25271 PE-1206D SUMMERFIELD EAST
1
'
' SUMMERFIELD EAST DEVELOPMENT
KEN TUPPER
,
' SPOKANE, WASHINGTON
(Sechon 35, T 36N, R44E WM)
'
'
SUMMERFIELD EAST, 4TH ADDITION ' RESIDENTIAL SUBDIVISION
I STORM WATER
DESIGN BRIEF RECEIVED
'
MAR 14 ?001
' * * * * * SPOKANE COUIV7Y ENGlNEER t prepared by
OFFtCU1L R11HUC OQCUMENT
t SPOKIINE COUMY ENGINEER'S OFRCE
PRa ~RIV~.
WYATT ENGINEERING, INC.
' 1220 N. Howard Street ${JBMffTAL 0 14
Spokane, Washington 99201 ; pMRN TO COUNTY ENGINEER
(509) 328-5139 PH ' (509) 328-0423 FX
' Original Submittal Date: October 19, 2001
Resubmittal Date: March 12, 2002
'
[679300\dramage report.wpd] Copy No. I
'
1
' DESIGN REPORT
' FOR
SUMMERFIELD EAST, 4T" ADDITION -
' RESIDENTIAL SUBDIVISION
' SPOKANE COUNTY, WASHINGTON
(S1/2, Sec. 35, T36N, R44E, W.M.)
1 ,
~~p P 35634 t~~IST~'.
' NALErU
r EXPIPEs 7/11/c7-j ~
1 -
' "The design rmprovemenfs shown in this set of plans and calculations conform fo fhe appficable
editions of the Spokane County Standards for Road and Sewer Consfruction and the Spokane
County Guidefines for Stormwafer Monagement. A!1 design deviations have been approved by
, fhe City of Spokane. 1 approve these plans for conshuction."
1
'
'
WYATT ENGINEERING
' 1220 N. Howard
Spokane, Washington 99201
(509) 328-5139 PH
(509) 328-0423 FX
'
' ` -
' '
'
' Summefieid East 41 Addition
Subdivision
, Table of Contents .
' Secrion Pa e
1.00 Introducrion 1
' 2.00 Drainage Area Summary 1
' 3.00 Summary of Stormwater Calculations 4
4.00 Erosion Control Considerarions 6
' 5.00 Summary/Conclusions 6
' List of Tables
' 3.01 Tabular Summary of Storm water Analysis 5
' List of Annendices
' Appendix I- Project Location Map _
Appendix II- Drainage Area Map
Appendix III - Soils Information
' Appendix N- Rational Method Calculations
Appendix V- Miscellaneous Figures
Appendix VI- Miscellaneous Letters
'
'
'
'
1
(92001. Wyatt Engmeenng (679300) Storm Water Brief
' October 19, 2001 (rev. 3/12/02)
1
'
' Summerfield East 41 Addihon
Subdivision
' Basis of Design for Storm Water System
' 1.00 Introduction
The intent of this design brief is to determine the peak storm water runoff resulting from the construction
' of Summerfield East 41 Addition located on the north side of Olympic, including unconstructed portions of
Burns Road and Crown Road. The project includes construction of 25 residential lots, portions of the
paved streets Crown Road, Burns Road and Queen Avenue. This improvement project includes curb,
, gutter and sidewalk as well as the necessary storm drainage areas to handle the runoff. The proposed
project will be located in Spokane County, Washington (T26N, R44E WM). (See Appendix I- Project
Location Map).
' The storm drainage system (i.e. type "A" and "B" drywells, grassed percolation areas (GPA) or "208"
swales) will be installed to accommodate the storm water runoff generated by the impervious areas
' created by constructing Crown Road, Queen Avenue and Burns Road. Additional drywells will be
installed to accommodate stormwater runoff &om non-impervious surfaces of the lots. (See Appendix II
- Drainage Area Map).
2.00 Drainage Area Summary
' The project area consists of eleven (11) drainage areas (DA). All drainage areas consist of the pervious
lot acreage and impervious asphalt, curbing, sidewalk, roof and driveway, which comprise the subdivision
' facilities. DA-1 is 6,941 ft2 in size and includes the area south of the Queen Avenue right of way. DA-2
consists of the area in the south half of the Queen Avenue right of way and is 4,060 ft2 in size. DA-3
consists of the north half of the Queen Avenue right of way, including some of the adjacent lot, and is
, 8,355 ft2 in size. DA-4 consists of the area west of Burns Road, between Crown and Queen and is
25,967 ft2 in size. DA-5 consists of the area in the south half of Crown Road, west of Burns and is 4,706
ft2 in size. DA-6 is 19,846 ft2 in size and includes the area north of Crown and west of Burns. DA-7
' consists of the area west of Burns and north of Crown and is 7,612 ft2 in size. DA-8 consists of the area
east of Burns and north of Crown and is 4,512 ft2 in size. DA-9 consists of the area north of Crown and
is 98,785 ft2 in size. DA-10 consists of the area south of Crown and east of Burns and is 90,625 ft2 in
' size. DA-11 consists of the area east of Bums and south of Crown and is 64,568 ft2 in size.
' The slope within each DA generally ranges from approximately 0.4% to 1.4% in the area of construction.
Following is a summary description of each Drainage Basin:
'
'
C2001. Wyatt Engmeering (679300) StOrn1'Water Brief
' October 19, 2001 (rev. 3/12/02) Storm-1
'
'
' Summerfield East 4t° Add►fion
Subdivision
' Basin DA-1:
T'his basin is 6,941 ft2 in size and includes the area west of Burns Road and South of Queen.
, Flow from this basin will be diverted off the street area via a Type 1 curb opening located on
Burns Road. Based on the equations for capacity of curb opening inlets on page 6-40,
"Guidelines for Stormwater Management," a 2 foot opening is adequate. The flow will be
' directed to swale #1. Swale #1 will have a minimum swale bottom area of 100 ft2 and treatment
volume of 100 ft3. Discharge from this basin will be deposited into one (1) type "A" drywell.
' Basin DA-2:
' This basin is 4,060 ft2 in size and includes the area in the south half of the Queen Avenue right of
way. Flow from this basin will be diverted off the parking area via a Type 1 curb opening located
near the west edge of the constructed portion of Queen Avenue. Based on the equations for
' capacity of curb opening inlets on page 6-40, "Guidelines for Stormwater Management," a 2 foot
opening is adequate. The flow will be directed to the drywell in swale #3 via a catch basin in
swale #2. Swale #2 will have a minimum swale bottom area of 86 ft2 and treatment volume of
' 86 ft3. Discharge from this basin will be deposited into the type "B" drywell in basin DA-3.
Basin DA-3:
~ This basin is 8,355 ft2 in size and includes the north half of the Queen Avenue right of way and a
portion of the adjacent lot. Flow from this basin will be diverted off the road via a Type 1 curb
' opening located near the west edge of the constructed portion of Queen Avenue. Based on the
equarions for capacity of curb opening inlets on page 6-40, "Guidelines for Stormwater
Management," one inlet is adequate. The flow will be directed to swale #3. Swale #3 will have
' a minimum swale bottom area of 121 ft2 and treatment volume of 121 ft3. Discharge from this
basin will be deposited into one (1) type "B" drywell. A type "A" drywell is adequate, but more
flow could be accepted from future phases with a type "B" drywell.
, Basin DA-4:
' This basin is 25,967 ft2 in size and includes the area west of Burns Road between Queen and
Crown. Flow from this basin will be diverted off the parking area via (3) Type 1 curb opening
located on the west side of Bums. Based on the equations for capacity of curb opening inlets on
' page 6-40, "Guidelines for Stormwater Management," two 2 foot openings are adequate. The
flow will be directed to swale #4. Swale #4 wil] have a minimum swale bottom area of 287 ft2
and treahnent volume of 287 ft3. Discharge from this basin will be deposited into one (1) type
' "A" drywell.
42001. Wyatt Engineering (679300) Storm Water Brief
' October 19, 2001 (rev. 3/12/02) Storm-2 _
'
' -
' Summerfield East 4' Addihon
Subdrvision
, Basin DA-5:
This basin is 4,706 ft2 in size and includes the south half of Crown west of Bums. Flow from this •
' basin will be diverted off the road via a diversion ditch located at the west end of the constructed
pavement for Crown Road. The ditch will transfer runoff from the gutter into swale #5. The
flow will be directed to the drywell in swale #6 via a catch basin in swale #5. Swale #5 will
, have a minimum swale bottom area of 123 ft2 and treatment volume of 123 ft3. Discharge from
this basin will be deposited into the type "B" drywell in basin DA-6.
' Basin DA-6:
This basin is 19,846 ft2 in size and includes the area north of Crown Road and west of Burns..
' Flow from this basin will be diverted off the road via a diversion ditch located at the west end of
the constructed pavement of Crown Road. The ditch will transfer runoff from the gutter into
swale #6. Swale #6 will have a minimum swale bottom area of 160 ft2 and treatment volume of
' 160 ft3. Discharge from this basin will be deposited into one (1) type "B" drywell. A type "A"
drywell is adequate, but more flow could be accepted from future phases with a type "B"
drywell.
' Basin DA-7:
' This basin is 7,612 ft2 in size and includes the area west of Bums Road and north of Crown.
Flow from this basin will be diverted off the parking area via a Type 1 curb opening located on
Burns. Based on the equations for capacity of curb opening inlets on page 6-40, "Guidelines for
' Stormwater Management," a 2 foot opening is adequate. The flow will be directed to swale #7.
Swale #7 will have a minimum swale bottom area of 109 ft2 and treatrnent volume of 109 ft3.
Discharge from this basin will be deposited into one (1) type "B" drywell. A type "A" drywell is
t adequate, but more flow could be accepted from future phases with a type "B" drywell.
' Basin DA-8:
This basin is 4,512 ft2 in size and includes the area east of Bums Road and north of Crown. Flow
, from this basin will be diverted off the parking area via a Type 1 curb opening located on Burns.
Based on the equations for capacity of curb opening inlets on page 6-40, "Guidelines for
Stormwater Management," a 2 foot opening is adequate. The flow will be directed to swale #8.
' Swale #8 will have a minimum swale bottom area of 109 ft2 and treahnent volume of 109 ft3.
Discharge from this basin will be deposited into one (1) type "B" drywell. A type "A" drywell is
adequate, but more flow could be accepted from future phases with a type "B" drywell.
'
,
' @2001. Wyatt Engmeenng (679300) Storm Water Brief
October 19, 2001 (rev 3/12/02) Storm-3
'
~
'
' Summerfield East 41 Addrtion
Subdivision
, Basio DA-9:
• This basin is 98,785 ft2 in size and includes the area north of Crown. Flow from this basin will be
' diverted off the road via four (3) Type 1 curb opening located along Crown. Based on the
equations for capacity of curb opening inlets on page 6-40, "Guidelines for Stormwater
Management," three inlets are adequate. The flow will be directed to swale #9. Swale #9 will
t have a minimum swale bottom area of 890 ft2 and a volume capacity of 890 ft3. Discharge from
this basin' will be deposited into one (1) type "B" drywell.
' Basin DA-10:
This basin is 90,625 ft2 in size and includes the area south of Crown to the east of Burns. Flow
~ from this basin will be diverted off the road via (3) Type 1 curb opening located on the south side
of Crown. Based on the equations for capacity of curb opening inlets on page 6-40, "Guidelines
for Stormwater Management," three 2 foot openings are adequate. The flow will be d'uected to
' swale #10. Swale #10 will have a minimum swale bottom area of 958 ft2 and treatment volume
of 958 ft3. Discharge from this basin will be deposited into one (1) type "B" drywell and one (1)
type "A" drywell.
' Basin DA-11:
' This basin is 64,568 ft2 in size and includes the area east Bums to the south of Crown. Flow
from this basin will be diverted off the road via (3) Type 1 curb opening located on the east side
of Bums. Based on the equations for capaciiy of curb opening inlets on page 640, "Guidelines
' for Stormwater Management," three 2 foot openings are adequate. The flow will be directed to
swale #11. Swale #11 will have a minimum swale bottom area of 473 ft2 and treatment volume
of 473 ft3. Discharge &om this basin will be deposited into one (1) type "B" drywell.
' Soils in the area consist of Garrison Gravelly Loam (GgA) and Garrison Very Gravelly Loam( GmB), and
are shown on the attached SCS soils map (See appendix III - Soils Information) for Spokane County,
' Washington. As per the Spokane County Stormwater Guidelines, this soil allows for the use of drywells
to dispose of stormwater runoff.
t 3.00 Summary of Stormwater Calculations
' Attached are worksheets (See appendix N- Rational Method Calcularions) which determine the peak
storm water runoff for Post-Development conditions for each roadway DA. The defined drainage areas
are less than 10 acres in size and were analyzed using the rational method (Q=CIA) to determine the
' peak storm water runoff based on a 10 YR design frequency. The time of concentration (Tc) for the
farthest sub-basin (longest Tc) was determined using the method outlined in the "Guidelines for
Stormwater Management", Spokane County, WA.
'
' 02001. Wyatt Engmeering (679300) Storm Water Brief
Octaber 19, 2001 (rev. 3/12/02) Storm4
1
'
, Summerfield East 41 Addition
• Subdivision
' For all drainage areas using the Rational Method, the Intensity-Duration Curve for the Spokane Area was
used to determine the corresponding intensity (n for each time of concentration. A weighted runoff
coefficient (C) is calculated for the Post-Development conditions, using the surface types and areas
' within the each drainage area (DA).
Grassed percolation areas (or "208" swales) will be used for storm water treatment and detenrion for the
' Summerfield Subdivision drainage areas (DA's). Type "A" and/or Type "B" drywells will be installed
within the grass percolation area (GPA). The drywell rims will be elevated 0.5 feet above the bottom
elevation of the GPA. The intent is to provide storage for the first'/z inch of storm water generated from
' impervious areas that require treatment. These areas include the road, curbs and driveways.
The capacity of each type "A" drywell is 0.3 cfs and for each type "B" drywell is 1 cfs in the Garrison
' soils as outlined in the Spokane County Guidelines for Storm water Management, Pg 4-15.
Using the Bowstring Method, the peak runoff is routed through each respecrive GPA to determine the
' Minimum Required Storage Volume. The Minimum Required Storage Volume is then determined and
compared to the Provided Storage Volume by the GPA.
' The Minimum Required Storage Volume consists of both the volume required for treatment (described
above) plus the required detention volume. The detention volume is the difference between the inflow
and outflow rates. (See Design Calculations). In each DA, the Provided Storage Volume will exceed the
' Minimum Required Storage Volume.
Curb inlets, sidewalk inlets or catch basins wil] be used to divert storm water from the roadway areas into
' the grassed percolation area (or "208" swale). The minimum required length of curb opening is
determined based on the procedure outlined in the Spokane County "Guidelines for Storm water
Management". For a sump condition, the procedure is based on a full opening of 0.5 feet (or 6 inches) of
' a type A curb along with a 2" inlet depression (See Spokane County Standard, B-9 for dimensions) or is
based on a full opening of 4" in the case of a Type 2 sidewalk inlet. For a catch basin inlet on a grade, ,
figure 15 from the Spokane County "Guidelines for Storm water Management" was used to determine the
' amount of flow captured and the amount bypassed to downstream basins. These calculations are
included in each basin calculation.
'
'
1
'
02001. Wyatt Engineering (679300) Storm Water Brief
' October 19, 2001 (rev. 3/12/02) Storm-5
1 ,
1
, Summerfield East 41 Addition
Subdivision
'
3.01 Tabular Summary of Storm water Analysis
1
Drainage Time of Rainfall Weighted Total Peak Runoff Minimum
' Area, Concentration, Intensity, I Coefficient, Area, A Q10YR Required
DA Tc (min.) (in/hr) C (acres) (cfs) Storage
(CF)
' Post-Development - Summerfield East, 4t6 Addition
DA-1 I 0.93 I 3.18 I 0.72 I 0.16 I 037 I 109
' DA-2 & 3 I 1.40 I 3.18 I 0.64 I 0.29 I 0.58 I 335
DA4 I 0.96 I 3.18 I 0.61 I 0 60 I 1.15 I 551
' DA-5 & 6 1.29 I 3.18 0.59 I 0.56 I 1.05 I 388
DA-7 1.16 I 3.18 I 0.56 I 0.17 I 031 208
' DA-8 I 2.27 I 3.18 I 0.74 I 010 I 0.24 I 184
DA-9 I 039 3.18 I 0.53 I 2.27 I 3 80 I 1840
' DA-10 I 1.35 3.18 I 0.60 I 2.08 I 3.95 I 1648
DA-11 I 1.85 I 3.13 I 0.52 I 1.48 • I 2.45 I 935
'
' 4.00 Erosion Control Considerations
' The erosion or sediment control plans are included as part of this project.
The Contractor is responsible for insuring the use of proper erosion control and shall maintain such
' measures throughout construction, until all pertinent landscaping and permanent erosion control measures
(i.e. grassed areas, paved surfaces) have been established. Maintenance shall include daily inspecrions
and repair of the silt fencing, hay bales, or other. The Contractor will also inspect all erosion control
' measures following each storm water event during construction or until the permanent measures are
established.
' Specific temporary measures which will be used during construction include the installation of silt fences,
hay bale check dams, and construction entrances. The measures will be installed along the down gradient
properiy lines, parallel with the existing ground contours or perpendicular to the storm water runoff
' direcrion. The upstream ends of all existing culverts will be protected by the installation of hay bales.
(02001. Wyatt Engineenng (679300) Storm Water Brief
' October 19, 2001 (rev 3/12/02) Storm-6
t
'
' Summefield East 4i° Addttion
Subdivision
' Construction entrance will be required in order to clean the tires of trucks and vehicles exiting the
construction area.
, Periodically, the temporary erosion control measures must be cleaned of debris and siltation. The
contractor shall dispose of the materials so as not to damage any reclaimed areas or create other erosion
problem areas. Upon direction by Spokane County, Owner or Engineer, the Contractor may also be
' required to clean the County roadway of siltation or other debris which may occur along Crown Road or
Burns Road at the construction entrances.
' 5.00 Summary/Conclusions
, The storm water runoff generated by post-development conditions of the Summerfield Subdivision project
will be directed to `208' swales sized to handle the first'h inch of stormwater runof£ Discharge from
these swales will be directed into the subsurface native soils using either type "A" or type "B" drywells.
, The GPAs (or "208" swales) will function as storm water detention areas as well as provide treatment
prior to discharge into type "A" or "B" drywells.
