Storm Drainage
Storm Drainage
Analysis and Report
#97018
Site Location
1208 Yelm Ave. E.
Prepared For
Bonnie Tasche
POBox 318
Yelm, WA 98597
(360) 458-3341
Prepared By.
SKILLlNGS-CONNOLL Y, INC
Consulting Engineers
5016 Lacey Boulevard S E
Lacey, Washington 98503
(360) 491-3399
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TABLE OF CONTENTS
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SECTION
PAGE
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1 Proposed Project Description
2 EXisting Conditions
3 Infiltration Rates / Soils Report
4 Wells and Septic Systems
5 Fuel Tanks
6 Basin Description and Facility Sizing
7 Analysis of 100- Yr Flood
8 Aesthetic Considerations for Facilities
9 Downstream Analysis
10 Covenants, Dedications, Easements
11 Property Owners Articles of Incorporation
12 Erosion Control
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APPENDICES
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A. Project Maps
Vicimty Map
Soils Map
USGS Regional Topography
Basin Map
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B Calculations & Computer Analysis
Facility Sizing
Waterworks Computer Modeling
FaCIlity Summary
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C. Supporting Documentation
SOils Data
SCS and Thurston County SBUH Input Data
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SKILLlNGS-CONNOLL Y INC.
Consulting Engineers
Bonnie Tasche
Storm Drainage AnalYSIS & ReDort
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SECTION 1 Proposed Project Description
The Bonnie Tasche site is located on the east side of Yelm Ave in the City of Yelm A new
building addition, 40 X 30 ft in size is proposed in addition to rebuilding the existing fire damaged
building Included with this building, 18 parking stalls and one handicapped accessible parking
stall will be added
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The property is located in Section 30, Township 17N, Range 2E W M
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Increase in stormwater runoff resulting from the addition of paved surfaces will be mitigated by
two infiltration basins sized to infiltrate 100% of the 100-yr, 24-hr design storm
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After collection from the pavement and gravel, runoff will be directed over grass filter strip to a
retention basin where it will then be infiltrated into the ground
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Facility sizing and design calculations are in Appendix B of this report.
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SECTION 2 EXISTING CONDITIONS
The total site is approximately 1 8 acres of which .29 acres will be converted into impervious and
the rest will remain in it original state The existing site has a gravel driveway and a burnt out
building that will be removed during construction The areas surrounding the building other than
the driveways are vegetated with grass
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To the east of the site there is a lawn that will infiltrate any water that will enter the adjacent
property To the north of the project a grass field is sloping away from the site and will not
contribute to the stormwater on site The existing gravel parking area and roadway slopes to the
ditch adjacent to Yelm Ave
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There is no well defined downstream drainage courses It is evident in the existing condition that
il storm runoff percolates rapidly and none leaves the site
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'1 SECTION 3 INFIL TRA TION RA TE / SOILS REPORT
LJ Site soils are identified by the Soil Conservation Service Soil Survey of Thurston County,
Washington as a Spanaway gravely sandy loam, a Type 'B' soil This soil is characterized as
II very deep, somewhat excessively drained and formed on terraces
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An investigation of the site soils was performed by Skillings-Connolly, Inc and in essence
verifies the presence of the Type 'B' gravely sandy loam soil for the site
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Infiltration tests were performed in the vicinity of the proposed basins The SOils were found to
be dark brown to gray brown, very gravely, medium to coarse sand The soil was very
consistent throughout the three infiltration test sites Therefore, all infiltration surfaces can
safely be assumed to exhibit the characteristics descnbed
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Upon examining the test hole it was determined that the SOils on site Will have a Infiltration rate In
excess of 30 in/hr A conservative infiltration rate of 20 in/hr will be used for design to include a
factor of safety for possible Siltation of the drainage baSin's bottom over time
SKILLlNGS-CONNOLL Y INC.
Consulting Engineers
Bonnie Tasche
Storm Drainage Analysis & ReDort
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il SECTION 4 WELL AND SEPTIC SYSTEM
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approximately 50' away from the proposed drainage basin
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SECTION 5 FUEL TANKS
There are no known underground storage tanks in the immediate area
SECTION 6 BASIN DESCRIPTIONS AND FACILITY SIZING
The drainage basins were sized and analyzed using the Department of Ecology's guidelines
Water Works, a drainage design software, was used to size and analyze the design As
previously described, conservative infiltration rates were used for the design calculations
Please see the calculations in Appendix B section of this report.
