1 Double
BOWSTRING METHOO PROJECT: Riverwalk Sth AddiUon
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition DETENTION BASIN DESIGN BASIN: Pre-dev G
. Y vsvwv~
BASIN: Pre-dev G 1QYear Design Storm DESIGNER: S. Murphy
ToL Area 1.40 Acres DATE: 4/11l96
Imp. Area 0 SF
%
C = 0.30
Time IncremeM (min) 5
CASE 1 Time of Conc. (mtn) 5.00
Outflow (cfs) 1
150 ft. Ov@rtand FloW ~r~~~•,~ Destgn Year Flow 10
y~µ; Area (acres) 1.4
Ct = 0.15 : zr, Impervious Area (sq ft) 0
L= 150 ft. C' Factor 0.3
n= 0.40 ~ } z2 ~'208' Volume Provided 0
S= 0.040 ~i;r : Area ' C 0.420
x ~z
~z.z.;~.. ,
••t•:xz: :
Tc = 4.64 min., by Equation 32 of Guideliries
0 ft. Gutter fiow m ne Time~. Irtt~ f Q De~ sl. ~.I~n Vol. Oft St ~ fte
M ~ ~ ~ ~ ( ) (c ) )
: ;i;i ~..::z
, .xr ;tx,r
Z1 = 50.0 For 7-2 5.00 300 3.18 1.34 537 300 237
~x :z
Z2 = 3.5 Type B= 1.0
5 300 3.18 1.34 537 300 237
n= 0.016 Rolled = 3.5
S= 0.005 10 600 2.24 0.94 660 600 60
~=~t~ 15 soo 1.77 0.74 745 soo -155
d= 0.206 ft. m" ?~m 20 1200 1.45 0.61 793 1200 -407
"~~~ti•i ~ 25 1500 1.21 0.51 814 1500 -686
A R a Tc Tc total t Qc ' 30 1800 1.04 0.44 831 1800 -969
--------~.~,,%i 35 2100 0.91 0.38 842 2100 -1258
i.: ~i?;i ;;~:'i`i
1.14 0.10 1.64 0.00 5.00 3.18 1.34 40 2400 0.82 0.34 862 2400 -1538
~..s`„. ;~=r~,c`
45 2700 0.74 0.31 871 2700 -1829
Qpeak for Case 1= 1.34 cfs r~% 50 3000 0.68 0.29 886 3000 -2114
:"x.;;~,~?:. 55 3300 0.64 0.27 914 3300 -2386
60 3600 0.61 0.26 948 3600 -2652
CASE 2 65 3900 0.60 0.25 1009 3900 -2891
«70 4200 0.58 0.24 1048 4200 -3152
Case 2 assumes a Time oi ConcentraUm less than 5 minutes so that the 75 4500 0.56 0.24 1082 4500 -3418
ak flow =.90 3.18 Im Ar~ 0.00 cfs 80 4800 0.53 0.22 1091 4800 ~709
Pe ( P• ) _ rc'rsi:
85 5100 0.52 0.22 1136 5100 -3964
n, 90 5400 0.50 0.21 1155 5400 -4245
So, the Peak flaw for the Basin is tlhe greater of the two flows, ; 95 5700 0.49 0.21 1194 5700 -4506
1.34 Cfs 100 6000 0.48 0.20 1230 6000 4770
i:;;208' DRAINAGE POND CALCULATIONS
""Required'208' Storage Volume
impervious Area x.5 in / 12 INft 0 cu ft
:N~208' Storage Volume Provided 0 cu ft
REQUIREMENTS-10YEAR DESIGN STORM
Ma)dmum Storage Required by Bovvstring 237 cu ft
Number and Type of Drywells Requlred 0 Single
1 Double
BOWSTRING METHOD PROJECT: Rivenwalk Sth AddiGon
PEAK FLOW CALCULATION PROJECT RNerwalk Sth Additbn DETENTION BASIN DESIGN BASIN: Developed G
BASIN: Develaped G 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.40 Acte.s DATE: 4/11 /96
Imp.Area 0 SF
C = 0.15
Time IncremeM (min) 5
CASE 1 Time of Conc. (mtn) 5.00
Outflow (cfs) 1
150 ft. Overland Flaw Deslgn Year Flow 10
'ki' Mea (acres) 1.4
K
Ct = 0.15 ImpeMous Area (sq ft) 0
L= 150 R. ~:.•.••^~;c.'C Factor 0.15
n= 0.40 '08' Volume Provided 0
S= 0.040 Area ' C 0.210
-k:~.?i:~~ .
Tc = 4.60 min., by Equation 3-2 of Guideiines ~;,-M
Time Time Inc. Intens. Q Devel. Voi.ln Vof.Out Storage
0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For Z2 5.00 300 3.18 0.67 268 300 -32
Z2 = 3.5 Type B =1.0 ;~M,
n= 0.016 Rolled a 3.5 5 300 3.18 0.67 268 300 -32
S = 0.005 a
10 600 2.24 0.47 330 600 -270
15 900 1.77 0.37 372 900 -528
d= 0.147 ft. 20 1200 1.45 0.30 396 1200 -004
25 1500 1.21 0.25 407 1500 -1093
A R Q Tc Tc tohal I Qc 30 1800 1.04 0.22 415 1800 -1385
~ i;ei:::~ 35 2100 0.91 0.19 421 2100 -1679
0.58 0.07 0.67 0.00 5.00 3.18 0.67 V40 2400 0.82 0.17 431 2400 -1969
45 2700 0.74 0.16 435 2700 -2265
Qpeak for Case 1= 0.67 cfs 50 3000 0.68 0.14 443 3000 -2557
55 3300 0.64 0.13 457 3300 -2843
60 3600 0.61 0.13 474 3600 -3126
CASE 2 65 3900 0.60 0.13 504 3900 -3396
70 4200 0.58 0.12 524 4200 -W6
Case 2 assumes a Time of ConceMratfon less than 5 minutes so that the 75 4500 0.56 0.12 541 4500 -3959
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.11 546 4800 -4254
85 5100 0.52 0.11 568 5100 4532
90 5400 0.50 0.11 578 5400 -4822
So, the P~k flow for the Basin is the 9reater of the two 8ows,
95 5700 0.49 0.10 597 5700 5103
0.67 Cfs •>'a;;z.: zz: : 100 6000 0.48 0.10 615 6000 5385
,
. 208' DRAINAGE POND CALCULATIONS
Required'Z08' Storage Volume
Impervious Area x.5 In / 12 tNft 0 cu ft
% 208' Storage Volume Provided 0 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Storage Required by Bowstring -32 cu ft
Number and Type of DryNrells Required 0 Single
•zzii3•,~,:::::::,?: 1 Double
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1
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CURB INLET CALCULATIONS
'
1 ,
,
,
'
'
'
1 .
'
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1
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208' Pond Calculations
Project: Riverwalk 5th Addition
Date: 01-Apr-96
Designer: S. Murphy
Upstream Carryover Accumul. Pond '208'
'208' Curb Inlet Imper. Storage Storage Storage Type/ Storage Carryover
Sub-Basin Station R/L Area Re4't Req't Req't Size Provided Downstream
A1 43+73 R 4068 169.5 169.5 10x30 180.0
A2 41 +72 R 3319 138.3 138.3 13x18 140.3
A3 40+85 R 3994 166.4 166.4 14x25 204.3
B 1 43+88 R 1955 81.5 81.5 11 x12 83.3
62 42+70 L 2088 87.0 87.0 12x12 90.0
63 40+85 L 5699 237.5 237.5 16x26 240.0
CURB INLET CALCULATIONS
Curb Inlet Depression = 2 in.
Standard Curb Inlet Length = 4 ft.
Upstream 10.Yr. Gutter Roughnes Reciprocal Depth Length
Curb Inlet Impervious Peak Flow Slope Coeff. Cross slope of Flow Required
Sub-Basin Station R/L Area c.f.s. ~ S n Z ZJn d' Qa/La** Q/(Qa/La) _ Remarlcs _
A1 43+73 R 4068 0.27 0.0081 0.0160 50 3125 0.09 0.063 4.26 Need - 1 4' (nlet
A2 41+72 R 3319 0.55 0.0052 0.0160 50 3125 0.13 0.090 6.12 Need - 1 4' Inlet
A3 40+85 R 3994 0.85 Sump Condition
61 43+88 R 1955 0.43 0.0052 0.0160 50 3125 0.12 0.082 5.25 Need - 1 5' Inlet
62 42+70 L 2088 0.46 0.0052 0.0160 50 3125 0.12 0.084 5.47 Need - 1 5' Inlet
63 40+85 L 5699 0.74 Sump Condition
D 40+85 L 3125 0.26 0.0160 0.0160 50 3125 0.08 0.055 4.73 Need - 1 4' Inlet
F 40+85 R 2090 0.15 0.0160 0.0160 50 3125 0.07 0.083 1.81 Need - 1 4' Inlet
* Calculated per Figure 18 of Guidelines
" Calculated per Figure 16 of Guidelines
A 4 foot curb drop with a 6" gutter has a capacity of 4.0 cfs in sump condition
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)KANE COUNTY, WASHINGTON - SHEET NUMBER 67
, R qq E~P 45 E (Joins sheet 58)
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i
I STORM DRAINAGE ANALYSIS
1 for
` RIVERWALK
5TH ADDITION
~
~
' April 11, 1996
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!
Prenared Bv:
~ Inland Paci rc En 'neerin
f ~ g
707 West 76 Suite 200
t Spokane, WA 99204
(509)-458-6840
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~ DRAINAGE REPORT
' for
~
RIVERWALK
~ 5TH ADDITION
1
APRIL 11, 1996
~ Prepared by:
, Inland Pacific Engineering Company
707 West 7th Suite 200
, Spokane, WA 99204
(509)458-6840
' This report has been prepared by the staff of Inland Pacific Engineering Company under the direction
of the undersigned professional engineer whose seal and signature appear hereon. This report
~ conforms to the applicable editions of the Spokane County Standards for Road and Sewer
Construction and the Spokane County Guidelines for Stormwater Management.
