Prelim Drainage Facility Calcs
, ~:/\
PO Box 3485
lacey, Washington
98509-3485
677 Woodland Square Lp SE
Lacey, Washington 98503
Lacey (360) 493-6002
Fax (360) 493-2476
Yelm (360) 458-2487
s. Chamberlain & Associates, Inc.
June 10, 1996
George Barry
Five Corners, LLC
518 Flora Vista
OlympIa, W A 98506
RE. Creek Place Commercial Plat, Y elm, Washington
Preliminary Drainage Facility Calculations
SCA #96010
Dear George
The followmg desIgn calculatIOns were performed to verIfy that the proposed
storm water area proVIded on the sIte plan IS adequate to contam, treat and
mfiltrate all storm water run-off from the proposed Creek Place development.
Please mclude these calculatIOns wIth your sIte plan submIttal package
Soils Analysis
SCA performed four SOlI test logs wIthm the. project SIte boundary All soil test
pIts we observed were conSIstent WIth the SCS Soil Survey of Thurston County
Spanaway Stony Sandy Loam soil classIficatIOn. A copy of the SCS soil
classIficatIOn and our soil logs are attached. In addItIOn SCA staff performed two
SOlI mfiltratIOn tests at an approXImate depth of five feet. Both infiltratIon tests
resulted m a 72 mch per hour average mfiltratIOn rate However, our desIgn
mfiltratIOn rate for modehng of the storm facility was ten mches per hour
Stormwater Facility
Stormwater Treatment
Stormwater run-off from the proposed commercIal project will sheet flow mto area
catch basms and be conveyed to a 225 foot long by five foot WIde bio-fIltratIOn
swale The bIO-filtratIOn swale will provIde stormwater treatment for a SIX month
frequency storm event. In addItIOn, the bIO-filtratIOn swale was SIzed to convey a
100 year storm event. The bIO-filtratIOn swale was SIzed per Chapter III-6 of the
WSDOE Stormwater Manual. ReqUIrements and cntena outlined m the Storm-
water Manual were mput mto the "Flowmaster" hydrology program whIch
resulted m the five foot WIde swale sIzmg Please see the followmg desIgn
calculatIOns for a detailed analysIs of cntena used for the bIO-filtratIOn swale
deSIgn.
. BIO-filtratIOn Swale DeSIgn
Ref. Chapter III-6, "BIO-filtratIOn Swales and VegetatIve Filter Stnps",
WSDOE Stormwater Manual.
ENGINEERING
PLANNING
SURVEYING
.
.
- . '*"-'~-''''-''~''-'-' ,
· ~:9'\
George Barry
June 10, 1996
Page 2
DesIgn Cntena
1 6 Month DesIgn Storm flow rate = 1 16 cfs
2 Swale MaxImum Flow VelocIty - 1 5 fps
3 TrapezoIdal Swale Cross SectIOn
4 MmImum of 200 If of swale
5 Swale mmImum bottom slope = 1%
6 Swale sIde slope = 3 1
7 DesIgn flow depth = 4 mches
8 Mannmgs 'n' = 0 07 (Dense grass up to 6 mches tall)
Usmg "Flowmaster Hydrology Software, a 225 foot long BIO-filtratIOn Swale wIth
a 5 foot bottom wIdth will proVIde treatment for the sIte's Impervious surface
stormwater runoff. See the attached "Flowmaster" data output for swale flow
depth and velocIty
Stormwater Storage
Stormwater run-off from the project sIte will flow through the bIO-filtratIOn swale
and dIscharge mto a retentIon pond facility The retentIOn pond will have a
bottom elevatIOn of 342 feet whIch will proVIde a 3 foot separatIOn above the
known seasonal hIgh water encountered at elevatIOn 339 The retentIon pond will
be approxImately 6 feet deep and will store 19,797 CUbIC feet of storage at an
elevatIOn of 347 feet. Usmg a desIgn mfiltratIOn rate of ten mches per hour we
used "Waterworks" hydrology software to model the hundred year desIgn storm to
determme the desIgn storm peak water surface elevatIOn. Our modelmg resulted
m a peak storm elevatIOn of 346 9 feet whIch results m 19,215 cf of reqUIred
stormwater storage Therefore, the retentIOn facility has the capacIty to store a
100 year deSIgn storm.