Local topography and the surrounding roadways preclude any off-site runoff contributions The
on-site area can be broken into two sub-basins for treatment and retention The north basin
includes a gravel overflow parking area and an infiltration basin located north of the overflow
parking The south basin will include a paved parking lot and an infiltration basin located west of
the paved parking lot.
The stormwater from the north basin will flow over 730 square feet of grass filter strip for a
minimum length of 15' which exceeds the DOE requirement of 200 square feet (see sheet
"biofiltration treatment" in Appendix B) After treatment of the stormwater a drainage basin will
be used to infiltrate the water into the ground The north drainage basin is 2 0' deep, by 40'
long, by 10' wide, with side slopes of 4 horizontal to 1 vertical The required volume for the 100-
yr, 24-hr storm event is calculated to be 209 cubic feet. This volume is exceeded by the basin
design volume of 616 cubic feet. During the 100-yr, 24-hr design event the level of the water is
expected to be less than 0 33' in the north drainage basin One and one half feet of freeboard is
supplied in the design of the drainage basin to provide extra volume over the 100-yr, 24-hr storm
event.
The stormwater from the south basin will flow over a 852 square feet of grass filter strip for a
minimum distance of 11' which exceeds the DOE requirement of 200 square feet (see sheet
"biofiltration treatment" in Appendix B) After treatment of the stormwater, an infiltration basin
Will be used to infiltrate the water into the ground The south drainage basin is 1 5' deep, by 20'
wide, by 20' long, with side slopes of 6 horizontal to 1 vertical The required volume for the 100-
yr, 24-hr storm event is calculated to be 262 cubiC feet which is exceeded by the baSin design
volume of 356 cubic feet. During the 100-yr, 24-hr design event the level of the water IS
expected to be less than 0 37' in the south drainage basin A foot of freeboard is supplied In the
design of the drainage basin to provide extra volume over the 100-yr, 24-hr storm event.
Because of the high permeability of the site soils, it is anticipated that there will be no post-
development runoff from the site
SKILLlNGS-CONNOLL Y INC.
Consulting Engineers
2
Bonnie Tasche
Storm Drainage Analysis & Report
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Il SECTION 7 ANAL YSIS OF THE 100-YR FLOOD
U The site is not subject to flooding during a 100-yr, 24-hr storm event, nor will development of the
site contribute to flooding on downstream property
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SECTION 8 AESTHETIC CONSIDERA TIONS FOR FACILITIES
The south drainage basin will feature gentle side slopes at 6 horizontal to 1 vertical maximum
and will take the shape of the existing lawn area. The pond areas will be replanted after
construction as needed The north drainage basin will have side sloped of 4 horizontal to 1
vertical and will be replanted with grass to blend into the surrounding landscape
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SECTION 9 DOWNSTREAM ANAL YSIS
A downstream analysis will not be necessary for this site because of the high probability of
infiltrating 100% of the 100-yr, 24-hr event.
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SECTION 10 COVENANTS, DEDICA TIONS, EASEMENTS
The storm management facility for this site will remain privately owned and maintained A
maintenance agreement should be executed to ensure future maintenance of the facilities
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SECTION 11
Not Applicable
PROPERTY OWNERS ARTICLES OF INCORPORA TION
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SECTION 12 EROSION CONTROL
Erosion control features are shown on the construction plans If properly administered, the
erosion control features shown should prove to be sufficient in preventing sedimentation The
site is relatively flat, possesses extremelY porous soils and will remain vegetated along the
perimeters while grading activity occurs
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SKlLLlNGS-CONNOLL Y, INC.
Consulting Engineers
3
Bonnie Tasche
Storm Drainage Analysis & Report
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APPENDIX A
Project Maps
VicinIty Map
SOIls Map
USGS Regional Topography
Basin Map
SKILLlNGS-CONNOLL Y, INC.
Consulting Engineers
Bonnie Tasche
Storm Drainage Analysis & ReDort
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CoNSulTiNG ENGiNEERS
TITLE
USGS REGIONAL TOPOGRAPHY
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SkilliNGs ' CoNNOlly INc.