1
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25w 46L
~~OIVpl,
'
~ EXPiRES 9/24/ ~
' Todd R. Whipple, P.E.
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i
I PURPOSE
, The purpose of this report is to determine the extent of storm drainage facilities which will be
required to dispose of stormwater runoff created by the development of Riverwalk Sth Addition.
The storm drainage facilities on this project will be designed to dispose of stormwater runofffor
1 the 10-year storm event as required by Spokane County and The Guidelines for Stormwater
Manaeement. This development is within the Aquifer Sensitive Area and is subject to `208'
requirements.
, ANALYSIS METHODOLOGY
, The Rational Method, which is recommended for basins less than ten acres in size, will be used to
determine the peak discharges and runoffvolumes for the 10-year storm event. Bowstring
' calculations will be used to deternune the volume of stormwater created by the 10-year storm
event. The drainage analysis for this project will follow The Snokane Countv Guidelines for
Stormwater Manaeement.
, PROJECT DESCRIPTION
~ Riverwalk P.U.D. 4th Addition is a 7.10 acre, 261ot sub-division, located in the S'/z of the SW
1/4 and Government Lots 5 and 6 of Section 8, T. 25 N., R. 45 EWM. Sheet 67 of the Soil
Survev of Snokane Countv. Washington (copy attached) shows the soils types to be GgA,
~ (Garrison gavelly loam, 0 to 5% slopes), GgB, (Garrison gavelly loam, 5 to 20% slopes), and
Rh (Riverwash).
1 PROJECT SOILS DESCRIPTION
A brief description from the USDA -Soil Conservation Service, Soil Survev of Sookane Countv.
~ Washineton for each soil type follows.
Garrison gravelly loam with 0 to 5 percent slopes (GgA) is a somewhat excessively drained
, soil formed from a variety of igneous rock. Surface runoff is slow, and the hazard of water
erosion is slight to moderate. Spokane County Guidelines for Stormwater Management has
, pre-approved this soil for drywell installation. The soil is suited for homesite development.
Garrison gravelly toam with 5 to 20 percent slopes (GgB) is similar in all characteristics to
1 GgA except this soil type has a surface layer thinner than GgA soil types. Garrison gravelly loam
with 5-20% slopes (GgB) soil types have runoffwhich is medium, and the hazard of erosion is
moderate. Spokane County Guidelines for Stormwater Manaaement has pre-approved this soil
1 for drywell installation.
Riverwash (Rh) consists of gavel, cobblestones and stones, with very little finer material, found
. '
Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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~ on low bottoms along perennial and intermittent streams. The areas are flooded nearly every year
from runoff, and only serve to protect against channel cutting.
~ DEVELOPED CONDITION
1 In the developed condition, the project can be divided into 7 basins, (A through G) by the crowns
and high points of the various road improvements, and the natural topography.. (See Basin Map,
copy attached.)
' BASIN AND STORMWATER DISPOSAL SUMMARY
, Basins A through F will be designed to dispose of stormwater created by the 10-year storm event.
The stormwater created by this event will be disposed of in ponds and Spokane County Standard
, drywells.
Basin A consists of portions of the road impervious areas on the south side of Riverwalk Lane,
~ and the west side of Ivi'ichielli Lane. This basin also includes half of lot 1, of lots 2 through 5,
block 3, and lots 1 and 2, block 4. The peak flow of 0.27 c.f.s. for sub-basin A1 will be disposed
of in intermediate Pond A1, the peak flow of 0.55 c.f.s. will be disposed of in intemnediate Pond
' A2, and the peak flow for sub-basin A3 of 0.85 c.f.s. will be disposed of in Pond A3, which has
one Type "B" drywell: in sump condition.
, Basin B consists of a portion of the road impervious area on the north side of Riverwalk Lane.
This basin also a section of lot 1, block 5 and of lots 1 through 7, block 6. The peak flow of 0.43
c.f.s. for sub-basin B 1 will be disposed of in intermediate Pond B1, the peak flow of 0.46 c.f.s. in
sub-basin B2 will be disposed of in intermediate Pond B2, and the peak flow of 0.74 c.f.s. for
sub-basin B3 will be disposed of Pond B3, which has one Type "B" drywell in sump condition.
, Basin C consists of portions of the road impervious area on the east side of Michielli Lane, and
the south side of Riverwalk Lane.This basin also includes half of lot 3, and all of lots 4 and 5,
~ block 2. The peak flow of 0.64 c.f.s. will be disposed of in Pond C which one Type "A" drywell
in sump condition.
Basin D consists of portions of the road impervious on the north side of Shannon Lane, and the
' west side of Michielli Lane. This basin also includes half of lot 1, block 3, and a portion of one
future lot. The peak flow of 0.21 c.f.s. will be disposed of in Pond D with one Type "A" drywell.
~ Basin E consists of a portion of the road impervious area on the south side of Shannon Lane.
This basin also includes half of lot 1, block 1. The peak flow of 0.15 c.f.s. will be disposed of in
' Pond E.
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' Basin F consists of the northern section of lot 1, block 5, and lots 1 through 7, block 6, and all of
Tract C. The basin has been analyzed in the pre-developed and developed condition. The pre-
' developed condition assumes a"C" factor of 0.30, representing meadows and pastureland. The
peak flow was calculated to be 1.89 c.f.s.. In the developed condition, the northern section of lot
1, block 5 and lots 1 through 7, block 6 were assumed to be landscaped with lawn, in sandy soil
, rolling terrain, which reduces the "C" factor for that portion to 0.15.. The Tract C area falls
within the Spokane County Shoreline Progam, and will remain undisturbed. The "C" factor for
that portion will remain 0.30. Using a weighted "C" factor, the peak flow for the developed
' condition was calculated to be 1.64 c.f.s.. The peak flow in the developed condition is lower than
the peak flow from the pre-developed condition by 0.25 c.f.s..
' Basin G consists of the northern section of lots lthrough 3, block 7, and exsiting lots 1, block 3,
and lots 1 through 4, block 4 of Riverwalk 3rd Addition, and all of Tract A. The basin has been
analyzed in the pre-developed and developed condition. The pre-developed condition assumes a
, "C" factor of 0.30, representing meadows and pastureland. The peak flow was calculated to be .
1.34 c.f.s. In the developed condition, the entire area was assumed to be landscaped with lawn, in
, sandy soil rolling terrain, which reduces the "C" factor to 0.15. The peak flow for the developed
condition was calculated to be 0.67 c.f.s.. The peak flow in the developed condition is lower than
the peak flow from the pre-developed condition by 0.67 c.f.s..
~ Pond Al, Riverwalk 3rd Addition, was designed as part of the drainage plan for Riverwalk 3rd
. Addition, but will be built as part of Sth Addition. It is located at the southwest end of Micheilli
, Lane, and was designed as an intermediate pond to store `208' volume from the road impervious
area upstream. Pond A2, Riverwalk 3rd Addition, will store the storm volume. See the
calculations and Basin Map for Riverwalk 3rd Addition.
1 Pond B1, Riverwalk 3rd Addition was designed as part of the drainage plan for Riverwalk 3rd
Addition. It is located on the north side of Nfichielli Lane, and was designed as an intermediate
, pond to store `208' volume from the road impervious area upstream. Pond 112, Riverwalk 3rd
Addition, will store the storm volume. See the calculations and Basin Map for Riverwalk 3rd
, Addition. The north half of these lots are included in Basin G calculations for Riverwalk Sth
Addition.
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STORMWATER CALCULATIONS
, The stormwater from the 7 basins will be disposed of in'208' retention ponds and Spokane
County drywells as shown on the plans and in the attached Bowstring Calculation sheets.
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Inland Pacific Enginesring, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' The stormwater from the 7 basins will be disposed of in'208' retention ponds and Spokane
County drywells as shown on the plans and in the attached Bowstring Calculation sheets.
Table 1 lists the total and impervious areas and the "C" factor for the Time of Concentration and
Peak Flow calculations.
~ Table 2 summarizes the retention volumesrequired for each basin as calculated by the Bowstring
Calculations, as well as the depth, area, perimeter and volume provided.
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~ ~ . . . > y~"~*t a ,xsxrc: ; t;t~^h~ , . ,x, •sxs•• x s, • ~;aWz f
' • , .+a.%x,' Y.~Y3~3~% f., ~ l .R:ic'.~cYx v,.t..x....~F .s~
' >'h> r ° { _Y' , ~c.a~•`.'C:£kGk 4:wfi`~};;k:x'y`l
fi ~.~n~ ;~4~~s~f ~.~4~ ` ~.►,~i. . E r st,~ , t
z . n E,ff ~,~~Kr..,,~ ;
BASIN TOTAL TOTAL IlVIP. AREA # LOTS DU/GA "C"
1 AREA (S.F.) AREA (AC.) (S.F.)
, A1 15,483 0.36 4068 1.0 2.78 0.25
1 A2 21,259 0.49 3319 2.5 5.10 0.40
A3 34,133 0.78 3994 3.0 - 3.85 0.35
, A 70,875 1.63 11,381 6.5 5.65 0.40
B1 10,034 0.23 1955 1.5 6.52 0.60
' B2 10,764 0.25 2088 1.5 6.00 0.60
, B3 28,470 0.65 5699 3.0 4.62 0.40
B 49,268 1.13 9742 6.0 5.31 0.40
, C 15,609 0.36 4884 2.5 6.9 0.60
D 9281 0.21 3125 1.0 4.76 0.40
' E 5135 0.12 2090 0.5 4.17 0.40
F 86,355 1.98 - - - 0.26
, G 60,927 1.40 - - - 0.15
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Liland Pacific Engineering, Inc. Riverwallc P.U.D. Sth Addition - Drainage
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' `208 RETENTION VOLUME CALCUI.ATIONS
''208' retention volumes were calculated using the following formula:
Volume (cu. ft.) _ (depth)(area) + (slope azea)(perimeter)
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ON . , f .,§-*'A
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Mi~•:.•.,,. . '~"`:.A7.>r
POND DEPTH AREA PERIlMEET'ER VOL. REQ'D. VOL. PROV.
