20070404 Storm Drain Rpt 04012009Creek Street Mixed Use - Christensen Commercial
FINAL STORM DRAINAGE REPORT
Creek Street Mixed Use/Christensen Commercial
Yelm, Washington
Revised April 2OO9
Project Information
Project: Creek Street Mixed Use SpR-07-O404-yL
Prepared for: Rick ChristensenContact: Rick Christensen
(360) 4s8-3602
Project Engineer
Prepared by: Shea, Carr & Jewell, Inc.
2LO2 Carriage Drive Bldg. H
Olympia, WA 98502
Phone: (360) 352-t465
Contact: James E. Gibson, p.E.
Project Manager
Project Number: 1290.01
Al.i3 0 r ?t0g
Creek Street Mixed Use - Christensen Commercial
CERTIFICATE OF ENGINEER
: I hereby certify that this preliminary
Drainage Report for the Creek Street Mixed Use/Christensen Commercial in yelm
Washington has been prepared by me or under my supervision and meets theminimum standards of the 1992 Department of Ecology Stormwater ManagementManual for the Puget Sound Basin and normal standards of engineering practice. Iunderstand that the jurisdiction does not and will not assume liabitity for the
sufficiency, suitability, or performance of drainage facilities designed by me.
TowARo \
Z.;í.-wii,,\,\%
ttr\Ti""ílii."l
red by James E. Gibson, p.E.
Creek Street Mixed Use - Christensen Commercial
TABLE OF CONTENTS
1. STORM DRAINAGE REPORT ......... 1
1.1 PROPOSED PROJECT DESCRIPTION....,.... .........,. 1
L,2 EXISTING CONDITIONS...,. ..,,,,4
1.3 TNFTLTRATTON RATES/SOILS REPORT.... .............4
T,4 WELLS AND SEPTIC SYSTEMS ........... ...,... 5
1.5 FUEL TANKS............. ....., 5
1.6 SUB-BASIN DESCRIPTTON ,......., ................. 5
T,7 ANALYSIS OF 1OO YEAR FLOOD .,....... 5
1.8. AESTHETIC CONSIDERATIONS FOR FACILITIES....... ,...... 5
1.9 DOWNSTREAM ANALYSIS ....... ....... 5
1.10 COVENANTS, DEDICATIONS, EASEMENTS ..........5
1.11 PROPERTY OWNER'S ASSOCIATION ....... ..,......... 6
2. EROSION CONTROL REPORT. ,,,,,,,,.,7
2.L CONSTRUCTION SEQUENCE AND PROCEDURE ............ ...,......,7
2,2, TRAPPING SEDIMENT ,.,,,...7
2,3 PERMANENT EROSION CONTROL AND SITE RESTORATION...........,......... B
2.4 GEOTECHNICAL ANALYSIS AND REPORT. .......... B
2.5 INSPECTTON SEQUENCE..,, ....... B
2,6 CONTROL OF POLLUTANTS OTHER THAN SEDIMENTS ....,....... ....... 8
3. MAINTENANCE PLAN. ..,....9
3.1 REQUTRED MAINTENANCE . .........9
Appendices
Appendix A-1 - Drainage Calculations
Appendix A-2 - Drainage Basin Map and Preliminary Grading and Drainage Plans
Appendix A-3 - Vicinity Map
Appendix A-4 - FEMA Map
Appendix A-5 - Soils Repoft + SCS Soils Report
Appendix A-6 - AquaSwirl Data
Appendix A-7 - Mounding Analysis, Landau Associates
Appendix A-B - Draft Maintence Agreement
Creek Street Mixed Use - Christensen Commercial
1.STORM DRAINAGE REPORT
The format of this report follows the outline provided in the Drainage Design and
Erosion Control Manual (DDECM) for Thurston County, 1994 Edition and meets the
requirements of the 1992 Department of Ecology Stormwater Management Manual
for the Puget Sound Basin.
1.1 PROPOSED PROJECT DESCRIPTION
Project Proponent:Rick Christensen
11915 Clear Lake Rd S
Eatonville, WA 98328
(360) 4s8-3602
64303400501 and 64303400502
A portion of Section 29, Township 17
North, Range 2 East, W.M.