CoNSulTiNG ENGiNEERS
TITLE
SCS SOILS MAP
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APPENDIX B
Calculations & Computer Modeling
FacIlity SIzing
Waterworks Computer Modeling
FacIlity Summary
SKILLlNGS-CONNOLL Y, INC.
Consulting Engineers
Bonnie Tasche
Storm Drainage AnalysIs & Report
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CONsuLTiNG ENGiNEERS
PO Box 5080
LAuy, W. 98509-5080
~60/491-n99
FAX }60/491-~857
PrOject Name: BONNIE- rASCI-IE
Project No.. 97018 - E,X I
Date: /2/2..4-/ q 7
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Sheet:
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1."1 SkiLLiNGs" CONNOLLy INC.
CONsuLTiNG ENGiNEERS
PO Box 5080
'-'ny, WA 98509-5080
}60/491-H99
FAX }60/491-}857
PrOject Name: BONNIE r/7SCfIE
Project No Cj 7018 - E,X I
Date: /~/z4-l9 7 By' L C.5
Sheet: B/OPIL TRfinoN T'R.EfiT/'VIENT Page ~ of ~
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BIOFILT/C/9TIO/V OF RUNOFF PER. OQ.6.
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NORTH B/15/N
AND
SOUTH B,I9SIN
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Trapezoidal Channel Analysis & Design
Open Channel - Uniform flow
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Worksheet Name Bonnie Tasche
Comment
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~ Given Input Data
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Bottom Width
Left Side Slope
Right Side Slope.
Manning's n
Channel Slope
Discharge.
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Computed Results
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Depth
Velocity
Flow Area
Flow Top Width
Wetted Perimeter
Critical Depth
Critical Slope
Froude Number
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45 00 ft
3 00 1 (H V)
3 00 1 (H V)
o 070
o 0200 ft/ft
o 05 cfs
o 00 ft
o 13 fps
o 39 sf
45 05 ft
45 06 ft
o 00 ft
o 4765 ft/ft
o 24 (flow is Subcritical)
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Open Channel Flow Module, Version 3 11 (c) 1990
Haestad Methods, Inc * 37 Brookside Rd * Waterbury, Ct 06708
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INFIL TRA TION RATES
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Sanaway soils hydrologic group B
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20 m/hr was use as a conservatIve mfiltratIOn rate
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NORTH AND SOUTH RETENTION BASINS
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Where mfiltratIOn rate
-4
f= mfiltratIOn rate = 20 m/hr = 463 x 10 ft/s
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h = height of water
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InfiltratIOn Rates
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Basin Elevation h i A (sf) Q (cfs)
North 955 0 - 400 0
965 1 0 1.33 864 053
975 20 1 66 1456 1 12
South 975 0 - 400 0
985 1 0 1.33 1024 063
990 1 5 1 5 1444 100
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2 7 2 pm
Skillings Connolly, Inc
#97018-EX1
12/24/97
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BONNIE TASCHE
page
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BASIN SUMMARY
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BASIN ID S-100YR NAME SOUTH BASIN 100 YR EVENT
SBUH METHODOLOGY
TOTAL AREA o 27 Acres BASEFLOWS o 00 cfs
RAINFALL TYPE TYPE1A PERV IMP
PRECIPITATION 6 15 inches AREA 0 17 Acres o 10 Acres
TIME INTERVAL 10 00 min CN 80 00 98 00
TC 5 00 mln 5 00 min
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NAME NORTH BASIN 100 YR EVENT
BASIN ID N-100YR
SBUH METHODOLOGY
TOTAL AREA .
RAINFALL TYPE
PRECIPITATION
TIME INTERVAL
0 18 Acres BASEFLOWS 0 00 cfs
TYPE1A PERV
6 15 inches AREA.. . 0 OS Acres
10 00 min CN 80 00
TC 5 00 min
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ABSTRACTION COEFF 0 20
PEAK RATE 0 21 cfs VOL
o 08 Ac-ft TIME
480 min
NAME NORTH BASIN 2 YR EVENT
BASIN ID N-2YR
SBUH METHODOLOGY
TOTAL AREA .