DA-1 is 0.16 acres in size with 0.11 acres of impervious area. Drainage will be directed to a`208' swale
with a minimum capacity of 109 CF and will be discharged into the subsurface strata via one (1) type "A"
drywell.
' DA-2 and DA-3 are 0.29 acres in size with 0.15 acres of impervious area. Drainage from DA-2 and
DA-3 will be directed into two `208' swales with a minimum capacity of 334 CF. Discharge from DA-2
' will flow into a Catch Basin and then into the Drywell in DA-3. Discharge from DA-3 will flow into the
subsurface strata via one (1) type "B" drywell.
' DA4 is 0.60 acres in size with 0.31 acres of impervious area. Drainage will be directed to a`208' swale
with a minimum capacity of 551 CF and will be discharged into the subsurface strata via one (1) type "A"
drywell.
' DA-5 and DA-6 are 0.56 acres in size with 026 acres of impervious area. Drainage from DA-5 and
DA-6 will be directed into two `208' swales with a minimum capacity of 389 CF. Discharge from DA-5
' will flow into a Catch Basin and then into the Drywell in DA-6. Discharge from DA-6 will flow into the
subsurface strata via one (1) type "B" drywell.
' DA-7 is 0.17 acres in size with 0.08 acres of impervious area. Drainage will be directed to a`208' swale
with a minimum capacity of 208 CF and will be discharged into the subsurface strata via one (1) type "B"
drywell.
, DA-8 is 0.10 acres in size with 0.08 acres of impervious area. Drainage will be directed to a`208' swale
with a minimum capacity of 184 CF and will be discharged into the subsurface strata via one (1) type "B"
' drywell.
02001 Wyatt Engmeering (679300) Storm Water Brief
' October 19, 2001 (rev 3/12/02) Storm-7
, .
, ' .
, Summerfield East 41 Addition
Subdivision
' DA-9 is 2.27 acres in size with 0.86 acres of impervious area. Drainage will be directed to a`208' swale
with a minimum capacity of 1840 CF and will be discharged into the subsurface strata via one (1) type
"B" drywell. -
' DA-10 is 2.08 acres in size with 1.03 acres of impervious area. Drainage will be directed to a`208'
. ~ .
swale with a minimum capacity of 1648 CF and will be discharged into the subsurface strata via one (1)
' type "B" drywell and one (1) type "A" drywell.
DA-11 is 1.48 acres in size with 0.49 acres of impervious area. Drainage will be directed to a`208'
' swale with a minimum capacity of 908 CF and will be discharged into the subsurface strata via one (1)
type "B" drywell.
' The Contractor(s) will be responsible for the proper installation and maintenance of all temporary erosion
control measures necessary to protect down gradient areas from siltation. The Contractor shall also
' protect against siltarion of the drywells and GPAs (or "208" swales) throughout construction.
A one foot berm will be constructed along the north boundary of the plat to prevent runoff from the north
' &om entering the plat. Type "B" drywells will be installed at the east and west ends of the berm to
handle any runoff that accumulates against the berm. These measures are outlined by Spokane County
as a requirement for the plat. The one foot interceptor berm and two type B drywells shall be constructed
' along the north boundary of the plat to provide an additional factor of safety against flooding from the
Zone B flood plain, as stipulated by Tammy Williams, Spokane County Flood Plain Administrator. See
letters from Tammy Williams and Dean Franz in Appendix VI.
' The bottoms of the swales in the development are constructed parallel to the road curbs and 1.2 feet
below the top of curb. All swales are less than 1 percent in slope and are considered flat as per the
' Spokane County "Guidelines for Stormwater Management." Driveways will be constructed across the
swales when the lots are developed. The area of these driveways has already been subtracted from the
area of the swales, and the runoff from the driveways calculated for treatment. Driveways will be
' conshucted across the swales with a low point 6" above bottom of the swale. This will allow areas
between driveways to act as mini GPA's and prevent a single large area of ponding. Overflow from
these mini GPA's will continue to the drywell location and be discharged to the subsurface.
'
,
'
'
C2001 Wyatt Engmeenng (679300) Storm Water Brief
' October 19, 2001 (rev. 3/12/02) Storm-8
,
1
, Summerfield East 4'" Addihon
Subdivision
~
~
,
'
' APPENDIX I- Project Location Map
1
'
'
'
1
'
'
'
'
~
' Q2001. Wyatt Engmeering (679300) Storm Water Bnef
October 19, 2001 (rev. 3/12/02)
1
, . . . . . ~ . _ -
. a I Z , . _
BOWDISH
. -
tx)
0
. m
i'
PINES PINES RD ~
. ~ _
c~
~
' . ° ~
, D m
_ m m
~ as
MCDONALD o
~ ~ .
rtt C
~ v .
. EVERGREEN ~ EVERGREEN RD
ADAMS
Od
' ~
PROGRESS
, SULUVAN _ SULUVAN RD
; 1 -
. _ . . . - - ~ . . .
_ . _ , _ . _ .
'
' Summerfield East 4' Addition
Subdivision
' .
'
'
A.PPENDIX II- Drainage Area Map
'
'
'
'
1
'
'
,
'
' 02001 Wyatt Engineenng (679300) Storm Water Brief
October 19, 2001 (rev. 3/12/02)
'
■ pA8
IMPE5I~100S AREA=2,620 SF IMPERUIOUS AREA= 2,620 SF
r,' TOTAL AREA=7 612 TOTAL ARFA-4,512 ` I ~
, ~ r■■~~~ ~ ~ ~ ~ ~o~ ~
, ~ I1I
~p3g ~'r ~ ^a~l` Wf~ T~MPORARI' ~t W O=p~
~ GRAPHIC SCALE ~ 5 ~Gtz
rF • n ~ ~f-~~ ` ~
f.''~ ~ w / R~ ~ 9CI p 10 80 180 cc ~
' 1 ~ Y ~
LOT
4 LOT , 0
"urce ~
~ ~ar t
Lor e 1 inch ~80 ~ !k
LOT z 1
PERVIOUSr EA=3,830 S cc
T(}TA1/AR = 19,846
LCFT I ~ I W
uj a~'?ae
/ ~""n
5 f ~ 1 ~
i ~
I MLS` APEA=2, 9 F - ~ Y a o a
~ N
gt~°rAZ af7E4- , 06 Lor,o aT o DA9 ~
~ a \
' `tot a I~i ERVI
OUS AREA=21,360 SF
roc ,~r, TOTAL ARE4=98,785 Si~
4 1~\ / ~ r
G
IATa Z
4 a
F
- LOT 3
IMPERVIOLIS REA=6,880 5F ~
T0~'AL A EA=25,967 wr Eo-m w
urr d clJ C4 ~
w ~ r e LCYT +
LLT 1 ig IAT 12 cn E- ~
~ 3 W Z
I ~ W
MPERVtOUS A EA=2,910 5F
TOtAL A EA=8,355 ~ ~ia ~ ~ ~ o Z
swn~ : _ , ~ 1 ~ ~ E w
ie L) ~
QQ~ 0~r1 ST. ~ ~QAII GW9 Q
Fr+~ h ~ ti W'~
fMPERlOUS AREA=2,060 SF if p 1MPERVlOUS ARFA=11,35Q SF r lOP 2
TAt A~REA-d,Q60 'toc ~ fiQTAL ARE4-64,568 5F
~r i
-
DAfD
DA1 ~r , ~ or~w+
BCIB ~r: a~p~NL
w\ iMPERvtaus aREa-z2,se0 sF T ~ DESiM Erf.
__4MRt&V191J5 AR ~4,400 SF 70TAL ARE4=90,625 SF BM
TOTAL AR 6,9~41 1'-e0`
"WA NAACk-2002
4 PR5EM 6793fJ6
R
. SHEET ~ QF 1
f
I
'
' Summerfield East 4' Addition
Subdrnsion
1
,
'
'
APPENDIX III - SCS Soils Information
.1
'
~
1
'
'
'
,
,
'
r
' C2001. Wyatt Engineenng (679300) StOrm Water Bnef
October 19, 2001 (rev. 3/12/02)
'
(Joins sheet 57)
. -.Zl J.......... ~ . . ,
~
E~(,~ , ~J r~ ♦ ~ ~
\J
~
~~~r ~c.'3 ~W~~~'(:~ y~(~y~ ~ i i ~ ` t 3j•i .+~y •k +r t .
~~'rI y~ ~ , ~ , ~ , r
F ~~~c ~ ` C'~~`'t~~ ~ ~4`'.~a~.~~~t~~ • ~P V ` . r €tl~,t('y; A ~.v ,t*4,+`'>,
~ ~ ; t . . F [ i :t c".d i , g `~r S. y $~'w ~ ~k~~'^."~4'i: F ~ t,~ ~K . Z ~ `~1.~i~^ ~ ~xl ~ ~t•: i. a , r
~ ~ • ,y~ ~ ,~q~; - " K ^ ~ t.~ ~ • ~ , - y ' ~ v lJlt y~,~ ;r r~~z ~ ~w ~ ,A•~~~"`~
, ' , ` f ` . 2 ' i~v;'~~~~w. ~y'"~ i ~`y15i.~ ~ i ~ 4 M ~ d ~~`[i~i st '',~'~g~ ~,,~~e~~S•,; ,~„t
a.T
i~+ p ~S ~ §~t k<i:~'~ i rA ' ' .t r~.tl ~ . ~ .i~ ~ s-4:Y
`s$h,~.Y~~'i{~ '~',s{~ .+ert ' . ~ - • , J: ;t "X`"~ ~r,':.~'`r"~{;~i ' . ' ~ ~ ~ Tt'~,`, ` ~ a~~'' .r."` i ~ • ~ r'
`p ; ~~.~~,~J~.F~ 5ry~.. ,nr ~ v.~ _ (tn7 ~'~~~toi~tii,;, i~ hl ~ l•~ . j.+~{ ~'e p, Lr"'Sel'~,~~ ~ ~p ~ r~
.rCAl`y, •~rk~ r' ~x :+,~x . ~ ' ~ ~ ~ ~ f~ t~ t~u~ t. et t^i~`
, * { R' y, : ~1~< < i~ t 7. ,
r ~ ..F,- * ' l ~ j d ~ e , ; ' -~`Z r . 2>. ~ { I y 1 ~k ~ 1 r •r..} ^.2 10~
,s,l ~ q ,~'~u~`~k` ' 'y~`? ~ ° ~ ; uh, :t ~ ("1't• r:: x "`~r~' ,~yi _~~s ~T~,~ b^~~ ~....a,.__ _
< i-, s. { • .tY~ 4- >n. . .d~ 2~ y~• i~ . `t F.
J1
i. t1' r j ~p' `t f ♦ ~ i ~ V ,i ~ , .r . ~ '~i~ ,
~ d {to, v~l~ r r €3Lv~ , r . t / +r• ~'xt ( ~ ~ ~ } ~ - , . . ~i~~s/,,,'~, i ~t .am~- ~
`Y5 ~ ' 6 y~ w ~ ~ Y•> ` r~ ~ ~ ~ ~p i , • ~2. Y yt ~ ~~i.,.y ~ ~ ~ ` • ~ ' u, ~ n 1~ '
1,~[~yy ~a ~ F 7 S ~ ~ ~ Y "T ~1 ,~:i ~ ~
~ ^ µ • + 9'~, 5~ i ~ li ;y`, ~AYS ~ 'f' (`u;Y«Y-SF ~r ~ }r i~~r :~~:~t~ri'~;",rw 1~~ r.J" ~ ~ t~ . • ~~?~c3 ~ Uv i ~p~ a~~4.a
t
...A "A'~~ ~
• 4 Z . y c.A.. ^ ~ $i; ; pg y ,,jj.,! ~a~A t ~ 4 • ~ .i. • A I ~ ~ ~ A ~
;~;~S~~y ;~~r~~~~'x,~ 4#~z;~'~* ~f~ ~ . . , / a' 6.;. n
Iwo gr~. ,j~~ ~ .:.JII~~~'S.~_~~s~t.}r~`,g•,~~5r
~ }S~l , 'i »5*=•v. ~.a _ . _ _ l.~.~.... ..i..
° r'Iw' ~ ~t}r f4 i ~ ~ --~.^-.x•.~ ~ ~ t~
~.~,~l~r r1 1
•J ~°~:.~~j ~t;~• 1 ~ , .•nlsLk. ~ - ~ • ~ ~ .Et { ~ st1 . ~ ~ ,i~;~ ^ ' ` ~gQ~ ~i~ 'Y~i6a~
s~, k j , ,•l~y,t'`Y ~ \ i F ~ ~~.yw ~i% ''~'t' ~r ~~y i.~ .~,~}~e~'.,~~ p~ + . ~II ~ •7~14'j`1`~ ~~,'}y~< ~p~?''t`
~a. ~ ~ X"~: . ..q, . > ,°qh~t _ ~ A ` 6 yy~ # h~.. • ,~r >r
~ i ~ijpl' ( ~ yr i "Y~. ! '{"1 . k~..~~-:,._~~ ~~~',~`r ~ ~ H Z . k~•'~A y, i► ..f~f ~ " ~ ~~{4 t~ 1 ~ ~t ~'Qc , ~ ~ ~sy
, y
ro~~y`'q y~
,2}~f~ a Y~;~ i'•y~~, f~~~ ~q}
~ `"icai•a:~,~ , r . , t~~j, . ~
~ ~t~,;t~~``~'~~~.~~ ' s .n•AU' i°' . t p ~ ~ ~ ! ~~[,~j~i'~~i:~ t~,' i~~ , ~~j~ ~~7~y~,~~ C1: ~'W~~+;~{+I:M~t ~ •,w`~.~,~r r , ,~~r, . , ' , n , ly~~*~ I i.f .:~'`tiLa~~ ~t ~'~c~~` `y~~j ~ ~ eR ~~f T~f'3~%~~ ~}y,~~
`~'x~s~~.,;."a~,t, Y , • g Tj ~5e:
fl"4,,C.R 4~µ~ .`fi ~»~~•t)~~~ •4'fhf."v~k~~,
r~~y,Tz~ ;r , n ~ ~ a E~~, ~i
~:Y.G'X`k' d..~,` t ~ ~ t . , e. •a~~,.~ $ ~ i~~'.G + .bc ~~s"~~~r~,'.~'~'~ ~ " :
~q a~,~„ "f ~ 3~ a • • / .43„ ~ r" t ~ ~ ~ r f"
i~Fp k in , ' • / ~ .k}. i .~S „A I " b.f ' d t~a ' ~ ~I~,~y ~~t ~r+{
~ ~ . • fl[~ Po . .a ~ ' , ~N, <
,s' e ' , / ~ 4~,~rn H ► ~ 1. ~p~~ h
t, ~~i i• ,1~;'~ ru t''wYq
'
~'~'f~; } }i ` Ul ' Cl » -\,•~4• C 4J i>•(`fks~ " ~ ~T~7
~
~'~t ~ • ~ ~~Y ~ 8 ~ • ~t • ~ • ~ . ~w n i~yy ~ ' {„ia ~b,~" , ~ ~ ~ • 4r ~
~ 43i+~1-_.._ ~ ` r~ ~ • w , a} x : ] j.~~j K~, : `5~' , ~ 3, • ~t~.. ('p ~ a .
~t2, W a ~y ^ e~1 '9 V.J cy~ t
~ S YX.~v . i T 1•~ }d p ~L x ~ ~i ~ ~~.1 ~3 ~
, Y~~. , !i~ • r ~ ' V ~ "(i•'~y Evy,-F~ ~ ~y y$ ~.F ~ ` t, ~~„zJ"s~~, ,L f
~
k,~r,~ ~y i,~~ ~ ...~s ..',R~. p ~p. ~ ~D . ' ~ ~ ~ ~S°" • ` y'~~, ~ ~Y Sri ' J 11
~ ~j~'~' i ~ ~ -•~y+ ~a5~ ' f ~t~~~~ S~ • ~tiY4e~ y , ~ ~y ~,'9"' ' ~ ~ t a ~ ai~.` ~t.A'~.e:~~ ` ~1
~ jt i ~ "+';'~r ~N aj ~ ' , 41y. Y " ~.S"IIi' ':.e.~ ~ l
, • ^~S~,< , B v'`r ~ r ~~,y, ~ ~ ~ }~?~ia~~ ( . x~ Y - h § ,
h.,t 4~f'
. ^ • 6.. C. # t. F' f$~~ t~~, `i ~t~'r~ tl ~ . "'.ti.<.~",.~.y~
f f' y' •;~e~'~1 . t~~ ~ • _ ^ 1~`3, a; ~ Ay ,,~,,,~Y~y~>_, : .~t; ` w.•.4.
~ ,~'+~~3~n "~r ~ ' V "i'4 s~ r • ` ' ' > ' ~ ~ ~
~ ~ ~ ~ ~~~jf~l ;y i ^m ~a~~~t3 a~ ri` ,k^ ( ~Y ~~!y~'~
1-~{~7p
q?$~. _ ~a~r p ~h y q d _~,p'. i.~~r 3. ~f' ~ ~~k1~tp1• ~ ~ ~ c N , y~i?:w~z~ ~ a ~ fn,,~. " ~
~ ~4 ~ ►'E~ ~`vff~ , t~~ s ~i ~;~,G' ~ M~ u~j,p y,~<,~e~,, e "Y~^` °~t . pr'F yi~~ f 7
p' ~ ' !„~•<F ~ i,(~• N~ ~j y ~ v o- ~~t t ',f ~ .,y "Y W 'w1 'a • 6~y~,~p t ~M ?(~~~f~ , r ~ ~,f~.gjk~3~; ^ 'e
eN~ lC ,A ' ,~~k` ~ ~ '~i ~ `~~~a ~,~S S.~ ~~Y j~ ~ S' ~ ~ ( i~~i~~~~ <.~Cr~ * t ti'M7s ~~a~t~
, ~ ♦ r ~ d~X`Y' 'd~ ~ #y • ~ + +~~"~'pAl~~iq~, ~ ~ ~r„~ i ~~~n7a.~' ~ r y so-~..! ' ' , < ~
, .
:ooKana,tcunir, wasNtncron usoa-iGt
7•92
' S O( l F N i 9 R►A E T S i[ Q V f R C C C R O
' GqG G00.R(SON CRAVELIY lOSM. O 70 S ISACdNT SlOPE2 .
