20170254 Storm Drain Rpt 1L
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dMANS
Preliminary Storm Drainage
Report
PREPARED FOR:
Josh Angel
International Construction Equipment, Inc.
8101 Occidental Ave S
Seattle, WA 98108
PROJECT.
ICE Storage Yard
Yelm, WA
2170274.10
PREPARED BY.
Matt Whittlesey, EIT
Project Engineer
REVIEWED BY:
J. Matthew Weber, PE
Principal
DATE
June 2017
Civil Engineers • Structural Engineers • Landscape Architects • Community Planners • Land Surveyors
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07/03/20/7
I hereby state that this Storm Drainage
Report for ICE Storage Yard has been
prepared by me or under my supervision
and meets the standard of care and
expertise which is usual and customary in
this community for professional engineers.
I understand that City of Yelm does not and
will not assume liability for the sufficiency,
suitability, or performance of Construction
SWPPP BMPs prepared by me.
Preliminary Storm Drainage
Report
PREPARED FOR:
Josh Angel
International Construction Equipment,
Inc.
8101 Occidental Ave S
Seattle, WA 98108
PROJECT.
ICE Storage Yard
Yelm, WA
2170274.10
PREPARED BY.
Matt Whittlesey, EIT
Project Engineer
REVIEWED BY.
J. Matthew Weber, PE
Principal
DATE
June 2017
Table of Contents
Section Page
1.0 Project Overview .............................................................................................. ..............................1
1.1 Proposed Project Description .............................................................. ............................... 1
2.0 Summary of Minimum Requirements ............................................................ ..............................1
2.1
MR 1 — Preparation of Stormwater Site Plans ..................................... ............................... 1
2.2
MR 2 - Construction Stormwater Pollution Prevention ........................ ............................... 1
2.3
MR 3 — Source Control of Pollution ...................................................... ............................... 1
2.4
MR 4 — Preservation of Natural Drainage Systems and Outfalls ......... ............................... 2
2.5
MR 5 — Onsite Stormwater Control ...................................................... ............................... 2
2.6
MR 6 — Runoff Treatment .................................................................... ............................... 2
2.7
MR 7 — Flow Control ............................................................................ ............................... 2
2.8
MR 8 — Wetlands Protection ................................................................ ............................... 2
2.9
MR 9 — Basin/Watershed Planning ...................................................... ............................... 2
2.10
MR 10 — Operation and Maintenance .................................................. ............................... 2
3.0 Existing
Site Conditions ................................................................................. ............................... 2
3.1
Offsite drainage to the property ........................................................... ............................... 2
3.2
Creeks, lakes, ponds, wetlands, ravines, gullies, steep slopes, springs, and other
environmentally sensitive areas on or down gradient of the property . ............................... 3
3.3
Is the project located in an aquifer recharge area or wellhead protection area, as defined
by the Thurston County Health Department, the Environmental Protection Agency, or the
County? ................................................................................................ ............................... 3
3.4
Are there any specific requirements included in a basin plan for the area ? ....................... 3
3.5
Are there drains, channels, and swales within the project site and immediately adjacent ?3
3.6
Points of exit for existing drainage from the property .......................... ............................... 3
3.7
Are there any known historical drainage problems such as flooding, erosion, etc. ?.......... 3
4.0 Soils Reports ................................................................................................... ............................... 3
5.0 Wells and Septic Systems .............................................................................. ............................... 3
6.0 Fuel Tanks ....................................................................................................... ............................... 4
7.0 Sub -Basin Description ..................................................................................... ..............................4
8.0 Analysis of the 100 -Year Flood ...................................................................... ............................... 4
9.0 Facility Sizing and Downstream Analysis .................................................... ............................... 4
9.1 Facility Sizing ....................................................................................... ............................... 4
Preliminary Storm Drainage Report IMID130 ICE Storage Yard
2170274.10
9.2 Conveyance System Calculations ....................................................... ............................... 5
9.3 Downstream Drainage Analysis ........................................................... ............................... 5
10.0 Utilities ............................................................................................................. ............................... 5
11.0 Covenants, Dedications, and Easements ...................................................... ..............................6
12.0 Property Owners Association Articles of Incorporation ............................. ............................... 6
13.0 Other Permits or Conditions Placed on the Project .................................... ............................... 6
14.0 Conclusion ........................................................................................................ ..............................6
Preliminary Storm Drainage Report IBID133
ICE Storage Yard
2170274.10
Appendices
Appendix A
Exhibits
A -1
A -2
Appendix B
Exhibits
B -1
B -2
Appendix C
Vicinity Map
Existing Conditions Map
Proposed Basin Limits
Water Quality and Quantity WWHM Output
South Sound Geotechnical Consulting Report
Addendum to Geotechnical Report dated 6/28/2017
Preliminary Storm Drainage Report IBID133
ICE Storage Yard
2170274.10
1.0 Project Overview
The proposed ICE Storage Yard is located at 925 N.P. Road SE in the City of Yelm, Thurston
County, WA on Tax Parcel No. 64300900300. The site is currently bounded by undeveloped land
to the northeast, Yelm Water Reclamation Facility to the northwest, industrial development to the
southwest and North Pacific Road to the southeast. The site is currently zoned as an industrial
area. See Appendix A -1 for the Vicinity Map.
This report demonstrates that the stormwater design for this project has met the requirements of
the 2014 Department of Ecology (ECY) Stormwater Management Manual for Western
Washington (SMMWW), as adopted by the City of Yelm.
1.1 Proposed Project Description
The proposed project consists of site improvements associated with an existing 6,650- square foot
building, including new paved parking and gravel equipment storage areas, a washing slab with
recycle system, a paved driveway and gravel entry road. The project includes clearing, grading,
erosion control, sewer improvements, and storm treatment and infiltration facilities.
2.0 Summary of Minimum Requirements
This project is subject to the SMMWW. This project is a new development that will add more than
10,000 square feet of impervious surfaces; therefore, all Minimum Requirements apply to this
project.
2.1 MR 1 — Preparation of Stormwater Site Plans
This report and the project plans represent the Stormwater Site Plan for this project and satisfy
MR 1.
2.2 MR 2 - Construction Stormwater Pollution Prevention
A Construction Stormwater Pollution Prevention Plan (CSWPPP) will be prepared by AHBL under
separate cover during final design.
2.3 MR 3 — Source Control of Pollution
The proposed project is required to provide source control of pollution. The following are
proposed measures to be implemented as part of the civil plans.
• All pollutants, including waste materials and demolition debris created onsite during
construction, shall be handled and disposed of in a manner that does not cause
contamination of surface water.
• Cover, containment, and protection from vandalism shall be provided for all chemicals,
liquid products, petroleum products, and non -inert wastes present on the site (see
Chapter 173 -304 WAC for the definition of inert waste).
• Maintenance and repair of heavy equipment and vehicles that may result in discharge or
spillage of pollutants to the ground or into surface water runoff must be conducted using
spill prevention measures such as drip pans.