RAINFALL TYPE
PRECIPITATION
TIME INTERVAL
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BASEFLOWS
o 00 cfs
PERV
o OS Acres
80 00
5 00 mln
o 18 Acres
TYPE1A
2 80 inches
10 00 min
AREA
CN
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ABSTRACTION COEFF 0 20
PEAK RATE 0 09 cfs VOL
o 03 Ac-ft TIME
480 min
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NAME NORTH BASIN 6 MONTH EVENT
BASIN ID N-6MO
SBUH METHODOLOGY
TOTAL AREA
RAINFALL TYPE
PRECIPITATION
TIME INTERVAL
AREA
CN
TC
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BASE FLOWS
o 00 cfs
PERV
o 05 Acres
80 00
5 00 min
o 18 Acres
TYPE1A
1 79 inches
10.00 min
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ABSTRACTION COEFF 0 20
PEAK RATE 0 05 cfs VOL
o 02 Ac-ft TIME
480 min
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ABSTRACTION COEFF 0 20
PEAK RATE 0 28 cfs VOL
o 10 Ac-ft TIME
480 min
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IMP
o 13 Acres
98 00
5 00 min
IMP
o 13 Acres
98 00
5 00 min
IMP
o 13 Acres
98 00
5 00 min
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12/24/97
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Skillings Connolly, Inc
#97018-EXl
page
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BONNIE TASCHE
=====================================================================
I)
BASIN SUMMARY
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BASIN ID S-2YR
SBUH METHODOLOGY
TOTAL AREA
RAINFALL TYPE
PRECIPITATION
TIME INTERVAl:.
NAME SOUTH BASIN 2 YR EVENT
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0.27 Acres
TYPEIA
2 80 inches
10 00 min
BASEFLOWS
o 00 cfs
PERV
0.17 Acres
80 00
5 00 min
IMP
o 10 Acres
98 00
5 00 min
AREA
CN
TC
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ABSTRACTION COEFF 0 20
PEAK RATE 0 00 cfs VOL.
o 00 Ac-ft TIME
o min
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BASIN ID. S-6-MO NAME SOUTH BASIN 6 MONTH EVENT
SBUH METHODOLOGY
TOTAL AREA o 27 Acres BASE FLOWS o 00 cfs
RAINFALL TYPE TYPEIA PERV IMP
PRECIPITATION 1 79 inches AREA o 17 Acres o 10 Acres
TIME INTERVAL 10 00 min CN 80 00 98 00
TC 5 00 min 5 00 min
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ABSTRACTION COEFF 0 20
PEAK RATE 0 00 cfs VOL
o 00 Ac-ft TIME
o min
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BASIN
10
-------------------------------------------------------------------------
-------------------------------------------------------------------------
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N-I00YR
N-2YR
N-6MO
S-100YR
S-2YR
S-6-MO
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-- - - - VOLUME - - - -
---cf-- Ac-ft
3501
1412
819
4563
o
o
o 08
o 03
o 02
o 10
o 00
o 00
BASIN RESULT SUMMARY
-RATE-
--cfs-
----TIME----- Hydrograph
-min- hours Methodology
o 21
o 09
o 05
o 28
o 00
o 00
480
480
480
480
o
o
8 00 SBUH Method
8 00 SBUH Method
8 00 SBUH Method
8 00 SBUH Method
o 00 SBUH Method
o 00 SBUH Method
Area
Acres
o 18
o 18
o 18
o 27
o 27
o 27
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HYDROGRAPH SUMMARY
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PEAK TIME VOLUME
HYD RUNOFF OF OF Contrib
NUM RATE PEAK HYDRO Area
cfs min cf\AcFt Acres
---------------------------------------------
---------------------------------------------
1 0 213 480 3501 cf 0.18
2 0 086 480 1412 cf 0 18
3 0.050 480 819 cf 0 18
4 0 282 480 4563 cf 0 27