1~.+
C~RALSCN SLAt12 CCNSI575 01 ~eR• OE_P SOfIS IGRMlC IN C~SC[~l 9UTw43M WITN A HANTL! Ot YOLCiHIC A+N ANO L0855 QN lGV6l
TJ CEVTLY SLOP[NC i~AR4CE+ 6N0 S7EEP :0 MOOlA6illT Si2HP tIIVR6C4 lAC6K5 vtCHTA T[ON IS NaiVIY GASSS iN0 :CSTTCRE2 SfGNOL
OI TaESS 7YOfCAIIY. TNCSZ S4[l5 MSVB a OeNK CAOYI3N BROWN :CaM SU0.POCS C~YSR ?GCV: I6 tH THSCX, O 6AOwN CRAVZLLY LppM
' SYD50(l l INCNHS TNit% 6N0 a'7AOwN vaRY GAevEILY 10AM7 C06R5[ SANO 5U8STN~TUM t0 SO IHCMGS.
i lAMOSG]iC SNO CliM6TE DqpV!RTfSS
' 6MNUAL a1A fNOST •AEE ' SNNUVI 61818T10N ORilNGGL :~Qa~
iiMO!ASiVR9 i OAti >AEG[i[J]T[ON ` lF71 C1655 Ip[:1 ~
~ tt.i0 ' 1:0-ITO ' IS•:S , ~atl0•:l00 ~ 52
~ [STiM6iE0 50[~ ►40P!qTIZ4
~<i2N~ ~ra3CT fR6C7 ~PEAC_NT pf MCTL4(1L Lt55 AY
~
[N.~ U503 i6%'UNQ ~ UNII[CO ~ OASN70 >10 INi]•IOIVi TMaN S' oiSSiNC SI?V! NO ~ ^
I I ~ ~ ~tacri ,Iacr~ + io ao . o ftvc-i;
~ o-is;ca-L ~sH, cH ia.s i o i o-io ;io•ao 'ss-70 so-eo sa-s :o o
•44CAV-L. CN-l ~cn. sH ~A-z. a•1. a.a o•i: jas-~;s ae-ZO is-so is-as ;io•is~
, ~•4-so;sa-cav•~cas-car-st (cH ~a-1 ~ o-s ~ao~o ~s-ss :o•ao io-io ~ s
~eo-To:CA%-CoS, GAY-COS, CeX-LS cv-cH IA-i o•1o ,io•.s I~s••s s•zs o-io
~ ~ ~ ~ I I I I
lOCPih;lI0Ul0 PloS- MO[5T lUIK j rQRMCG• AVG(~A4lS SOIt SdLi:1I:Y 230. C!C G?C03 CrPSUM ~
NSI7Y ![LlTY !~W4TBN CSiGCt7Y~ ACACT{GM ~ ~ i ~ ~
M,j~ L(M[T ~T[CL'7t OC (
• Itnoex I fcic4ii• ~ tr/Nai H/tMt ~ (nNt !tH.+NasicHl; Ifyellooct~ (vc n ! I res i ~
o•is' :o''o vv-s i ia•i ~s o s-:.o o i:-o.~s a e•~.a : i ~ : : ~
xo .i - ~ a 1 1 I S_o I I' I
~i-sa~ -zs ~4P-5 ~ i.zs-~.as ~ o.a•:.o i o.~:
~ ~ I 1
H o
v so ~ 'zo ~ o o.•o.os T. a z
~ss
na ~ t.ss-t 75 ~ >zo ~ 0 .01-0 o~ ~ ~.i-7 o.: I ( I
I 1 I I I 1 I I I I I I ~
f f I 1 1 1 I 1 , , ~ ~
~OGiTN:0AG.1f11C' S11A(NR• ~ROSION ' WIVC WiNO CORROS[YITY
' i(IN I;MA' cTLA ~ SWEIL i (i[:OAS ' CROO.~ EA00 ` '
~ rort !VC7CNTtiI! c Kr~ caauv~ txoex ~ sreeL ;coNCae-E~
o-is; -s < t¢w i 2 ~ t as ttiooeRa7e: ~ow
1-2
<aw
10 ~ tow ~.~o~.zz; i I I
~eo•~o~ c.s S Low ~.os
' I 1 I I j l -
I t 1 ;
DSIOC~CE MYOi➢OTHN7'ki
' llCOOIyG i HiCM wGiCR 7AE1! : CL-lYT!O CCONOLX ;SU i
OC➢TN ~CSMO NONTYIi OtPTH'MDqOr1C45 0lYTN HCRONlSS~IN~T TOTAL
Nl CRP 1R05T
, fA!OttCNCY DURGitQY :NONTNS lITI I I IIINI i ! IINI I ;ft 'IIMI ~ ~ 6C'tON ~
. >a Q )QO i ] ;v00lR~T£j
YOHe I
~ 5.1NIT'JAY rGC « <T:ffS CaNSTqUGTION '~pTlR[6l
, ~ SEY,AL•PCCR r ILTZA I{ ~GO00 I
~SLVTlC raMx ~ II I ~
~ aesoairtaH ~ tl naonrttt ~ I
~ rttLCS
~ SGVGaE-56EDOG4 irnaaoaLa ~
~ SweGG
c aLcaoM ~ sANO
~ aa[as ~ 11 I ~
~ 5lV~R6-SlEPOCL ~i jTRODAOIC i
~ SANITARY
~ lAMOIILI ~ caave~ ~ ~
j ~iREtICNI
' ~ CYeAt-SflBPOGE ~i ii00R-SMYLL SiON65.ARQA RSGLO[M ~
~ SAMI7oRT
~ taxoP tii ~ II ~ovsast ~ I
~ Iaaeoi
POOA'SHOLL :70NC5 wei~A MoM6GEN941
OaIIT (
~ caveR raa isareac•saeraca ~
i Lanor nt. QesePOG
nvaca ~ j
II °ata ~ - ~
eucLatec strE oeveiavr+cHr ~
ISlVGRG•CLiDOMK+ CA V G CNOiNXMQNT3 iSlYGRG-SdCPAG! ;
'
~ 3N41L0w ~
~=xcavarcaKS ~ II .veeso ~ j
I I II 1
i~SlYGRG-MO woTCR ~
~ ~SLIGMT i
~ owe~~tHes ~ exc~rezeo +
WITHOUT
easev6YTS i ~(SOYtlG0.sl~0 ~ I
~ si:cHr II ioesv ra warea ~
i OwltlIMCS ; ~j pROINAC! I
W27N '
~ lASCY6NT3
' I sLrcHr 40ROUCNTY ~
~ COMMeRC:AC IARICOTION i I
i DUIISIvCS
~ 00CAGT!•PA05: .1CTIaN ' •SRGE SLGNGS,TCC SoN6T I
1f~ . TIIRRGCSS i j
las ne n ,sQ otveas~cHS ~ j
~ Rsr
j:M06LAPiC-SMiI' 5:6NLS,CRCUGi1T1 iLiRGL S:ONCS,OAOUGMTY ~
~ :1WM5,
~r.~NOSCSV[ac c~~ssao ~ I
, ~ ano ae~r waceawars `
~..:ntRwars
, ' .
1 -
CiRAf50N CRAVCIIY LOnM, O TO ! 1t RCLN7 SIQP_S US~n•iG5
7-f2
' RIIC~G~~:QNG~ 0[VLtOVM[Vi
i iMaoeaarl -ausrY ~sevene-sr,a~~ s:ones ~
CAMP aneas ~ ;vLarcRaunas t I
~ 'r.aocRara•ausrr ;HOaensre-ousrr s
. { , ji P~NOS I {
iICH(C JplAS~
' ~ TACIl3 ~ ~ .
CAPAIIItITY SNO YtElOS P!R SCA° OP CROPS'ana P45TVRE {NfGN lE~Cl MnN4G!"IENiI
cava- wMSAr, wHear, j eoaI ar ~ caoss• ~ vasruae S oars czass, :eac'j
~ i QIlL7Y wfNTlA ~ SPR14G L$GUM! NGY
~ ~su~ tt ~ laui ~ lcons~ ~ {nuNI ~ raui rLssi ~
~N(RR'IAA 'VIRR ~iAA 'YfqAau i1R0. V[.70. ~[RR 'VIAR IqA ~4 I0.A ~[AR "1iAR 'i4R 'VIRR !IAp I
]S , ]E ~ Jo 60 ; ]o co Zo 1.o a o ; :.S 8 0 ]o ~ aoo
( I i I I I i I I I I ( I I i I
I ~ ~ ~ I I , I I 1 l t l ! 1 { 1 1
~ I 1 I f I ' I "I I t ' 1 I ' I I
~ I I I I I ' I 1 I ' I 1 I I 1 I l
~ ` f f i I I i 1 I I I I I I I 1 I
~ I ' ~ I I I 1 I t 1 I 1 I I I
~ I ~ l 1 ' I 4 f I I I 1 1 I I
~ I 1 I I I I I I I ( i I I I I
~ 1 ! I I ~ I ~ I I I [ , ~ 1 . S
. ~OCOLANO SUfT08[l[iV
ORO j pp7ENT1Al mQOOUGYIvfTY
MoN6G[VlVT oqpalSYS
' ;SYM EAOS'M•dOUiP.;SCzOI.'W[Y6TN'P:GNT ' CaMMUM iRGIS i5(tC'VROO~ 7R6C3 t0 PtaMT ~
PT~ j[NOX:CL}5~
~ 1NO:GRO~Lth1IT ~TtORT'Y!N62IIROICOM[
•A;SlSCMT'MOOER_'MOCLR.`SllGi1T'M008R.'PCNOCA05.1 i1MQ ]6 • 4 lOPDEROSA YINE
I ~ ~ ~ ~ ~ ~oouccas-icn ~ ~ ~ I
~ I I I I ! t ' 1 1 ! 1
~ 1 1 1 1 I I I . I t ' 1
I I ~ I I I I I 1 t I 1
i ' I I 1 I I I I I 1 I I
1 I I I I 1 I t S I I f
1 I I 1 I I I I 1 I I
~ t I I i { ' I 1 I l {
~ I I 1 1 I I I I I I I
I I I 1 I 1 1 I I ' I ~
' , " I l 4 { { 1 I 1 1 t I
~ I 1 I I I 1 I I l ' ;
•rcnoeRe.axs
i i Sa![[ES iNT' SP!CIaS ' NT' SiCCS55 !MT: SVCCi!5 jH7
PGK[NC C070NEPST~R ;1 iLlIAOVG?N PRIVGT i6 'i!DlRION PGASMRUO ~'OiIILdC
jftGCXY 717 JUN[iCP ~IS 0.USSioN-OLl`/C I8 ~USTR(GN P[NG S GAG~N OSN S
PONOEROSi pING N LM i30~DlALX LOCIJ57
i ; ;21`SC OTCN 7[ N t i70i5[BCR[ .t G
1 1 I ~ I I I I
wtu~ne Manc,-n,- sutTaetLtrv
i -O7ENTIJt /OR IIGa:Ta: Cl!MaMTS ' POTEHT[.1l .15 4A0[Tii /GR
~GRGIV {'Ca455 i' WIlO MA0.0W0 ;LON[rffR'SMRUlS WCTLaMO'SNaLtOw'OVSlIlO 'MOOOLO Y/ETLONO'ReNGEIG~
SEEO ~L~CUMC ~ MZRD { TRGaS !PIANTS ~ ~PlOM75 ~ wGTCQ ~'MIIOI~ ~wILOIF ~W~LCIF ~'NIIOLf ,i
lJIR rv[R GOOO f41A fvlR /A1A 700R V. VOOR' IAiR /AIR IOON'
~ ~ ~ ~ ~ ~ ~ ~ ~ { {
1 { 1 i I ' i I I I I I 1 1
' ' ' ~ 1 ! 1 I I I I I I I ~
•nTEYTiAt NLTIVE ilANT LOMMUMITV IRaNG[11N0 OR YORHST UNOERSSOR• -CC8TA710N1
i pl.1Ni ~ PERCEH7AGd CG11v45[Ti4N 'ONY `i/C(GMtI
' COMMON PLSNT NAM! i S7MOOl
NlsvNl i ~
~P[YCCROSS CARU 3
~ntue ++TLoare ~ eL cL.
' ~svIKa ratseTUM ~ rnsrz
~eLueauacn wMeoarcaass ~ aCs► ~ 1 < < ~ ~ I
~Sw[LT3NTEO casTaow ~ carn3
'svneaotC IInc swecrxaor ~ ascH
~MOOK VtOt6T ~ VIdO
`5[lK' L uvt.re < <usea
~C6MMOM SNO`/ECRRY ~ 57L1 i 70
' ~wMtra svcaea ~ sveez
~sasxarooN aea~tcaeeaav ~ ~M4~z
~aaecaHCanve ~ eerte
~owaar Rasa ~ AOCY
~^OMMON CNOKlCMERRY Pa~t t S I I I ~ ~
i!l]CX M6WTNONN ` CA001
►OTGNTlAL P4C6UCTIOM {LO1.J?C ON7 WT)• 1 ~
rAYCp60l! 76.~R5 ' 630 (
; NORMLI TlARS ' 1.0
~ uaFevcRaete renRS
RANGE SITE 047%Y002wY
l~pTMOT~S
1 CXCLSSIY~ PffAMloOILITY R4TC MLY C?U3E POLlUTS0f/ Ot GAQUN WGtlR
SISL I110LX I$ A SU7~MGR7 O! S OR MOAC NCdSURCMl4TS ON TN[5 SOIC.
1 ~
i .
1
,j SiOKA»L COUMTY, W4$N[MGTOr • USC4•3CS
7-9:
S 0 I l I M 7! A 7 R! T O T[ O N 5 R G C O R 0
' Cme CGAN[SCN YLR7 G~~V6ll~ lOOM, O 70 6 P!RC4Vi SlOVeS
C1A0.t1CN SCR[LS CONSIS75 0• V~R1 OElP 50[LS FORMGO IN GIaCIAC QUTweSM wI7N 6 M6nYLG G7 YOLCAN(C SSN iN0 L0lSS O LdVCl
70 GEN'CY SICPIYC T6ANACLS SN6 5T84? TO MOOEAALELY STCLP TLR0.1~p l0.E0.X3 VlCflTiT[CN IS MAINIY Ga63$ SNO SC~77C0.C N0 SLSNCS
0/ T0.!!5. iY➢fCAllY, TNHS! 50[l5 NYVR
i OARK GR01(SN ~ROWN ~QAM SuRf6C4 IaYQA LBOU7 IS IN iMICX, S 7AOWN ~qiVaLLy I.A.
' SUeSQII D(NCNE$ TNIC% aN0 a EA6WN YEAY G0.GVCllY ICdM• Cpaqg6 SoNO SUlSTRATVM f0 60 INCH QS
' LSVOSCSOE CNO CLfYn7E V4pO!q1iG5 ~
aNNU6L J[R PROST tRlB iNNUGL CItYaT(OX ORYlM4G2 SLppE ~
i T!NO!Q6TURt 06Y5 ~ ORlG[P[7iTiON ~ SrTI CL6S5 ~ (PC:1
~ al-SO . 1:0•170 , IS -:S , Ia00-:SOO , SL , 0•3
' !S7iMAT!0 5O[L PROVCRTf_5
~oePrN; ;FRaCT,j1RaCT.;yC3Cflni ar .4u,-eniAL Less ;cLar ~
tH usoa rexrupe ~ uHtt;eo ' aoshra ;>io [H,3-iotH~ rwaH 1- aass[NC s[eve Ma
~ i cTi !{vcrt a ~o ao zoo aeri
~ o-is~cav-~ ~cN ~o•I. a-z ; o i o•~o ;ao-so 33•1o =o•as :o•3s 1z-:o;
, IS-as CAV•SL, GRV•l, CR-t CM, SM ~•2, 4-1, a-a O O•15 3S-TS •O-TO :5-60 IS•~S ~t0•IS'
~.a.eo~sa-cxv.tcos•cav-si ~cH ~A•1 zo ~ao -eo ~s-ss :o-ao io-zo
o-rojcnx-cos, cav -ens, cnx-Ls ~C➢, CD-CM ~o•1 s•ss o-io ~ o -s ~
1 I I I t I ~ 1 I
~O!➢TM:I[OV10 ; PLSS~ MCI57 7UlK 7GAMCC- SVG(LGEIE 30[L 54LYNITY ' Si0. C!C ~ COCOS CYiSUM ~
~(IN lIM[T T[CITY~ 0 ~YSITY ~ OllltY ~WATCR CSPaCIT~' RGAC7IDn
, i ' - itVO!% ~ IC/G471 ; ![M/Mql ~ ~IN/SNI I !VM) S/CMIj • ~IN!/IOOG7' tVGT! ~ IPC:1 i
o-IS' So-]o HV-S I.IS•1.75 O.0•2.0 0.10•0.12 5.6-7.1 !•ta
xo-zs iar-s i i xi-t.as o.s-x.o i o.os-o.iz i 7 a t I 1~.~0 1 f
>:o ~ e ~ e s-7.a t I t=.~ I I
~so-~o' . ~ NP ~ i.sa•i.~s ~ >zo oa ~ a.~-> > 0_= . I . I
I 1 I 1 I 1 I I I I I I
I i I I I I I I I I I
`DQPYM;ORG:.NIC' SM 6AOSiOf~ wlNO M~INO C7RAG5[Y(TY ~
' (INA. TGA ~ S R w I~lNlK- ~ IaC:ORS ~SA00.i CROO. ~ ~
I➢CTI ~iOTGM7ISL~ (i~ i LROVP: (NO[7f ~ ST!?L 'CGNCR(T[~
~ O•IS' 2•5 lOW .ISl' :a; $ i 7 I 73 1MODLRATl:- lOw ~
~is -aa~ 1•i ~ Lcw 1.'a.=
~aa.~o~ <t ~ Law .io~ az!
~ow ~.os~ zo~
1 I I 1 1 1 t "
~ /LOCOING i MIGN W67E4 7ASLG : CEN2!4720 V6N lCORCCX 'SVlS[OEMCS H1IO;PO7CYT'lj
OdPTN R{VO ;MCNtM1 OlPTM'l16ROMESS;CEPiN !(ARONlSS'INIi.'TOTJL~CAP FROST
i FRLOULVGY ; JUA.ITIQN ;~aNTMS ` frTl ~ `IINJ ~ ~[NI j ~~fNl [NI < < SC7SON i
. ~ YONC >B >ao , e vcoeanre.