' A1 .5 300 80 170 180
AZ .5 234 62 138 140
, A3 .5 350 78 166 204
' Bl .5 132 46 81 83
B2 .5 144 48 87 90
B3 .5 416 84 237 240
C .5 360 92 204 215
1 D .5 230 66 130 140
E .5 140 48 87 88
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Notes: Typical sideslopes are 3:1 maximum.
1 Ponds Al, A2, B 1 and B2 are intermediate `208' Ponds designed to handle the upstream
impervious areas only.
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Inland Pacific Engineering, Inc. Riverwallc P.U.D. Sth Addition - Drainage
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, STORM VOLUME STORAGE
`208' storage is provided in the first .5' of depth in all ponds. Pond bottom elevations of intermediate ponds are
' set .5' below the flow line, and sized to contain the upstream `208' requirement only. Should there be an
overflow, water will flow out of the lowest curb inlet in each intermediate pond to the next pond downstream.
1 Pond bottom elevations of terminal ponds with drainage structures (located at the low point of a basin) are set .9'
below the flow line. This allows an additional.4' storage above the `208' storage.
, Pond A3 illustrates the storm volume storage above the .5' depth for `208' storage:
Total `208' storage required for Sub-basin A3 166.0 cubic feet
' Total `208' storage provided at .5' depth 204.3 cubic feet
Total Bowstring requirement for Basin A(See Sheet 8) 578.0 cubic feet
~1 208' storage provided, Ponds A1, A2 &A3 474.0 cubic feet
Storm volume storage required 104.0 cubic feet
~ Storage volume provided at .7' depth, Pond A3 302.3 cubic feet
`208' Storage provided 166.0 cubic feet
1 Storm volume provided 136.3 cubic feet
Pond E also will store storm volume above the .5' depth reserved for `208' storage:
' Total `208' storage required for Basin E 87.0 cubic feet
Total `208' storage provided at .5' depth 88.0 cubic feet
' Total Bowstring requirement (See Sheet 18) 130.0 cubic feet
`208' storage provided, Pond E 87.0 cubic feet
' Storm volume storage required 43.0 cubic feet
Storage volume provided at 7 depth 133.5 cubic feet
1`208' Storage provided 87.0 cubic feet
Storm volume provided 46.5 cubic feet
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Inland Pacific Engineering, Inc. Riverwalk P.U.D. Sth Addition - Drainage
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' CURB INLET AND GRATE INLET CALCULATIONS
~ It is necessary to check the adequacy of curb inlets provided to divert the flows from the gutter to the retention
ponds. The Curb Inlet Calculation Sheet included in this report (see calculation sheet, copy attacherl) shows the
required lengths of curb openings. As shown on the calculation sheet, various ponds have different curb inlet
~ requirements. Therefore, the required curb openings have been provided according to the tabulated results. All
curb inlets shall be standard 4' openings, unless otherwise noted.
It is also necessary to check the capacity of grate inlets on continuous grade. The Grate Calculation - Continuous
Grade worksheets have been included. The calculations have been completed in accordance with Fisure 15 of
St)okane Countv Guidelines for Stormwater Manasement. (See calculation sheets, copy attached.)
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Inland Pacific Engineering, Inc. Riverwallc P.U.D. Sth Addition - Drainage
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' APPENDIX
' Developed condition 1-7
Peak Flow and Bowstring 8- 22
, Curb Inlet calculations 23 -24
Soils Map 25
Basin Map 26
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PEAK FLOW AND BOWSTRING
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BOWSTRING METHOD PROJECT: Riverwalk 5th Addition
PEAK FLOW CALCUTATION PROJECT Rlverwalk Sth Adddion DETENTION BASIN DESIGN BASIN: A
BASIN: A ;z~,114 , 10-Year Destgn Storm DESIGNER: S. Murphy
Tot. Area 1.63 Actes ~ DATE: 411/96
Imp. Area 11381 SF
C = 0.40 ~r s
' ~ : Time Increment (min) 5
CASE 1 Time of Conc. (min) 8.59
_=====70 ft. Overtand Fbw rn ' Outflow (cfs) 1
~ Design Year Fbw 10
~ t Area (acres) 1.63
Ct = 0.15 `~U M, : ImpeMous Area (sq ft) 11381
L= 70 ft. 'C Factor 0.4
n= 0.40 Volume Provided 474
S= 0.020 Area • C 0.652
Tc a 3.58 mtn., by Equation 3-2 oi Guidelines
~i~r
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Stwage
;
460 ft. Gutter flow ;.s^,.l~~ (min) (INhr) (c~) (cu ft) (cu ft) (cu ft)
a ccca====
i ~~2; } i~^`• aw=aae
Z1 0 50.0 For Z2 8.59 515 2.43 1.58 1093 515 578
Z2 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 5 300 3.18 2.07 833 300 533
S= 0.006 10 600 2.24 1.46 1132 600 532
15 900 1.77 1.15 1241 900 341
d= 0.186 ft. 20 1200 1.45 0.95 1300 1200 100
~w.~ 25 1500 1.21 0.79 1371 1500 -178
i,~:~ ~
A R Q TC TC total I QC a~~:r.}.' zi 30 1800 1.04 0.68 1339 1800 -461
=~~r 35 2100 0.91 0.59 1350 2100 -750
.az.z•••
1.03 0.10 1.57 5.01 8.59 2.43 1.58 40 2400 0.82 0.53 1377 2400 -1023
ii~....::~'45 2700 0.74 0.48 1387 2700 -1313
Qpeak for Case 1= 1.58 cfs M, µ„~:lz~ 50 3000 0.68 0.44 1408 3000 -1592
r: 55 3300 0.64 0.42 1450 3300 -1850
60 3600 0.61 0.40 1501 3600 -2099
CASE 2 z'~ i 65 3900 0.60 0.39 1594 3900 -2306
70 4200 0.58 0.38 1655 4200 -2545
Case 2 essumes a Time of ConcentraUon less than 5 minutes so that the 75 4500 0.56 0.37 1707 4500 -2793
peak
flow =.90(3.18)(Imp. Area) = 0.75 cfs ;
x~~;``?:;:x,•w 80 4800 0.53 0.35 1719 4800 -3081
85 5100 0.52 0.34 1789 5100 3311
90 5400 0.50 0.33 1818 5400 3582
:'~z;,z.A ~
So, the Peak Baw tor the Basln is the 9reater of the two flovvs, 95 5700 0.49 0.32 1877 5700 -3823
1.58 Cfs 100 6000 0.48 0.31 1933 6000 -4067
xrz
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r~~gw~,208' DRAINAGE POND CALCULATIONS
Required'ZOS' Storage Volume
Impervious Area x.5 in / 12 in/ft 474 cu ft
~ i• r~~~ 208' Starage Volume Provided 474 cu ft
3' D R Y W ELL REQUIREMENTS -10 YR. DESIGN STORM
Maximum Stora9e Requlred bY Bowstrin9 578 cu ft
Number artd Type of Drywells Required 0 Si ~ngb~
BOWSTRING METHOO PROJECT: Rivenrralk Sth Addition
PEAK FLOW CALCULATION PROJECT RNerwalk Sth Addition
DETENTION BASIN DESIGN BASIN: A1
BASIN: A1 [1, PE: 10-Year Design Storm DESIGNER: S. Murphy
To2. Area 0.36 Acres
DATE: 411/96
Imp. Area 4068 SF
C = 0.25
~~22-TIme InaemeM (mtn) 5
CASE 1 Time of Conc. (min) 6.66
Outflow (
_=====70 ft. Overtand Flaw cfs) 1
} t' ~ Deslgn Year Flow 10
Ct = 0.15
rea rvious Area ft4068
m
L = 70 ft. ;z Pe )
,;0 'C Fador 0.25
n= 0.40 Volume Provfded 180
S= 0.020 Area ' C 0.090
Tc = 3.58 min., by Equatbn 3-2 of Guidellries
.Mh Time Time Inc. IMens. Q Devel. Vol.ln Vd.Out Storage
200 ft. Gutter flow (min) (sec) (Whr) (cfs) (cu ft) (cu ft) (cu R)
;~=`a~ii;i
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Zl = 50.0 FOf Z2 6.66 400 2.74 0.25 132 400 -268
7-2 = 3.5 Type B =1.0
n= 0.016 Rolled a 3.5 5 300 3.18 0.29 115 300 -185
~ .
S= 0.008 PW%t k~ 10 600 2.24 0.20 148 600 -452
. ~ 15 900 1.77 0.16 7 65 900 -735
d= 0.09:i ft. ~r ",:;j~:c 20 1200 1.45 0.13 174 1200 -1026
u ::e...~.,.
25 1500 1.21 0.11 178 1500 -1322
A R Q Tc Tc total I Qc 30 1800 1.04 0.09 181 1800 -1619
35 2100 0.91 0.08 183 2100 '1917
0.23 0.05 0.25 3.08 6.66 2.74 0.25 ~NN 40 2400 0.82 0.07 187 2400 -2213
zz.