• Concrete Handling (BMP C151) and Sawcutting and Surface Pollution Prevention
(BMP C152) shall be used to prevent or treat contamination of surface water runoff by pH
modifying sources.
The Construction SWPPP, submitted under separate cover, provides details on the control of
pollution during construction.
Preliminary Storm Drainage Report IBID133
ICE Storage Yard 1
2170274.10
2.4 MR 4 — Preservation of Natural Drainage Systems and Outfalls
The project proposes to infiltrate all stormwater runoff, so all runoff will be retained in the
developed condition. Therefore, there are no natural drainage systems or outfalls to preserve.
2.5 MR 5 — Onsite Stormwater Control
This project will meet the LID performance standard. The onsite soils have a high infiltration
capacity, and all runoff will be retained onsite through two bio- retention swales and one gravel
infiltration trench *.
* The bio- retention Swale #1 infiltrates 94% of tributary runoff and overflows to the trench which
infiltrates the remaining 6% of runoff. All runoff is retained.
2.6 MR 6 — Runoff Treatment
Over 10,000 square feet of pollution generating impervious surface (PGIS) will be added as part
of these improvements; therefore, runoff treatment is required for this site. The proposed storage
area and driveway will be composed of compacted gravel, which will sheet flow runoff to two bio -
retention swales to provide treatment of all onsite stormwater. The gravel area will have to be
maintained in order to remain compacted and act as an impervious surface. Required
maintenance will be described in a separate Operations and Maintenance Manual.
2.7 MR 7 — Flow Control
The project exceeds the thresholds for new development projects and must provide flow control.
Proposed flow control is achieved with the use of two bio- retention swales, one that will infiltrate
all runoff and one that will overflow to a gravel infiltration trench.
2.8 MR 8 — Wetlands Protection
To our knowledge, there are no wetlands on or adjacent to the site.
2.9 MR 9 — Basin/Watershed Planning
To our knowledge, there are no existing basin plans.
2.10 MR 10 — Operation and Maintenance
The owner will be responsible for inspection and maintenance of stormwater facilities including
management of onsite impervious surfaces and other Best Management Practices for source
control of pollution during regular operations. Refer to section 10 for additional information.
3.0 Existing Site Conditions
The existing 4.0 -acre site is currently occupied by a 6,650- square foot warehouse building. The
site is relatively flat with no steep slopes. The project site is bounded by a private drive and
undeveloped land to the northeast, Yelm Water Reclamation Facility to the northwest, industrial
development to the southwest and North Pacific Road to the southeast.
3.1 Offsite drainage to the property.
To our knowledge, the adjacent properties do not drain to the project site.
Preliminary Storm Drainage Report DID133
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3.2 Creeks, lakes, ponds, wetlands, ravines, gullies, steep slopes, springs, and other
environmentally sensitive areas on or down gradient of the property.
To our knowledge, there are no environmentally sensitive areas on or down gradient of the
property.
3.3 Is the project located in an aquifer recharge area or wellhead protection area, as defined
by the Thurston County Health Department, the Environmental Protection Agency, or the
County?
The project site is located within a wellhead protection area according to Thurston County GIS
data.
3.4 Are there any specific requirements included in a basin plan for the area?
To our knowledge, there are no specific requirements other than the general requirements of the
most recent issue of the SMMVVW.
3.5 Are there drains, channels, and swales within the project site and immediately adjacent?
To our knowledge, there are no drains, ditches, or swales within the project site or immediately
adjacent.
3.6 Points of exit for existing drainage from the property.
The site generally slopes from the southwest to the adjacent private drive in the northeast.
However, it is our assumption that the majority of stormwater runoff is retained onsite.
3.7 Are there any known historical drainage problems such as flooding, erosion, etc.?
To our knowledge, there are no known historical drainage problems within the site or any areas
adjacent to the site.
4.0 Soils Reports
A geotechnical report prepared for the project by South Sound Geotechnical Consulting on June
12, 2017, indicates that soils onsite consist of 1 -1.5 feet of fill and 6 -18 inches of topsoil,
underlain by glacial outwash soils ranging from sand with trace to some silt to gravelly sand with
cobbles and trace to some silt.
The report also indicates corrected infiltration rates of 40.5 in /hr and 31.0 in /hr at two test pits on
site. An infiltration rate of 20 inches per hour was conservatively assumed for the design of the
onsite infiltration facilities.
Cation Exchange Capacity and organic content tests were completed at two test pits, and the
native soils were found to satisfy SSC -6, Soil Physical and Chemical Suitability for Treatment" per
Volume 3, Chapter 3 of the SMMWW. See Appendix C for the complete geotechnical report.
5.0 Wells and Septic Systems
To our knowledge, there are no wells onsite. The existing building is connected to the City's
water system. We understand that the site is served by septic. The septic system will be
abandoned in accordance with health department standards and the building will be connected to
the City's Sewer Step system.
Preliminary Storm Drainage Report 01BOO
ICE Storage Yard 3
2170274.10
W
7.0
1
M
9.1
Fuel Tanks
To our knowledge, there are no existing underground fuel tanks on the site. If located during
construction, the fuel tanks will be abandoned according to Thurston County Health Department
standards.
Sub -Basin Description
The developed site will infiltrate all new impervious surfaces using bio- retention swales for
treatment and a gravel infiltration trench for flow control. The site was split into two basins. The
table below summarizes the assumptions for contributing basin areas. See Appendix B -1 and for
Proposed Basin Limits.
Water Quality Basins
Basin
Total PGIS Area (ac)
Basin #1
0.532
Basin #2
0.358
Tota 1
0.890
Analysis of the 100 -Year Flood
The site is not located within the 100 -year floodplain.
Facility Sizing and Downstream Analysis
Stormwater management facilities have been sized using the Western Washington Hydrology
Model (WWHM 2012). All runoff is proposed to be retained onsite using infiltration facilities for
treatment and flow control therefore no impacts to downstream property, waterways, or
groundwater is anticipated.
The following sections describe the design and calculations for each facility.
Water Quality Facility Sizing
Water quality facilities were sized to provide treatment for at least 91 % of runoff, as per the
SMMVVW. Treatment will be provided through the use of two bio- retention swales.
The site was split into two water quality basins. See the Proposed Basin Limits Map in Appendix
B -1 for delineations. Basin 1 consists of the gravel storage yard area. The storage yard will
sheet flow to the southeast into a perimeter bio- retention Swale. Basin 2 consists of the onsite
gravel access road. The gravel road will slope to the south west into the perimeter bio- retention
Swale.
See the table below for a summary of the treatment facilities. See Appendix B -2 for the Water
Quality and Quantity WWHM Output.