SONITANY '6C[LIT(GS '[ONSTAUC'iQN NC7EA[Al
' SCYGAC-P06R r[LitR CO00 ~
isevrtc raHK ~ 11 I 1
~ oasanvrtcn ~ aonorit~ ~ ;
~ rca~os ~ II I
I i I II 1 I
~ i111111 -46HP4GII P0.08iCLC '
~ SCWOGE i i i ~ •
~acaaM soNO ~ I
ARlAS
~ SEVLAC-SE~P4GE 7R00061G I
I SLNSTIIRT f - t
t!aOerMrl« eaaveL
(rcnt I It I I
SCVlR!-SCSDOCt ' V7QR-SMGCL 37CNE5,.10.CA AGCIAIM
~ ~SANITiRT ~ Ii I ~
tonartLL ~ fl T¢vso[L ~ - ~
I ~oa=a) I II' I
I I !I I ~
IPOOR•SNOIL STONES ' t
~ outLr II weTZa vnHnerNenr
~ Coven Io■ isCVaRa-sGeraGC ~
L4NOftlL RESE iONO
~ I II O[A ~ I
ARAVC4 i ~
9Vtl0CiNG SfT! 0LV2LCiM[Hi
' SGYGRL-UTOANKS CAYC ' StVCRQ•SElIUCII
i
~ sHa«aw ~ erseNxMnHis ~ I
iSXC-YATfON3 O[KES iN0 i i
I I' LLYGG3 I '
SIIGNT iSlYZRE-NG W¢TCR ~
~ awe~~cncs ~ e~e~rureo ~
' ~ wtrnour ~ 11 aonos ~ I
~ aoser+enrs ~ ~~~oucrea rao ~ ;
StIGMT
`OlSa i0 waTtR ~
~ Ow~lL2NCS ~ 11
~ 'MITM ~ OaG[NaCE ~ i
easeHenrs
~ ~yooeAare•s~ave iSCOPS,ORCUGHTY ~
SNaLI ~
~ coHrenc[aL ~ II taaccA rtaH
~ SutLatHCS
~ iN006RATE•PROST .1CTS0l1 IARGL SiONt5,TC0 SAN07 i
' LOCSt TSiRACSS I ~
I R6-03 oN0 ~ ~ ~NO ~
~ sTncers < otv:astoas
I I II I ~
~ :AWe15, 26YGAC•SMOLI Si071GS l?RGL STONCS,OXDUGNTY
`t~MOSCA/IMC ~ oQassaa i ~
~~a cet~ warenw4r
s
t.0[AWOYS i II I ~
'
!
' G~0 GiRaISCM vSAT G~i6V!I,tY lG6M, O:G d vCRCCMT SlpitS USOA•gC1
7•92
RECaZi710NG1 0lvEC6PN[YT
~MOOlRA7H•OUSTY i~ f5lYLRZ-SMAIL STOVHS
' CAMV anaas ~ • ~;r~arcaounos ~ '
~ 1V0080.G:C-OUSTY MOOCRAiM•OUSTT I
~ y yaTXS ~
PICnfG 3AE64; 4M7
iRall3 i ~
.:.PnB[L(TY ONO YIELOS DEA 0.CAE 0F CAdPS SNO ?ASTURE (YfGN L?VEl wGNAGENcMTI
i C1pa• WMEdT, WMf11T, BAALlY CRG55• ➢ASTURE 0175 ;GRp55, 58_D~
~ 0(LITY ~ WSNTt0. S➢RING ~ ~CCLUME MdY ~ ~
ISUI ~ iaui ~ IeV! ~ t'CYSI (6lIMI ~ L9V1 ~ fL9S1 i
i ~NIA4'[RR ~4 1 .7R '[RR ~N[R0. '(Ali. ~4(0.0. '(xA ~H{AR 'fAR '41AR ~1RR ~NIRR ~[RR 'HfmR '!Rq
' IE 21. 30 ~ ao ]o i Bo i 20 i i I o i a.o ; 7 o S 5 i 20
i •i r i ~ i t t i i t i i i t
, . . , ~ . , . , . ,
WooaLai+o surraecLtvv
GRO; NON6GEMlMi i0.081!NS . ➢CTENT[Al PRGUUCT(YtTY
~SYN~CROS'V'•OU[).;SdaGDI 'W{M07N'YC.~MT ' COMMON 7RL85
i S(7Z;PRCO! 7RCn! TO PIGNT ~
~ ~ ~Haz~ao~i~N~r ~ai•v;wntAao~CoMVCr' cNOx
I !cLas! ~
ap:SIICMTi'M00lR I VODlR.;S1.jGNTI'MOOlR
I~iaOuNc O tCAas05 rA [ a VING ~76 I • j1ONOG1056 ➢[NC ~
1 I • ~ ~ I
I I I I I t I t 1 l I 1
I I 1 i 1 I I I I I I I
I 1 I t t I t I I 1 I I
, ' I i I I 1 i' ! I 1 S 1
j I t I ~ I I I I 1 l I
( t f 1 1 I I I I I 1 I
I I I I t 1 I t I t I t
, 1 1 1 ! l { 1 I 1 1 I I
I i t ! I I I I I I I I
! 1 I I I ~ 1 l I i ~
wcnoeQeaKs
i ' SvtCi[5 57CCiE3 i MT'y SDlLt=S 'N7~ SGlCitS ;NT .
PGK[NC COi0Nt15T~R + EUR6VCAN VRII CT ! SI6CRtAN PC~iSMRUO f0'I [LAC 11~
~ ~AOCX7 1M7, .1UNIV~R ~iS,AIISSteN-pl2V! ~18~SUSTRfAN PSMC ~2S~GACIIN ASN
' 1YONOIIAOSd /SM! ~~SCGtCN PINL 1 701SIGGR1oN !LM iS017lAGX lOCU3T
I i t I I I 1~
~ WELoL tre rnetror sutrsa[Lt:r ~
i0i!Y7Iil 10R MLBITp7 11. _fflV75 ~ PUTgVi[iC A5 X4lITpT IOA•
~ 'CR6IN 1;GflASS J WILO N4ROW0 CONI/LA•SMRt105 WlTLONO;SMGILOW'QPCNlO WOOOLO WGTL?NC;R~NGEIU!
SCEO .LCCUMC ~ ML0.7 'tAELS ~PLJNTS ~ j➢lANTS ! N'OTGA ~W[tOlP ~WILOLY !WllOll !WIIOLr ~
f4lR i F6[A i GDOO i /GIR i /JIA /4IR i YOOR i~ Y 700R' IAfR { /A/R {Y, iOOR'
~ ~
I l 4 { { t I 1 I i 1 I 1 I
, t t I I t { I I I I I I I i
IQTENTS1l YGTiV! oLpHT CONMUMITT IRaMGLLANO OA 1ORH57 UNOEASiORY Y!LET6:ION1
➢L6NT PEAC°YTGGC COMPOSIT(QN 1ORY wC[CNiI
I COMMCN iIANT NYMC ~^YMeOt ~ i
t I ~NisvNi ~ I i I I
IAIMrCR4S5 ~ caau ! s f I I I I
~n~ue W4lORTE 'duG~
' ~srtKe ra~se~uM ~ rasaz
~sLuaeuNC» wNenrcaass ; acsa
~sweerscaarco nsosranw cAra3
~svaa~ocnc sweetaoor t oscn ~ s ~ I I I 1
~HOOx rtotar ~ vtao ~ ~ ~ ~ ~ ~
~stLxr Lurtne ~ ~usea ss
' ~CCMMCN SNGWII6RRY I STAL ± 30 I ' I ' I
WMITC srlntn SPlG: 1 '
~Si5XA700N SQAYICElERRY ~ aMal:
i0RlCONGAOPC ' lERC ` 1
OWAqI 403! ROCY 5 ~
iLOmMCn C)tCXLCNlRRT ~ VRV!
;eLacx N4WTMORN ~ cnoaz
POTLdT[Al PRGOYC:[ON 1L35.(3c, 3qY WT{:
raroreaeta YG.aA3 ~ eso
1 N0RN4l YCARS ~ 100 I { I ~ ~
UN/6VGNGdL! TCGRS ~00
R6XCG 5174 OA3%YOO:W6
FQOTNOTGS
1 EXCE9S(VG p!RMl4a1LITT R67E VAt C.~VS! iOILUTIOfl O1 GACUN YIYTaA
' • SITC [NGCX SS 3+UMMARY ar S CA 40RE MlASURCMtNTS ON TIII$ 50[1.
,
1
'
' Summerfield East 41 Addition
- Subdivision '
'
'
~
APPENDIX N- Rational Method Calculations
,
'
'
~
'
,
'
~
'
~
'
' C2001. Wyatt Engineenng (679300) Storm Water Brief
October 19, 2001 (rev 3/12/02)
,
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA1.wb3
Date: 03/12/02 Page 1
Name: SUMMERFIELD EAST SUBDIVISION
, Project: 4TH ADDITION
- Basin Name: DA-1 Design Frequency = 10YR
' No, of Subareas: None
1. Determine Time of ConcentraGon:
' Segment 1- Overland Flow OVERLAND FLOW
Length, L= 70 ft(Length) MAX LENGTH= 300 ft.
' Slope,S = 0.01 ff/ ft (Slope) -
n= 0 030 Roughness Coefficient (Grass)
Ct = 015 From Figure 3, Page 6-5, "Guidetines for Stormwater IVlanagement"
' Tc1 = Ci'(L'n/(S^.5))^(0.6); From "Guidelines for Stormwater Management".
Tc1 = 0.93 min
Segment 2- Shallow Concentrated Flow CURB GUTTER
' Length, L = 0 ft
Slope,S = 0.005 ff/ ft
n = 0.014 Roughness Coefficient
, Depth, y= 0.080 ft. (Assumed depth of flow)
Cross slope, s= 0A2 fUft
Z = 50.00 ft/ft (Z= 1/s)
Area, A= 0.16 ft(A= 1/2'(Z)'(y^2))
, Q gutter = 0.15 cfs
Velocity,V = 0.97 ft/sec (V= Q/A)
' Tc2 = (Length)/(Velocity)
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
' Length, L= 0 ft
Slope, So = 1 ft/ft
n = 0.012 Roughness Coefficient (Manning's)
Diameter = 0 inches '
' Area, A = 0.000 sf
R= D/4 = 0.21 ft
Velocity, V= (1.49/n)"(R"2/3)'(So^1/2) (Manrnngs Equation)
' Velocity, V= 43.62 ff/sec
Tc3 = (LengthY(Velociry) _
Tc3 = 0.00 min
' Total Tc = 0 93 min
,
,
'
~
' .
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA1.wb3
Date: 03/12/02 Page 2
' Name: SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-1 Design Frequency = 10YR
' No. of Subareas: None
2. Determine Weighted Runoff Coeffiaent (C) and Area:
' Area
Surface Type (sf) (acres) C. CA
' Open land (2%-10% slope) 2,031 0.05 0.30 0.01
Roof & Sidewalk 2,510 0 06 0.90 0.05
Asphalt, Curb & Dnveway 2,400 0.06 0.90 0 05
From Bypass DAx 0 0.00 0.98 0.00
' Total Drainage Area 6,941 0.16 acres Sum CA 0.12
Total Impervious Treated Area 2,400 0.06 acres
From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY"
Weighted C=(sum CA)/(sum A) = 0.724
' 3. Determine Peak Runoff (Q=CIA):
Duration (Tc) = 0.93 min.
, Weighted C = 0.724
Intensity (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 0.16 acres
Peak 10 YR Discharge (Q) = 0.37 cfs
,
4. Determine Volume of "208" Swale:
' Total Impervious Treated Area = 2,400 SF (Includes 0 ft2 bypass from DAx)
Reqwred "208" Swale Volume = Impervious Area x 05712 m/ft
Reqwred "208" Swale Volume = 100 cu. ft.
, "208" Swale Bottom Width 2.0 ft Irregular size - see site plan
"208" Swale Bottom Length 50.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
, "208" Swale Side Slopes (X 1) 4.0 fl
"208" Swale Bottom Area 100.0 SF
"208" Swale Top Area 300.0 SF Conservative Straight Wall
' "208" Swale Volume 100 CF POND SIZE CHECKS
'
,
'
'
1 ,
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA1.wb3
Date. 03/12/02 Page 3
' Name. SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-1 Design Frequency = 10YR
' No. of Subareas: 0
5. Determine the Maximum Outflow (Qo):
' Number of Type "A" (0.3 cfs) Drywells Required: 1
Number of Type "B" (1.0 cfs) Drywells Required: 0
' Outflow (Qo) = 0.30 cfs (SEE ATTACHED CALCULATIONS)
6. Determine Required Detention Storage Using Bowstring Method
' Time Increment = 5 min.
Elapsed time Intens. Qin Vol. In Vol. Out Storage
, (min) (sec) (in/hr) (cfs) (cu.ft.) (cu.ft) (cu.ft)
0.93 55.9 3.18 0.37 28 0 28
, 0 0 3.18 0.37 0 0 0
5 300 3.18 0.37 117 8 109
10 600 2.24 0.26 160 64 96
15 900 1.77 0 20 188 123 65
' 20 1200 1.45 0.17 204 181 23
25 1500 1.21 0 14 212 235 -23
30 1800 1.04 0.12 218 290 -72
35 2100 0.91 0.11 223 344 -122
' 40 2400 0.82 0.09 229 403 -174
45 2700 0.74 0.09 232 459 -227
50 3000 0.68 0.08 237 518 -281
55 3300 0.64 0.07 245 584 -339
, 60 3600 0.61 0.07 255 654 -399
65 3900 0.61 0.07 276 744 -468
70 4200 0.61 0 07 297 834 -537
75 4500 0.61 0.07 318 924 -606
' 80 4800 0.61 0.07 339 1014 -675
85 5100 0.61 0.07 360 1104 -743
90 5400 0.61 0.07 382 1194 -812
Storage = (Vol in. - Vol. out)
,
'
'
'
'
' Rational Method and Detention Basin Design Wyatt Engmeenng, Inc.
DA1.wb3
Date• 03/12/02 Page 4
Name: SUMMERFIELD EAST SUBDIVISION
' Project: 4TH ADDITION
Basm Name: DA-1 Design Frequency = 10YR
, No. of Subareas: 0
7. Determine the Minimum Reqwred Depth Above "208" Swale:
' Reqwred Detention Storage 1088 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 100.0 CF
Reqwred Storage Above "208" Swale 8.8 CF
~ "208" Swale Top Width NA ft (See "208" Swale Volume Calculations)
208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 300.0 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0 10 ft ASSUMED
' Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Detention Pond Area 300.0 SF
Volume Above "208" Swale 30.0 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56`(Zln)"(S^1/2)'(d^8/3)
Flow, Q= 0.37 cfs Included Basin DAx Bypass
Slope, S= 0 005 fUft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ft/ft
Z= 1/s = 100 00 ff/ft
' Flow Depth, d= 0.083 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC. FLOW (CHECK)
a) Curb Opening at Low Poin# (See Page 6-40, "Guidelines for Stormwater ManagemenY')
, Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 0.37 cfs
Flow Depth, d= 0.083 ft
Length of Opening = 2 ft
' Use Q= 3.087(L)(H^3/2); Solve for H
Depth , H = 0.15 feet
' H/h = 0.30 O K. - H/h =<1
IIUse 2 ft curb ooening
'
1
'
' .
~ Rafional Method and Detention 8asin Design Wyatt Engineenng, Inc
❑A2-3.wh3
Da#e. []3112102 Pags 1
Name SUMIVIERFIELC] EAST SUeDIVl51[)N
' Project 4TH ADDf71QN
Basin Name: DA-2 & DA-3 ❑esign Frequency = 10YR
1 hl❑ of 5ubareas None
1 {7etermtne Time af Concentration•
~ 5egrnent 1 - flVerland Flow OVERLAND FLOW
Length, L= 40 ft (Lsngth) MA,X LENGTH= 300 ft.
~ 5tape,S = 0.01 fl/ ft (Slope)
n = 0.016 Fioughness Goefficient {Pavement}
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines fvr Sformwater Management°
Tc1 = Ct "(L'n](S° 5)]"(0.$); From "Guidelinss foe Stormwafer Management"
Tc1 = 0 46 mtr,.
Segment 2- Sha!!ow Cancentrated Flaw CL1RB GLlTTER
1 Length, L = 80 ft
51ope,5 = 0.009 ftl ft
n = 0.014 Rflughnsss Coefficient
' Depth, y= 0 090 ft(Assumed depth vf flow)
Crass slope, s= 002 ftlft
Z= 5000 ft]ft {Z= 1!s}
Area, A= 020 ft{A= 112'(Z)'(y"2)y
~ C] gutter = 028 cfs
Velvcity,V = 1 41 fUsec {V= QIA}
~ Tc2 = {Length}!(Velacsty)
"I"c2 = 095 min
Segment 3- Ghannel Fiow NONE
~ Length, f.= D ft
Sfape, So = 1 ftlft L
n = 0012 Roughness Cvefficient (EAanning's)
❑iameter = U inches
' Area, A = 0.000 sf
R= Q!4 = 0.21 ft
Velvcity, V= {1 491n}*(R42I3}'(5c7"h12) (Mannings Equation)
' Vetacity, V= 43 62 ftlsec
Tc3 = {Length}f(IJe3ocitY)
Te3 = 0.00 min
1 Total Tc = 1 40 rnm
~
'
~
~
~ ,
' Rational Method and Detention Basin Design Wyatt Engineering, Inc
DA2-3.wb3
Date: 03/12/02 Page 2 _
Name SUMMERFIELD EAST SUBDIVISION
' Project: 4TH ADDITION
Basin Name: DA-2 & DA-3 Design Frequency = 10YR
' No. of Subareas: None
2. Determine Weighted Runoff Coefficient (C) and Area:
' Area
Surface Type (sf) (acres) C. CA
' Open land (2%-10% slope) 5,295 0.12 0 30 0.04
Roof & Sidewalk 2,150 0.05 0.90 0.04
Asphalt, Curb & Dnveway 4,970 0.11 0 90 010
From Bypass DAx 0 0.00 0.98 0 00
' Total Drainage Area 12,415 0.29 acres Sum CA = 0.18 -
Total Impervious Treated Area 4,970 0.11 acres
From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY"
Weighted C=(sum CA)/(sum A) = 0.644
' 3. Determine Peak Runoff (Q=CIA):
Duration (Tc) = 1.40 min.