6.12 acres
c-2
10602 106th Ave SE Yelm, Wa.
Parcel Number:
Legal Description:
Total Site Area:
Zoned:
Site Address:
Project Overview:
The 6.12 acre site is generally located in the eastern quadrant of the City of Yelm,
Washington. This site is more specifically located to the north of State Route (SR)
507, east of Creek Street and west of Yelm Creek. The site is bisected by 106th Ave
that begins at creek street and terminates at sR 507. This property and all
surrounding properties are zoned C-2,
The Creek Street Mixed Use project is a small portion of a larger project referred to
as Yelm creek Apartments, Inc, The city of Yelm's Hearing Examiner granted
approval for the project and issued the conditions of approval under City of Yelm'sproject number SPR-07-0404-YL. The multi-family portion of the project was
engineered by sound Engineering Inc. and does not include tax parcels
64303400501 and 64303400502.
This project will construct 3 new commercial building pads and associated parking to
accommodate these uses. The proposed buildings are: a two story, 26,t6o square
foot furniture store, 10,500 square foot retail building and 7,800 square foot retail
building. This site already contains an 11,000 square foot building and parking lot.
The developed area is to remain generally unchanged. The remainder of the site
area is currently undeveloped and is mostly bare soil, sporadic brush and weedy
vegetation.
Shea, Carr & Jewell, Inc.
April 2009
Creek Street Mixed Use - Christensen Commercial
Development Coverage Summary:
Proposed Building Roof Area
Proposed Parking and Sidewalk Area
Proposed Disturbed Pervious Area
0.69 Acres
1.43 Acres
0.41 Acres
Existing Developed Right of Way 0.63 Acres
Existing Developed Building Area 1.17 Acres
Undisturbed Creek/Wetland Area 1.80 Acres
Total Area 6.12 acres
In 2004, a previous land use proposal was approved for this property. Jerome W.
Morrisssette and Associates designed a storm water facility to provide adequate
capacity to serve the entire 6.12 acres. The City of Yelm has since updated itsCritical Area Code and the storm water facility is no longer in conformance withcurrent codes. Given this, the project developer has elected to provide separatestorm water treatment and storage for the new buildings and associated additionalparking. These facilities have been sized to provide storm water mitigation for the
additional 2.52 acres of new developed area. See Appendix A-2 for Drainage BasinMap. This project will also be replacing the existing bioswale stormwater treatmentwith an Aqua Swirl AS-3 treatment device,
Stormwater Treatment:
The roof runoff will be collected and conveyed directly to the stormwater conveyancesystem. Therefore, the sizing calculations for treatment were based on a total areaof 2,52 acres, 2.11 acres of impervious area and 0.41 acres of disturbed pervious
area. The basin area has been divided into 2 sub-basins. These are referred to thenorth and the south basins.
According to Section I-2.8 of the DOE Manual, the required stormwater treatmentflow is computed based on the 6 month storm flow. The 6 month storm is computed
as 640/o of the 2 year storm. According to the isopluvial maps in Appendix AIII-1.1of the DoE stormwater manual, the yelm area has a 2 year storm of 2 inches,Therefore, the 6 months storm is 1.28 inches. Storm Shed software was used tocompute the 6 month stormwater flow. This flow was found to be 0.26 cfs in thenorth basin and 0.06 cfs in the south basin. See Appendices A-1 for Storm Shedmodel output showing this calculated flow.
Stormwater treatment for the north basin will be provided by an AquaSwirl ModelAS-3 Stormwater Treatment System. This model will treat a water quality flow of upto 1.8 cfs. This will provide ample treatment for this basin. The 100 year storm forthe north treatment area was computed to be 1.57 cfs (see Storm Shed output inappendices). This is also well within the allowable flow for the unit and, therefore, an
Shea, Carr & Jewell, Inc.
April2O09
Creek Street Mixed Use - Christensen Commercial
on-l¡ne system can be used without a bypass. see appendices for furtherinformation on the AquaSwirl system.
Stormwater treatment for the south basin will be provided by an Aqua Swirl ModelAS-2 Stormwater Treatment System. This model will treat a water quality flow of upto 1.1 cfs. This will provide ample treatment for this basin. The 100 year storm forthe south treatment area was computed to be 0.59 cfs (see Storm Shed output in
appendices). This is also well within the allowable flow for the unit and, therefore, an
on-line system can be used without a bypass. See Appendices A-1 for further
information on the Aqua Swirl system.