Preliminary Storm Drainage Report DID133
ICE Storage Yard 4
2170274.10
9.2
9.3
9.4
10.0
Water Quality Facilities
Facility Name
PGIS (Ac)
Bottom Area Swale (sf)
% Filtered
Bioretention Swale #1
0.532
280
94.12
Bioretention Swale #2
0.358
1060
100
Water Quantity Facility Sizing
A flow control facility is proposed for the storage yard basin. Runoff above the water quality
runoff will overflow into an infiltration gallery for infiltration of the remaining site runoff.
Basin 2's bio- retention Swale will infiltrate 100% of the tributary runoff and an overflow to an
infiltration gallery is not required.
See the table below for a summary of the flow control facilities. See Appendix B -2 for the Water
Quality and Quantity WWHM Output.
Water Quantity Facilities
Facility Name
PGIS (Ac)
Bottom Area Swale /Trench (sf)
% Infiltrated
Gravel Infiltration
Trench
0.532
550
100
Bioretention Swale #2
0.358
1060
100
Conveyance System Calculations
Conveyance is not proposed. The impervious areas will be graded to sheet flow stormwater
directly into the two bio- retention swales.
Downstream Drainage Analysis
A downstream drainage analysis has not been conducted since the project will infiltrate all
stormwater runoff onsite. No adverse impacts associated with water quality or flooding will occur
to downstream properties.
Operation and Maintenance Manual
An operation and maintenance manual consisting of maintenance checklists for stormwater
management facilities and the onsite gravel impervious surfaces, as well as source control
measures will be developed during final design.
The owner will be responsible to maintain onsite gravel surfacing in an impervious condition and
fill pot holes and other defects to ensure onsite runoff is directed to treatment facilities.
The owner operates an onsite, self- contained, washing facility that is utilized to clean equipment
prior to storage to reduce deposition of pollutants.
Preliminary Storm Drainage Report DID133
ICE Storage Yard 5
2170274.10
11.0 Utilities
The site is served by domestic water. A new fire hydrant is proposed for fire protection of the
existing building. A new step system will be installed to connect the existing building to the city's
step system.
12.0 Covenants, Dedications, and Easements
A 10 -foot Right of Way dedication is required along North Pacific Road for future road
improvements.
A blanket easement is required for access and maintenance of the proposed onsite STEP
system.
13.0 Property Owners Association Articles of Incorporation
Not applicable.
14.0 Other Permits or Conditions Placed on the Project
The following permits will also be required for this project:
Site Development Permit.
15.0 Conclusion
The proposed project involves site improvements associated with an existing 6,650- square foot
warehouse building. The project includes clearing, grading, erosion control, sewer improvements,
and stormwater management facilities. The site, as proposed, will meet the requirements of the
2014 Department of Ecology Stormwater Management Manual for Western Washington. This
report and associated plans have been prepared within the guidelines established by the City of
Yelm for stormwater management.
This analysis is based on data and records either supplied to or obtained by AHBL, Inc. These
documents are referenced within the text of the analysis. The analysis has been prepared utilizing
procedures and practices within the standard accepted practices of the industry. We conclude that this
project, as proposed, will not create any new problems within the existing downstream drainage system.
This project will not noticeably aggravate any existing downstream problems due to either water quality or
quantity.
AHBL, Inc.
Matt Whittlesey, EIT
Project Engineer
MKW /Isk
June 2017
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Preliminary Storm Drainage Report IBID133
ICE Storage Yard 6
2170274.10
Appendix A
Exhibits
A- 1 ....................Vicinity Map
A- 2 ....................Existing Conditions Map
Preliminary Storm Drainage Report IBID133
ICE Storage Yard
2170274.10
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Appendix B
Exhibits
B- 1 ....................Proposed Basin Limits
B- 2 ....................Water Quality and Quantity WWHM Output
Preliminary Storm Drainage Report IBID133
ICE Storage Yard
2170274.10
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INEAR BIO- RETENTION
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T A C O M A S E A T
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2215 North 30th Street, Suite 300, Tacoma,
WA 98403 253.383.2422 TEL
316 Occidental Avenue South, Suite 320, Seattle, WA 98104 206.267.2425 TEL
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BASIN BOUNDARY LIMITS ■ ■ ■ ■ ■ ■ ■ ■ ■
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Appendix 6 -2
Water Quality and Quantity WWHM Output
Basin #1
Schematic = I Ej. Basin 1 Mitigated
SCENARIOS
❑ Predeveloped
Q Mitigated
Run Scenario
Basic Elements
0® ®®
Pro Elements
® ®0
LI[t Toolbox
Commercial Toolbox
Move Elements
7
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Save x,y Load x,,,
Y
�J�]
Subbasin Name: Basin 1 1 Designate as Bypass for POC:
Surface Interflow Groundwater
Flows To: ISurface ention Swale Surface ention Swale
Area in Basin TV Show Only Selected
Available Pervious Acres Available Impervious Acres
i✓ C, Forest, Flat p� fV ROADS /FLAT .532
C, Lawn, Flat
Pervious Total Acres
Impervious Total p:532 Acres
Basin Total p.532 Acres
Fri 11:49a -Basin 1 -Finish Mitigated �� I Deselect Zero Select By: F_ GO
ttl
E5,- Basin 1 Bio- Retention Swale Mitigated
Facility Name jBasin 1 Bio - Retention Swale
Outlet 1 Outlet 2 Outlet 3
Downstream Connection lGravel Trench Bed 1 0 10
Facility Type Biorekenkian Swale
v Use simple Bioretention Quick Swale Size Water Quality Size Facility
Underdrain Used
Bioretention Bottom Elevatior
Bioretention Dimensions
Bioretention Length (ft) 1140.000
Biorekenkion Bottom Width (ft) 12.000
Freeboard (fk) 10.500
Over -road Flooding (ft) 10.000
Effective Total Depth (ft) 1
Bottom slope of biorekenkion.(0 -1) 0.000
F_ Sidewall Invert Location -
Fronk and Back side slope (HN) 3.000
Left Side Slope (HN) 13.000
Right Side Slope (HN) 13.000
Material Layers for
Layer 1 Layer 2 Layer 3