, Weighted C = 0.644
Intensity (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 0 29 acres
' Peak 10 YR Discharge (Q) = 0.58 cfs
4. Determme Volume of "208" Swale:
' Total Impervious Treated Area = 4,970 SF (Includes 0 ft2 bypass from DAx)
Reqwred "208" Swale Volume = Impervious Area x 05712 in/ft
Required "208" Swale Volume = 207 cu. ft.
' "208" Swale Bottom Width 2.0 ft Ircegular size - see site plan
"208" Swale Bottom Length 165.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
, "208" Swale Side Slopes (X:1) 4.0 ft
"208" Swale Bottom Area 3300 SF
"208" Swale Top Area 990.0 SF Conservative Straight Wall
' "208" Swale Volume 330 CF POND SIZE CHECKS
~
1
1
'
' -
' Rational Method and Detention Basm Design Wyatt Engineenng, Inc.
DA2-3.wb3
Date: 03/12/02 Page 3
' fVame: SUMMERFIELD EAST SUBDIVISION
Project: 4TH AODITION
Basin Name; DA-2 & DA-3 Design Frequency = 10YR
' No. of Subareas: 0 _
5. Determine the Maximum Outfiow (Qo).
' Number of Type "A" (0.3 cfs) Drywells Reqwred• 1
Number of Type "B" (1.0 cfs) Dryweils Reqwred: 0
' Outflow (Qo) = 0.30 cfs (SEE ATTACHED CALCULATIONS)
6. Determine Required Detention Storage Using Bowstnng Method
' Time Increment = 5 min.
Elapsed time Intens. Qin Vol. !n Vol. Out Storage
' (min) (sec) (in/hr) (cfs) (cu ft.) (cu.ft) (cu.ft)
1.40 84.3 3.18 0.58 66 0 66
' 0 0 3.18 0.58 0 0 0
5 300 3.18 0.58 192 0 192
10 600 2 24 0.41 259 Q 259
15 900 1.77 0.32 302 0 302
' 20 1200 145 0.27 327 0 327
25 1500 1.21 0 22 340 4 335
30 1800 1.04 019 349 21 328
35 2100 0.91 0.17 356 37 318
' 40 2400 0.82 0.15 366 62 303
45 2700 0.74 0.14 371 81 289
50 3000 0.68 0.12 378 107 271
55 3300 0.64 0.12 391 147 244
' 60 3600 0 61 0.11 406 196 210
65 3900 0.61 0.11 440 286 154
70 4200 0.61 0.11 474 376 98
75 4500 0.61 0 11 507 466 41
' 80 4800 0 61 0 11 541 556 -15
85 5100 0.61 0.11 574 646 -72
90 5400 0.61 0.11 608 736 -128 _
Storage = (Vol in. - Vol out)
'
'
'
'
1
1
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA2-3 wb3
Date: 03/12/02 Page 4
' Name: SUMMERFIELD EAST SUBDIVISION Project: 4TH ADDITION
Basin Name: DA-2 & DA-3 Design Frequency = 10YR
' No. of Subareas: 0 7. Determine the Minimum Required Depth Above "208" Swale:
' Reqwred Detention Storage 335.2 CF (See Bowstrmg Method, maximum value)
"208" Swale Volume 330.0 CF
Reqwred Storage Above "208" Swale 5.2 CF
' "208" Swale Top Width NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 990.0 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft •
Detention Pond Top Length NA ft
Top of Detention Pond Area 990.0 SF
Volume Above "208" Swale 99.0 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56'(ZJn)`(S11/2)'(d118/3)
Flow, Q= 0.58 cfs Included Basin DAx Bypass
Slope, S = 0.009 fUft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ft/ft
Z = 1/s = 100.00 fUit
, Flow Depth, d= 0.088 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC FLOW (CHECK)
a) Curb Openmg at Low Point (See Page 6-40, "Guidelines for Stormwater ManagemenY")
, Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 0.58 cfs
Flow Depth, d= 0.088 ft
Length of Opening = 2 ft
' Use Q= 3 087(L)(H^3/2); Solve for H
Depth , H = 0.27 feet
' H/h = 0 42 O.K. - H/h =<1
IIUse 2 ft curb opening
1
,
'
'
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA4.wb3
Date: 03/12102 Page 1
' Name: SUMMERFIELD EAST SUBDIVISION
Project• 4TH ADDITION
Basin Name: DA-4 Design Frequency = 10YR
' No. of Subareas: None
1. Determine Time of Concentration:
, Segment 1- Overland Flow OVERLAND FLOW
Length, L= 74 ft(Length) MAX LENGTH= 300 ft.
' Slope,S = 0.01 ft/ ft (Slope)
n = 0.030 Roughness Coefficient (Grass)
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines for Stormwater Management".
, Tc1 = Ct'(L*n/(S^.5))^(0.6), From "Guidelines for Stormwater Management"
Tc1 = 0.96 min.
Segment 2- Shallow Concentrated Flow CURB GUTTER , Length, L = 0 ft
Slope,S = 0 005 ff/ ft
n = 0.014 Roughness Coefficient
, Depth, y= 0.130 ft. (Assumed depth of flow)
Cross slope, s= 0.02 ff/ft
Z = 50.00 ft/ft (Z= 1/s)
Area, A= 0.42 ft. (A= 1/2'(Z)'(y^2))
, Q gutter = 0.57 cfs
Velocity,V = 1.36 ft/sec (V= Q/A)
' Tc2 = (Length)/(Velocity) .
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
, Length, L= 0 ft
Slope, So = 1 ft/ft
n = 0.012 Roughness Coefficient (Manning's)
Diameter = 0 inches
, Area, A = 0.000 sf
R= D/4 = 0 21 ft
Velociry, V= (1.49/n)'(R^2/3)`(So^1/2) (Mannings Equation)
' Velociry, V= 43.62 ft/sec
Tc3 = (Length)/(Velocity)
Tc3 = 0 00 min
' Total Tc = 0.96 mm
'
'
'
'
'
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA4.wb3
Date: 03/12/02 Page 2
' Name: SUMMERFIELD EAST SUBDIVISION .
Project: 4TH ADDITION
Basin Name: DA-4 Design Frequency = 10YR
' No. of Subareas: None
2. Determine Weighted Runoff Coefficient (C) and Area:
' Area
SurFace Tvpe (sf) (acres) C. CA
' Open land (2%-10% slope) 12,657 0.29 0.30 0 09
Roof & Sidewalk 6,430 0.15 0.90 0.13
Asphalt, Curb & Driveway 6,880 0.16 0.90 0.14
From Bypass DAx 0 0.00 0.98 0.00
' Total Drainage Area 25,967 0 60 acres Sum CA = 0.36
Total Impervious Treated Area 6,880 0.16 acres
From Table 1, Page 6-2, "Guidelines for Stormwater Management"
Weighted C=(sum CAY(sum A) = 0.608
' 3. Determine Peak Runoff (Q=CIA):
Duration (Tc) = 0.96 min.
' Weighted C = 0 608
Intensiry (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 0.60 acres ,
' Peak 10 YR Discharge (Q) = 1.15 cfs 4 Determine Volume of "208" Swale.
' Total Impervious Treated Area = 6,880 SF (Includes 0 ft2 bypass from DAx) .
Required "208" Swale Volume = Impervious Area x 0.5"/12 in/ft
Reqwred "208" Swale Volume = 287 cu. ft.
' "208" Swale Bottom Width 20 ft Irregular size - see site plan
"208" Swale Bottom Length 237.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
' "208" Swale Side Slopes (X:1) 4.0 ft
"208" Swale Bottom Area 4740 SF
"208" Swale Top Area 1422.0 SF Conservative Straight Wall
208" Swale Volume 474 CF POND SIZE CNECKS
11
'
'
'
' .
, Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA4.wb3
Date. 03112/02 Page 3
, Name: SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name, DA-4 Design Frequency = 10YR
' No of Subareas. 0
5. Determine the Maximum Outflow (Qo)'
' Number of Type "A" (0.3 cfs) Drywells Reqwred: 1
Number of Type "B" (1.0 cfs) Drywells Reqwred: 0
' Outflow (Qo) = 0.30 cfs (SEE ATTACHED CALCULATIONS)
6. Determine Required Detention Storage Using Bowstring Method
' Time Increment = 5 min.
Elapsed time Intens. Qm Vol. In Vol. Out Storage
' (min) (sec) (in/hr) (cfs) (cu.ft.) (cu ft) (cu ft)
0.96 57.8 3.18 1.15 89 0 89
' 0 0 3.18 1 15 0 0 0
5 300 3.18 1 15 368 0 368
10 600 2.24 0 81 503 5 498
15 900 1.77 0 64 590 48 541
, 20 1200 1.45 0.53 640 89 551
25 1500 1.21 0.44 666 126 540
30 1800 1.04 0 38 685 162 523
35 2100 0.91 0.33 699 199 500
' 40 2400 0 82 0.30 719 241 477
45 2700 0.74 0.27 729 279 449
50 3000 0.68 0.25 744 323 421
55 3300 0.64 0.23 769 377 393
' 60 3600 0.61 0.22 800 436 363
65 3900 0.61 0.22 866 526 340
70 4200 0.61 0.22 932 616 316
75 4500 0.61 0.22 998 706 292
' 80 4800 0.61 0 22 1065 796 268
85 5100 0 61 0.22 1131 886 245
90 5400 0.61 0.22 1197 976 221
Storage = (Vol in. - Vol. out)
'
'
1
1
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA4.wb3
Date 03/12/02 Page 4
, Name. SUMMERFIELD EAST SUBDIVISION
Project. 4TH ADDITION
Basin Name: DA-4 Design Frequency = 10YR
' No. of Subareas: 0
7. Determine the Mmimum Required Depth Above "208" Swale:
, Reqwred Detention Storage 551.3 CF (See Bowstring Method, maximum value)
"208" Swale Volume 474.0 CF
Reqwred Storage Above "208" Swale 773 CF "208" Swale Top Width . NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 1422.0 SF (See "208" Swale Volume Calculations)
, "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Detention Pond Area 1422.0 SF
Volume Above "208" Swale 142.2 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56'(ZJn)'(S^1/2)'(d^8/3)
Flow, Q= 1.15 cfs Included Basin DAx Bypass
Slope, S = 0.005 ft/ft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ft/ft
Z= 1/s = 10000 fUft
' Flow Depth, d= 0.127 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC. FLOW (CHECK)
a) Curb Opening at Low Point (See Page 6-40, "Guidelines for Stormwater ManagemenY")
, Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 1.15 cfs
Fiow Depth, d= 0.127 ft
Length of Opening = 2 ft
' Use Q= 3.087(L)(H^3/2); Solve for H
Depth, H = 0.33 feet
' H/h = 0.65 O.K. - H/h =<1
IlUse 2 ft curb openina
'
'
1
'
'
' Rational Method and Detention Basin Design Wyatt Engmeenng, Inc.
DA5-6.wb3
Date: 03/12/02 Page 1
, Name: SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-5 & DA-6 Design Frequency = 10YR
' No. of Subareas. None ~
1. Determine Time of Concentration: .
' Segment 1- Overland Flow OVERLAND FLOW
Length, L= 120 ft(Length) MAX LENGTH= 300 ft.
' Slope,S = 0.01 fU ft (Slope) '
n = 0.030 Roughness Coefficient (Grass)
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines for Stormwater ManagemenY'.
' Tc1 = Ct'(L'n/(S^.5))^(0.6), From "Guidelines for Stormwater Management"
Tc1 = 1 29 min
Segment 2- Shallow Concentrated Flow CURB GUTTER
Length, L = 0 ft
Slope,S = 0.005 ft/ fl
n = 0.014 Roughness Coefficient
' Depth, y= 0.120 ft. (Assumed depth of flow)
Cross slope, s= 0.02 fUft
Z = 50.00 fUft (Z= 1/s)
Area, A= 0 36 ft. (A= 1/2'(Z)'(y^2))
' Q gutter = 0 46 cfs
Velociry,V = 1 28 ft/sec (V= Q/A)
' Tc2 = (Length)/(Velocity)
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
' Length, L= 0 ft
Slope, So = 1 ft/ft
n= 0 012 Roughness Coefficient (Manning's)
Diameter = 0 inches
' Area, A = 0.000 sf
R= D/4 = 0.21 ft
Velocity, V= (1.49/n)'(R^2/3)'(So^1/2) (Mannings Equation)
' Velocity, V= 43.62 fUsec
Tc3 = (Length)/(Velocity)
Tc3 = 0.00 min
' Total Tc = 1 29 min
1
1
'
'
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA5-6.wb3
Date: 03/12/02 Page 2
' Name: SUMMERFIELD EAST SUBDIVISION
Project. 4TH ADDITION
Basin Name: DA-5 & DA-6 Design Frequency = 10YR
' No. of Subareas None
2. Determine Weighted Runoff Coeffiaent (C) and Area:
' Area -
Surface Type (sfl (acres) C` CA
' Open land (2%-10% slope) 12,812 0 29 0.30 0.09
Roof & Sidewalk 4,960 0.11 0.90 0.10
Asphalt, Curb & Dnveway 6,780 0.16 0.90 0 14
From Bypass DAx 0 0.00 0 98 0.00
' Total Drainage Area 24,552 0.56 acres Sum CA = 0.33
Total Impervious Treated Area 6,780 0.16 acres
From Table 1, Page 6-2, "Guidelines for Stormwater Management"
Weighted C=(sum CA)/(sum A) = 0.587
' 3. Determine Peak Runoff (Q=CIA): -
Duration (Tc) = 1.29 min.
' Weighted C = 0.587
Intensity (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 0.56 acres
' Peak 10 YR Discharge (Q) = 1.05 cfs
4. Determine Volume of "208" Swale:
' Total Impervious Treated Area = 6,780 SF (Includes 0 ft2 bypass from DAx)
Reqwred "208" Swale Volume = Impervious Area x 0 5"/12 in/ft
Reqwred "208" Swale Volume = 283 cu. ft. '
' "208" Swale Bottom Width 20 ft Irregular size - see site ptan
"208" Swale Bottom Length 194.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
' "208" Swale Side Slopes (X:1) 4.0 ft
"208" Swale Bottom Area 388.0 SF
"208" Swale Top Area 1164.0 SF Conservatrve Straight Wall
' "208" Swale Volume 388 CF POND SIZE CHECKS
1
'
'
1
1
~ Rafional Method and Detentian Basin Design Wyatt Engineenng, [nc
QA5-6 wb3
❑ate Q3f12102 F'age 3
~ Alame• SUMMERFIELD EAST SIJBDCV15EOhI
Project 47H ADOITION
Basin Name, DA-5 & DA-fi Dssign Frequency = 9 DYR
1 No vf 5ubareas. 0
5. C)eterrmne the Maximum DutFlaw (0fl):
~ Nurnbsr of Type "A° {0 3 cfis} Drywells Required'
Number of Type "B" (1 Q cfs) C7rywells Reqwrecf 1
~ (7utilaw (4o) = 1.00 cfs (5EE ATrACHEQ CALCEJLRT901+15)
6. Deiermdne Required Defention 5tvrage Llsmg Bowstrmg AAethod
~ Time Increment = 5 min
Elapsed time lntens. Qin Val, In Vol Out 5torage
' (mirr) (sec) [inlhr) (cfs) [cu.ft ) Icu ft3 (cu ft)
1.29 773 3.18 1.05 1[]9 fl 109
' 0 0 318 1.05 6 Q 0
5 300 318 1 05 343 0 343
ID 600 2.24 0 74 464 76 388
15 904 1.77 0 59 542 237 305
' ZO 1200 1.45 0 48 588 391 197
25 1500 1.21 0.40 641 531 80
34 18(}0 1.04 034 628 672 -44
35 2100 4 91 030 640 • 81 1 -171
~ 40 24[]0 82 0.27 658 970 -311
45 2700 4.74 024 687 1115 448
50 3000 0 68 0 22 681 1275 -594
55 3300 064 a 21 704 1457 -763 -
~ 60 3500 0 61 020 732 1677 -945
65 3900 061 0 20 792 1977 -1185
70 4200 0 61 020 853 2277 -1424
75 4500 061 020 913 2577 -1664
~ 80 48[]0 063 020 974 2877 -1903
85 5106 4.67 0 20 10334 3177 -2143
90 5400 061 020 1095 3477 -2382
■ ` 5tarage = (Vol in. - Val out)
~
1
~
1
~
1 '
~ '
' Rational Method and Detention Basin Design 4Vyatt Engineering, Inc
DA5-6 wb3
Date: 03/12/02 Page 4
' Name: SUMMERFIELD EAST SUBDIVISION
Project. 4TH ADDITION
Basin Name: DA-5 & DA-6 Design Frequency = 10YR
' No, of Subareas. 0 '
7. Determine the Minimum Required Depth Above "208" Swale:
, Required Detention Storage 387.7 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 388.0 CF
Required Storage Above "208" Swale -0.3 CF
' "208" Swale Top Width NA ft (See "208" Swale Volume Caiculations)
208" Swale Top Length NA ft (See "208" Swaie Volume Calculations)
"208" Swale Top Area (SF) 1164.0 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X•1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
~ Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Detention Pond Area 1164.0 SF
Volume Above "208" Swale 1164 CF POND SIZE CHECKS
' 8. Determme Length of Curb Opening:
' Q = 0.56'(ZJn)'(S"1/2)'(d^8/3)
Flow, Q= 1.05 cfs Included Basin DAx Bypass
Slope, S = 0.005 ft/ft
, n = 0.014 Roughness Coefficient
Cross Slope,s= 0 01 ft/ft
Z = 1 /s = 100.00 ft/ft
' Flow Depth, d= 0.123 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC FLOW (CHECK)
a) Curb Opening at Low Point (See Page 6-40, "Guidelmes for Stormwater Management")
' Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 1 05 cfs
Flow Depth, d= 0 123 ft
Length of Opening = 2 ft
' Use Q= 3 087(L)(H^3/2); Solve for H
Depth , H = 0.31 feet
' H/h = 0.61 O K. - H/h =<1
IIUse 2 ft curb opening I~
'
1
1
1
1
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA7.wb3
Date• 03/12/02 Page 1
, Name. SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-7 Design Frequency = 10YR
' No. of Subareas: None
1. Determine Time of Concentration:
' Segment 1- Overland Flow OVERLAND FLOW
Length, L= 110 ft(Length) MAX LENGTH= 300 ft
' Slope,S = 0.012 N ft (Slope)
n = 0.030 Roughness Coefficient (Grass)
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines for Stormwater Management"
' Tc1 = Ct'(L`n/(S^.5))^(0.6); From "Gwdelines for Stormwater ManagemenY".