In August 2004 JWM&A designed the existing stormwater facilities to treat andinfiltrate the entire 4.90 acres of the site. The treatment is obtained with a grass
lined bioswale. We have proposed to replace this swale with an Aqua Swirl AS-3
treatment device. We have verified JWM&A's calculations and also resized the
treatment flows based on the new collected areas for the existing stormwater pond.
The area contributing to the existing pond is now reduced to 1.66 Acres from 4.90
Acres. See calculations located in Appendix A-2.
Stormwater Storage:
Stormwater in the south basin will be conveyed from the AquaSwirl treatment
system to an infiltration trench meeting the requirements of Section III-3.6.5 of the1992 DOE Manual. It will be located along side the parking area east of theproposed building and has been sized to accommodate the 100 year storm event, Inaddition, per Section III-3.6.5 of the DOE manual, it must be demonstrated that the
required volume for the 10 year storm can be recovered in 24 hours and the 100yearstorm in 48 hours. According to the isopluvial maps in Appendix AIII-1.1 of the
DOE stormwater manual, the Yelm area has a 10 year storm of 3 inches and a 100year storm of 4 inches.
The proposed infiltration trench will be comprised of washed rock only and will not
contain perforated pipe. Therefore, per the WAC 173-218-050 Exemptions from UICwell status item #4, this stormwater system will not qualify as an UIC well.
Roof runoff will be conveyed to the infiltration trench. Therefore, sizing calculationswere based on a total area of 0.74 acres, 0.52 acres of impervious area and 0,22
acres of disturbed pervious area.
StormShed software was used to model and size the infiltration trench. Per therecommendations of the geotechnical investigation (see appendices), an infiltrationrate of 20 inches per hour was used for design. In Storm Shed, infiltration is
modeled as a rating curve. A steady rate of flow of 0.33 cfs was computed based onthe bottom area of the trench. The rate is calculated by multiplying the square
footage of the trench bottom by the infiltration rate in cubic feet second. (720 sf x(2O in/hr / 43200)). Per the model, a total volume of 430 cubic feet is required toprovide storage for the 100 year storm (see model output in appendices), Theinfiltration trench will be 6 feet wide, 120 feet long and 3 feet deep. This provides atotal available volume of 713 cubic feet with an additional 1 foot of freeboard above
the active storage volume. See Appendix A-1 for model output and calculations.
Shea, Carr & Jewell, Inc.
April2009
Creek Street Mixed Use - Christensen Commercial
Stormwater in the north basin will be conveyed from the Aqua Swirl treatment
system to an infiltration gallery. It will be located in the parking area south of the
proposed furniture building and has been sized to accommodate the 100 year storm
event. In addition, per Section III-3.6.5 of the DOE manual, it must be
demonstrated that the required volume for the 10 year storm can be recovered in 24
hours and the 100 year storm in 48 hours.
The proposed infiltration gallery will be constructed using washed rock wrapped in
geotextile fabric. The bottom of the pond area will located in native Spanaway
gravelly soils conducive for infiltration.
Roof runoff will be conveyed to the infiltration gallery via the parking lot storm water
conveyance system. Therefore, sizing calculations were based on a total area of
1,77 acres, 1.59 acres of impervious area and 0.18 acres of disturbed pervious area.
StormShed software was used to model and size the infiltration gallery. Per the
recommendations of the geotechnical investigation (see appendices), an infiltration
rate of 20 inches per hour was used for design. In Stormshed, infiltration is modeled
as a rating curye. A steady rate of flow of 1.11 cfs was computed based on the
bottom area of the trench. The rate is calculated by multiplying the square footage
of the trench bottom by the infiltration rate in cubic feet second. (2,400 sf x (20
in/hr / 43,200)), Per the model, a total volume of 788 cubic feet is required to
provide storage for the 100 year storm (see model output in appendices), The
infiltration gallery will be 40 feet wide, 60 feet long and 2 feet deep. This provides a
total available volume of 1,584 cubic feet. See Appendix A-1 for model output and
calculations.