. Stormwater RetentIOn Pond DeSIgn
The followmg retentIOn pond stage storage relatIOnshIp and 10"!hr deSIgn
mfiltratIOn rate resulted m a 100 year peak water surface elevatIOn of 346.9 ft.
RetentIOn Pond/Swale Stage Storage Table
Pond Bottom
6 Month Storm
ElevatIon
3420
3430
344.0
3450
3460
3470
3480
Volume
o cf
1,537 cf
5,341 cf*
8,319 cf*
11,802 cf*
19,797 cf*
DeSIgn Storm
l' Freeboard
..
*Indicates total storage volume mcluding blOfiltratlOn swale volume of 5625 cf.
ENGINEERING
PLANNING
.
SURVEYING
.
, ~~)\
George Barry
June 10, 1996
Page 3
Total pond storage capacIty of 19,797 cf exceeds the 100 year desIgn storm volume
of 19,214 cf usmg a conservatIve 10"lhr InfiltratIOn rate. See attached
"Waterworks" output data for modehng results.
Summary
Based on our modehng and analysIs of the proposed storm pond and bIO-filtratIOn
swale, the sIte plan does allow sufficIent area to contam all storm water run-off
from the commercIal project. Please see the attached desIgn calculatIOns and
modehng output for df;ltailed results.
Smcerely,
S. CHAMBERLAIN & ASSOCIATES, INC.
aitJ ~'
Robert W Balmelh
Project Engmeer
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6/6/96
2:55:26 pm
S Chamberlain & Assoc. Inc.
CREEK PLACE (96010)
REVISED SITE POND SIZING
INCLUDES ALL ROOF AREA
page
1
BASIN SUMMARY
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BASIN ID: 100YR
SCS METHODOLOGY
TOTAL AREA.......:
RAINFALL TyPE....:
PRECIPITATION....:
TIME INTERVAL....:
NAME: Q100 YR STORM EVENT
3.60 Acres BASEFLOWS: 0.00 cfs
TYPE1A PERV
6.15 inches AREA. . : 0.60 Acres
10.00 min eN....: 78.00
TC. . . . : 5.00 min
ABSTRACTION COEFF: 0.20
TcReach - Sheet L: 480.00 ns:O.1300 p2yr: 2.80 5:0.0200
impTcReach - Sheet L: 87.00 ns:0.0110 p2yr: 2.80 s:0.0200
impTcReach - Channel L: 440.00 kc:42.00 s:0.0100
impTcReach - Shallow L: 200.00 ks:11.00 s:0.0100
PEAK RATE: 4.68 cfs VOL: 1.61 Ac-ft TIME: 500 min
IMP
3.00 Acres
98.00
5.94 min
BASIN ID: 10YR NAME: Q10 YR STORM EVENT
SCS METHODOLOGY
TOTAL AREA.......: 3.60 Acres BASEFLOWS: 0.00 cfs
RAINFALL TyPE....: TYPE1A PERV IMP
PRECIPITATION....: 4.35 inches AREA. . : 0.60 Acres 3.00 Acres
TIME INTERVAL. . . . : 10.00 min CN . . . . : 78.00 98.00
TC. . . . : 5.00 min 5.94 min
ABSTRACTION COEFF: 0.20
TcReach - Sheet L: 480.00 ns:0.1300 p2yr: 2.80 5:0.0200
impTcReach - Sheet L: 87.00 ns:0.0110 p2yr: 2.80 s:0.0200
impTcReach - Channel L: 440.00 kc:42.00 s:0.0100
impTcReach - Shallow L: 200.00 ks:11.00 s:0.0100
PEAK RATE: 3.21 cfs VOL: 1.10 Ac-ft TIME: 500 min
BASIN ID: 6MONTH
SCS METHODOLOGY
TOTAL AREA.......:
RAINFALL TyPE....:
PRECIPITATION....:
TIME INTERVAL....:
NAME: Q6 MONTH STORM EVENT
3.60 Acres BASEFLOWS: 0.00 cfs
TYPE1A PERV
1. 79 inches AREA. . : 0.60 Acres
10.00 min CN . . . . : 78.00
TC. . . . : 5.00 min
ABSTRACTION COEFF: 0.20
TcReach - Sheet L: 480.00 ns:0.1300 p2yr: 2.80 s:0.0200
impTcReach - Sheet L: 87.00 ns:0.0110 p2yr: 2.80 s:0.0200
impTcReach - Channel L: 440.00 kc:42.00 s:0.0100
impTcReach - Shallow L: 200.00 ks:11.00 s:0.0100
PEAK RATE: 1.16 cfs VOL: 0.40 Ac-ft TIME: 500 min
IMP
3.00 Acres
98.00
5.94 min
6/6/96
2:55:26 pm
REVISED SITE POND SIZING
INCLUDES ALL ROOF AREA
S Chamberlain & Assoc. Inc.