45 2700 0.74 0.07 189 2700 -2511
Qpeak for Case 1= 0.25 cfs 50 3000 0.68 0.06 7 92 3000 -2808
55 3300 0.64 0.06 198 3300 -3102
• i•~ x 60 3600 0.61 0.05 205 3600 -3395
CASE 2 65 3900 0.60 0.05 218 3900 -3682
70 4200 0.58 0.05 226 4200 -3974
Case 2 assumes a Time of Concentration less than 5 minutes so that the ~ 75 4500 0.56 0.05 234 4500 -4266
peak ftow =.90(3.18)(Imp. Area) = 0.27 cfs j:~ ; i~~ ~ 80 4800 0.53 0.05 235 4800 -4565
85 5100 0.52 0.05 245 5100 -4855
90 5400 0.50 0.05 249 5400 -5151
g •x;~.
So, the Peak flow for tlhe Basin is the greater of the two flows, 95 5700 0.49 0.04 257 5700 -5443
0.27 cfs L 100 6000 0.48 0.04 265 6000 -5735
:.x ~z ,
~„v., }~.2 ZOS' DRAINAGE POND CALCULATIONS
Required 208' Storage Volume
Imperv(ous Area x.5 in / 12 INft 170 cu ft
208' Storage Volume Provided 180 cu ft
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
• HNi;.~~~:azt
Maximum Storage Required by Bovvstdng -185 cu ft
Number and Type of Drywells Required 0 Single
:~"'~•:"2~, ~ 1 Double
■ ~ ~ ~ ~ r ~ r ~ ~ ~ ~ ~ ~ r ~ ~ ~ ~ ~
BOWSTRING METHOD PROJECT: Rivermik Sth Addition
PEAK FLOW CALCULATION PROJECT Rivenralk Sth Addition DETENTION BASIN DESIGN BASIN: A2
BASIN: A2 10-Year Destgn Stortn DESIGNER: S. Murphy
Tot. Area 0.49 Acres DATE: 4/1/96
Imp. Area 3319 SF
C = 0.40
Time Incrertient (min) 5
CASE 1 Time of Corx. (min) 6.42
Ouitlow (cfs) 1
70 ft. Overland Flow Design Year Flow 10
~'t;;i Ar~ (acres) 0.49
Ct = 0.15 ~ qM~kr Impervious Area (Sq ft) 3319
L= 70 R. 'C' Factor 0.4
n a 0.40 `-I- '208' Volume Provided 140
S= 0.020 w: Area ' C 0.196
}ot; ,
Tc = 3.58 min., by Equation 3-2 of GuideUnes x:x~;r.
~;'M~ Time Time Inc. Intens. Q Devel. Vd.ln Vd.Out Storage
190 ft. Gutter flow ; (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (a R)
~ : -
Zi = 50.0 For 72 6.42 365 2.79 0.55 282 385 -103
7-2 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.62 251 300 -49
S = 0.005
10 600 2.24 0.44 321 600 -279
15 900 1.77 0.35 358 900 S42
d= 0.136 R. 20 1200 1.45 0.28 378 1200 -872
25 1500 1.21 0.24 387 1500 -1113
A R Q Tc Tc taQal I Qc
30 1800 1.04 0.20 394 1800 -1406
.;i35 2100 0.91 0.18 398 2100 -1702
0.49 0.07 0.55 2.84 6.42 2.79 0.55~„„•,•"„'~""r 40 2400 0.82 0.16 407 2400 -1993
45 2700 0.74 0.15 411 2700 -2289
Qpeak for Case 1= 0.55 cfs 50 3000 0.68 0.13 417 3000 -2583
$ ~ 55 3300 0.64 0.13 430 3300 -2870
60 3600 0.61 0.12 446 3600 -3154
CASE 2 65 3900 0.60 0.12 474 3900 3426
70 4200 0.58 0.11 492 4200 -3708
Case 2 assumes a Time of Cortcentration less dran 5 minutes so that the ~x 75 4500 0.56 0.11 508 4500 -3992
peak flow =.90(3.18)(Imp. Area) = 0.22 cfs ,...":•t;. 2
80 4800 0.53 0.10 512 4800 -4288
85 5100 0.52 0.10 533 5100 -4567
90 5400 0.50 0.10 542 5400 -4858
So, Uhe Peak fiow for the Basin is the greater of the two flaws, x K 95 5700 0.49 0.10 560 5700 5140
0.55 cfs ffli ~"i %'k 100 6000 0.48 0.09 577 6000 5423
ZOS' DRAINAGE POND CALCULATIONS
>i;:r ~ Required'208' Storage Volume
= Impervious Area x.5 in ! 12 iNR 138 cu ft
~k
i?.'w
208' Storage Volume Provided 140 cu ft
i
Z DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
zg" z R, MaAmum Storage Required by Bowstring -49 cu ft
~42a~ Number and Type of Drywells Required 0 Single
1 Double
:.:w..
BOWSTRING METHOD PROJECT: Riverwa[k Sth Addition
PEAK FLOW CALCULATION PROJECT Rivervralk 5th Addition DETENTION BASIN DESIGN BASIN: A3
BASIN: A3 10-Year Qe.slgn Storm DESIGNER: S. Muryhy
Tot. Area 0.78 Acres . DATE: 4/1/96
~ " .
ImPArea 3994 SF a
C = 0.35 M
~.~r ~ Time Increment (min) 5
Ti
CASE 1 me oi Conc. (min) 5.29
OUifIOW (Cf8) 1
70 R. Ovedand Flow Design Year Flow 10
~ ~M?„
>z . Area (acres) 0.78
r~ :
Ct = 0.15 Impervious Area (sq ft) 3994
L= 70 ft. `'C Facior 0.35
.
n= 0.40 `i~~~~ '208' Volume Provided 204
S= 0.020 g~; Area ' C 0.273
i
Tc = 3.58 mfn., by Equatlon 3-2 of Guidelines
Time Time Inc. Intens. a Devel. Vol.in Vd.Out Storege
150 R. Gutter flow (min) (sec) (INhr) (ois) (cu R) (cu ft) (cu ft)
t:~':~+r =====aca ~aaa_aaa aar.aaaea ao~ona~ ~
Z7 = 50.0 For Z2 5.29 317 3.10 0.85 361 317 43
7-2 = 3.5 Type B =1.0 ZZk,r~::;i:
S= 0.016 Rolled = 3.5 z?? 5 300 3.18 0.87 349 300 49
10 600 224 0.61 433 600 -167
15 900 1.77 0.48 487 900 -413
d 0.148 ft. 20 1200 1.45 0.40 518 1 Z00 -682
25 1500 1.21 0.33 531 1500 -969
A R Q Tc Tc total I Qc i~ µ30 1800 1.04 0.28 542 1800 -1258
\
c===c=v : a=~~~ac~ ~ee===e= a=n====n =e= _==a=~aa a~a~a~aa . S.....y 35 2100 0.81 0.25 549 2100 '1$$1
0.58 0.07 0.85 1.71 5.29 3.10 0.85 40 2400 0.82 0.22 561 2400 -1839
45 2700 0.74 0.20 567 2700 -2133
Qpeak for Case 1= 0.85 cfs 50 3000 0.68 0.19 577 3000 -2423
:za.~w55 3300 0.64 0.17 595 3300 -2705
,
60 3600 0.61 0.17 617 3600 -2983
CASE 2 65 3900 0.60 0.16 657 3900 -3243
70 4200 0.58 0.16 682 4200 -3518
Case 2 assumes a Time of ConceMratlan less than 5 minutes so that the 75 4500 0.56 0.15 704 4500 -3796
a "^C".S :
peak flow -.90(3.18)(Imp. Area) 0.26 cis ~Zo'aµ',ti;ti "80 4800 0.53 0.14 710 4800 -4090
T= .k.:i:}22
85 5100 0.52 0.14 739 5100 -4361
90 5400 0.50 0.14 752 5400 -4648
a x.. 95 5700 0.49 0.13 777 5700 -4923
So, the Peak fbw for the Basin Is the 9reater of the two tbws,
0.85 cfs ~ :i.x : 100 6000 0.48 0.13 800 6000 ~Z00
~a:k~"~i:x;^;;
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~:aw~..i 208' DRAINAGE POND CALCULATIONS
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Required '208' Storage Volume
1,100
lmpervlous Area x.5 in / 12 iNft 166 cu ft
? {g 208' Storage Volume Provided 204 cu ft
a:;>~w
--k`My':
DRYWELL REQUIREMENTS -10 YR. DESIGN STORM
~„Ma)dmum Storage Required by BoHrstring 49 cu ft
Number and Type of Drywells Required 0 Single
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1 Double
=Zl BOWSTRING METHOD PROJECT: RNerwalk Sth Addtdon
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addition ""`^~^r? DETENTION BASIN DESIGN BASIN: B
BASIN: B ~ 2 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.13 Acres ~iDATE: 4/11/96
Imp. Area 9742 SF
C = 0.40
Time Incremert (min) 5
CASE 1 Time of Conc. (min) 9.10
_ • Outfiow (cfs) 1
70 ft. Overland Flaw ;;t Design Year Fbw 10
Area (acres) 1.13
Ct = 0.15 Impervious Area (sq ft) 9742
L= 70 ft. 'C' Factor 0.4
'208' Volume Provided 406
n0.40 ;
S= 0.020 ~~2"Area C 0.452 i~
1"N
Tc = 3.58 min., by EquaUon 3-2 of Guidelines nk''
5 ft. Gutter flow '(min) llm I~~ Q Devel ) R) V~~ ft S(~