Depth (ft) 1.500 0.000
Soil Layer 1 1 SMMWW 12 in/hr
Soil Layer 2 ISand
Soil Layer 3 IGRAVEL
Edit Soil Types
Sat Safety Factor
(- None (- 2 4
Native Infiltration JYes ^�
Measured Infiltration Rake (in&) 20
Reduction Factor (infilkxfackor) I
Use Wetted Surface Area (sidewalls) 7N07_
O
Flow Through Underdrain (ac-ft) 0
Total Outflow (ac-ft)
WQ Percent Filtered 94.12
Facility Dimension Diagram
R iser O uklek S kruckure
Outlet Structure Data
Riser Height Above biorekenkion surface (ft)
Riser Diameter (in) 12
Riser Type Flak
Orifice Diameter Height
Number (in)
(ft)
5.809
Total Volume Through Faciliky(ac -ft)
98.857
Percent Infiltrated
94.12
Precipitation on Facility (acre-ft)
Bioretention Volume at Riser
Head (ac-ft) .096
Show Bioretention
10pen Table J
Total Volume Infiltrated (ac-ft)
93.048
Total Volume Through Riser (ac-ft)
5.809
Total Volume Through Faciliky(ac -ft)
98.857
Percent Infiltrated
94.12
Precipitation on Facility (acre-ft)
6.97
Evaporation from Facility (acre-ft)
1.493
�� Gravel Trench Bed 1 Mitigated
Facility Name
Downstream Connection
Facility Type
F- Precipitation Applied to Facility
F- Evaporation Applied to Facility
Facility Dimensions
Layer 1 Thickness (fk)
Trench Length (fk)
F1
Trench Bottom Width (fk)
10
Effective Total Depth (fk)
Layer 2 Thickness (fk)
Top and bottom slope (HN)
0.0001
Left Side Slope (HN)
Right Side Slope (HN)
C�
Gravel Trench Bed 1
Outlet 1 Outlet 2 Outlet 3
0 10 10
Gravel Trench /Bed
Quick Trench
Facility Dimension Diagram
Material Layers for Trench /Bed
Layer 1 Thickness (fk)
Use Wetted Surface Area (sidewalls)
F1
Layer 1 porosity (0-1)
5.809
0.33
Layer 2 Thickness (fk)
Size Infiltr5tion Trench
0
Layer 2 porosity (0-1)
0.333
Layer 3 Thickness (fk)
0
Layer 3 porosity (0-1)
0.333
Infiltration Yes J
Measured Infiltration Rake (in/hr) 20
Reduction Factor (infilkxfactor)
F
Use Wetted Surface Area (sidewalls)
Yes
Total Volume Infiltrated (ac -fk)
5.809
Total Volume Through Riser (ac -fk)
0
Size Infiltr5tion Trench
Target %: 100
Outlet Structure Data
Riser Height (fk)
Riser Diameter (in) 12
Riser Type Flak
Notch Type
Orifice Diameter Height
Number (in) (ft)
Trench Volume at Riser Head (ac -fk) .013
Show Trench 10 pen Table
Initial Stage (fk) 0
Total Volume Through Face iky ac k 5.809
Percent Infiltrated
100
Basin #2
1•:hematic
o r z,z
SCENARIOS
❑ Predeveloped
❑� Mitigated
Run Scenario
Basic Elements
Pro Elements
Commercial Toolbox
4 f
Move EII lements --
Save x,y Load x,y
Y
!�
E-1 - Basin 2 Mitigated
Subbasin Name: Basin 2 r Designate as Bypass for POC:
Surface Interflew Groundwater
Flows To: I Surface ention Swale Surface ention Swale
Area in Basin
Available Pervious Acres
C. Forest, Flat
r C, Lawn, Flat 0
Show Only Selected
Available Impervious Acres
RDADSIFLAT .358
Pervious Total 0 Acres
Impervious Total 0.358 Acres
Basin Total 0.358 Acres
Deselect Zero + Select By: F- GO
FE-3
E� Basin 2 Bio - Detention Swale Mitigated
Facility Name jBasin 2 Bio - Retention Swale
Outlet 1 Outlet 2 Outlet 3
Downstream Connection 10 10 10
Facility Type I Bioretention Swale
v Use simple Bioretention Quick Swale Size Water Quality Size Facility
Underdrain Used
Bioretention Bottom Elevatior
Bioretention Dimensions
Bioretention Length (fk)
Biorekenkion Bottom Width (ft) 12.000
Freeboard (ft) 0.500
Over -road Flooding (ft) 0.000
Effective Total Depth (ft) 0
Bokkom slope of biorekenkion.(0 -1 ) 10.000
r Sidewall Invert Location -
Frank and Back side slope (H N) 0.000
Left Side Slope (HN) 0.000
Right Side Slope (HN) 3.000
Material Layers for
Layer 1 Layer 2 Layer 3
Depth (ft) 1.500 HE
Soil Layer 1 1 SMMWW 12 in/hr
Soil Layer 2 Sand
Soil Layer 3 GRAVEL
Edit Sail Types
Sat Safety Factor ,
t Clone 2 4
Native Infiltration Yes
Measured Infiltration Rake (in/hr) 20
Reduction Factor (infilkxfackor)
Use Wetted Surface Area (sidewalls) H0 J
Flow Through Underdrain (ac-ft) 0
Total Outflow (ac-ft)
WQ Percent Filtered 100
Facility Dimension Diagram
Riser Outlet Structure ^�
Outlet Structure Data
Riser Height Above biorekenkion surface (fk)
Riser Diameter (in) 12
Riser Type Flak
Orifice Diameter Height
Number (in)
(ft)
1 Fo-----d
Fo---J
72.04
Percenk Infiltrated
100
Precipitation on Facility (acre-ft)
Bioretention Volume at Riser
Head (ac-ft) .341
Show Bioretention
10penTable J
Total Volume Infiltrated (ac-ft)
72.04
Total Volume Through Riser (ac-ft)
0
Total Volume Through Faciliky(ac -ft)
72.04
Percenk Infiltrated
100
Precipitation on Facility (acre-ft)
14.02
Evaporation from Facility (acre-ft)
4.811
Appendix C
South Sound Geotechnical Consulting Report
Addendum to Geotechnical Report dated 6/28/2017
Preliminary Storm Drainage Report IBID133
ICE Storage Yard
2170274.10
South Sound Geotechnical Consulting
June 12, 2017
International Construction Equipment (I.C.E.)
8101 Occidental Avenue S.
Seattle, WA 98108
Attention: Mr. Josh Angel
Subject: Geotechnical Engineering Report
ICE Facility Expansion
925 North Pacific Road SE
Yelm, Washington
SSGC Project Number: 17042
Mr. Angel,
South Sound Geotechnical Consulting (SSGC) has completed a geotechnical assessment for the planned
ICE facility expansion in Yelm, Washington. Our services have been completed in general conformance
with our proposal P17029 (dated April 18, 2017) and authorized per signature of our agreement for
services. Our scope of services included completion of six test pits and two infiltration tests, laboratory
testing, engineering analyses, and preparation of this report.
PROJECT INFORMATION
The ICE facility expansion will consist of two new equipment storage buildings, a crane pad, and a
recycling system building and adjacent slab wash area. Expansion will also include a new asphalt and /or
concrete access drive leading into the facility, and parking areas.
We understand conventional spread footings are planned for support of the new buildings with concrete
slab -on -grade floors. The crane pad and slab wash will be concrete. Infiltration facilities (such as bio-
retention) are planned along the east side of the existing access drive and south of the existing parking
area of the existing building to control storm runoff The City of Yelm utilizes the 2014 Washington
State Department of Ecology (DOE) "Stormwater Management Manual for Western Washington" for
assessing infiltration.