5 0 094 480 1613 cf 0 27
6 0 046 480 840 cf 0 27
11 0.070 500 1412 cf 0 18
12 0 176 500 3501 cf 0 18
13 0.041 500 819 cf 0.18
14 0 077 500 1613 cf 0.27
15 0 232 500 4563 cf 0 27
16 0 037 500 840 cf 0 27
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STAGE STORAGE TABLE
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CUSTOM STORAGE ID No Sl
Description- NORTH DRAINAGE BASIN
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STAGE <----STORAGE--.-> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE---->
(ft) - --cf u_ uAc-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac - Ft-
========================================================================================================
95 50 0 0000 0 0000 96 10 379 20 0 0087 96 70 864 00 0 0198 97 30 1560 0 0358
95 60 63 200 0 0015 96 20 442 40 0 0102 96 80 980 00 0 0225 97 40 1676 0 0385
95 70 126 40 0 0029 96 30 505 60 0 0116 96 90 1096 0 0252 97 50 1792 0 0411
95 80 189 60 0 0044 96 40 568 80 0 0131 97 00 1212 0 0278 97 50 1792 0 0411
95 90 252 80 0 0058 96 50 632 00 0 0145 97 10 1328 0 0305
96 00 316 00 0 0073 96 60 748 00 0 0172 97 20 1444 0 0331
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STAGE STORAGE TABLE
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CUSTOM STORAGE ID No S2
Description SOUTH DRAINAGE BASIN
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STAGE <----STORAGE--.-> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE---->
(ft) ---cf-n nAc-Ft- (ft) n-cfn- nAc-Ft- (ft) -ncf-n --Ac-Ft- (ft) n-cfn- nAc- Ft-
========================================================================================================
97 50 0 0000 0 0000 98 00 356 00 0 0082 98 50 712 00 0 0163 99 00 1329 0 0305
97 60 71 200 0 0016 98 10 427 20 0 0098 98 60 835 40 0 0192 99 00 1329 0 0305
97 70 142 40 0 0033 98 20 498 40 0 0114 98 70 958 80 0 0220
97 80 213 60 0 0049 98 30 569 60 0 0131 98 80 1082 0 0248
97 90 284 80 0 0065 98 40 640 80 0 0147 98 90 1206 0 0277
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LEVEL POOL TABLE SUMMARY
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MATCH INFLOW -STO- -OIS- <-PEAK-> OUTFLOW STORAGE
<--------OESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id (cfs) VOL (cf)
=====================================================================================
2 YR EVENT-NORTH 0 00 0 09 Sl 01 95 63 11 0 07 83 95 cf
100 YR EVENT-NORTH 0 00 0 21 Sl 01 95 83 12 0 18 209 33 cf
6 MONTH EVENT-NOTTH 0 00 0 05 Sl 01 95 60 13 0 04 63 20 cf
2 YR EVENT-SOUTH 0 00 0 09 S2 02 97 62 14 0 08 86 72 cf
100 YR EVENT-SOUTH 0 00 0 28 S2 02 97 87 15 0 23 262 48 cf
6 MONTH EVENT-SOUTH 0 00 0 05 S2 02 97 60 16 0 04 71 20 cf
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APPENDIX C
Supporting Documentation
Salls Data
SCS and Thurston County SBUH Input Data
SKILLlNGS-CONNOLL Y, INC.
Consulting Engineers
Bonnie Tasche
Storm Drainage Analysis & Report
Il
u 266 Soil Survey
il
TABLE 14. --ENGINEERING INDEX PRQPERTn:s--Continued
U
I , , ClassJ.fication : Fraq- , Percentaqe [)assinq I
I I I I I
Soil Dame and :Depthl USDA texture I , : ments I sieve number-- :Liquid Plas-
II I I I
symbol I I I crnified I AASHTO I > 3 I , , , I 11mit tieity
map I I I I I I I I I I
LJ I I I I linehesl 4 I 10 I 40 I 200 I index
I I I I I I I I
In , , I I Pet. , , , I , Pet
I I I I I I I I
I I I I- I I I I I
I I I I I I I I I