Conveyance:
Per the attached StormShed computations, the maximum 100 year flow for the
entire site (including the roof) is 1.57 cfs. The proposed storm drainage conveyance
pipes will be 72 inches in diameter and will have a minimum slope of 0.5%, Per
Manning's Equation, a pipe with that diameter and slope has a capacity of about 3
cfs. Therefore, all pipes have sufficient capacity to accommodate on-site flows as
they will be carrying flows from smaller areas.
1..2 EXISTING CONDITIONS
The project area is mostly vacant. The site slopes east toward Yelm Creek, the
existing building and existing stormwater facility. Slopes are generally flat varying
from 1 to 3olo. There are no significant trees or vegetation. The existing ground
cover is what has naturally grown in this area following the mass grading of the site
in 2004. The site is located to the west of the Yelm Creek. The site contains
associated wetlands, wetland buffers and 200' shoreline buffer of Yelm Creek. All
work being proposed by this phase of the project is being done outside all critical
areas.
1.3 INFILTRATIONRATES/SOILSREPORT
The Soil Conservation Service (SCS) Soil Survey of Thurston County classifies on-site
soils as Spanaway (110) series and NisquallV QÐ series.
Shea, Carr & Jewell, Inc.
April 2009
Creek Street Mixed Use - Christensen Commercial
Soil testing was performed on-site to establish the expected infiltration rates of thesoils and to evaluate slope stability (report located in appendices). According to thisreport, on-site soils have infiltration rates of 20 inches per hour.
Each stormwater facility has been sized by multiplying the bottom area of the
infiltration gallery by the infiltration rate of 20 in/hr. This infiltration capacity is therate that was entered into StormShed modeling software. See separate modelingoutput for each gallery infiltration rate.
L.4 WELLS AND SEPTIC SYSTEMS
No wells or septic systems are known to be on-site. The existing STEP tank systemfor the current building has been designed in conformance with the City of Yelm's
sewer system. The proposed infiltration facilities are not within 100 feet of anyadjacent parcels.
water and sewer services will be connected to the city of yelm systems.
1.5 FUEL TANKS
No fuel tanks are known to be on-site. A review of the Department of Ecology's
Leaking Underground Storage Tanks (LUST) list did not indicate any existing orabandoned fuel tanks on the project site.
1.6 SUB-BASIN DESCRIPTION
Stormwater from this development is contained on-site. No stormwater will be
conveyed or directed to adjacent properties.
There is no off-site drainage tributary to this site.
L.7 ANALYSIS OF lOO YEAR FLOOD
This project is adjacent to Yelm Creek. Yelm Creek does have a mapped 100-year
flood plain and a copy of the FEMA FIRM Map has been províded in the appendices.This project is not constructing any improvements within the 100 year mapped floodplain.
1.8. AESTHETIC CONSIDERATIONS FOR FACILITIES
All disturbed pervious area will be vegetated and landscaped. All above ground
stormwater facilities will be landscaped after construction is complete.
1.9 DOWNSTREAM ANALYSIS
All stormwater generated will be stored and infiltrated on-site, All retention facilities
have been designed to retain and infiltrate the 100-year storm event. Therefore,
downstream facilities will not be affected by this project,
1.10 COVENANTS, DEDTCATIONS, EASEMENTS
On-site drainage facilities will require routine maintenance. A draft maintenanceagreement between the owner and City is attached in the appendices that will allow
Shea, Carr & Jewell, Inc.
April20O9
Creek Street Mixed Use - Christensen Commercial
the City to access the facilities. The owner is responsible for performing regular
maintenance of the storm drainage facllities.
1.1I PROPERTY OWNER'S ASSOCIATION
The entire parcel is under a single ownersh¡p and will not require an association.
Shea, Carr & Jewell, Inc,
Aprll2009
Creek Street Mixed Use - Christensen Commercial
2.
2,1
EROSION CONTROL REPORT
coNsTRucTIoN SEQUENCE AND PROCEDURE
The proposed commercial development will include site grading and erosion control
measures designed to contain silt and soil within the project boundaries during
construction until permanent vegetation and site improvements are in place.
Erosion/sedimentation control shall be achieved by a combination of
structural/vegetative cover measures and construction practices tailored to fit the
site.