41 )
zl = 50.0 Fwzs 9.10 sas 236 1.06 ns sas 233
72 = 3.5 Type B= 1.0
S= 0 010056 ROlled = 3.5 nM10 5 300 3.18 1.44 578 300 278
600 2.24 1 01 795 600 195
y ~::aza.:>;::iw
µr.;t,;;Mx;:" 15 900 177 0.80 869 900 -31
d= 0.167 R. 20 1200 1.45 0.66 908 1200 -292
` riR 25 1500 1.21 0.55 922 1500 -578
wi
A R Q Tc Tc total I Qc . , 30 1800 1.04 0.47 933 1800 -867
= 35 2100 0.91 0.41 J40 2100 -1160
0.74 0.08 0.93 5.52 9.10 2.36 1.06;;„„'r 40 2400 0.82 0.37 956 2400 -1442
45 2700 0.74 0.33 965 2700 -1735
Qpeak for Case 1= 1.06 cfs 50 3000 0.68 0.31 979 3000 -2021
55 3300 0.64 0.29 1008 3300 -7292
60 3600 0.61 0.28 1044 3600 -2556
„3~: , a•~;'
CASE 2' 65 3900 0.60 0.27 1108 3900 -2792
70 4200 0.58 0.26 1150 4200 -?O~aO
ks~t~.:~~,"`•'i ;
Case 2 assumes a Time of Concentratlon less than 5 minutes so that the 2s 75 4500 0.56 0.25 1186 4500 3314
peak flaw =.90(3.18)(Imp. Area) = 0.64 cfs 80 4800 0.53 0.24 1194 4800 ~fi06
85 5100 0.52 0.24 1242 5100 -3858
90 5400 0.50 0.23 1262 5400 -4138
So, the Peak flow for the Basin is the greater of the two 8aws, 95 5700 0.49 0.22 1304 5700 -4396
1.06 cis 100 6000 0.48 0.22 1342 6000 -4658
,i~~•~ ~ 208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
~M~~ = Impervious Area x.5 In / 12 INft 406 cu ft
.:n'x; ; ; 208' Storage Volume Provided 406 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
FAaximum Storage Required by Bowstring 278 cu ft
"
r: ~0 Number and Type of Drywells Requlred 0 Single
1 Double
BOWSTRING METHOD PROJECT: Rivervralk Sth Addidon
PEAK FLOW CALCULATION PROJECT Rivervralk Sth AddRion '.rg. DETENTION BASIN DESIGN BASIN: 61
BASIN: 81 1QYear Design Storm DESIGNER: S. Murphy
Tot. Area 0.23 Acres DATE: 4111/96
Imp. Area 1955 SF
C = 0.60
Time IncremeM (min) 5
CASE 1 Time of Conc. (min) 5.33
Outflow (Cis) 1
rm~;i`a"•;
70 R. Overiand Flaw Design Year Fbw 10
Area (acres) 0.23
Ct = 0.15 ~'impervlous Ar~ (sq ft) 1955
L= 70 ft. w
z'C' Fector 0.6
n= 0.40 208' Volume Provided 83
S= 0.020 Area' C 0.138
Tc = 3.58 min., by Equation 32 oi Guidelines
Time Time Inc. IMens. Q Devel. Vof.ln Vof.Out Storage
110 ft. Gutter flow (min) (sec) (INhr) (cis) (cu R) (cu R) (cu ft)
i ~ca~;;~:..,.
. :
Z1 = 50.0 For Z2 5.33 320 3.09 0.43 183 320 -137
Z2 = 3.5 Type B=1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.44 176 300 -124
S= 0.006 10 600 2.24 0.31 219 600 .381
15 900 1.77 0.24 246 900 -654
d= 0.124 ft. ZO 1200 1.45 0.20 262 1200 -M
25 1500 1.21 0.17 269 1500 -1231
x:~;~;rx;a:•
A R Q Tc Tc total I pc 30 1800 1.04 0.14 274 1800 -1526
- - - hiai~M~x~':w 35 2100 0.91 0.13 277 2100 -1823
- - ~
0.41 0.06 0.43 1.75 5.33 3.09 0.43 ;;r~s~~``~',"'•M,?: i~ 40 2400 0.82 0.11 284 2400 -2116
45 2700 0.74 0.10 287 2700 -2413
Qpeak for Case 1= 0.43 cfs z,~:„ 50 3000 0.68 0.09 292 3000 -2708
55 3300 0.64 0.09 301 3300 -2999
60 3600 0.61 0.08 312 3600 -3288
CASE 2 65 3900 0.60 0.08 332 3900 -3568
70 4200 0.58 0.08 345 4200 -3855
Case 2 assumes a Time of ConcentraUon less Uian 5 minutes so that the 75 4500 0.56 0.08 356 4500 4144
peak (low =.90(3.18)(Imp. Area) = 0.13 cfs 80 4800 0.53 0.07 359 4800 4441
85 5100 0.52 0.07 374 5100 -4726
2;:. `M2
90 5400 0.50 0.07 380 5400 -5020
So, the Peak flow for the Basin fs the greater of the two flows, 95 5700 0.49 0.07 393 5700 -5307
0.43 cis 100 6000 0.48 0.07 405 6000 5595
~:..k
208' DRAINAGE POND CALCULATIONS
2 Required "ZOS' Storage Volume
"
Impervious Area x.5 in / 12 iNft 81 cu ft
:.2:: i 2
208' Stora9e Volume Provided 83 cu ft
:''~:ixzxzzx•zt
: •f.. .:4~
'';;NDRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Max(mum Storage Required by BawsMng -124 cu ft
ia;: x;z•;~:z
Number and Type of Drywells Required 0 Singie
1 Doubde
.
,~~x„` BOWSTRING METHOD PROJECT: Rfverwatk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverv~ralk Sth Adddlon ~ u' DETENTION BASIN DESIGN BASIN: B2
BASIN: B2 tU-Year Design Storm DESIGNER: S. Murphy
Tot. Area 0.25 Acres DATE: 4/11/96
Imp. Area 2088 SF
. :
C = 0.60 r ~
Time Incrertsent (min) 5
CASE 1 rn:Mg Tlme of Conc. (min) 5.46
Outflow (cis) 1
70 ft. OveAand Flow Design Year Flow 10
• Area (acres) 0.25
KYwCt = 0.15 ~sImpervious Area (sq ft) 2088
L= 70 ft. `~~,~'C' Factor 0.6
n a 0.40 •i~~} 208' VOIUme Provkied 90
S= 0.020 ~Mt Z Area • C 0.150
Tc = 3.58 min., by Equation 3-2 oi Guidelines
Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
120 ft. Gutter flaw (min) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft) mn,
Zt = 50.0 Fat 7-2
;5.46 327 3.06 0.46 201 327 -126
7-2 = 3.5 Type B =1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.48 192 300 -108
S= 0.005 10 600 2.24 0.34 239 600 -361
15 900 1.77 0.27 269 900 -631
d= 0.127 ft. 20 1200 1.45 0.22 285 1200 -915
` 25 1500 1.21 0.18 292 1500 -1208
A R Q Tc Tc toffiI I Qc x~'~` 30 1800 1.04 0.16 298 7800 -1502
. : 35 2100 0.81 0.14 302 2100 -1798
„az:z r...t..
0.43 0.06 0.46 ~ 1.87 5.46 3.06 0.46 w 40 2400 0.82 0.12 309 2400 -2091
45 2700 0.74 0.11 312 2700 -2388
Qpeak for Case 1= 0.46 cis 50 3000 0.68 0.10 317 3000 -2683
:~~„r 55 3300 0.64 0.10 327 3300 -2973
~ M;g 60 3600 0.61 0.09 340 3600 -3260
CASE 2 65 3900 0.60 0.09 361 3900 -3539
m;;;;;,~ 70 4200 0.58 0.09 375 4200 -3825
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.08 387 4500 -4113
peak flow =.90(3.18)(Imp. Area) ~ 0.14 cfs 80 4800 0.53 0.08 390 4800 -4410
}M 85 5100 0.52 0.08 406 5100 -4694
90 5400 0.50 0.08 413 5400 -4987
So, the Peak flow for the Basln Is the greater of the two flows, 95 5700 0.49 0.07 427 5700 -5273
0.46 cfs ; 100 6000 0.48 0.07 440 6000 -5560
~
208' DRAINAGE POND CALCULATIONS
r. . 2....
Required 208' Storage Volume
Impervious Area x.5 in / 12 iNft 87 cu ft
208' Stora9e Volume Provided 90 cu ft
DRYWELLREQUIREMENTS-10YEARDESIGNSTORM
z~zzz~ zMaAmum Storage Required by BowsMng -108 a ft
Number and Type oi Drywells Requ(red 0 Single
1 Double
BOWSTRING METHOD PROJECT: Rivervvalk Sth AddRion
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Addiiti~on DETENTION BASIN DESIGN BASIN: 63
BASIN: B3 10-Y~r Design Stotm DESIGNER: S. Murphy
Toi.Area 0.65Acres DATE: 4111/96
Imp.Area 5699 SF
C = 0.40 •
Time Incremerrt (min) 5
CASE 1
Time oi Conc. (min) 6.19
,x,..;Outflow (Cfs) 1
70 ft. Overland Flaw Deslgn Year Flow 10
AfPa (8Cfe3) 0.65
Ct = 0.15 I mpervious Area (sq ft) 5699
L= 70 ft. c' Faaor 0.4
n= 0.40 '208' Volume Provided 240
S= 0.020 ri.