Tc1 = 1.16 min.
Segment 2- Shallow Concentrated Flow CURB GUTTER
' Length, L = 0 ft
Slope,S = 0.005 fU ft
n = 0.014 Roughness Coefficient
, Depth, y= 0.080 ft. (Assumed depth of flow)
Cross slope, s= 0.02 fUft
Z= 50 00 fUft (Z= 1/s)
Area, A= 0.16 ft. (A= 1/2'(Z)'(y^2))
' Q gutter = 0.15 cfs
Velociry,V = 0.97 ft/sec (V= Q/A)
~ Tc2 = (Length)/(Velocity)
Tc2 = 0.00 mm
Segment 3- Channel Flow NONE
' Length, L= 0 ft
Slope, So = 1 fUft
n = 0.012 Roughness Coefficient (Manning's)
Diameter = 0 inches
, Area, A = 0.000 sf
R= D/4 = 0.21 ft
. Velocity, V= (1.49/n)'(R^2/3)`(So^1/2) (Mannings Equation)
, Velocdy, V= 43.62 ft/sec '
Tc3 = (Length)/(Velocity)
Tc3 = 0.00 min
' Total Tc = 1.16 min
'
,
'
'
' ,
, Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA7.wb3
Date. 03/12/02 Page 2
~ Name: SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-7 Design Frequency = 10YR
' No. of Subareas: None
2. Determine Weighted Runoff Coefficient (C) and Area:
' Area .
Surface Type (sf) (acres) C. CA
' Open land (2%-10% slope) 4,322 010 0.30 0.03
Roof & Sidewaik 670 0.02 0.90 0.01
Asphalt, Curb & Driveway 2,620 0 06 0.90 0.05
From Bypass DAx 0 0 00 0.98 0.00 _
' Total Drainage Area 7,612 0.17 acres Sum CA = 0.10
Total Impervious Treated Area 2,620 0.06 acres
From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY"
Weighted C=(sum CA)/(sum A) = 0.559
' 3. Determine Peak Runoff (Q=CIA): '
Duration (Tc) = 1.16 min.
' Weighted C = 0 559
Intensity (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 0 17 acres
' Peak 10 YR Discharge (Q) = 0.31 cfs
4 Determine Volume of "208" Swafe:
' Total Impervious Treated Area = 2,620 SF (Includes 0 ft2 bypass from DAx)
Reqwred "208" Swale Volume = Impervious Area x 0.5712 in/ft
Required "208" Swale Volume = 109 cu. ft.
' "208" Swale Bottom Width 2.0 ft Irregular size - see site plan
"208" Swale Bottom Length 1060 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
~ "208" Swale Side Slopes (X.1) 4.0 ft
"208" Swale Bottom Area 212.0 SF
"208" Swale Top Area 636.0 SF Conservative Straight Wall
' 208" Swale Volume 212 CF POND SIZE CHECKS
'
'
'
t
'
~ Rationaf Mefhod and Detention Basin flesign Wyatt Engineering, [nc
DA7 wb3
Llate: 031121(}2 Page 3
1 lVame. SLfMMERFiELO EA5T SUBI71VI51ON
Project 4TH ADDIT9C]N
Basin Name DA-7 Qesign Frequency = 10YR
~ Nv. of Subareas' 6
5 Deterrnine the Maximum Outflaw (Qv)
~ Number vf T'ype "A" {0 3 cfs} #7rywelis Ftequired, 1
Nurnher vf Type "B" (1.0 cfs) Drywekls Reqwred 0
OuTflovv (Qv) = 0 30 cfs {5EE ATf'ACHEQ CRLCL1lA71ON5} _
~
fi Determine Required DeYentiarr 5torage Using Bowstnng Methad
' Time Increment = 5 min
Elapsed tirne Infens. Qin Vol In Val. Out 5tvrage
~ (min) (see) [inlhr) {cfs} (cuft) {cu ft) icu ft)
1.16 69.4 118 ' 0.31 29 U 29
~ 0 0 3.18 031 D 0 0
5 300 318 0.31 101 0 101
10 600 2 24 0.22 137 a 137
15 900 177 017 16[] a 160
~ 20 1200 1 45 014 173 0 173
25 1540 1 21 012 180 4 180
30 1800 1 44 010 1155 Q 185
35 2100 0.91 0.49 189 4 189 ,
~ 40 2400 0 82 008 194 D 194 -
45 2700 074 007 197 0 197
50 3000 0.68 a.oT 201 a 201
55 3300 064 0.06 208 a 208
~ so ssoa 0.61 0.06 216 13. 203
ss 3900 061 006 234 103 131
,
70 azao 061 • 006 252 193 59
75 4500 061 006 270 283 -14
~ av asoa 0.61 006 288 373 -86
as 5100 a.si 006 305 463 -j 5s
90 5440 0.81 006 323 553 -230
Starage = (Vvl in. - Val, vut)
~
~
~
~
1
~ • .
' Rational Method and Detention 8asin Design Wyatt Engineenng, Inc.
DA7.wb3
Date: 03/12102 Page 4
' Name SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADD1T10N
Basin Name: DA-7 Design Frequency = 10YR
' No. of Subareas: 0
7 Determme the Mirnmum Required Depth Above "208" Swale-
' Reqwred Detention Storage 207.9 CF (See Bowstring Method, maximum value)
"208" Swale Volume 212.0 CF
Required Storage Above "208" Swale -4.1 CF .
' 208" Swale Top Width NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 636.0 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Detention Pond Area 636.0 SF
Volume Above "208" Swale 636 CF POND SIZE CHECKS
' 8 Determine Length of Curb Opening:
' Q = 0.56"(ZJn)*(S^1/2)'(d^8/3)
Flow, Q= 0.31 cfs Included Basin DAx Bypass
Slope, S = 0.005 ft/ft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ft/ft
Z= 1/s = i 00 00 ft/ft
' Flow Depth, d= 0.078 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC FLOW (CHECK)
a) Curb Opening ai Low Point (See Page 6-40, "Guidelines for Stormwater Management")
, Curb Height (h)= 0 50 ft(Type 1 Curb Inlet)
Discharge, Qn = 0.31 cfs
Flow Depth, d= 0.078 ft
Length of Opening = 2 ft
'
Use Q= 3.087(L)(H^3/2); Solve for H
Depth , H = 0.14 feet
' H/h = 0.27 O.K. - H/h =<1 ,
' IIUse 2 ft curb openinq_I~
'
~
'
1
' RationaR Method and Detention Basin DesEgn Wyatt Engineering, Inc
L7R8 wb3
❑ate. 03117J02 Page 1
~ Name SiJMMERFIELD EAST SUB11IVISiON
Project 4Ti H ADDITIpN
Basin Name; DA-S mesign Frequency = 1 0YR
~ No, of Subareas hlone
1, Determine Time of Cancentration.
~ 5egment 1 - Dveeiand Flflw bVERLANO FLaW `
Length, L= 0 ft {Length} MR7( LENG7H= 300 ft.
~ Slape,S = 0.012 ft/ ft (Siape)
n = {].030 Rvughness CoefficsenC (Grass)
Ct = 015 From Figure 3, Page 6-5, "Guidelines for St❑rm+,v-ater Managernent".
~ Tc1 = Ct '(L'N(5" 5)]^(0E), Fram "GUidelines for Stormwater Management"
7c1 = 000 min
Segment 2- SMaffow Concentrated FCaw CUFtB GUTTER
~ Length, L = 720 it
51aps,S = 0 005 ft/ ft
n = 0014 Raughness Coefficient
' Depth, y= 0070 ft {Assumed depth pf flow}
Cross slvpe, s= 002 ftIft
Z= 5000 ftlft (Z= 1Is)
Area, A = 0.12 ft. {A= 1J2'(Z)'(y"2)}
~ Q gutter = 0 ll cfs
Velocity,V = 0 88 ftlsee (V= QIFI)
~ Tc2 = (Length)I{lAelocity}
Tc2 = 2 27 min
5egment 3 - Channel FIvw NONE
~ Length, Lr fl ft
51vpe, So = I ftlft
n= 0012 Roughness Coe#Ffcient 4Manrnng°s}
Diameter ~ 0 inches
~ Area, A = O,006 sf ~
R= a14 = 021 ft
V01aCity, V-(1 491n)*(R"~8)*(SO"1i2) (Mannmgs Equation)
i Veloaty, V= 43.62 filsec
Tc3 = {Length}!{Velaciry}
TG.3 = fl 04 mm
' 7oial Te = 2 ZT min
~
~
~
'
1 ,
~ Rational Method and ❑etentian Basin aesign Wyatt Engineermg, lnc.
Dla$.wb3
Qaie' 03112102 Page 2
Name SUMMERFIELa EAST SUgoIW1510N
~ RrajeGt: 4TH AD01TIC]N
Basm Name DA-8 Design Frequency = 1 pYR
No af 5ubareas- None
~ 2 Determine Wei9hted Runoff CoefFcEent (C) and Area.
' Area
5urface Tvpe (sf) (aeres) C. CA
Open land (2%-14°/o slope) 1,222 003 0 30 0.01
~ Roaf & Sidewalk 670 0.02 0 90 001
Asphalt, Curb & ariveway 2,620 006 090 005
Frvm Bypass DAx C] 0 00 0.98 0 00
~ Total Qrainage Area 4,512 010 acres Sum CA = 0 08
Tvial Imperviaus Treaied Arsa 2,620 0,[]6 acres
'Irom Table 1, Page 1-2, "Guidehnes for Starmwatsr Management"
~ liVeEghted G=(sum CA)I(sum R) = 0.738
~ 3 Determine Peak Runoif (Q=CIR)
❑vratiQn (Tc) = 2 27 rrnn.
~ Weighted C = 0.738
Intens3ty (3) = 3 18 inlhr From kDF eurve fvr Spakane, 4VA
Area (A) = 0.10 acres
Peak 10 YR Discharge (Q) _ 024 cfs
~
4 petersnine Vvlume of "208" Swale:
~ Total Impervious Treated Area = 2.620 SF (Includes 0 ft2 bypass from DAx)
Required "208° Swale Vvlume = Impervivus Area x 0.5"112 inlft
Requ3red "208" Swale Volume = 109 cu ft•
~ "ZOB" Swa1e Bbftom Width 2.[] ft Irregular s¢e - see site plan
"208" Swale 8attom Length 1060 ft [rregular size - see site pian
°208" Swale [7epth 05 ft
~ °208" Swale Side 51opes (X:9 ) 4.0 ft
"208" Swale Bottom Area 2120 SF
"208" Swale Top Area 6360 5F Cflnservative Straight Walf
' "208" Swale Valurne 212 CF P[3ND SIZE CHECKS
1
~
~
'
~ I l
' Rational Method and Detention Basin Design Wyatt Engmeenng, Inc.
DA8 wb3
Date• 03/12/02 Page 3
' Name: SUMMERFlELD EAST SUBDIVISlON
Project: 4TH ADDITION
Basin Name: DA-8 Design Frequency = 10YR
~ No. of Subareas. 0
5 Determme the Maximum Outflow (Qo):
, Number of Type "A" (0.3 cfs) Drywells Required: 1
Number of Type "B" (1.0 cfs) Drywells Required: 0
' Outflow (Qo) = 0.30 cfs (SEE ATTACHED CALCULATIONS)
6. Determine Required Detention Storage Using Bowstnng Method
' Time Increment = 5 min.
Elapsed time Intens. Qin Vol. In Vol. Out Storage
' (min) (sec) (in/hr) (cfs) (cu.ft.) (cu.ft) (cu.ft)
2.27 136.5 3.18 0 24 44 0 44
' 0 0 3.18 024 0 0 0
5 300 3.18 0.24 84 0 84
10 600 2.24 0.17 111 0 111
15 900 1.77 014 128 0 128
1 20 1200 1.45 0.11 138 0 138
25 1500 1.21 0.09 143 0 143
30 1800 1.04 0 08 147 0 147
35 2100 0.91 0.07 149 0 149
' 40 2400 0.82 0.06 153 0 153
45 2700 0 74 0.06 155 0 155
50 3000 0.68 0.05 158 0 158
55 3300 0.64 0.05 164 0 164
~ 60 3600 0.61 0.05 170 0 170
65 3900 0.61 0.05 184 0 184
70 4200 0.61 0.05 198 0 198
75 4500 0.61 0.05 212 0 212
~ 80 4800 0.61 0.05 226 75 151
85 5100 0.61 0 05 240 165 75
90 5400 0.61 0.05 254 255 -1
Storage = (Vol in. - Vol. out)
'
'
1
,
'
'
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA8.wb3
Date. 03/12/02 Page 4
' Name. SUMMERFiELD EAST SUBDIVISION
Project. 4TH ADDITION
Basin Name: DA-8 Design Frequency = 10YR
' No. of Subareas* 0 ,
7 Determme fhe Minimum Reqwred Depth Above "208" Swale-
' Required Detention Storage 183.9 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 212.0 CF
Reqwred Storage Above "208" Swale -28.1 CF
, "208" 5wale Top Width NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 636.0 SF (See "208" Swale Volume Calculations)
~ "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Oetention Pond Area 836.0 SF
Volume Above "208" Swale 63.6 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56'(Zln)'(S^1/2)'(d118/3)
Flow, Q= 0.24 cfs lncluded Basin DAx Bypass
Slope, S = 0.005 ft/ft
, n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ftJft
Z = 1/s = 100.00 fUft
' Flow Depth, d= 0.071 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC. FLOW (CHECK)
a) Curb Opening at Low Point (See Page 6-40, "Guidelines for Stormwater ManagemenY")
' Curb Height (h)= 0 50 ft(Type 1 Curb Infet)
Discharge, Qn = 0.24 cfs
Flow Depth, d= 0 071 ft
Length of Opening = 2 ft
, Use Q= 3 087(L)(H^3/2); Soive for H
Depth , H = 0.12 feet
' H/h = 0.23 O K. - H/h =<1
liUse 2 ft curb openinp I~
'
'
' •
1
1
~ Rationat Method and Detention Basin Design Wyatt Engineenng, Inc,
DA9.wb3
Date: 03/12/02 Page 1 ' Name: SUMMERFIELO EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-9 Design Frequency = 10YR
' No. of Subareas; None
1 Determine Time of Concentration:
' Segment 1- Overland Flow OVERLAND FLOW
Length, L= 190 ft(Length) MAX LENGTH= 300 ft.
, Slope,S = 1.4 ft/ ft (Siope) _
n= 0 030 Roughness Coefficient (Grass)
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines for Stormwater Management".
' Tc1 = Ct `(L'n/(S^.5))^(0.6); From "Gwdelines for Stormwater ManagemenY".
Tc1 = 0.39 min.
Segment 2- Shallow Concentrated Flow CURB GUTTER
' Length, L = 0 ft
Slope,S = 0.005 ft/ ft
n = 0.094 Roughness Coefficient
' Depth, y= 0.200 ft. (Assumed depth of flow)
Cross slope, s= 0.02 ft!ft
Z= 50 00 fUft (Z= 1/s)
Area, A= 1.00 ft. (A= 1!2'(Z)'(y^2))
' Q gutter = 1.83 cfs
Velocity,V = 1.83 ff/sec (V= Q/A)
' Tc2 = (LengthY(Veloary)
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
' Length, L= 0 ft
Slope, So = 1 fl/ft
n = 0.012 Roughness Coefficient (Manning's)
Diameter = 0 inches
' Area, A = 0.000 sf
R= D/4 = 0 21 ft
Velociry, V= (1.49/n)'(R^2/3)'(So^1/2) (Mannings Equation)
, Velocdy, V= 43.62 fUsec
Tc3 = (LengthY(Velocity)
' Tc3 = 0.00 mm
Total Tc = 0.39 min
1
'
'
'
'
~ Rationa! Method and Detention Basin Design Wyatt Engineering, Inc.
DA9 wb3
Date: 03/12/02 Page 2
, tVame: SUMMERFIELD EAST SUBDIVISIOM
Project: 4TH ADDITION
Basin Name: DA-9 Design Frequency = 10YR
' No of Subareas: None
2 Determine Weighted Runoff Coeffiaent (C) and Area: , Area
Surface Type (sfl (acres) C. CA
~ Open land (2%-10% slope) 61,365 1.41 0.30 0.42
Roof & Sidewalk 16,060 0.37 0.90 0 33
Asphalt, Curb & Dnveway 21,360 0.49 0 90 0.44
From Bypass DAx 0 0.00 0.98 0.00
' Total Drainage Area 98,785 2.27 acres Sum CA = 1.20 Total Impervious Treated Area 21,360 0.49 acres
From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY"
Weighted C=(sum CA)/(sum A) = 0.527
' 3. Determine Peak Runoff (Q=CIA).
Duration (Tc) = 0.39 min.
' Weighted C = 0.527
Intensity (I) = 3 18 in/hr From IDF curve for Spokane, WA
, Area (A) = 2.27 acres
' Peak 10 YR Discharge (Q) = 3.80 cfs
4. Determine Volume of "208" Swale:
' Total Impervious Treated Area = 21,360 SF (Includes 0 ft2 bypass from DAx)
Reqwred "208" Swale Volume = Impervious Area x 0 5"/12 in/ft
Reqwred "208" Swale Volume = 890 cu ft
' "208" Swate Bottom Width 2.0 ft Irregular size - see site plan
"208" Swale Bottom Length 820.0 ft Irregular size - see site ptan
"208" Swale Depth 0.5 ft
' "208" Swale Side Slopes (X 1) 4 0 ft
"208" Swale Bottom Area 1640.0 SF
"208" Swale Top Area 4920.0 SF Conservatroe Straight Wall
' 208" Swale Vofume 1640 CF POND SIZE CFIECKS
'
,
'
1
r
' Rational Method and Detenhon Basin Design _ Wyatt Engineering, Inc.
DA9.wb3
Date. 03/12/02 , Page 3
' Name: SUMMERFIELD EAST SUBDIVISION
Project. 4TH ADDITION
Basin Name. DA-9 Design Frequency = 10YR
' No. of Subareas: 0
5. Determine the Maximum Outflow (Qo).
' Number of Type "A" (0.3 cfs) Drywelis Required: 0
Number of Type "B" (1.0 cfs) Drywells Reqwred: 1
' Outflow (Qo) = 1.00 cfs (SEE ATTACHED CALCULATIONS)
6. Determine Required Detention Storage Usmg Bowstnng Method
, Time Increment = 5 min.