Best Management Practices (BMP's) will be employed to properly clear and grade the
site and to schedule construction activities. Before any construction begins onsite,
erosion control facilities shall first be installed. The planned construction sequence is
follows:
1. Schedule preconstruction conference with the City, contractor, project
engineer and construction staking surveyor.
2, Install rock construction entrance. use 4" to B" diameter quarry spalls with
12" minimum depth.
3. Install filter fabric fencing in the locations shown on the plans.
4, Provide inlet protection around existing catch basins.
5, Clear site (grubbing and rough grading).
6. Construct sediment trap.
7. Maintain equipment and water supply for dust control.
B. Designate an area for washing concrete trucks to control the runoff andeliminate entry in the storm drainage system.
9. Install underground utilities.
10. Provide inlet protection around all new catch basins.
ll.Maintain all erosion control facilities until the entire site is stabilized and silt
runoff ceases.
2.2. TRAPPING SEDIMENT
Filter fabric fencing will be installed to trap sediment before runoff exits the site. In
addition, inlet protection will be installed around all existing and new catch basins tofilter out sediment before runoff enters the storm system.
A stabilized construction entrance will be installed to prevent construction vehiclesfrom tracking soil onto roadways. If sediment is tracked off-site, it shall be swept or
Shea, Carr & Jewell, Inc,
November 2008 Page 6
Creek Street Mixed Use - Christensen Commercial
shoveled from paved surfaces on a daily basis, so that it is not washed onto existingcatch basins or other storm drainage facilities.
During the rainy season from November 1 through March 31, the contractor mustcover any disturbed areas greater than 5,000 sf in size if they will be unworked for
more than 12 hours. Mulch, sodding, or plastic covering shall be used to prevent
erosion in these areas.
2.3 PERMANENT EROSION CONTROL AND SITE RESTORATION
All disturbed areas will be paved with asphalt, covered with buildings, or tandscapedwith grass, shrubbery, or trees per the landscaping plans,
2.4 GEOTECHNICAL ANALYSIS AND REPORT
None of the storm drainage facilities are located near the top of a steep slope.
Therefore a geotechnical analysis for slope or soil stability was necessary.
2.5 INSPECTTON SEQUENCE
In addition to required Cíty inspections, the project engineer will inspect facilitiesrelated to stormwater treatment, erosion control, storage, and conveyance duringconstruction. At a minimum, the following items shall be inspected at the time
specified:
1. The erosíon control facilities shall be inspected before the start of clearing andgrading to ensure the following structures are in place:a. Construction Entranceb. Filter Fabric Fencec. Inlet protection of existing catch basins.2. The conveyance systems will be inspected after construction of the facilities,but before project completion to ensure the following items are in working
order:a. Pavement Drainageb. Catch Basinsc. Conveyance piping
3. The stormwater treatment and storage systems shall be inspected during andafter construction to ensure:a. The facility is constructed to design specifications and that protection
from sediments in place.4, The permanent site restoration measures shall be inspected after landscapingis completed.
A final inspection shall be performed to verify final grades, settings of controlstructures and all necessary information to complete the Engineer's ConstructionInspection Report Form. This form must be completed prior to final public works
construction approval.
2,6 CONTROL OF POTLUTANTS OTHER THAN SEDIMENTS
The contractor will be required to designate a washdown area for concrete trucks aswell as a temporary stockpile area for construction debris. Vehicle fueling, washing,or maintenance shall occur in designated areas only.
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November 2008 Page 7
Creek Street Mixed Use - Christensen Commercial
3. MAINTENANCE PLAN
3.1 REQUIRED MAINTENANCE
The following pages contain maintenance needs for most of the components that arepart of the project's drainage system, as well as for some components that theproject may not have. The checklist should be competed for all system components
on the following schedule:
M. Monthly from November through April
A. Once in late summer (preferably September).
S. After any major storm event (use 1" in 24 hours as a guideline) items markedttS" only.
Using photocopies of these pages, check off the problems investigated each time aninspection was performed, Add comments on problems found and actions taken.
Keep these "Checked" sheets in the files as they will be used to rite an annual report(due in May). Some items do not need to be looked at every item an inspection isdone. Use the suggested frequency at the left of each item as a guideline for theinspection,
The jurisdiction may be called for technical assistance. Please do not hesitate to call,
especially if it is unclear whether a particular situation may be a problem.