r;~1l0 , 111------ 0-15lGravelly sandy IGM, SM lA-I, A-2 I 0-5 :55-85 :50-75 : 30-50 : 15-25 I 35-50 NP-IO
I I
U Spanaway I loam. I I I I I I I I
I I I I I I I I I
15-20tVery gravelly :GM IA-1, A-2 , 0-10 135-55 :25-50 \15-45 \10-35 I 35-50 NP-10
I I
I loam, very I I I I I I I
I I I , , I I I
I gravelly sandy I I I I I I I
II I I I I I I I I
I ~oam, extremely I I I I I I I
I I I I I I I I
U I gravelly sandy I I I I I , I
I I I I I I I I
I loam. I I I , I I ,
I I I I I I I I I
: 20-60: Extremely : Gl', G'1i :A-1 :10-25 25-35 :20-30 :10-20 , 0-5 I NP
I I
n I I gravelly sand, I I , I I , I
I I I I I I I , I
I I extremely I I I I I I I
U I I I I I I I I I
I I gravelly loamy I I I I I I I
I I I I I I I I I
I I sand. I I I I , I I
I I I , I I I I I
I I I I I I I I I
n , I , I I I I I I
~112, 113--------: 0-16 : S tony sandy loam ISM :A-2 I 5-20 70-90 :60-80 \40-50 :25-35 , 35-50 NP-10
I I
LJ Spanaway i16-22:Very gravelly :GM IA-1, A-2 I 0-10 ,35-55 :25-50 '20-40 : 10-30 I 35-50 NP-IO
I ,
I I loam, very I I I I I I
I I I I I I I I
I , gravelly sandy I I I , I I
n I I I I I I I I
I , loam, extremely I I I I , I
I I I I I I I I
I I gravelly sandy I I I I I
U I I I I I I I
I I loam. I I I I I
I I I I I I I
: 22-60: Extremely : Gl', GW IA-1 10-25 125-35 :20-30 10-20 I 0-5 NP
I
Il I I gravelly sand, I I I I ,
I I I I I I I I
I I extremely I , I I I I
LJ I I I I I I I I
I I gravelly loamy I I I I I I
I , I I I I I I
I I sand. I I I I I I
I I I I I I I I
I I I I I I I I
n I I I I I I I I
114*: I I I I I , I I
I I I I I I I I
U Spanaway--------: 0-15 \ Gravelly sandy I G.."1, SM IA-l, A-2 0-5 :55-85 150-75 : 30-50' : 15- 25 35-50 NP-10
, I loam. I I I I I I
I , I I I I I I
115-20:Very gravelly :GM IA-i, A-2 0-10 :35-55 125-50 :15-45 :10-35 35-50 NP-10
n I I loam, very I I I I I I
I I I I I I I I
I I gravelly sandy I I I , I I
LJ I I I I I I I I
, I loam, extremely , , I I I I
I I I I I I I I
I I gravelly sandy I I I I I I
I I 1 I , I I I
I I loam. I I I I I I
il I I I I I I I I
: 20-60: Extremely lGP, GW :A-1 10-25 :25-35 120-30 :10-20 I 0-5 NP
I
LJ , I gravelly sand, I I I I I I
I I I I I 1 I I
I I extremely I I I I 1 I
I I t I \ I I I
I , gravelly loamy I , I I I ,
I I 1 I I I I I
!1 I I sand. I I , I 1 I
, , 1 I I I I I
I I I I , I I I
U I I I I I I , I
Nlsqually-------l 0-5 iLoamy fine sand iSM IA-2 0 I 100 I 100 :SO-80 i 15-30 NP
I I
, 5-31lLoamy sand, loamy 1 SM 1A-2 0 I 100 I 100 :60-80 :20-30 NP
I I I
II , I fine sand. I , I I I I
I I I I I I I I
: 31-60: Loamy fine sand, iSl'-SM, SM :A-3, A-2 0 I 100 I 100 :65-75 I 5-20 NP
I I I
LJ I I loamy sand, I I 1 I \ 1
I I I I 1 I 1 1
I I sand. I , I I I I
I I I I \ I I 1
1 1 , I I I I I
il I 1 I I 1 I 1 I
115--------------( 0-7 :Silt loam--------iML iA-4 0 I 100 , 100 :80-90 :70-80 20-30 NP-5
I I
Sultan I 7-60:Silt loam, silty iCL-ML, cr. IA-4, A-6 0 I 100 I 100 :95-100:80-90 25-35 5-15
LJ I I I
1 I clay loam. I I I , I I
I I I I I I I I
I I I I I I I I
I I I I I I I I
il i16--------------1 0-7 :Silt loam------1ML, OL iA-4 0 I 100 I 100 :90-100:70-90 30-40 NP-iO
I I
Tacoma 7-50;Silt loam, very :ML IA-4 0 I 100 I 100 195-100:85-95 25-35 NP-10
I I I
U I I fine sandy loam. : , I I I I
I I I I 1 I I I
i50-60:Silt loam, silty Ie. IA-6, A-7 0 I 100 I 100 :95-100:90-100: 30-50 10-25
1 I
, I clay loam, clay. : I I I I , I
n I I I I I 1 I 1
I I I I I I 1 I I
I I I I I 1 1 I I
LJ See footnote at end of tal:lle.