„ Area C 0.260
Tc = 3.58 min., by Equatian 3-2 of Guidelines
Time Tirtse Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
185 ft. Gutter flow (min) (sec) (iNhr) (cis) (cu ft) (cu ft) (cu ft)
-
Z1 = 50.0 For Z2 619 371 2.84 0.74 368 371 -3
ZZ = 3.5 Type B= 1.0
z.,z•:
n= 0.016 Rolled = 3.5 5 300 3.18 0 83 332 300 32
S= 0 005 10 600 2.24 0.58 423 600 -177
15 900 1.77 0.46 472 900 -428
d= 0.153 ft. 20 1200 1.45 0.38 500 1200 -700
25 1500 1.21 0.31 512 1500 -988
A R Q Tc Tc total I Qc ~ q~x x: 30 1800 1.04 0.27 521 1800 -1279
- ==c===a= =aaaaaaa ~Iz 35 2100 0.91 0.24 527 2100 -1573
-
: a;
0.82 0.08 0.74 2.61 6.19 2.84 0.74 40 2400 0.82 0.21 539 2400 -1861
45 2700 0.74 0.19 544 2700 -2156
Qpeak for Case 1 = 0.74 cis ~ 50 3000 0.68 0.18 553 3000 -2447
55 3300 0.64 0.17 570 3300 -2730
60 3600 0.61 0.16 591 3600 3009
CASE 2 65 3900 0.60 0.16 628 3900 -3272
'a:a
z" ;i ;i?s iizw : 70 4200 0.58 0.15 652 4200 3.riA8
Case 2 assumes a Time of Concentration less than 5 minutes so that the r« 75 4500 0.56 0.15 674 4500 -W26
peak flow =.90(3.18)(Imp. Area) = 0.37 cfs 80 4800 0.53 0.14 679 4800 -4121
85 5100 0.52 0.14 707 5100 -4393
90 5400 0.50 0.13 718 5400 -4682
So, the P~k flow for the Basln is the greater of the two flows, 95 5700 0.49 0.13 742 5700 -4958
0.74 cfs ~ 100 6000 0.48 0.12 765 6000 5235
wcN"":ix%t::
i 208' ORAINAGE POND CALCULATIONS
i Required 'ZOB' Storage Volume
~ = Impervious Area x.5 in / 12 iNft 237 cu ft
v • ~7~
µ208' Storage Volume Pravided 240 cu ft
DRYWELL REQUIREMENTS - 10 YEAR DESIGN STORM
;~~ii
;x;;~~:.:;;;:;; ; Ma)dmum Storage Required by Bowstring 32 cu ft
;»;~~~Number and Type of Drywells Required 0 Singie
1 Double
BOWSTRING METHOD PROJECT: RNerwralk Sth Addition
PEAK FLOW CALCULATION PROJECT Riverwalk Sth Additlm DETENTION BASiN DESIGN BASIN: C
BASIN: C { 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 0.36 Acres r' DATE: 4/11196
Imp. Area 4884 SF
C= 0.60
Time IncremeM min 5
CASE 1 ~~,```.,k..: • ~ )
Time of Conc. (min) 5.79
Outflow cfs 0.3
70 ft. Overland Flow Design Year Flow 10
_
: Area (acres) 0.36
CL = O 70 ft. IC pe ~~s Area (sq ft) 4884 0.6
n= 0.40 Volume Provided 215
S= 0.020 X•~•,~~~~k: Area' C 0.216
E.z,;.i~
Tc = 3.58 min., by EquaUon 3-2 oi Guidelines ~>,.~,~µN Time Time Inc. Intens. Q Devel. Vol.ln Vol.Out Storage
180 ft. Gutter fbw :x;,n (min) (sec) (INhr) (cfs) (cu ft) (cu ft) (cu ft)
ai
Z1 = 50.0 FOf 7-2 ",z :;.z:&-t~ 5.79 347 2.96 0.64 297 104 193
Z2 = 3.5 Type B= 1.0
n= 0.016 Rolled a 3 5 ;h•;,~x;i~~z' S 300 3.18 0.69 276 90 186
S= 0.008 n n ~A,,~ 10 600 2.24 0.48 347 180 167
• , ~~15 soo 1.77 0.38 sas 270 119
d= 0.133 ft. ZO 1200 1.45 0.31 413 360 53
25 1500 1.21 0.26 423 450 -27
A R Q Tc Tc total I Qc ~ 30 1800 1.04 0.22 431 540 -109
__====~v e~~a~c~~ ~~cc~aa~ ~vo~~~a~ o=c= =a~ caacaaaa ~i`.x~'~{ \ 35 21~ 0.91 0.'~ 4.~ 6~ -1~
0.47 0.07 0.64 2.20 5.79 2.96 0.64 40 2400 0.82 0.18 446 720 -274
45 2700 0.74 0.16 450 810 -360
Qpeak for Case 1= 0.64 Cfs 50 3000 0.68 0.15 458 900 -442
55 3300 0.64 0.14 473 990 517
A, ~ ;x60 3600 0.61 0.13 490 1080 -590
CASE 2 i- 65 3900 0.60 0.13 521 1170 -649
zz ia ,a
70 4200 0.58 0.13 541 1260 -719
Case 2 assurt►es a Time of Coricentration less than 5 minutes so that the =75 4500 0.56 0.12 559 1350 -791
peak ftow =.90(3.18)(Imp. Area) = 0.32 cfs 80 4800 0.53 0.11 563 1440 -877
` i`::"<"`- ^."•r'r;~ 85 5100 0.52 0.11 586 1530 -944
90 5400 0.50 0.11 596 1620 -1024
So, the Peak flow for the Basin is the greater of the two tlavvs, ,r`,..;,:';,,.. 95 5700 0.49 0.11 616 1710 -1094
0.64 cfs 100 6000 0.48 0.10 634 1800 -1166
• „r:„,..x,.,
rz.,; "„.208' DRAINAGE POND CALCULATIONS
z~~~~~
na: Required'208' Storage Vdume
ZZ~ ImpeMous Area x.5 in / 12 iNft 204 cu ft
~MM~ ?%Z~ci^e
h~w c=~ 208' Storage Volume Provided 215 cu ft
2C:S2..
h;%:.
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
-"~~;~Ma)dmum Storqqe Required by Bowstrir~g 193 cu ft
: ;a~ :r,:z
Number arsd Type of Orywells Required 1 Single
~ 0 Double
BOWSTRING METHOD PROJECT: RNervvalk Sth Addifion
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth Addition ~ DETENTION BASIN DESIGN BASIN: D
BASIN: D ~ 10-Year Design Storm OESIGNER: S. Murphy
Tot. Ar~ 0.21 Acres DATE: 4/11 P96
w ; ~*``z • :i
Imp. Area 3125 SF
z „nx,::.•~
C = 0.40
CASE 1 ~Time Increment (min) 5
Time of Conc. (min) 5.12
Outflow (cfs) 0.3
70 ft. Overtand Flaw Design Year Flow 10
Area (acres) 0.21
Ct = 0.15 ImpeMous Area (sq ft) 3125
L= 70 ft. 'C Factor 0.4
s:
n= 0.40 „208' Volume Provided 140
S= 0.020 Area ' C 0.084
Tc = 3.58 min., by Equation 32 oi Guidelines
.
Time Time Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
130 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu R) (cu ft) (cu ft)
Z1 = 50.0 For 72 5.12 -----307 3.15 0.26 109 92 17
72 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.27 107 90 17
S a 0.016 R~?'10 600 2.24 0.19 133 180 -47
,.,<i^z?~•~^,•~ai
EIM1s soo I.n o.1s 1as r7o -121
d0.083 R ZO 1 Z00 1.45 0.12 159 360 -201
~~~t 25 1500 1.21 0.10 163 450 -287
A R Q Tc Tc total I Qc Em'~ 30 1800 1.04 0 09 166 540 ~74
=_e_a_a_ ====ca aaaaaaaa x~~~.= e_=_on=: e==-==-- .....~i2 3J 2100 0.91 0.08 169 630 -461
0.18 0.04 0.26 1.54 5.12 3.15 0.26 ~~z~:a•,.,w,~ 40 2400 0.82 0.07 173 720 -547
ii~~ 45 2700 0.74 0 06 174 810 -636
Qpeak for Case 1= 0.26 cis 50 3000 0.68 0.06 177 900 -723
55 3300 0.64 0.05 183 990 -807
:•~;:~.2w.3`~2N 60 3600 0.61 0.05 190 1080 490
CASE 2 ' 2. ~ 65 3900 0.60 0.05 202 1170 -968
~~70 4200 0.58 0.05 210 1260 -1050
Case 2 essumes a Time of Concentration less than 5 minutes so that the
75 4500 0.56 0.05 217 1350 -1133
peak fbw =.90(3.18)(Imp. Area) = 0.21 cfs ~`N 80 4800 0.53 0.04 218 1440 -1722
85 5100 0.52 0.04 227 1530 -1303
`~;i~
~`~czi~`'aa.•„~~i~ 90 5400 0.50 0.04 231 1620 -1389
So, the Peak tbw for the Basin fs the greater of the lwo flaws, 95 5700 0.49 0.04 239 1710 -1471
0.26 cfs
x•r`.,;r
100 6000 0.48 0.04 246 1800 -1554
'•r, rs.•...a:i~
~n208' DRAINAGE POND CALCULATIONS
3> ;3z;w;t~
•.«<.~;•Hµ ~ Required'208 Storage Volume
Impervious Area x.5 in / 12 iNft 130 cu ft
~z.
208' Storage Volume Provided 140 cu ft
:s
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
~:Y Maximum Storage Required by BowsMng 17 cu ft
:'x~C`'t~,~z#i
Number and Type of Drywells Required 1 Single
0 Double
BOWSTRING METHOD PROJECT: Riverwalk Sth Addftion
PEAK FLOW CALCULATION PROJECT Rivervraik 5th Addiiti~on DETENTION BASIN DESIGN BASIN: E
BASIN: E 10-Year Design Storm DESIGNER: S. Murphy
Tat. Area 0.12 DATE: 4/11196
Imp. Area 2090 SF
<.:rA
C = 0.40
Time IncremeM (min) 5
CASE 1 Time of Conc. (min) 5.00
"'M: Outflow (cfs) 0
70 ft. Overtand Flow Design Year Flow 10
Area (acres) 0.12
Ct = 0.15
ft. IC' Facto us Area (sq ft) 2090
70
~z~,,..,...
n= 0.40 '208' Volume Provlded 88
S = 0.020
Area ' C 0.048
Tc = 3.58 m(n., by Equation 3-2 of Guidelines
Time Time Inc. IMens. Q Devel. Val.ln Vol.Out Storage
100 ft. Gutter (low (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
:xiz:.a~;:z;z K
~:::r.\\`.x~'aa_ae_~c~ e=~eov=~ v_====__ =oaaea~a aaa~e_e--
: .