CREEK PLACE (96010)
page
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HYD
NUM
PEAK
RUNOFF
RATE
cfs
TIME
OF
PEAK
min.
HYDROGRAPH SUMMARY
VOLUME
OF
HYDRO
cf\AcFt
contrib
Area
Acres
---------------------------------------------
---------------------------------------------
1
2
3
0.437
0.847
1. 057
560
610
650
17320 cf
48056 cf
70323 cf
3.60
3.60
3.60
6/6/96
2:55:27 pm
S Chamberlain & Assoc. Inc.
CREEK PLACE (96010)
page
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REVISED SITE POND SIZING
INCLUDES ALL ROOF AREA
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STAGE STORAGE TABLE
CUSTOM STORAGE ID No. ST04
Description: RETENTION POND STORAGE
STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE---->
eft) ---cf--- --Ac-Ft- eft) ---cf--- --Ac-Ft- eft) ---cf--- --Ac-Ft- eft) ---cf--- --Ac-Ft-
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
342.00 0.0000 0.0000 343.60 3939 0.0904 345.20 9016 0.2070 346.80 18198 0.4178
342.10 153.70 0.0035 343.70 4340 0.0996 345.30 9364 0.2150 346.90 18998 0.4361
342.20 307.40 0.0071 343.80 4740 0.1088 345.40 9712 0.2230 347.00 19797 0.4545
342.30 461.10 o 0106 343.90 5141 0.1180 345.50 10061 0.2310 347.10 20303 0.4661
342.40 614 80 o 0141 344.00 5541 0.1272 345.60 10409 0.2390 347.20 20810 0.4m
342.50 768 50 o 0176 344.10 5819 O. 1336 345.70 10757 0.2469 347.30 21316 0.4894
342.60 922 20 o 0212 344.20 6097 0.1400 345.80 11105 0.2549 347.40 21823 0.5010
342.70 1076 o 0247 344.30 6374 o. 1463 345.90 11454 0.2629 347.50 22329 o 5126
342.80 1230 0.0282 344.40 6652 0.1527 346.00 11802 0.2709 347.60 22835 0.5242
342.90 1383 0.0318 344.50 6930 0.1591 346.10 12602 0.2893 347.70 23342 0.5359
343 00 1537 0.0353 344.60 7208 0.1655 346.20 13401 0.3076 347.80 23848 0.5475
343 10 1937 0.0445 344.70 7486 0.1718 346.30 14201 0.3260 347.90 24355 0.5591
343 20 2338 0.0537 344.80 7763 0.1782 346.40 15000 0.3444 348.00 24861 0.5707
343.30 2738 0.0629 344.90 8041 O. 1846 346.50 15800 0.3627
343 40 3139 0.0721 345 00 8319 0.1910 346.60 16599 0.3811
343 50 3539 0.0812 345.10 8667 0.1990 346.70 17399 0.3994
6/6/96
2:55:27 pm
S Chamberlain & Assoc. Inc.
CREEK PLACE (96010)
page
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REVISED SITE POND SIZING
INCLUDES ALL ROOF AREA
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STAGE DISCHARGE TABLE
DISCHARGE LIST ID No. DIS4
Description: REVISED POND DISCHARGE RATE
STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE--->
eft) -- -cfs-- ------- eft) ---cfs-- ------- eft) ---cfs-- ------- eft) ---cfs-- -------
--------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------------------------------
342.00 o 2900 343.60 0.5040 345.20 0.7540 346.80 1 .0340
342.10 o 3030 343 70 0.5180 345.30 0.7710 346.90 1.0520
342.20 0.3160 343 80 0.5320 345.40 0.7880 347.00 1 .0700
342.30 o 3290 343 90 0.5460 345.50 0.8050 347.10 1.0700
342 40 0.3420 344 00 o 5600 345.60 0.8220 347 20 1 .0700
342.50 o 3550 344 10 0.5760 345.70 0.8390 347.30 1 .0700
342.60 0.3680 344.20 0.5920 345.80 0.8560 347.40 1.0700
342.70 0.3810 344.30 o 6080 345.90 0.8730 347 50 1 .0700
342.80 0.3940 344.40 0.6240 346.00 0.8900 347 60 1 .0700
342 90 0.4070 344.50 0.6400 346.10 0.9080 347 70 1.0700
343.00 0.4200 344.60 0.6560 346.20 0.9260 347.80 1.0700
343. 1 0 0.4340 344 70 0.6720 346.30 0.9440 347.90 1 .0700
343.20 0.4480 344 80 o 6880 346.40 0.9620 348.00 1.0700
343 30 0.4620 344.90 0.7040 346.50 0.9800
343 40 0.4760 345.00 o 7200 346.60 0.9980
343 50 0.4900 345 10 o 7370 346.70 1.0160
6/6/96
2:55:28 pm
S Chamberlain & Assoc. Inc.