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Thurston County Washington
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TABLE 16.--RATER FEATtmES-Cont1nued
277
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Soil name and
map symbol
Duration
Months
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IHydroloqic:
: group :
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t I
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I I I
: D INone---:
I I I
I I I
I I I
I I
, 102, 103---------------: B I None----------
Schneider : :
I I
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104--------------------: C I Rare------------
Semiahmoo i :
I I
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INone------------,
I
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IOccasiona1----- Long----------
I
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I None------------
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INone-----------:
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:None------------:
I I
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:None------------:
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:None------------:
I I
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:Occasional------:Brief---------
I I
I I
I I
I I I
:Frequent--------IBrief---------:
I I I
, , I
I I I
I I I
:None------------:
I I
I I
I I
I I
IRare------------:
I I
I I
I I
I I
INone-----------:
I I
I I
I I
I I
INone------------:
I I
I I
I I
I I
IRare------------:
I I
I I
I I
r I
INone------------:
I I
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Flooding
Frequency
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100, 101-------
Scamman
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105---------------------
Shalcar
D
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106-------------------
Shalcar Variant
D
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107, 108----------------
Skipopa
D
109---------------------:
Spana :
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~110, 111, 112, 113------:
Spanaway :
I
I
114* :
Spanaway---------------:
I
I
Nisqual1y--------------:
I
I
115---------------------:
Sultan :
I
I
116---------------------:
Tacoma :
I
I
117, 118, 119-----------:
Tenino :
I
I
120---------------------:
Tisch :
I
I
121, 122----------------:
Vail ton :
I
I
123, 124----------------:
Wilkeson :
I
,
125---------------------;
Xerorthents :
I
I
126, 127, 128-----------:
Yelm :
I
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D
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D
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D
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c
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c
Months Depth
Ft
0.5-1.5
>6.0
1.5-3.0
+1-0
Nov-May +1-0
1.0-2.0
1.0-3.0
I
I )6.0
I
I
I
I
I
I
I
I )6.0
I
I
I
( >6.0
I
I
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Nov-Apr I 2.0-4.0
I
I
I
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I
Nov-Jun I +1-0
I
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,
I
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I >6.0
I
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I 0-1.0
I
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I
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I
,
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I >6.0
I
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I
I
I )2.0
I
I
I
I
I
I 1.5-3.0
I
I
I
I
I
Hiah water table
l
I
I
I
I
,
I
I
I
: Perched
I
I
I
I
I
I
I
I
I
I
: Apparent
I
I
I
I
: Apparent
I
I
I
I
: Apparent
I
I
I
I
I Perched
I
I
I
I
: Apparent
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
: Apparent
I
I
I
,
: Apparent
I
I
I
I
I
I
I
,
I
I
I Apparent
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
: Apparen t
I
I
I
I
: Apparen t
I
I
I
I
Kind
Nov-Mar
Nov-May
Oct-May
Oct-May
Nov-May
Nov-Apr
Nov-Apr
Nov-Jun
Dec-Apr
Nov-Mar
II
Dee-Mar
* See description of the map unit for composition and behavior characteristics of the map unit..