Zt = 50.0 For 7-2 5.00 300 3.18 0.15 61 0 61
7-2= 3.5 Type B=1.0
n = 0.016 R olled = 3.5
„ 5 300 3.18 0.15 61 0 61
S z 0.016 • 10 600 2.24 0.11 75 0 75
W2"?~.
15 900 1.77 0.08 85 0 85
d= 0.068 ft. 20 1200 1.45 0.07 91 0 91
25 1500 1.21 0.06 93 0 83
A R Q Tc Tc total I Qc 30 1800 1.04 0.05 95 0 95
iZZ 35 2100 0.91 0.04 96 0 96
0.12 0.03 0.15 1.35 5.00 3.18 0.15 ? 40 2400 0.82 0.04 98 0 98
45 2700 0.74 0.04 100 0 100
apeak for Case 1= 0.15 Cis ~~,,2' 50 3000 0.68 0.03 101 0 101
55 3300 0.64 0.03 105 0 105
"•z,;.~~:.•:,i 60 3600 0 61 0 03 108 0 108
CASE 2 65 3900 0.60 0.03 115 0 115
70 4200 0.58 0.03 120 0 120
Case 2 assumes a Time of Concentration less than 5 minutes so that the 75 4500 0.56 0.03 124 0 124
peak flow =.90(3.18)(Imp. Area) = 0.14 cfs 80 4800 0.53 0.03 125 0 125
85 5100 0.52 0.02 130 0 130
90 5400 0.50 0.02 132 0 132
So, the Peak flow for the Basin Is the greater of the two 8ows, ~~„;95 5700 0.49 0.02 136 0 136
0.15 cfs 100 6000 0.48 0.02 141 0 141
"i;•~
z;x"%
:208' DRAINAGE POND CALCULATIONS
R Impervious Asea x 95 n/ 12 irUR 87 cu ft
M`~`~ ZOS' Storage Volume Provided 88 cu R
DRYWELL REQUIREMENTS -10 YEAR OESIGN STORM
~:,.M.,.,
Ma)dmum Stora9e Required bY BovrsMn9 130 cu ft
?sa# \.~~~;~t:z
Number and Type of Drywells Required 0 Single
ERR Double
oMM.~, ~..,e
BOWSTRING METHOD PROJECT: Rivervralk Sth Additlon
PEAK FLOW CALCULATION PROJECT Riverwalk 5th Additian
DETENTION BASIN OESIGN BASIN: Pre-dev F
BASIN: Pre-dev F 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.98 Acres DATE: 4111196
.
Imp. Area 0 SF ~i: x;;::
C = 0.30 i;
~ .
Time Increment (mIn) 5
CASE 1 ~zTime of Conc. (min) 5.00
Outflow (cfs) 1
~ x r^. .
150 ft. Overtand Flow Deslgn Year Flow 10
A ea (acres) 1.98
= 0.15 mpervious Area (sq ft) 0
L= 150 ft. M ~ 'C Fador 0.3
n= 0.40 x
~ z;,, '208' Vdume Provided 0
S= 0.040 Area ' C 0.504
s
s i.•r~
Tc = 4.60 min., by Equation 32 ai Guidelines
Time Time Inc. IMens. Q Devel. Vol.ln Vol.Out Storage
0 ft. Gutter flow ~i (min) (sec) pNhr) (cis) (cu ft) (cu R) (cu ft)
~;iba` ~~t=====---- =---=aaa c==°==___
Z1 = 50.0 For Z2 5.00 300 3.18 1.89 759 300 459
7-2= 3.5 TypeB=1.0
n= 0.018 Rolled = 3.5 5 300 3.18 1.89 759 300 459
S= 0.005 10 600 2.24 1.33 934 600 334
15 900 1.77 1.05 1053 900 153
d= 0.206 ft. a",i20 1200 1.45 0.86 1121 1200 -79
25 1500 1.21 0.72 1151 1500 -349
A R Q Tc Tc toQal I Qc `~z
30 1800 1.04 0.62 1175 1800 ~25
.:x;:;:a}:i. ~r 2100 0.91 0.54 1190 2100 ti910
~•an:;:,x,
1.14 0.10 1.64 0.00 5.00 3.18 1.89 , 40 2400 0.82 0.49 1219 2400 -1181
~c 45 2700 0.74 0.44 1232 2700 -1468
Q k for Case 1= 1.89 Cfs
pea rµ 50 3000 0.68 0.40 1253 3000 -1747
55 3300 0.64 0.38 1293 3300 -2007
60 3600 0.61 0.36 1341 3600 -2259
CASE 2 65 3900 0.60 0.36 1426 3900 -2474
aaaoaoa " ~
70 42 0.58 0.34 1482 4200 -2718
Cese 2 assurtses a Time oi CorsceMration less than 5 minutes so that the x•• 75 4500 0.56 0.33 1531 4500 -2969
peak flow =.90(3.18)(Imp. Area) = 0.00 Cfs 80 4800 0.53 0.31 1543 4800 -3257
'MM85 5100 0.52 0.31 1607 5100 -3493
90 5400 0.50 0.30 1634 5400 -3766
So, the Peak fiow for the Bastn is the greater of the Nw (tows, ~ 95 5700 0.49 0.29 1689 5700 -4011
1.89 cfs 100 6000 0.48 0.29 1740 6000 -4260
, c
i„i;~% 208' DRAINAGE POND CALCULATIONS
~
~ Requfred'208' Storage Valume
Impervlous Area x.5 in / 121Nft 0 cu ft
'.Y ~ ` • t:
208 Storage Volume Provided 0 cu ft
^~;ar:zx~~:~~?`
.~z~ •:~~=2~ DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
M1Aa)dmum Storage Required by BowsMng 459 cu ft
m '
•ttit,i~~~~=2~ Number arsd TYPe of DMweIls Re4utred 0 Sin9le
1 Double
-•~2 BOWSTRING METHOD PROJECT: Rivervraik Sth AddiUon
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth Add'Rion DETENTION BASIN DESIGN BASIN: Developed F
BASIN: Developed F 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.98 Acres
OATE: 4111/96
Imp. Area 0 SF
C = 0.26 p p
`i
Time IncremeM (min) 5
CASE 1 `tt Tirrse of Conc. (min) 5.00
:.M„J~ Outflow (cfs) 1
150 ft. Overtand Flow Deslgn Year Flow 10
~
Area (acres) 1.98
Ct = 0.15 Impervtous Area (sq ft) 0
L= 150 ft. ~};,.i.:'C Factor 0.26
n= 0.40 i 208' Volume Provided 0
~ .
S = 0.040 % •
Area C 0.515
Tc 4.60 min., by EquaUon 3-2 of Guidelines t",;; a u•:~z: t;'i:.~r'>zz:
Time Time irsc. IMens. Q Oevel. Vol In Vol.Out Storage
0 ft. Gutter flow (min) (sec) (infi~ (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For Z2 5.00 300 3.18 1.64 658 300 358
r;r~•,;
72 = 3.5 Type B= 1.0
n= 0.016 Rofled = 3.5 5 300 3.18 1.64 658 300 358
S= 0.005 10 600 2.24 1.15 810 600 210
15 900 1.77 0.91 913 900 13
d= 0.206 ft. 2. . ; ZO 1200 1.45 0.75 972 1200 -228
~s~.
: ZS 1500 1.21 0.62 998 1500 -502
A R Q Tc Tc total I Qc 30 1800 1.04 0.54 1018 1800 -782
~„:~:`,r,",.`~,~~.. 35 2100 0 91 0 47 1032 2100 -1068
1.14 0.10 1.64 0.00 5.00 3.18 1.64 N40 2400 0.82 0.42 1056 2400 -1344
#„;',',•,•;a„:; 45 2700 0.74 0.38 1067 2700 -1633
Qpeak for Case t= 1.64 cfs M2~ ~ ~pp 0.64 0.33 1~21 3300 2979 -114 3000
...~.~.t,~...:
60 3600 0.61 0.31 1163 3600 -2437
CASE 2 65 3900 0.60 0.31 1236 3900 -2664
70 4200 0.58 0.30 1285 4200 -2915
Case 2 assumes a Time of Concerrtratbn less than 5 minutes so that the i~'~`~:" ~ 75 4500 0.56 0.29 1327 4500 -3173
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs :..a; 80 4800 0.53 0.27 1337 4800 -3463
~:2":
` :8S 5100 0.52 0.27 1393 5100 -3707
90 5400 0.50 0.26 1416 5400 3984
So, the Peak flow for the Basin is the greater oi the two (lows, 95 5700 0.49 0.25 1464 5700 -4236
1.64 cfs 100 6000 0.48 0.25 1508 6000 -4492
~•`•.~µx,z
,
~ ~ WN 208' DRAINAGE PONO CALCULATIONS
R uUed'208' Stora e Volume
zi•"
= mpervtous Area x S in / 12 INR 0 cu ft
i xtrac.;^?