CREEK PLACE (96010)
page
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REVISED SITE POND SIZING
INCLUDES ALL ROOF AREA
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LEVEL POOL TABLE SUMMARY
MATCH INFL~ -STO- -DIS- <-PEAK-> STORAGE
<--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf)
-----------------------------------------------------------------------------
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Q6 MONTH STORM ...............
Q10 YR STORM ......
Q100 YR STORM ...... ..
0.00 1.16 ST04 DIS4
0.00 3.21 ST04 DIS4
0.00 4.68 ST04 DIS4
343.12 1 2019.62 cf
345.75 2 10925.69 cf
346.93 3 19214.52 cf
Thurston County Washington
summer irrigation is needed for lawn grasses, shrubs,
vines, shade trees and ornamental trees Mulch,
fertilizer, and irrigation are needed to establish lawn
grasses and other small-seeded plants Topsoil can be
stockpiled and used to reclaim areas disturbed during
construction
The main limitation affecting septic tank absorption
fields is a poor filterrng capacIty in the substratum If the
density of housing is moderate or high, community
sewage systems are needed to prevent the
contamination of water supplies caused by seepage
from onsite sewage disposal systems The slope
hinders the installation of the absorption fields.
Absorption lines should be installed on the contour
Douglas-fir is the main woodland species on this unit.
Among the trees of limited extent are Oregon white oak,
lodgepole pine, and red alder Douglas-fir and Scotch
pine are grown on Christmas tree plantations On the
basis of a 1 OO-year site curve, the mean site index for
Douglas-fir is 140 On the basis of a 50-year site curve,
it is 108 The highest average growth rate of an
unmanaged, even-aged stand of Douglas-fir is 145
cubic feet per acre per year at 65 years of age
This soil is suited to year-round logging Unsurfaced
roads and skid trails are slippery when wet. Logging
roads require suitable surfacing material for year-round
use Rounded pebbles and cobbles for road
construction are readily available on this unit.
Disturbance of the protective layer of duff can be
minimized by the careful use of wheeled and tracked
equipment.
Seedling establishment and seedling mortality are the
main concerns In the production of timber Reforestation
can be accomplished by planting Douglas-fir seedlings.
If the stand includes seed trees, natural reforestation of
cutover areas by Oregon white oak and lodgepole pine
occurs infrequently Droughtiness in the surface layer
reduces the seedling survival rate When openings are
made in the canopy, invading brushy plants can delay
the establishment of planted Douglas-fir seedlings
Common forest understory plants are cascade
Oregon-grape, salal, western brackenfern, western
Swordfern, Indian plum, and Scotch-broom
This map unit is in capability subclass IVs.
112-Spanaway stony sandy loam, 0 to 3 percent
slopes. This very deep, somewhat excessively drained
soil is on terraces It formed in glacial outwash and
volcanic ash The native vegetation is mainly grasses,
ferns, and a few conifers Elevation is 200 to 400 feet.
The average annual precipitation is 40 to 50 inches, the
average annual air temperature is about 51 degrees F,
91
and the average frost-free period is 150 to 200 days
Typically, the surface layer is black stony sandy loam
about 16 Inches thick The subsoil is very dark brown
gravelly sandy loam about 6 inches thick The
substratum to a depth of 60 inches or more is grayish
brown extremely gravelly sand
Included in this unit are small areas of Alderwood
soils on till plains, Baldhill soils on terminal moraines,
and Everett Indianola, and Nisqually soils on terraces.