Elapsed time Intens. Qin Vol. In Vol Out Storage
' (min) (secl (in/hr) (cfs) (cu ft.) (cu.ft) (cu.ft)
0.39 231 3.18 3.80 118 0 118
, 0 0 3.18 3.80 0 0 0
5 300 3.18 3.80 1171 0 1171
10 600 2.24 2.68 1628 0 1628
15 900 1.77 2.12 1921 125 1796
' 20 1200 1.45 1.73 2094 254 1840
25 1500 1.21 1.45 2182 367 1815
30 1800 1.04 1.24 2248 481 1767
35 2100 0 91 1 09 2294 593 1701
' 40 2400 0.82 0.98 2361 727 1634
45 2700 0 74 0.88 2396 847 1549
50 3000 0.68 0.81 2446 983 1463
55 3300 0.64 0.77 2531 1157 1374
' 60 3600 0.61 0.73 2632 1352 1280
65 3900 0.61 0.73 2850 1652 1199
70 4200 0.61 0.73 3069 1952 1118
75 4500 0.61 0.73 3288 2252 1036
, 80 4800 0.61 0.73 3507 2552 955
85 5100 0.61 0.73 3726 2852 874
90 5400 0.61 0.73 3945 3152 793
Storage = (Vol in. - Vol out) ,
'
'
,
'
1
1
' Rational Method and Detention Basin Design Wyatt Engineenng, Inc.
DA9 wb3
Date: 03/12/02 Page 4
' Name: SUMMERFIELD EAST StJBDIVISIOtJ
Project: 4TH ADDITION
Basin Name: DA-9 Design Frequency = 10YR •
, No. of Subareas 0
7. Determme the Mirnmum Required Depth Above "208" Swale:
' Requued Detention Storage 1840.1 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 1640.0 CF
Reqwred Storage Above "208" Swale 200.1 CF
' "208" Swale Top Width NA ft (See "208" Swale Volume Calculations) -
"208" Swale Top Length NA ft (See "208" Swale Volume Calculatrons)
"208" Swale Top Area (SF) 4920.0 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft
Detention Pond Top Length NA ft
Top of Detention Pond Area 49200 SF
Volume Above "208" Swale 4920 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56'(Z/n)*(S^1/2)'(d^8/3)
Flow, Q= 3.80 cfs Included Basin DAx Bypass
Slope, S = 0.005 ff/ft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 fUft
Z = 1 /s = 100.00 ft/ft
' Flow Depth, d= 0.199 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC. FLOW (CHECK)
a) Curb Opernng at Low Point (See Page 6-40, "Guidelines for Stormwater Management")
' Curb Height (h)= 0 50 ft(Type 1 Curb Inlet)
Discharge, Qn = 3.80 cfs
Fiow Depth, d= 0.199 ft
Length of Opening = 4 ft .
, Use Q= 3.087(L)(H^3/2); Solve for H
Depth , H = 0.46 feet
, H/h = 0.91 O.K. - H/h =<1
IlUse 4 ft curb opening II
~
'
'
'
'
' Rationai Method and Detention Basin Design Wyatt Engineering, Inc.
DA10 wb3
Date. 03/12/02 Page 1
' Name: SUMMERFIELD EAST SUBDiVIStON
Project: 4TH ADDITION
Basin Name: DA-10 Design Frequency = 10YR
' No of Subareas: None _
1. Determine Time of Concentration:
, Segment 1- Overland Flow OVERLAND FLOW
Length, L= 130 ft(Length) MAX LENGTH= 300 ft.
' Slope,S = 0.01 ft/ ft (Slope)
n = 0.030 Roughness Coefficient (Grass)
Ct = 015 From Figure 3, Page 6-5, "Guidelines for Stormwater ManagemenY".
' Tc1 = Ct '(L'n/(S^.5))^(0.6); From "Guidelines for Stormwater Management".
Tc1 = 1.35 min.
Segment 2- Shallow Concentrated Flow CURB GUTTER
' Length, L = 0 ft
Slope,S = 0 005 fU ft
n = 0.014 Roughness Coefficient
' Depth, y= 0.200 ft. (Assumed depth of flow)
Cross slope, s= 0.02 ft/ft
Z= 50 00 ft/ft (Z= 1/s)
Area, A= 1.00 ft(A= 1/2'(Z)'(y^2))
' Q gutter = 1.83 cfs
Velocity,V = 1 83 fUsec (V= Q/A)
' Tc2 = (LengthY(Velocity)
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
, Length, L= 0 ft
Slope, So = 1 ft/ft
n = 0.012 Roughness Coefficient (Manrnng's)
Diameter = 0 inches
t Area, A= 0.000 sf .
R=D/4= 021 ft
Velocity, V= (1 49/n)'(R"213)'(So^1/2) (Mannings Equation)
' Veloaty, V= 43.62 ff/sec
Tc3 = (Length)/(Velocdy)
Tc3 = 0 00 min
' Totaf Tc = 1 35 min
'
'
1 .
,
'
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA10.wb3
Date• 03/12/02 Page 2
Name: SUMMERFIELD EAST SUBDIVISION
, Project: 4TH ADDITION ,
Basm Name: DA-10 Design Frequency = 10YR
No. of Subareas: None
' 2. Determine Weighted Runoff Coefficient (C) and Area:
' Area
Surface Tvae (sfl (acres) C. CA
Open land (2°/a-10% slope) 45,705 1.05 0.30 0.31
' Roof & Sidewalk 21,940 0.50 0 90 0.45
Asphalt, Curb & Dnveway 22,980 0 53 0 90 0.47
From Bypass DAx 0 0 00 0.98 0.00
, Total Drainage Area 90,625 2.08 acres Sum CA = 1.24
Total Impervious Treated Area 22,980 0 53 acres
" From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY"
' Weighted C=(sum CA)/(sum A) = 0.597
' 3. Determme Peak Runoff (Q=CIA):
Duration (Tc) = 1.35 min.
Weighted C = 0.597
' Intensity (I) = 3.18 inlhr From IDF curve for Spokane, WA
Area (A) = 2.08 acres
Peak 10 YR Discharge (Q) = 3 95 cfs
1
4. Determine Volume of "208" Swale:
' Total Impervious Treated Area = 22,980 SF (Includes 0 ft2 bypass from DAx)
Required "208" Swale Volume = Impervious Area x 0.5712 in/ft
Reqwred "208" Swale Volume = 957 cu. ft.
' 208" Swale Bottom Width 2.0 ft Irregular size - see site plan
"208" Swale Bottom Length 658.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
"208" Swale Side Slopes (X.1) 40 ft
' "208" Swale Bottom Area 1316.0 SF
"208" Swale Top Area 3948.0 SF Conservatrve Straight Wall
' "208" Swale Volume 1316 CF POND SIZE CHECKS
,
'
'
1
' :
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA10 wb3
Date: 03/12/02 Page 3
Name: SUMMERFIELD EAST SUBDIVISION
, Project: 4TH ADDITION
Basin Name: DA-10 Design Frequency = 10YR
No. of Subareas: 0
'
5. Determine the Maximum Outflow (Qo):
, Number of Type "A" (0.3 cfs) Drywells Required 1
Number of Type "B" (1.0 cfs) Drywells Required: 1
Outflow (Qo) = 1.30 cfs (SEE ATT'ACHED CALCULATIONS)
' .
6 Determine Required Detention Storage Using Bowstnng Method
' Time Increment = 5 min.
Elapsed time Intens Qin Vol. In Vol. Out Storage
' (min) (sec) (in/hr) (cfs) (cu.ft ) (cu.ft) (cu ft)
1.35 81.1 3.18 3.95 429 0 429
' 0 0 318 3.95 0 0 0
5 300 3.18 3.95 1295 0 1295
10 600 2.24 2.78 1747 165 1582
15 900 1.77 2.20 2041 392 1648
' 20 1200 1.45 1.80 2212 611 1602
25 1500 121 1.50 2297 812 1485
30 1800 1.04 1 29 2362 1016 1346
35 2100 0.91 1 13 2406 1217 1189
' 40 2400 0 82 1.02 2474 1441 1033
45 2700 0.74 0.92 2509 1650 859
50 3000 0.68 0.85 2559 1876 683
55 3300 0.64 0.80 2647 2139 508
' 60 3600 0.61 0.76 2750 2423 327
65 3900 0.61 0.76 2978 2813 164
70 4200 0.61 0.76 3205 3203 2
75 4500 0.61 0.76 3433 3593 -161
' 80 4800 0.61 0.76 3660 3983 -323
85 5100 0.61 0.76 3887 4373 -486
90 5400 0.61 0.76 4115 4763 -649
Storage = (Vol in. - Vol. out)
1
,
'
1
,
,
' Rational Method and Detention Basin Design , Wyatt Engineering, Inc.
DA10.wb3
Date: 03/12/02 Page 4
, Name. SUMMERFIELD EAST SUBDIVISION
Project: 4TH ADDITION
Basin Name: DA-10 Design Frequency = 10YR
' No. of Subareas: 0
7. Determine the Minimum Required Depth Above "208" Swale:
' Required Detention Storage 16482 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 1316.0 CF
Required Storage Above "208" Swale 332.2 CF
' "208" Swale Top Width NA ft (See "208" Swale Volume Caiculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 39480 SF (See "208" Swale Volume Calculations)
' "208" Swale Side Slopes (X:1) 4.0 ft (See "208" Swale Volume Calculations)
Depth Above "208" Swale 0.10 ft ASSUMED
' Detention Pond Top Width NA ft •
Detention Pond Top Length NA ft
Top of Detention Pond Area 3948.0 SF
Volume Above "208" Swale 394.8 CF POND SIZE CHECKS
' 8 Determine Length of Curb Opening:
' Q = 0.56"(ZJn)'(S^1/2)`(d^8/3)
Flow, Q= 3.95 cfs Included Basin DAx Bypass
Slope, S = 0.005 ft/ft
' n = 0.014 Roughness Coefficient
Cross Slope,s= 0.01 ft/ft
Z = 1 /s = 100.00 fUft
t Flow Depth, d= 0 202 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC FLOW (CHECK)
a) Curb Opening at Low Pomt (See Page 6-40, "Gwdelines for Stormwater Management")
, Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 3.95 cfs
Fiow Depth, d= 0.202 ft
Length of Opening = 4 ft
' Use Q= 3.087(L)(H^3/2); Solve for H
Depth , H = ° 0.47 feet
' H/h = 0 94 O.K. - H/h =<1
IIUse 4 ft curb oaeninq 11
1
1
'
' •
' .
' Rational Method and Detention Basin Design Wyatt Engmeenng, Inc.
DA11.wb3
Date: 03/12/02 Page 1
Name: SUMMERFIELD EAST SUBDIVISION
' Project: 4TH ADDITION
Basin Name: DA-11 Design Frequency = 10YR
No. of Subareas: None
'
1. Determine Time of Concentration:
' Segment 1- Overland Flow OVERLAND FLOW
Length, L= 260 ft(Length) MAX LENGTH= 300 ft.
' Slope,S = 0.014 fU ft (Slope)
n = 0.030 Roughness Coefficient (Grass)
Ct = 0.15 From Figure 3, Page 6-5, "Guidelines for Stormwater Management".
' Tc1 = Ct'(L'n/(S^.5))^(0.6); From "Gwdelmes for Stormwater Management"
Tc1 = 1 85 min.
Segment 2- Shaliow Concentrated Flow CURB GUTTER
' Length, L = 0 ft
Slope,S = 0.005 fU ft
n = 0.014 Roughness Coefficient
' Depth, y= 0.170 ft. (Assumed depth of flow)
Cross slope, s= 0 02 ft/ft
Z= 50 00 ft/ft (Z= 1/s)
Area, A= 0.72 ft. (A= 1/2'(Z)'(y^2))
' Q gutter = 1.18 cfs
Velocity,V = 1.64 ft/sec (V= Q/A)
' Tc2 = (Length)/(Velocity)
Tc2 = 0.00 min
Segment 3- Channel Flow NONE
' Length, L= 0 ft
Slope, So = 1 fUft
n = 0.012 Roughness Coefficient (Manning's)
Diameter = 0 inches
' Area, A= 0 000 sf
R= D/4 = 0 21 ft
Velocity, V= (1.49/n)'(R"2/3)'(So^1/2) (Mannings Equation)
' Veloaty, V= 43.62 ft/sec
Tc3 = (Length)!(Velocity)
Tc3 = 0.00 min
' Total Tc = 1.85 min
'
'
'
'
1
' Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA11.wb3
Date: 03/12/02 Page 2
Name: SUMMERFIELD EAST SUBDIVISION
' Project: 4TH ADDITION
Basm Name: DA-11 Design Frequency = 10YR
No. of Subareas: None
'
2. Determine Weighted Runoff Coefficient (C) and Area.
t Area
Surface Tvpe (sf) (acres) C. CA
' Open land (2%-10% slope) 40,958 0 94 0.30 0.28
Roof & Sidewalk 12,260 0 28 0.90 0 25
Asphalt, Curb & Dnveway 11,350 0.26 0.90 0.23
From Bypass DAx 0 0.00 0.98 0.00
' Total Dramage Area 64,568 1.48 acres Sum CA = 0 77
Total Impervious Treated Area 11,350 0.26 acres
From Table 1, Page 6-2, "Guidelines for Stormwater ManagemenY'
Weighted C=(sum CA)/(sum A) = 0.519
' 3. Determine Peak Runoff (Q=CIA): .
Duration (Tc) = 1 85 mm.
' Weighted C = 0.519
Intensity (I) = 3.18 in/hr From IDF curve for Spokane, WA
Area (A) = 1.48 acres
' Peak 10 YR Discharge (Q) = 2 45 cfs
4. Determine Volume of "208" Swale:
' Total Impervious Treated Area = 11,350 SF (Includes 0 1`112 bypass from DAx)
Required "208" Swale Volume = Impervious Area x 05712 in/ft
Required "208" Swale Volume = 473 cu. ft.
' "208" Swale Bottom Width 2.0 ft Irregular size - see site pian
"208" Swale Bottom Length 375.0 ft Irregular size - see site plan
"208" Swale Depth 0.5 ft
, "208" Swale Side Slopes (X:1) 4.0 ft
"208" Swale Bottom Area 7500 SF
"208" Swale Top Area 2250.0 SF Conservative Straight Wall
' "208" Swale Volume 750 CF POND SIZE CHECKS
'
,
'
'
'
' Rational Method and Detention Basm Design Wyatt Engineenng, Inc.
DA11.wb3
Date• 03/12/02 Page 3
Name: SUMMERFIELD EAST SUBDIVISION
' Project: 4TH ADDITION
Basin Name: DA-11 Design Frequency = 10YR
No. of Subareas: 0
'
5. Determine the Maximum Outflow (Qo):
' Number of Type "A" (0.3 cfs) Drywells Required: 0
Number of Type "B" (1 0 cfs) Drywells Required: 1
' Outflow (Qo) = 1.00 cfs (SEE ATTACHED CALCULATIONS)
6. Determme Required Detention Storage Using Bowstring Method
' Time Increment = 5 min.
Elapsed time Intens. Qin Vol. in Vol. Out Storage
' (min) (sec) (in/hr) (cfs) (cu.ft.) (cu.ft) (cu ft)
1.85 111.1 3.18 2.45 364 0 364
' 0 0 3.18 2.45 0 0 0
5 300 3.18 2.45 827 0 827
10 600 2.24 1.72 1100 165 935
15 900 1 77 1 36 1278 350 928
' 20 1200 1 45 1.12 1382 528 854
25 1500 121 0.93 1433 695 738
30 1800 1.04 0.80 1471 863 608
35 2100 0.91 0.70 1498 1029 468
' 40 2400 0.82 0.63 1539 1212 327
45 2700 0.74 0.57 1560 1384 176
50 3000 0.68 0.52 1590 1567 23
55 3300 0 64 0.49 1645 1778 -133
' 60 3600 0.61 0.47 1708 2003 -295
65 3900 0.61 0.47 1849 2303 -454
70 4200 0.61 0.47 1990 2603 -613
75 4500 0.61 0.47 2131 2903 -772
, 80 4800 0.61 0.47 2272 3203 -931
85 5100 0 61 0 47 2413 3503 -1090
90 5400 0.61 0.47 2554 3803 -1249
Storage = (Vol m. - Vol. out)
'
'
'
'
'
'
~ Rational Method and Detention Basin Design Wyatt Engineering, Inc.
DA11.wb3
Date: 03/12/02 Page 4
Name: SUMMERFIELD EAST SUBDIVISION
, Project: 4TH ADDITION
Basin Name• DA-11 Design Frequency = 10YR
No. of Subareas• 0
'
7. Determine the Minimum Required Deplh Above "208" Swale:
, Reqwred Detention Storage 9348 CF (See Bowstnng Method, maximum value)
"208" Swale Volume 750.0 CF
Required Storage Above "208" Swale 1848 CF
' 208" Swale Top Width NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Length NA ft (See "208" Swale Volume Calculations)
"208" Swale Top Area (SF) 22500 SF (See "208" Swale Voiume Calculations)
"208" Swale Side Slopes (X:1) 40 ft (See "208" Swale Volume Calculations)
' Depth Above "208" Swale 0.10 ft ASSUMED
Detention Pond Top Width NA ft
' Detention Pond Top Length NA ft -
Top of Detention Pond Area 22500 SF
Volume Above "208" Swale 225.0 CF POND SIZE CHECKS
' 8. Determine Length of Curb Opening:
' Q = 0.56'(Z/n)'(S^1/2)'(d^8/3)
Flow, Q= 2.45 cfs Included Basm DAx Bypass
Slope, S = 0.005 ff/ft
' n = 0.014 Roughness Coeffiaent
Cross Slope,s= 0.01 ft/ft
Z = 1 /s = 100.00 fUft
' Flow Depth, d= 0.168 ft WITHIN 10% OF ASSUMED DEPTH FOR SHALLOW CONC. FLOW (CHECK)
a) Curb Opernng at Low Point (See Page 6-40, "Guidelines for Stormwater ManagemenY")
' Curb Height (h)= 0.50 ft(Type 1 Curb Inlet)
Discharge, Qn = 2.45 cfs
Flow Depth, d= 0.168 ft
Length of Opening = 4 ft
' Use Q= 3.087(L)(H^3/2); Solve for H
Depth, H = 0.34 feet
' H/h = 0.68 O K- H/h =<1
IlUse 4 ft curb opening I~
1
'
'
'
'
~
'
Summerfield East 4' Addition
Subdivision
'
1
' APPENDIX V - Miscellaneous Figures
~
'
'
1
'
'
1
t
'
t
' 02001 Wyatt Engmeering (679300) Storm Water Brief
October 19, 2001 (rev. 3/12/02)
'
MR "M m, !!I
~ ,..,.r, 7~ ~w... ~ • • -
~ - - - - - - _ _
- ---------_~c5r~----`~.6,- - - '_f~-, - ~ ------I--I--~- -
- - - - - - - - -
. _ - - - ~ - - 1-- - -
~ ~ ~1
-
- t-_`_ _
- - - -
- ~ - - - - - - ~
~
- - -------I-~ ~
- - - - - - - - - - - - - _ 1- - - _ I_ ~ -.----~-I--= I- _ -i- - _ _.-1 T - - - - - - _ _ _ e._ _
- - ^ - - ~ -
- - - - -
_ _ . _,---------------~-I ~ ---I - - -
_ - - -----------r
-==T= - - - _
5 ~ _ ~ ~
_ ~ - - ~ -
T
- ---ti~ --i-;_;~---
T__
_ _
-
!