,
„,208' Storage Volume Provided 0 cu ft
t
~;~"s
~;;\µ~~a~, DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
k?a;`:
x:"~~<< Ma)dmum Storage Required by Bowstring 358 cu ft
Number and Type of Drywells Required 0 Single
~ 1 Double
BOWSTRING METHOD PROJECT: Rivervvalk Sth Additiori
PEAK FLOW CALCULATION PROJECT Rivennralk Sth Additlon DETENTION BASIN DESIGN BASIN: Pre-dev G
BASIN: Pre-dev G 10-Year Design Stortn DESIGNER: S. Murphy
Tot. Area 1.40 Acres DATE: 4/11196
Imp. Area 0 SF
C = 0.30 ~i~
"~7; ~3c Time Increment (min) 5
CASE 1 ~ Time of Conc. (min) 5.00
Outflow (cfs) 1
150 ft. Overland Fbw Design Year Fbw 10
Area (acres) 1.4
Ct = 0.15 Impervious Area (sq ft) 0
L= 150 ft. 'C' Factor 0.3
n= 0.40 -M
'208' Volume Provided 0
S= 0.040 ;MwM • Area' C 0.420
Tc = 4.60 min., by Equadon 3-2 of Guidelines
min) Time I~ncc' 1~ f' Q D ~~l) (cu ft) V (cu ft S (cu ~
0 ft. Gutter flow
~~o~aeaa~ ===c==c= ==~e==== e=:===__ ==e~aene= ==a===== =e =aaaa
Z1 = 50.0 FOf 7-2 5.00 300 3.18 1.34 537 300 237
72 = 3.5 Type 8= 1.0 n= 0.016 Rolled = 3.5 5 300 3.18 1.34 537 300 237
S= zz
0.005 10 600 2.24 0.94 660 600 60
c"~•~~: 15 900 1.77 0.74 745 900 -155
d= 0.206 ft. ~'20 1200 1.45 0.61 793 1200 -407
25 1500 1.21 0.51 814 1500 -686
A R Q Tc Tc total I Qc 30 1800 1.04 0.44 831 1800 -969
~~a~==== :•:z;: 35 2100 0.91 0.38 842 2100 -1258
ix ;r.w;.:*i~::
1.14 0.10 1.64 0.00 5.00 3.18 1.34 ;n:~ 40 2400 0.82 0.34 862 2400 -1538
45 2700 0.74 0.31 871 2700 -1829
Qpeak for Case 1= 1.34 cfs 50 3000 0.68 0.29 888 3000 -2114
55 3300 0.64 0.27 914 3300 -2386
60 3600 0.61 0.26 948 3600 -2652
CASE 2
65 3900 0.60 0.25 1009 3900 -2891
s' 70 4200 0.58 0.24 1048 4200 -3152
Case 2 assumes a Time of ConceMraUon less than 5 minutes so that the 75 4500 0.56 0.24 1082 4500 -3418
peak flow =.90(3.18)(Imp. Area) = 0.00 cfs -02 ~ 80 4800 0.53 0.22 1091 4800 -3709
85 5100 0.52 0 72 1136 5100 -3964
90 5400 0.50 0.21 1155 5400 -4245
:xx.:xa: gi
So, the Peak flow for the Basin Is the greater of the Mro flows, 95 5700 0.49 0.21 1194 5700 -4506
1.34 cfs 100 6000 0.48 0.20 1230 6000 -4770
0" ta ~;x
m208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 tn / 12 INft 0 cu ft
M2`
kz
%ZOS' Storege Voiume Provided 0 cu ft
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
Ma)dmum Stwage Required by Bowstring 237 cu ft
;;x~i~EZ:` `•i
;;~;;ti~~~?Number and Type of Drywells Requfred 0 Single
~ 4?•,~ 1 Double
BOWSTRING METHOD PROJECT: Rivervvalk Sth Addition
PEAK FLOW CALCULATION PROJECT Rivervvalk Sth Adddlon DETENTION BASIN DESIGN BASIN: Developed G
BASIN: Developed G 10-Year Design Storm DESIGNER: S. Murphy
Tot. Area 1.40 Acres
Imp. Ar~ 0 SF ~ DATE: 4/11/96
C = 0.15 . ~;,A`t
Time Irscrement (min) 5
CASE 1 Ttme of Conc. (min) 5.00
Outfbow (cis) 1
150 R. Overland Fbw Design Year Flow 10
AfeB (aCfes) 1.4
Ct = 0.15 .~,......'...~;i Impervious Ares (sq ft) 0
L= 150 ft. ~~a 'C' Factor 0.15
n= 0.40 208' Volume Provided 0
~z :~::r
•
S ~ 0.040 `~`~;ti~ ~ Area C 0.210
Y ti Ck.
Tc = 4.60 min., by Equation 3-2 of Guideline,s
Time Time Irsc. Intens. Q Devel. Vol.ln Vol.Out Storage
0 ft. Gutter flow (min) (sec) (iNhr) (cfs) (cu ft) (cu ft) (cu ft)
Z1 = 50.0 For 72 5.00 300 3.18 0.67 268 300 -32
72 = 3.5 Type B= 1.0
n= 0.016 Rolled = 3.5 5 300 3.18 0.67 268 300 -32
S= 0.005 ~~~k?~ ~ 2N ' 10 600 2.24 0.47 330 600 -270
1;:„•~15 900 1.77 0.37 372 900 S28
d= 0.147 ft. ?~.ai .:i zw 20 1200 1.45 0.30 396 1200 -004
25 1500 1.21 0.25 407 1500 -1093
A R Q Tc Tc total I Qc ~wm' 30 1800 1.04 0.22 415 1800 -1385
:
35 2100 0.91 0.19 421 2100 -1679
;
0.58 0.07 0.67 0.00 5.00 3.18 0.67 40 2400 0.82 0.17 431 2400 -1969
45 2700 0.74 0.16 435 2700 -2265
QPeak for Case 1= 0.67 cfs
50 3000 0.68 0.14 443 3000 -2557
~z,x#aiz;a~x:c 55 3300 0.64 0.13 457 3300 -2843
60 3600 0.61 0.13 474 3600 -3126
CASE 2 65 3900 0.60 0.13 504 3900 -3396
:g,,;
Ri:::::µ 70 4200 0.58 0.12 524 4200 -3676
Case 2 assurtses a Time of ConceMration less than 5 minutes so that the 75 4500 0.56 0.12 541 4500 -3959
peak 8ow =.90(3.18)(Imp. Area) = 0.00 cfs 80 4800 0.53 0.11 546 4800 -4254
85 5100 0.52 0.11 568 5100 -4532
:>:?::;i•,
:ii; 90 5400 0.50 0.11 578 5400 -4822
So, the Peak flow for the Basin is the 9reater of the two flows, ;:r:95 5700 0.49 0.10 597 5700 -5103
}c~
0.67 Cfs 100 6000 0.48 0.10 615 6000 -5385
:;;::::208' DRAINAGE POND CALCULATIONS
Required'208' Storage Volume
Impervious Area x.5 in / 12 iNft 0 cu ft
, . r>. 208' Storage Valume Provided 0 cu ft
i.,;.: :r ~,5•...:.
DRYWELL REQUIREMENTS -10 YEAR DESIGN STORM
~ ,
Ma)dmum Storage Required by BowsUing -32 cu ft
x
Number and Type of Dryweils Required 0 Single
1 Double
1
t
'
'
,
CURB INLET CALCULATIONS
'
1
1
1
1
1
1
1
1
1 ,
1
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' r
'
208' Pond Calculations
Project: Riverwalk 5th Addition
Date: 01-Apr-96
Designer. S. Murphy
Upstream Carryover Accumul. Pond '208'
'208' Curb Inlet Imper. Storage Storage Storage Type/ Storage Carryover
Sub-Basin Station~ R/L Area Req't Req't Req't Size Provided Downstream
A1 43+73 R 4068 169.5 169.5 10x30 180.0
A2 41 +72 R 3319 138.3 138.3 13x18 140.3
A3 40+85 R 3994 166.4 166.4 14x25 204.3
61 43+88 R 1955 81.5 81.5 11 x12 83.3
62 42+70 L 2088 87.0 87.0 12x12 90.0
B3 40+85 L 5699 237.5 237.5 16x26 240.0
1 ~ ~ ~ ~ ~ ~ ~ ~ m 11111110 = = M M m m m m m
CURB INLET CALCULATIONS
Curb Inlet Depression = 2 in.
Standarcl Curb Inlet Length = 4 ft.
Upstream 10-Yr. Gutter Roughnes Reciprocal Depth Length
Curb Inlet Impervious Peak Flow Slope Coeff. Cross slope of Flow Required
Sub-Basin Station R/L Area c.f.s. S n Z ZJn d• Qa/La" Q/(Qa/La) Remarks
- . . _ . .
A1 43+73 R 4068 0.27 0.0081 0.0160 50 3125 0.09 0.063 4.26 Need - 1 4' Inlet
A2 41+72 R 3319 0.55 0.0052 0.0160 50 3125 0.13 0.090 6.12 Need - 1 4' Inlet
A3 40+85 R 3994 0.85 Sump Condition
B1 43+88 R 1955 0.43 0.0052 0.0160 50 3125 0.12 0.082 5.25 Need - 1 5' Inlet
62 42+70 L 2088 0.46 0.0052 0.0160 50 3125 0.12 0.084 5.47 Need - 1 5' Inlet
B3 40+85 L 5699 0.74 Sump Condition
D 40+85 L 3125 0.26 0.0160 0.0160 50 3125 0.08 0.055 4.73 Need - 1 4' Inlet
F 40+85 R 2090 0.15 0.0160 0.0160 50 3125 0.07 0.083 1.81 Need - 1 4' Inlet
' Calculated per Figure 18 of Guidelines
" Calculated per Figure 16 of Guidelines
A 4 foot curb drop with a 6" gutter has a capacity of 4.0 cfs in sump condition
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