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158
il
J~Spanaway Series
The Spanaway series consists of very deep
n somewhat excessively drained soils on terraces These
U soils formed in glacial outwash and volcanic ash Slope
is 0 to 15 percent. Elevation IS 100 to 400 feet. The
il average annual precipitation is 40 to 55 Inches the
average annual air temperature IS about 51 degrees F,
LJ and the average frost-free season is 150 to 200 days
These soils are sandy-skeletal mixed mesic Andic
il Xerumbrepts
LJ Typical pedon of Spanaway gravelly sandy loam, 0 to
3 percent slopes 4 miles southeast of Lacey about 250
II feet west and 400 feet south of the northeast corner of
U sec 25 T 36 N R 1 W
A-O to 15 Inches black (10YR 2/1) gravelly sandy
loam very dark grayish brown (10YR 3/2) dry, weak
fine granular structure loose very fnable nonsticky
and non plastic many fine medium and coarse
roots 25 percent pebbles strongly acid clear
smooth boundary
Bw-15 to 20 Inches dark yellowish brown (10YR 3/4)
very gravelly sandy loam light olive brown (2 5Y
5/4) dry weak fine subangular blocky structure
loose very friable nonsticky and non plastic, many
fine medium and coarse roots 55 percent pebbles
medium acid clear smooth boundary
C-20 to 60 inches dark yellowish brown (10YR 4/4)
extremely gravelly sand yellowish brown (10YR
5/4) dry single grained. loose, few fine roots, 80
percent pebbles 10 percent cobbles, slightly acid
II
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II
I
The thickness of the solum ranges from 15 to 25
inches The content of coarse fragments in the control
section ranges from 50 to 85 percent. The weighted
average texture of this section is very gravelly sand. or
extremely gravelly sand The umbric epipedon is 10 to
20 inches thick
The A horizon has hue of 10YR or 7 5YR, value of 3
or 4 when dry and chroma of 1 or 2 when moist or dry
It is medium acid or strongly acid The Bw horizon has
value of 4 or 5 when dry and 3 or 4 when mOISt. It is
very gravelly sandy loam very gravelly loam or
extremely gravelly sandy loam The C horizon has hue
of 10YR or 2 5Y value of 5 or 6 when dry and 4 or 5
when moist. and chroma of 3 or 4 when dry or moist. It
IS extremely gravelly sand or extremely gravelly loamy
sand and IS slightly acid or neutral
LJ
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I
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n
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II
I
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II
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Sultan Series
II
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The Sultan senes consists of very deep moderately
n
LJ
n
LJ
r'
well drained soils on flood plains These soils formed!
alluvium Slope is 0 to 3 percent. Elevation is 20 to 7.
feet. The average annual precipitation is 40 to 50
inches. the average annual air temperature is about 50j1f
degrees F, and the average frost-free season is 150 ta:
200 days -:1:
These soils are fine-silty. mixed. nonacid. mesic ; -:.
Aquic Xerofluvents , ,
Typical pedon of Sultan silt loam, 7 miles east of ,.,..
Lacey, about 1 000 feet east and 1,975 feet north of the'
southwest corner of sec. 16. T 18 N ,R 1 E. ~
Ap-O to 7 inches, dark yellowish brown (10YR 3/4) silt
loam brown (10YR 5/3) dry moderate fine and
medium granular structure, slightly hard, very
friable slightly sticky and slightly plastic, many fine,
medium and coarse roots, many very fine and fine
tubular pores slightly acid, abrupt smooth
boundary
BA-7 to 20 Inches dark yellowish brown (10YR 4/4)
silt loam, brown (10YR 5/3) dry: moderate fine and
medium subangular blocky structure. slightly hard,
very friable slightly sticky and slightly plastic: many
very fine fine, and medium roots many very fine
and fine tubular pores slightly acid. clear wavy
boundary
Bw1-20 to 25 inches, dark brown (10YR 3/3) silt loam,
graYish brown (2.5Y 5/2) dry, common fine
prominent red (2 5YR 5/8) mottles. moderate fine
and medium subangular blocky structure. slightly
hard very friable slightly sticky and slightly plastic:
common fine and medium roots. common very fine
and fine tubular pores, slightly acid, gradual wavy
boundary
Bw2-25 to 45 inches dark brown (10YR 4/3) silt loam
light brownish gray (1 OYR 6/2) dry: common
medium prominent red (2.5YR 5/8) mottles,
moderate medium and coarse 5ubangular blocky
structure slightly hard. very friable slightly sticky
and slightly plastic: few very fine and fine roots. few
very fine and fine tubular pores slightly acid
gradual wavy boundary
C-45 to 60 Inches graYish brown (10VR 5/2) silt loam
light gray (10YR 7/2) dry. common medium
prominent dark brown (7 5YR 4/4) mottles. massive
slightly hard very friable slightly sticky and slightly
plastic slightly acid
The Salls are slightly acid or neutral in the control
section and range from slightly acid to strongly acid
below a depth of 40 inches Mottles that have chroma
of 3 or more are at a depth of more than 20 Inches
'"'
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