Shea, Carr & Jewell, Inc,
November 2008 Page 8
APPENDIX A-1 -
DRAINAGE CALCULATIONS
Page I of3
Appended on: Thursday, March 26,200910:06:00 AM
LPOOLCOMPUTE [North Basin Level Pool] SUMMARY using Puls, 24 hr Storm
Event
Start of live
Summary Report of all Detention Pond Data VOL(JM€
èluug,c¡¡
seô
\^/A'rg Fa €LeV.
Project Precips
BASLIST2
[North Basin
lNorth Basin
LSTEND
100-year prel Using ITYPEIA.RAC] As [00 year] 124.01
100-year postl Using ITYPEIA.RAC] As [00 year] Í24.01
0.0181
BasinID Event Peak Q
(cfs)
Peak T
lhrsl
Peak Vol
lac-cfl
Area
lacl Method/Loss Raintype
North Basin 100-
year Dre
100
vear 0.7443 8.01 0.2686 1.7753 SCS IYPEIA.RAC
North Basin 100- |
LeaL post I
I roo
I y.ut 1.573 8.01 0.s23 1.7753 SCS TYPEIA.RAC
BASLIST
[North Basin 10O-year pre] fNorth Basin 1O0-year post]
LSTEND
Record Id: North Basin 100-year pre
TYPEIA.RAC
10.00 min
1.7753 ac
file:/Al:\Projects\1290 Rick Ch¡istensen\1290.01 l06th Ave. Commerical-Retail Develop... 312612009
Record Id: North Basin 100-year post
Page2 of3
HYDLIST SUMMARY
[00 year out]
LSTEND
STORLIST
fNorth Basin Pond - 1O0-year Storm]
fi le ://Ì.,1 :\Proj ects\ I 290 Rick Chri stensen\ I 290. 0 1
Pervious CN Calc
Sub cn
1.7753 ac
Pervious itcd CN ( AMC 2
Pervious TC Calc
5.00 min
Pervious TC 5.00 min
Design Method SCS Rainfall type TYPElA.RAC
Hyd Intv 10.00 min Peakine Factor 484.00
Storm Duration 24.00 hrs Abstraction Coeff 0.20
Pervious Area 1.7753 ac 0.00 ac
Perryious CN 9s.89 0.00
Pervious TC 5.00 min 0.00 min
Pervious CN Calc
Description SubArea Sub cn
Pervious Landscape Area 0.1785 ac 77.00
Impervious Parkine Area 1.0829 ac 98.00
I Impe*ious gldg er.a 0.5139 ac 98.00
Pervious Composited CN (AMC 2)9s.8885
Penious TC Calc
Type ll Description Length ll Stope fc".ff-l[-vri*TT
sheet I t- o.oo ft-l[.r'z,I 5r lfgoo-'5.00 min
Pervious TC 5.00 min
Peak T (hrs eak Vol (ac-ft
l06th Ave. Commerical-Retail Develop... 3126/2009
Page 3 of3
LSTEND
Record Id: North Basin Pond - 100-year Storm
DISCHLIST
fNorth Basin 40x60 Gallery]
LSTEND
Record Id: North Basin 40x60 Gallery
Staee-Discharse Ratine Curve
Descrip: llPrototype Structure ffit o.roft
Start El. ll 348.00 ft Max El. ll 350.00 ft
348.00 0.00
348.10 1.1I
3s0.00 r.l I
Licensed to: Engenious Systems, Inc.