Also included are small areas of Spanaway soils that
have a gravelly sandy loam surface layer and small
areas of Spanaway stony sandy loam that have slopes
of 3 to 15 percent. Included areas make up about 15
percent of the total acreage
Permeability is moderately rapid in the subsoil of the
Spanaway soil and very rapid in the substratum
Available water capacity is low Effective rooting depth
is 60 inches or more Runoff is slow, and the hazard of
water erosion is slight.
This unit is used mainly for hayland, pasture, or
homesites The main limitations affecting hay and
pasture are the low available water capacity and the
stones on the surface Proper grazing practices, weed
control, and fertilizer are needed to ensure maximum
quality of forage Rotation grazing helps to maintain the
quality of the forage Because of the surface stones.
spreading animal manure, mowing, and seeding are
difficult. In summer, irrigation is needed for maximum
production of most forage crops Sprinkler irrigation is
the best method of applying water The amount of water
applied should be sufficient to wet the root zone but
small enough to minimize the leaching of plant
nutrients
This unit is well suited to homesites Pebbles,
cobbles, and stones should be removed, particularly in
areas used for lawns In summer, irrigation is needed
for lawn grasses, shrubs, vines, shade trees, and
ornamental trees Mulch, fertilizer, and irrigation are
needed to establish lawn grasses and other small-
seeded plants Cutbanks are not stable and are subject
to sloughing
The main limitation affecting septic tank absorption
fields is a poor filtering capacity in the substratum If the
density of housing is moderate or high, community
sewage systems are needed to prevent the
contamination of water supplies caused by seepage
from onsite sewage disposal systems.
This map unit is in capability subclass IVs
113-Spanaway stony sandy loam, 3 to 15 percent
slopes. This very deep, somewhat excessively drained
soil is on terraces It formed in glacial outwash and
.__--..---.-:---n-
Pro\ec' Loca,\on
scs MAP ~UMa(R 25
(112) SPANAWAY S10NY s~NOY LO~~
o - 3% SLOPES
\
SCS SO\L MAP
CREEK PLACE COMMERCIAL PLAT
ITJ
~
Creek Street Retail
Date
On-Site Soils Analysis
January 18, 1995
Soils Logged By'
Robert W Balmelli, P.E
S Chamberlain & AssocIates
Applicant:
George Berry
518 FloravIsta Road NE
Olympia, W A 98506
SIte DescrIption.
Short Plat at 5 Corners, Yelm, WA
Soil Logs:
Depth
o - 22"
22" - 26"
26" - 59"
59" - 85"
86" - 93"
Depth
0- 19"
19" - 80 "
Depth
0- 24"
24" - 42"
42" - 81"
Test Hole #1
Texture and Color
Black very gravelly sandy loam
Gravel
Very gravelly loamy sand with cobbles up to 6" m diameter
Gravelly coarse sand wIth some cobbles
Gravel
Fme roots to 30"
Coarse roots to 80"
Test Hole #2
Texture and Color
Black very gravelly sandy loam
Very gravelly medium sand with cobbles up to 10"
m chameter
Fme roots to 22"
Test Hole #3
Texture and Color
Black very gravelly sandy loam
YellowIsh brown very gravelly loamy mechum sand
Gray very gravelly medium sand with cobbles ranging
from 2-20" m chameter
Fine roots to 42"
Coarse roots to 60"
Mottling
None
None
None
None
Water at 93"
Mottling
None
None
Mottling
None
None
None
S. Chamberlain & Associates, Inc.
January 1996
Page 1 of2
Creek Street Retail
Test Hole #4
Depth
0- 25"
25" . 83"
Texture and Color
Black very gravelly sandy loam
Very gravelly medium sandy loam wIth cobbles
Fine roots to 26"
Coarse roots to 70"
Mottling
None
None
(c:\data\6010 118.log)
S. Chamberlain & Associates, Inc.
January 1996
Page 2 of 2
CREEK PLACE
DOUBLE RING INFIL TROMETER TEST RESULTS
SCA #9601 0
I INFILTRATION RESULTS
Test Pit #
Start (Min) Stop (Min) Elapsed Time Total Inches Infiltration Rate
(Min) Drop (In/Hr)
8 58 907 9 12" 80
9 15 926 1 1 12" 65
Weather Conditions Sunny
Outside Temperature 70 degrees
Test Performed By Brad Shea
Test Holes Dug By Backhoe
(c:\data\60 10611 dtr)