SITE CONDITIONS
An existing commercial building is in the northeastern portion of the property. A gravel drive provides
access from North Pacific Road. The project area is generally level with an elevation change on the order
of 3 ( + / -) feet. Most of the area around the existing building is grass with some gravel covered areas.
The access road is currently gravel.
Geotechnical Engineering Report S S GC
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SUBSURFACE CONDITIONS
Subsurface conditions were characterized by completing six (6) test pits and two (2) infiltration tests on
June 1, 2017. Test pits were advanced to depths between 5 to 9 feet below existing ground surface.
Approximate locations of the explorations are shown on Figure 1, Exploration Plan. Logs of the test pits
are provided in Appendix A. A summary description of observed subgrade conditions is provided below.
Soil Conditions
Fill consisting of mixed silt, sand, gravel, with some cobbles was observed in test pits TP -1 and
TP -4 in the general vicinity of the existing building. Fill extended to depths of 1 to 1.5 feet in the
test pits, but may be thicker in other areas. Topsoil was below the fill in these test pits and below
the surface in the remaining test pits. Topsoil ranged in thickness from about 6 to 18 inches.
Native soil below the topsoil consisted of glacial outwash. These soils varied from sand with
trace to some silt to gravelly sand with cobbles and trace to some silt. Occasional boulders were
encountered. These soils were generally in a medium dense condition and extended to the
termination depth of the test pits.
Groundwater Conditions
Groundwater was not observed in the test pits or infiltration test holes at the time of excavation.
Mottling or other indicators of elevated groundwater was not observed in the excavations. Based
on available well logs from the Washington State Department of Ecology, groundwater in the
general vicinity of this site is on the order of 20 feet. Groundwater is not expected to adversely
impact planned development at this site.
Geologic Setting
The USDA Soil Conservation Service Soil Map of Pierce County, Washington (1979) maps soils
on the site as Spanaway gravelly sandy loam. Spanaway soils reportedly formed in glacial
outwash. Permeability is reportedly moderately rapid, with slow runoff, and the erosion hazard
is slight. Native soils in the test pits appear to conform to the mapped soil type.
GEOTECHNICAL DESIGN CONSIDERATIONS
The planned development is considered feasible based on observed subgrade conditions in the test pits
and infiltration tests completed. Native medium dense glacial outwash can provide suitable bearing for
foundations, slab -on -grade floors, and pavements. Infiltration tests in the outwash soil indicate
infiltration for stormwater control is feasible.
Recommendations presented in the following sections should be considered general and may require
modifications when earthwork and grading occur. They are based upon the subsurface conditions
observed in the test pits and the assumption that finish site grades will be similar to existing grades. It
should be noted that subsurface conditions across the site may vary from those depicted on the
Oil
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
exploration logs and can change with time. Therefore, proper site preparation will depend upon the
weather and soil conditions encountered at the time of construction. We recommend that SSGC review
final plans and further assess subgrade conditions at the time of construction, as warranted.
General Site Preparation
Site grading and earthwork should include procedures to control surface water runoff Grading the site
without adequate drainage control measures may negatively impact site soils, resulting in increased export
of impacted soil and import of fill materials, thereby potentially increasing the cost of the earthwork and
subgrade preparation phases of the project.
Site grading should include removal (stripping) of topsoil, fill, or other deleterious materials in new
building and pavement areas. Subgrades should consist of firm (medium dense) outwash following
stripping. Stripping depths are anticipated to be on the order of 1 to 3 feet, but may be locally deeper due
to due to previous development.
General Subgrade Preparation
Exposed subgrades should consist of firm native outwash soils. We recommend exposed subgrades in
building and conventional pavement areas are proofrolled using a large roller, loaded dump truck, or other
mechanical equipment to assess subgrade conditions following stripping. Proofrolling efforts should
result in the upper 1 foot of subgrade soils achieving a compaction level of at least 95 percent of the
maximum dry density (MDD) per the ASTM D1557 test method. Wet, loose, or soft subgrades that
cannot achieve this compaction level should be removed and replaced with structural fill. A
representative of SSGC should be present to assess subgrade conditions during proofrolling.
Grading and Drainage
Positive drainage should be provided during construction and maintained throughout the life of the
development. Allowing surface water into cut or fill areas, utility trenches, and building footprints should
be prevented.
Structural Fill Materials
The suitability of soil for use as structural fill will depend on the gradation and moisture content of the
soil when it is placed. Soils with higher fines content (soil fraction passing the U.S. No. 200 sieve) will
become sensitive with higher moisture content. It is often difficult to achieve adequate compaction if soil
moisture is outside of optimum ranges for soils that contain more than about 5 percent fines.
Site Soils: Existing fill and topsoil is not considered suitable for structural fill due to variable
organic content. Native soils can be used for structural fill provided they are moisture conditioned
to within optimal moisture content. Optimum moisture is considered within about +/- 2 percent of
3
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
the moisture content required to achieve the maximum density per the ASTM D -1557 test
method. If moisture content is higher or lower than optimum, soils would need to be dried or
wetted prior to placement as structural fill. Note that larger cobbles and boulders should be
removed from native soils used for structural fill. These particles tend to become clustered during
earthwork and can form voids and uneven compaction.
Import Fill Materials: We recommend import structural fill placed during dry weather periods
consist of material which meets the specifications for Gravel Borrow as described in Section 9-
03.14(1) of the 2014 Washington State Department of Transportation ( WSDOT) Specifications
for Road, Bridge, and Municipal Construction (Publication M 41 -10). Gravel Borrow should be
protected from disturbance if exposed to wet conditions after placement.
During wet weather, or for backfill on wet subgrades, import soil suitable for compaction in
wetter conditions should be provided. Imported fill for use in wet conditions should generally
conform to specifications for Select Borrow as described in Section 9- 03.14(2), or Crushed
Surfacing per Section 9- 03.9(3) of the 2014 WSDOT M -41 manual, with the modification that a
maximum of 5 percent by weight shall pass the U.S. No. 200 sieve for these soil types.
It should be noted that structural fill placement and compaction is weather- dependent. Delays due
to inclement weather are common, even when using select granular fill. We recommend site
grading and earthwork be scheduled for the drier months of the year. Structural fill should not
consist of frozen material.
Structural Fill Placement
Structural fill should be placed in lifts not exceeding about 10 to 12 inches in loose measure. It may be
necessary to adjust lift thickness based on site and fill conditions during placement and compaction.
Structural fill should be compacted to attain the recommended levels presented in Table 1, Compaction
Criteria. Structural fill should extend laterally out at least 5 feet from the edge of footings and then at a
maximum 2H: IV (Horizontal:Vertical) incline.
Table 1. Compaction Criteria
Fill Application
Compaction Criteria*
Footing areas (below structures and retaining walls)
95%
Upper 2 feet in pavement areas, slabs and sidewalks, and utility trenches
95%
Below 2 feet in pavement areas, slabs and sidewalks, and utility trenches
92%
Utility trenches or general fill in non -paved or - building areas
90%
Per the ASTM D 1557 test method.