fi le ://1.,1 :\Proj ects\ 1 290 Rick Chri stensen\ I 2 90. 0 I l06th Ave. Commerical-Retail Develop... 3/26/2009
INFILTRATION SIZING - NORTH GALLERY
PROJECT: Creek Street Mixed Use - Christensen Commerclal
PROJECT NO.: 1290.01
TE: 4lI7
lnfiltration Pond Design:
40 feet wide
60 feet long
2 feet tall
TotalVolume Provided = 4,800 cf
TotalVolume Provided =
Minus Rock Volume (33%) 1,584 cf
For StormShed lnput, need the following information: Area = TotalVolume/Total Depth
Elevation Area Volume Volume Summary02400001 2400 2400 24002 2400 2400 4800
INFILTRATION RATING CURVE
PRoJECT: CREEK STREET MIXED usE - cHRrsrENsEN coMMERcTAL
PROJECT NO.: 1290,0L
,TE: 4lI7
Ftow=kiA=k(y/d)A
Jç = infiltration rate (in/hr)i= unity[ = gallery bottom area (square feet)
y = feet above high ground water elevation
6l = 3 feet (minimum distance to groundwater)
North Drainage Basin lnfiltration Gallery:
ft = 20 in/hr[ = 2,400 sfy=3ftd=3ft
Q = 1.11 cfs Flow from infilhation gallery. Use for outlet
control in StormShed Model.
Page I of3
Appended on: Friday, October 24,200811246:46 AM
LPOOLCOMPUTE [South Basin Level Pool] SUMMARY using Puls, 24hr Storm
Event
Start of live stora :344.5fit
V ocL/ /Ø €Summary Report of all Detention
Project Precips
Event Precip (inl
5 month - treamenl 1.28
2vr24fu 2.00
l0 year 3.00
I 00 year 4.00
Pond Data
Pc ,t.-r r)
p.r=G.
(ì e eì \./ A*n o^./
BASLIST2
[South Basin
[South Basin
LSTEND
1O0-year prel Using ITYPEIA.RAC] As [100 year] t24.0)100-year postl Using ITYPEIA.RAC] As [100 year] t24.01
0.3143 0.3333
0.3143 EIA.RAC
Basin 100-
BASLIST
[South Basin 1O0-year pre] [South Basin 1O0-year post]
LSTEND
Record Id: South Basin 100-year pre
TYPEIA.RAC
10.00 min
Pervious CN
file://C:\Documents and Settings\JimG\Desktop\Christensen Comm Pond Verfication.html 10/24/200g
Page 2 of 3
0.00 min
Pervious CN Calc
Pervious Composited CN (AMC 2
Pervious TC Calc
Pervious TC
Record Id: South Basin 100-year post
Desien Method SCS Rainfall tvne TYPEIA.RAC
Hvd Intv 10.00 min Peakins Factor 484.00
Storm Duration 24.00 hrs Abstraction Coeff 0.20
Pervious Area 0.7496 ac DCIA 0.00 ac
Pervious CN 91.60 DC CN 0.00
Pervious TC 5.00 min DC TC 0.00 min
Pervious CN Calc
Description SubArea Sub cn
Impervious Parking Area 0.3426 ac 98.00
Impervious Area Blde 0.1786 ac 98.00
Pervious Landscaping Area 0.2284 ac 77.00
Pervious Composited CN (AMC 2)9r.6014
Pervious TC Calc
Type ll Description ll Leneth ll Slope c*ff-_lt Mir.TTsJ ll ooo t"5.00 min
Pervious TC 5.00 min
HYDLIST SUMMARY
[00 year out]
LSTEND
HydID llPeak Q (cfsl Peak T (hrs)llPeak Vol (ac-ftl Cont Area lacì
I 00 year out 0.3333 7.s7 0.1926 0.7496
STORLIST
[South Infrlt Gallery - 1OO-year Storm]
file://C:\Documents and Settings\JimG\Desktop\Christensen Comm Pond Verfication.html 1012412008
Page 3 of3
LSTEND
Record Id: South Infilt Gallery - 100-year Storm
DISCHLIST
[South Basin Infiltration Gallery]
LSTEND
Record Id: South Basin Infiltration Gallery
5 Gallery Sizing for 10O-year and Bl
Type Node
Staee-Discharse Ratins Curve
344.51 0.3333
347.s0 0.3333
Licensed to: Shea, Carc &, Jewell Inc.