~ rt r -
w , r
~ -
191 ]----------c__. - - ----fi~-'-----
-
- _ - - - = _ _ _ _ - - = - - - - _ ~~j~}__.- - - - ~ - - _ - - - - - - - -
- --,--;_t r_~L~~_ ~ ~
- - - 1- - - ~I ~ ~ _E _ - - - - _ _ - - - - - - - - -
- - - - ~ - - ~ - ~ - - _ _ C - - ~ I_ - - - - - - - - -
_'_-_--_~.._=-'ac-~c--_''~--- - - - - ~ ~--t~-r~-1 ~~_I_._
. ---~-`c--~- --f• ~ L - ~ ~ ~ ----•---------_r_ _
- - - - ~ - - ~ - ~ - - - - - - - - - - ---I- - - ~ - - - - - _ - - C--
- ~ _-)~c*-- - - 'c--- - - - - ~ - ' ~
~ --l--•~_- °---~-•--.-C~ ~ f -•--`✓-y-~I~ ~ ' _
-
~ - - - _ _ - -
~ - - - - - - - ---•^~c-- - - - _ -
' - • - - - - - -
- - - -
-S - - - - - - - - - - - - - - - - I~,_ - - - _ _ _ - _
ro - ----------'~----~c--- - -
-vi
` - - -
iv - - - - - - - - ~ _ c - - - - - - - ~ - - _ _ - - - - - - - - - - - _ _ _ _ -
_:~-C==T-----~ - - ~ - - -f
: - - -
~ - - - - - - -
- - - - -~.s _ _
~
~ - - - - - - -
_ _ - - - - - _ _ _ _ -
~ -1----- .~~L~,.~----- -'w=~-1-------~----------~_ ~ ~ ; I i ; ~ j .
O /O _ 20 30 • 40 ~.50 • 60 70 BD 90
___~-L RR
GENERAL NO TES WATERPROOF-~ CATCI BSIN YALL
pIPE (TYP.)
I. GRAVEL BACKFIIL QUAlIT17Y FOR DRYWEI.LS : NON-SHRINK NOTE.
TYPE "A" - 30 CU91C YARDS MINIµU}A / 42 TOM5 CROU? ----ib
TWE "B" -/0 CUBIC YARDS AIINIMUM / 58 TONS. ` 1_al PVC PIPE ADAPiERS AIJD CASKET MAY VARY
OR AS SPECIFIED Otl ROAD PLANS __4 IN SIfAPE ANn SIZE AS ILLUSTFtATEO IIJ
DETAIL 6Y ACCEPTABLE ALTfRNATE IH
2 SPEqAL 6AC{<FILI MATERIAL FOR DRYYrELLS SIIALL CONSIST OF ACCORDANCE N1TH A S 7.M.-C-428.
WASIiED CRAVEL CRADED FROld I' TO 3` N7IH A!AA%IRIUM Of SX ~:PVC PAS5117C i11E U.S. No. 200 SCREEtI, A5 MEASURED 9Y WEIGHT. ~ GASKET
A MAXIMUTA OF IOx Of TFIE AGCRECATE, A5 MEASURED BY V~EIGHT, ADAPTER
• AIAY 8E CRUSIIEU OR FRACIURED ROCK i11E REMAl111NC 907:
SVIAI,I 6E NAIURALI.Y OCCURRIfIG UNFRACiUREO MATERIAL P VC AD AP 7ER
3 FABRIC SIIALL BE lAODERATE SURVIVABfUTY AS OU1Lt1ED (SAND COLLAR)
IN STAPIDANO 5PECIfICATIONS 0-33
i SEE SIAl10ARD PLANS SFIEETS B-2 ANO B-J FOR , PRECA51 COtICRETE pETAIIS. MEJAL fRAlAE 7WE 4
5 ADJUSTMENT BIACHS SHALL BE CEIAENT CONCREiE ~ PAY LIMITS CR TE TYPE 4~ MORTAR IM PLACE
6. PRECAST RISER 61AY BE U5EU Itl COMBINAt1014 METAI, FRAME
WITII OR U! UEU OF AD.A15T1NG BLOCKS k CRA7E
~
7. WIIEN PVC PIPE IS USED A PVC ADAPIER SHAIL BE UISTALLED.
B PII'ES SIIALL BE GROUTED INTO ORYWfLLS TOP SOIL rMORTARED ADJUSTMENT
(;..RINGS
CRATf lYPEAE4 rWE 4 ~ GRAVEL BACKFILL 2'-0'
•
µORTAR IN PLACE TO BE COAtpLFTELY I
/ q COYE ED 1N711 FAORIC
/fr- _ - N
b ,~l
_IIlLET PIPE
cz ' ~ '
IOP SOIL ~ I MOR TARED
~ADJlJ51lAENf ftINGS . ~ O O Cl ~1
} < ~ I
CRAVEL BACKFII,I.
i0 BE COMPLETEIY
~ CF~ABRICQ H1 fH ~ 2-0" c W ~ ~ t ~,•~SEE IJOTE 7
~oiEGi"a~ ro
\ GRA4EL ;I SEEPACE pORTS Q _
~INI.ET PIPE
] c. BACKFILL, SEE DETAII., SfIT. B^2 2Q
f10TE INdc 2 FABRIC LIHER
BAC Ffi.l., -ii ~ O O I
~7
i •3 ~PopTO I1 SEEt
~ ~ •~i SEE 0 AI , S iEE B-2. a ..I
1, 1 FABRIC UtlER G'~. :I I '~~r' ~
. , '~~ta~Y •i- d~' !
, UtIDISRIRBEO
SoIL 56,~5nRaEo
DRYWELL - TYPE 'A' SWALE DRYWELL - TYPE 'B' SWALE
SPOKANE COUNTY APPROVED'• ~Att ~nw
t l OEPARTMEP~T OF PUBI_IC WORI<S cw~rT „c~~ j„ STAPIDARD~ st1EEr
t
Nn-IOATE 19YICK0 IAPPR I Kk~s~oN , , sra<u~E, wn as:oo ,x-,eoo unie~ PRECAST DRYWELL5 PLACED IN SWALES H-la
, . 11 w.a aPy^ ~
. . ' .
- •
~ .
Min, Berm elev.
~ Top of Sod ptus 1.0 ft
t Ton of curb (Tc) e3ev. Curb
3 max.
, 2° curb drap ~
N
. Arate elev. ~ ~
Top of Sod f 6- S. 4° concrete
Top of subgrade
~ ✓
/
' drywei4
~
~y.
1
' I
~
>
i
~ . R
- Grassed Percmlati.on Area (GPA)
Guidelines for Stormwater IYlana.gement
ri~ure 4-8 Addendum, Februaty 1998 S~~~OUh'TY
~ Pa. 6-8a
~ - v ,
GENERAL NOTES
1. CURB INI.ET SMALL BE CONSTRUCTED IN ACCORDANCE
N1t1/ ASTM C 478 (AASViTO N 1)8) k AST1.i C 890
UNl.ESS O7)1ERNISE SHOWN ON PLANS OR NOTED
lN T}IE PROJECT SPEGAL PKOV1540tJS
2 TOP SURFACE i0 BE BROOIA FINISIIED ,
• 3 ALl EXTERNAL EDCES NOT I.ABELED SHALL BE
TROWELLED N7TH 1/4" RADIUS EDGER.
4 DIMENSIOM 't' SHALL BE SHOWN ON THE PLANS
DRAINAGE Ct CURB UROP- -
SWALE
rL ORAINACE
L swa,LE
cuRa Ario ~ 1.~"•• CUT7ER
4" PORTLAND CEMENT ~
CONCRETE ~
~
B SECTION B-B 3~_u~_.~.- 3-..~ - •
• CURB INLFT TYPE 1
vy,~
61 `
~ SPOKANE COUNTY APPROVED• SHEET .
- B7,`P KGI:~- ` v,~SD~.IAE-FR' u swnC DEPARTMENT OF PU6UC WORKS cour~i icir+ +romt = STANDARp -
d ,~r~i srucu,e, wti o9:oa ~so-.uoo o~,c~~~,P..o<„.,. , CURB INLET TYPE 1 B-8
.
' 1z" ~
RU'. ~T ^8'
~
1/2`.._.. ~ za• ' "w'
2 3/4' & ~ 22"
2 3/1 -I-6---1-- i M6' 9 17' 18. 4.
~
1\ ~~i,~1 y ,1 1
• ~R-I• - nM~~
PAVEMENT '\\\'/.~-t'i\` ]/B- R
J.l I i~i YYPE
_ ,o a
~ 4 om QUANnTY 002Z833 C.Y L.F -JL
~ PORTLAND 'vi ,~o ,
CE~1ENT N
~ CONCREiE VARIESJ ~--6----i
ASPNALT CONCRETE
,r
TYPE "A" TYPE "B" TYPE "C" '
, OUANDTY, - 0.036025 C Y,/ LF OUANTITY . 0047657 C.Y. / LF WANiItt . 0023123 TONS / LF
SEE t101E 6, SEE NOiE 8 ' ~ . .
TYPE "S"
OUANTiIY - O.O1B519 C.Y / LF.
GENERAL NOTES
I
wI I. PpRiLANO CEMENT CONCREiE SHALL BE
CLASS ]OOQ CONFORIAIHG i0 TttE SIANDARD
24, EXISTWC CURB 18- SPEpfICATIONS.
2 1YEAKENED PLANE JOlNTS FOR PORTLAND
I SIDEWALK ~ CEuEr1T Cor~CREiE SHAU. HE PLtiCED A7 15' .
--10'--- 2'~-- t2' j~ g' INTFRVALS j r T ] 3/8' ExPANS10tt JOINTS IN PORTLANU CEMENT
iO r , C01tCRE1E SIIALL BE PLACED AT CUHB REiURNS
• _ i ~ ~ - 1 3,8•
2% R-12'1 ' 4 EPOxY CEMENT SHALL BE APPLIED AT A{0-15
R . ' MIL THICKNfSS AND 5/1ALL CONFORAI TO 1HE
~ ~ REQUIRENENTS OF SEC710N 8-26 OF 1HE
STANbARD SPEGFICAi10NS
IEPOXY
SEE NOTE 4 5 COHSiRUC110N OF TYPE 'U' CURB SHAU. CDNFORU
L L._ pORTLAND TO SECiION B-04 pF THE SfANDARD SPELIF{CA710N5
~ ~~~~6/ I I CEMENT EXCEPT THAT POR1LAND CEMENT SHALL BE REPLACEU
m '3 1/2- `~OPTIONAL FOR CONCRETE H7iH 'TRINITY WHITE' CEAIENT. 7NE FINISN SIIA4A. 6E
PORTLAND INiEGRAL POUR, STEEL TROwEU.ED 10 PRONOE A DENSE; 5uo01H
CEMENT CONCRETE CONCRETE GUTTER REFLECDVE FINISFi
TYPE ,~R,/ OUANi1N . 0.0244149 CY. / Lf 6 TO 8E USEO ONLY IN SPEGAI CASES Yrii1/ APPROVAI
OF TNE COUN7Y ENCINEER.
pUANT1TY - 0052259 C.Y, / L.F.
7. CURBS StIA4L HAYE A 41GHT BROOIAED fINISH. s
a`~ GUTiERS SHAL4 8E FIlIISHED N1TH A S1EEL TR01`hL
Lf2-Z2L 4&Z=.71 acr+ ~-`w' niueNSIoN Anoeo ro cuRa secnaa. SPOKANE COUNTY APROVEO. STANDARDsneEr
r o~~
~ RCH 1 OII~EN9dJ CORRECilOii - iYPF 'R' CUR9 DEPARTMENT OF PU9UC WORKS ~CURBS dc GUTTERS A-3
HFH51~?N J P9~ 4~-~ DAIY ~
K . APPR. I ~
,
, Summerfield East 41 Addition
Subdivision
'
'
,
'
APPENDIX VI - Miscellaneous letters
~
'
'
'
1
'
'
'
~
'
'
' Q2001. Wyatt Engineenng (679300) Storm Water Brief
October 19, 2001 (rev 3/12/02)
'
,
S _P O K A N' ~E• O Z.J N-r Y
' DIVISION OF ENGINE...zTtiNG AND ROADS • A DIvLSION OF TF-T..E PUBLIC WORI:S DE'ARTtviEDl'I'
William johns, P.E_, County Enginees Dennis M. Scott, P.E., Dsector
7uly 6, 1999 ,
' Dean Franz
' IPEC
707 W 7"', Suite 200
Spokane, WA 99204
' REE: Summerfield East 4`h and 5h Addition, PE-1205
Dear Dean,
1
I am in receipt of your letter dated 7/1/99 outlini.ng the conditions for building within the Zone B
' floodplain in the above noted development. The conditions outline what we agreed upon in the
field on 6i29/99, and clarify what has been discussed through previous correspondence. I believe
the floodpIai.n cancems will be adequately addressed if these conditions are adhered to.
t If you have questions, please let me lnaw. •
' Sincerely, "
1 f
Tammie Williams
' Floodplai.n Administrator . .
cc: Ken Tupper, file
1 -
'
' . .
1
'
1026 'vV 3roadlvay :4ve_ • Sookane, WA 99260-0170 •(509) 456-3600 FAX: (509) 32d-3478 TDD: (509) 324--3166
' _
. .
;1NLAND PAClF1C ENGINEERING, INC.
July 1, 1999
' IPE Pro}ect: 99004 •
' Tammie Williams
Floodplain Administrator
Spokane County Public Works -
1026 W. BroadNvay Ave, 2"d F1oor
Spokane, WA 99260-1070
' RE: Summerfield East ?`h & 5b Addition
(Spokane County No. PE-1206)
' Dear Tarnaue= , .
' Thank you for meeting with us at the proj ect site a few days 'ago. Given the unusual couditions of
having an `Alluvial Floociplain' impacting the area, this naturally creates the need for close
commurucation with Counry engineermg staff as this development embarks upon final design. We
have listed below our understanding of Nvhat was agreed upon during the field meeting.
' -
• The living spaces for single-family housing within the FEN1A Zone B flood zone is subj ect
' . to certain elevarion restrictions, as follows: 1) the tap of concrete foundauon/wall shall be
no less than 24 inches above the top of curb of the frontage road; 2) no openimgs (e.g_ doors
and wi.ndows) wiIl be allowed below the "mi.n. elevation of concrete wall"; 3) the garage
' slab shall be no less than 18 inches above the top of curb of the frontage road; and 4) the
livzng area can extend 42 inches beiow the descnbed top of concrete wall_ An exhibit
showingthese dimensions is enclosed for clarification, aud is labe3ed "Housing Construction
t in FEN1A Zone B Area-"
~ The finish grade of the proposed streets within this plat; (e_ g. the remaining phases within
' the FE~.ti1A Zone B area), is to be at or close to existing grade. The intent of this criteria is
to not have any of the anternal streets significantly below existing grade.
' - A one foot deep interceptor berm and two Type B cirywells will be constructed along the
north side of the Zone B area with the next phase of Summerfield East. While no flooding
of the area from the `Forker Draw' is eapected or has ever been observed, (due to the
' presence of highly permeable `valley gravels'), an interceptoz berm will be cnnstructed to
provide an additional factor oi safery againstfloocimg. lYlaintenance access shall beprovided
to this interceptor bemm, the bem wiJ1 be placed within an easement, and. mamtenance
' respons~biliues of said berm and dryvells will be assumed by the developer.
~ • . .
;
, .
.
' 0
~ Le-ter te Ta-mmie Williams ( 1-1-99)
Summerfield East (PE-1206)
~ page 2 • -
~
~ Ifa.ny af these items o.L'understa:nci.znb axe diffexent that wbat you undezstood, please cail me and we
can promptIy make the uecessa.ry ad,justrmezits.
~ Sancerely,
~~~~d Pacafie Engaue4xawg
Dean FTar~, P.E. ~
~ Engineering Managex
~ eraci= Ex."tiiErit - `Housxng Constructian in FEtiJA Zane B A-rea' (8 '/z" x 1 I
~ ec: Ken Tuppez
Piaject Ee
~
~
1 '
1
1 r
~
1- - - .
~ 19004.Ltr 4fUnderstanding.;'-1-99.wpd
~
~ 0
. .1
• ~ FRAME WALL
ROAD
WINDOW bR
~ FRAME WALL CONCRE7E SLAB
I FOR GARAGE , . •
FINISH ROAq MIN. ELEV. OF CONCRETE WALL
GRADE AT OR NEAR EXISTINC Z
GRADE z ~
~ x
F ~
K TOP CUftB
~ uvir~c Ar~Ea
LOWEST ELEV,
CONCftE7E WALL
UNBROKEN
SCALE; NOT TO SCALE
I NLAND
PACIFIc SUMMERFIELD EAST 4TH AND 5TN ADDITIO.N
~ ENGINEERING ~I T U ~-10~JNG CONSR CTION IN FCMA 70NE B ARCA
707 Weal %lh -Sultn 200 (508) 458-6840
Spokano, WA 89204 IPEC-99004-EX113 DWG
FAX: (509) 458-68M4J DATE: 6\30\99
` ~ ~ . ~