4
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
Trench backfill within about 2 feet of utility lines should not be over - compacted to reduce the risk of
damage to the line. In some instances the top of the utility line may be within 2 feet of the surface.
Backfill in these circumstances should be compacted to a firm and unyielding condition.
We recommend fill procedures include maintaining grades that promote drainage and do not allow
ponding of water within the fill area. The contractor should protect compacted fill subgrades from
disturbance during wet weather. In the event of rain during structural fill placement, the exposed fill
surface should be allowed to dry prior to placement of additional fill. Alternatively, the wet soil can be
removed. We recommend consideration be given to protecting haul routes and other high traffic areas
with free - draining granular fill material (i.e. sand and gravel containing less than 5 percent fines) or
quarry spalls to reduce the potential for disturbance to the subgrade during inclement weather.
Earthwork Procedures
Conventional earthmoving equipment should be suitable for earthwork at this site. Earthwork may be
difficult during periods of wet weather or if elevated soil moisture is present. Excavated site soils may
not be suitable as structural fill depending on the soil moisture content and weather conditions at the time
of earthwork. If soils are stockpiled and wet weather is anticipated, the stockpile should be protected with
securely anchored plastic sheeting. If stockpiled soils become unusable, it may become necessary to
import clean, granular soils to complete wet weather site work.
Wet or disturbed subgrade soils should be over - excavated to expose firm, non - yielding, non - organic soils
and backfilled with compacted structural fill. We recommend the earthwork portion of this project be
completed during extended periods of dry weather. If earthwork is completed during the wet season
(typically late October through May) it may be necessary to take extra measures to protect subgrade soils.
If earthwork takes place during freezing conditions, we recommend the exposed subgrade be allowed to
thaw and be re- compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen soil
can be removed to unfrozen soil and replaced with structural fill.
The contractor is responsible for designing and constructing stable, temporary excavations (including
utility trenches) as required to maintain stability of excavation sides and bottoms. Excavations should be
sloped or shored in the interest of safety following local and federal regulations, including current OSHA
excavation and trench safety standards. Temporary excavation cuts should be sloped at inclinations of
1.5H: IV (Horizontal:Vertical) or flatter, unless the contractor can demonstrate the safety of steeper
inclinations. Some caving of test pit sidewalls was observed during excavation. The contractor should be
prepared to shore excavations deeper than about 4 feet.
A qualified geotechnical engineer should be retained during the construction phase of the project to
observe earthwork operations and to perform necessary tests and observations during subgrade
preparation, placement and compaction of structural fill, and backfilling of excavations.
5
Geotechnical Engineering Report SSGC
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Foundations
Foundations can be placed on native subgrade soils or on a zone of structural fill above prepared
subgrades as described in this report. The following recommendations have been prepared for
conventional spread footing foundations.
Bearing Capacity (net allowable): 3,000 pounds per square foot (psf) for footings
supported on firm native soils or structural fill prepared
as described in this report.
Footing Width (Minimum) 18 inches (Strip)
24 inches (Column)
Embedment Depth (Minimum) 18 inches (Exterior)
12 inches (Interior)
Settlement: Total: < 1 inch
Differential: < 1/2 inch (over 30 feet)
Allowable Lateral Passive Resistance: 325 psf /ft* (below 18 inches)
Allowable Coefficient of Friction: 0.40*
*These values include a factor of safety of approximately 1.5.
The net allowable bearing pressures presented above may be increased by one -third to resist transient,
dynamic loads such as wind or seismic forces. Lateral resistance to footings should be ignored in the
upper 12- inches from exterior finish grade.
Foundation Construction Considerations
All foundation subgrades should be free of water and loose soil prior to placing concrete, and
should be prepared as recommended in this report. Concrete should be placed soon after
excavating and compaction to reduce disturbance to bearing soils. Should soils at foundation
level become excessively dry, disturbed, saturated, or frozen, the affected soil should be removed
prior to placing concrete. We recommend that SSGC observe all foundation subgrades prior to
placement of concrete.
Foundation Drainage
Ground surface adjacent foundations should be sloped away from buildings. Footing drains are not
considered necessary if the bases of footings are founded on native outwash deposits. We
recommend footing drains are installed around perimeter footings placed on structural fill. Footing
drains should include a minimum 4 -inch diameter perforated rigid plastic or metal drain line installed
at the base of the footing. The perforated drain lines should be connected to a tight line pipe that
ro
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
discharges to an approved storm drain receptor. The drain line should be surrounded by a zone of
clean, free - draining granular material having less than 5 percent passing the No. 200 sieve or meeting
the requirements of section 9- 03.12(2) "Gravel Backfill for Walls" in the 2014 WSDOT Standard
Specifications for Road, Bridge, and Municipal Construction manual (M41 -10). The free - draining
aggregate zone should be at least 12 inches wide and wrapped in filter fabric. The granular fill
should extend to within 6 inches of final grade where it should be capped with compacted fill
containing sufficient fines to reduce infiltration of surface water into the footing drains. Alternately,
the ground surface can be paved with asphalt or concrete. Cleanouts are recommended for
maintenance of the drain system.
On -Grade Floor Slabs
On -grade floor slabs should be placed on native soils or structural fill prepared as described in this report.
We recommend a modulus subgrade reaction of 225 pounds per square inch per inch (psi /in) for native
soils.
We recommend a capillary break is provided between the prepared subgrade and bottom of slab.
Capillary break material should be a minimum of 4 inches thick and consist of compacted clean, free -
draining, well graded course sand and gravel. The capillary break material should contain less than 5
percent fines, based on that soil fraction passing the U.S. No. 4 sieve. Alternatively, a clean angular
gravel such as No. 7 aggregate per Section 9- 03.1(4) C of the 2014 WSDOT (M41 -10) manual could be
used for this purpose.
We recommend positive separations and /or isolation joints are provided between slabs and foundations,
and columns or utility lines to allow independent movement, where needed. Backfill in interior trenches
beneath slabs should be compacted in accordance with recommendations presented in this report.
A vapor retarder should be considered beneath concrete slabs that will be covered with moisture sensitive
or impervious coverings (such as tile, wood, etc.), or when the slab will support equipment or stored
materials sensitive to moisture. We recommend the slab designer refer to ACI 302 and /or ACI 360 for
procedures and limitations regarding the use and placement of vapor retarders.
Seismic Considerations
Seismic parameters and values in Table 2 are recommended based on the 2015 International Building
Code (IBC).