fìle://C:\Documents and Settings\JimG\Desktop\Christensen Comm Pond Verfication.html ly/24/200g
Page I of I
Appended on: Friday, November 2102008 llz2l:24 AM
South Basin 6-month storm Event Summarv
Record Id: South Basin 6-month storm
Hvd Vol (acft
8.0117
2 vr 241'r 8.01 l7
0.1373
All results based on storm duration of 24.0 hours. This is ok if all precipitations are appropriate for the
duration. If some design event precipitations are for different duration storms, those results are
Desien Method SCS Rainfall tvne TYPEIA.RAC
Hyd Intv 10.00 min Peakine Factor 484.00
Storm Duration 24.00 hrs Abstraction Coeff 0.20
Pervious Area 0.571 ac DCIA 0.00 ac
Pervious CN 89.60 DC CN 0.00
Pervious TC 5.00 min 0.00 min
Pervious CN Calc
Description t@ Sub cn
Pervioius Landscape Area t@ 77.00
Impervious Parkins Area l@ 98.00
Pervious Composited CN (AMC 2)89 60
Pervious TC Calc
rype ll oes."iption --_]l- L"rsrh-lt-Stñ;l Tc*rr ll--ivli..-TT
sheet I [qloft ll-o0%5.0 ll 0.00 in ll 5.00 min
Pervious TC 5.00 min
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fì le :/Atr :\Proj ects\ I 290 Rick Chri stensen\ 1 290. 0 I 106th Ave. Commerical-Retail Develop. .. 11121/2008
INFILTRATION TRENCH
PROJECT: Creek Street Mixed Use - Christensen Commercial
ECT NO.: 1290.01
DATE: LUz4l2OOg
lnfiltration Gallery Design:
6 feet wide
120 feet
3 feet tall
TotalVolume Provided = 648 ,cf (Assumes 30% void space in gallery rock)
Volume 1 foot below top = _ 492 cf Allows for 1 foot of freeboard
For StormNet lnput, need the following information: Area = TotalVolume/Total Depth
Elevation Area Volume Volume Summarv0162001 162 162 1622 162 162 3243 162 162 486
INFILTRATION RATING
PROIECT: creek street Mixed use - christensen commercial
ECT NO.: 1290.01
DATE: ttlz4tzÙO9
Ftow=kiA=k(y/d)A
Jç = infiltration rate (in/hr)j= unity{ = pond bottom area (square feet)
y = feet above high ground water elevation
çl = 3 feet (minimum distance to groundwater)
Drainage Basin #1 lnfiltration Gallery:
Q = 0.33 cfs Flow from infiltratíon trench. Use for ouflet
control in StormShed Model.
ft = 20 in/hrfi= 720 sfy=3ftd=3ft
Page I of I
Appended on: Wednesday, April 22, 2009 10:55:09 AM
EX POND AFTER DEVELOPMENT Event Summary
\-TPE¿\-rI4€MT ÞeslRecord Id: EX POND AFTER DEVELOPMENî
Hvd Vol lacft
0.1475
0.7383
1.1325 0.3837
0.s2t9
All results based oÀs
duration. If some
luration of 24.0 hours. This is ok if all precipitations are appropriate for the
ign event precipitations are for different duration storms, those results are
TYPElA.RAC
10.00 min
bstraction Coeff
Pervious TC 0.00 min 0.00 min
Pervious CN Calc
Pervious Composited CN (AMC 2
l.bt *c
AF.FER
-TÐ Nl e,
Licensed to: Engenious Systems, Inc.
A¿e? To g:}- Po¡-t Þ
P-en¡ ò u r r,r 5 +-2:E7. Pô q TÈ_l)
w c>ALLæ-tes.
file ://1.,1 :\Proj ects\ I 290 Rick Chri stensen\ I 290. 0 I l06th Ave. Commerical-Retail Develop... 412212009
Page 1 of I
Appended on: Wednesday, April 22,200910:16:33 AM
EXISTING POND Event Summary BASED oM Jt z^¿ A PeFaz} ktçzø*
Record Id: EXISTING POND
Peak T (hrs
0.1916
8.01 l7 0.4195
8.01 l7
1 .1 534
I results based on storm duration of 24.0 hours. This is ok if all precipitations are appropriate forire
rrm duration. If some design event precipitations are for different duration storms, ihosé results are
TYPElA.RAC
10.00 min kins Factor
traction Coeff
Pervious CN Calc
SubArea
Impervious Area
Pervious Composited CN (AMC 2
Licensed to: Engenious Systems, Inc.
fi le :/AI :\Proj ects\ I 290 Rick Chri stensen\ I 290. 0 I 106th Ave. Commerical-Retail Develop... 412212009