7
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Table 2. Seismic Parameters
SSGC
PARAMETER
VALUE
2015 International Building Code (IBC)
Site Classification
D
Site Latitude
N 46.950670
Site Longitude
W 122.595520
S, Spectral Acceleration for a Short Period
1.250
S, Spectral Acceleration for a 1- Second Period
0.497g
Fa Site Coefficient for a Short Period
1.00
F„ Site Coefficient for a 1- Second Period
1.503
' Note: In general accordance with 2015 International Building Code, Section 1613.3.2 for risk categories
1,11,111. IBC Site Class is based on the specified characteristics of the upper 100 feet of the subsurface profile. Ss,
S,, Fa, and F„ values based on the USGS US Seismic Design Maps website using referenced site latitude and
longitude.
Liquefaction
Soil liquefaction is a condition where loose, typically granular soils located below the
groundwater surface lose strength during ground shaking, and is often associated with
earthquakes. The "Thurston County Liquefaction Hazard" map (dated 2011) identifies this area
as having a low risk to liquefaction. Based on observed soil types and conditions in the test pits,
the risk of liquefaction at this site is considered low for the design level earthquake.
Infiltration Characteristics
We understand infiltration facilities are being considered to support stormwater control. Two (2)
infiltration tests were performed at planned infiltration sites. Tests were completed in general
conformance with procedures outlined in the WDOE 2014 Stormwater Management Manual for Western
Washington, for small -scale PIT. Tests were completed in glacial outwash, with PIT -1 in gravelly sand
and PIT -2 in sand. Results of the infiltration tests are presented in Table 3.
Table 3. Infiltration Test Results
* Correction Factors from the 2014 WDOE Stormwater Management Manual for Western Washington.
8
Depth of Test
Uncorrected (Field)
Corrected
Infiltration
Correction Factor*
from surface
Infiltration Rate
Infiltration Rate
Test No.
(CFv /CFt/CFm)
(feet)
(in/hr)
(in/hr)
PIT -1
3.5
120
40.5
(0.75/0.5/0.9)
PIT -2
3.5
92
31.0 T
(0.75/0.5/0.9)
* Correction Factors from the 2014 WDOE Stormwater Management Manual for Western Washington.
8
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
The corrected infiltration rates are considered appropriate for the outwash soils tested. We recommend
the rate for PIT -1 is used for stormwater facilities around the existing building, with the rate for PIT -2
used along the access road. Other appropriate correction factors should be included in design plans to
modify infiltration rates as necessary to comply with other City of Yelm (or Thurston County)
requirements.
Groundwater or impervious soil layers were not observed in the test pits to the maximum depth of 9 feet.
Washington DOE well logs in the area show groundwater is below 20 feet. Groundwater levels should
not adversely affect infiltration in site soils, in our opinion.
Cation Exchange Capacity (CEC) and organic content test were completed on soils from the base of the
infiltration test holes. Test results are summarized in the table below.
Table 4. CEC and Organic Content Results
Test Location and Sample
CEC Results
CEC Required*
Organic
Organic
Number
(milliequivalents)
(milliequivalents)
Content
Content
Results ( %)
Required* ( %)
PIT -1, S -I (3.5)
6.0
> 5
4.07
>1.0
PIT -2, S -I (3.4 feet)
8.3
> 5
1.34
>1.0
*Per the DOE 2014 Stormwater Management Manual.
CEC results for the two test sites satisfy DOE criteria.
Pavements
Subgrades for conventional pavement areas should be prepared as described in the " Subgrade
Preparation" section of this report. Subgrades below pavement sections should be graded or crowned to
promote drainage and not allow for ponding of water beneath the section. If drainage is not provided and
ponding occurs, the subgrade soils could become saturated, lose strength, and result in premature distress
to the pavement. In addition, the pavement surfacing should also be graded to promote drainage and
reduce the potential for ponding of water on the pavement surface.
Pavement section designs have been prepared and are based on AASHTO design guidelines and the
following assumed design parameters:
• 15 -year life span;
• Estimated design life Equivalent Single Axle Loads (ESALs = 18 kips) of 370,000;
• Estimated subgrade CBR of 15;
• Terminal serviceability of 2.0; and,
• Level of reliability 85 percent.
D:
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSGC
Minimum recommended pavement sections for conventional pavements are presented in Table 5. We
should be notified if actual traffic (ESAL) loads will be greater than those assumed to verify or modify
the pavement sections.
Table 5. Minimum Pavement Sections
' 1/2 —inch nominal aggregate hot -mix asphalt (HN4A) per WSDOT 9- 03.8(1)
2 A 28 day minimum compressive strength of 4,000 psi and an allowable flexural strength of at least 250 psi
3 Crushed Surfacing Base Course per WSDOT 9- 03.9(3)
4Although not required for structural support under concrete pavements, a minimum four -inch thick base course layer is
recommended to help reduce potentials for slab curl, shrinkage cracking, and subgrade "pumping" through joints
5Not included in pavement section thickness
Conventional Pavement Maintenance
The performance and lifespan of pavements can be significantly impacted by future maintenance.
The above pavement sections represent minimum recommended thicknesses and, as such, periodic
maintenance should be completed. Proper maintenance will slow the rate of pavement
deterioration, and will improve pavement performance and life. Preventive maintenance consists of
both localized maintenance (crack and joint sealing and patching) and global maintenance (surface
sealing). Added maintenance measures should be anticipated over the lifetime of the pavement
section if any existing fill or unsuitable materials are left in -place beneath pavement sections.
REPORT CONDITIONS
This report has been prepared for the exclusive use of International Construction Equipment for specific
application to the project discussed, and has been prepared in accordance with generally accepted
geotechnical engineering practices in the area. No warranties, either express or implied, are intended or
made. The analysis and recommendations presented in this report are based on observed soil conditions
and test results at the indicated locations, and from other geologic information discussed. This report
does not reflect variations that may occur across the site, or due to the modifying effects of construction
or weather. The nature and extent of such variations may not become evident until during or after
construction. If variations appear, we should be immediately notified so further evaluation and
supplemental recommendations can be provided, as warranted.
10
Minimum Recommended Pavement Section
Thickness (inches)
Asphalt Concrete
Portland
Aggregate
Compacted
Traffic Area
Surface'
Cement
Base 3,4
Subgrade5
Total
Concrete
Course '
Car Parking
2
-
4
12
6
Access Drive/Truck
4
-
6
12
10
Loading
Access Drive /Truck
-
6
4
12
10
Loading
' 1/2 —inch nominal aggregate hot -mix asphalt (HN4A) per WSDOT 9- 03.8(1)
2 A 28 day minimum compressive strength of 4,000 psi and an allowable flexural strength of at least 250 psi
3 Crushed Surfacing Base Course per WSDOT 9- 03.9(3)
4Although not required for structural support under concrete pavements, a minimum four -inch thick base course layer is
recommended to help reduce potentials for slab curl, shrinkage cracking, and subgrade "pumping" through joints
5Not included in pavement section thickness
Conventional Pavement Maintenance
The performance and lifespan of pavements can be significantly impacted by future maintenance.
The above pavement sections represent minimum recommended thicknesses and, as such, periodic
maintenance should be completed. Proper maintenance will slow the rate of pavement
deterioration, and will improve pavement performance and life. Preventive maintenance consists of
both localized maintenance (crack and joint sealing and patching) and global maintenance (surface
sealing). Added maintenance measures should be anticipated over the lifetime of the pavement
section if any existing fill or unsuitable materials are left in -place beneath pavement sections.
REPORT CONDITIONS
This report has been prepared for the exclusive use of International Construction Equipment for specific
application to the project discussed, and has been prepared in accordance with generally accepted
geotechnical engineering practices in the area. No warranties, either express or implied, are intended or
made. The analysis and recommendations presented in this report are based on observed soil conditions
and test results at the indicated locations, and from other geologic information discussed. This report
does not reflect variations that may occur across the site, or due to the modifying effects of construction
or weather. The nature and extent of such variations may not become evident until during or after
construction. If variations appear, we should be immediately notified so further evaluation and
supplemental recommendations can be provided, as warranted.
10
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
SSG'
The scope of services for this project does not include any environmental or biological assessment of the
site including identification or prevention of pollutants, hazardous materials, or conditions. Other studies
should be completed if the owner is concerned about the potential for contamination or pollution.
We appreciate the opportunity to work with you on this project. Please contact us if additional
information is required or we can be of further assistance.
Respectfully,
South Sound Geotechnical Consulting
Timothy H. Roberts, P.E., R.G.
Member / Geotechnical Engineer
7
Attachments; Figure 1 — Exploration Plan
Appendix A — Field Exploration Procedures and Test Pit Logs
Appendix B — Laboratory Testing and Results
Unified Soil Classification System
cc: AHBL, Inc. — Mr. Scott Kau], P.E.
1
1
Legend
TP -1
69 Approximate Test Pit Location
PIT - 1
❑ Approximate Infiltration Test
Scale: NTS
Sea Ml Sa"d Geotechnical Consulting
P.O. Box 39500
Lakewood, WA 98496
(253) 973 -0515
Base map from Google Earth.
Figure I — Exploration Plan
I.C.E. Facility Expansion
Yelm, WA
SSGC Project #17042
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Appendix A
Field Exploration Procedures and Test Pit Logs
SSGC
A -1
Geotechnical Engineering Report SSGC
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Field Exploration Procedures
Our field exploration for this project included six (6) test pits and two (2) infiltration tests completed on
June 1, 2017. The approximate locations of the explorations are shown on Figure 1, Exploration Plan.
The exploration locations were determined by pacing from site features. Ground surface elevations
referenced on the logs were inferred from Google Earth Imagery. Test pit locations and elevations should
be considered accurate only to the degree implied by the means and methods used.
A private excavation company subcontract to SSGC excavated the test pits and infiltration sites. Soil
samples were collected and stored in moisture tight containers for further assessment and laboratory
testing. Explorations were backfilled with excavated soils and tamped when completed. Please note that
backfill in the explorations will likely settle with time. Backfill material located in roads or building areas
should be re- excavated and recompacted, or replaced with structural fill.
The following logs indicate the observed lithology of soils and other materials observed in the
explorations at the time of excavation. Where a soil contact was observed to be gradational, our log
indicates the average contact depth. Our logs also indicate the approximate depth to groundwater (where
observed at the time of excavation), along with sample numbers and approximate sample depths. Soil
descriptions on the logs are based on the Unified Soil Classification System.
A -1
Project: ICE I SSGC Job # 17042 TEST PIT LOGS PAGE 1 OF 3
Location: Yelm, WA
Depth(feet)
0 -1
1-2.5
2.5 -8
Depth (feet)
0 -1
1 -7
Depth (feet)
0-0.75
0.75-6
Test Pit TP -1
Material Describtion
Fill: Sod over mixed sand, gravel, silt, and cobbles: Loose,
moist, light brown.
Topsoil: Silty SAND with gravel, organics, and cobbles:
Loose, moist dark brown.
Gravelly SAND with cobbles and trace to some silt: Medium
dense, moist, grayish brown. (GW /GP)(Glacial Outwash)
Test pit completed at approximately 8 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 337 feet
Test Pit TP -2
Material Description
Topsoil
SAND with some silt, gravel and cobbles: Medium dense,
moist, brownish gray. (SW /GW) (Glacial Outwash)
Test pit completed at approximately 7 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 337 feet
Test Pit TP -3
Material Describtion
Topsoil
Gravelly SAND with cobbles and trace to some silt: Medium
dense, moist, grayish brown. (GW /GP)(Glacial Outwash)
Test pit completed at approximately 6 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 338 feet
TEST PIT LOGS
South Sound Geotechnical Consulting I TP -1 TO TP -6
FIGURE A -1
Logged by: THR
Project: ICE I SSGC Job # 17042 TEST PIT LOGS PAGE 2 OF 3
Location: Yelm, WA
Test Pit TP -4
Depth (feet) Material Description
0-1.5 Fill: Sand, gravel, silt, and cobbles: Loose, moist, light
brown.
1.5-2.5 Topsoil: Silty SAND with gravel, organics, and cobbles:
Loose, moist dark brown.
2.5-9 Gravelly SAND with cobbles and trace to some silt, and
occasional boulder: Medium dense, moist, grayish brown.
(GW /GP)(Glacial Outwash)
Test pit completed at approximately 9 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 335 feet
Test Pit TP -5
Depth (feet) Material Description
0-0.5 Topsoil
0.5— 1.5 Gravelly SAND with cobbles and trace to some silt: Medium
dense, moist, brownish gray. (GW /GP)(Glacial Outwash)
1.5-2.5 SAND with trace to some silt: Medium dense, moist, gray.
(SW /SP)(Glacial Outwash)
2.5-5 Gravelly SAND with cobbles and trace to some silt: Medium
dense, moist, brownish gray. (GW /GP)(Glacial Outwash)
Test pit completed at approximately 5 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 340 feet
TEST PIT LOGS
South Sound Geotechnical Consulting I TP -1 TO TP -6
FIGURE A -1
Logged by: THR
Project: ICE SSGC Job # 17042 TEST PIT LOGS PAGE 3 OF 3
Location: Yelm, WA
Test Pit TP -6
Depth (feet) Material Description
0-0.5 Topsoil
0.5-4 Gravelly SAND with cobbles and trace to some silt: Medium
dense, moist, brownish gray. (GW /GP)(Glacial Outwash)
4 - 5 SAND with trace to some silt: Medium dense, moist, gray.
(SW /SP)(Glacial Outwash)
Test pit completed at approximately 5 feet on 6/1/17.
Groundwater not observed at time of excavation.
Slight caving of test pit sidewalls
Approximate surface elevation: 341 feet
TEST PIT LOGS FIGURE A -1
South Sound Geotechnical Consulting TP -1 TO TP -6 Logged by: THR
Geotechnical Engineering Report
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Appendix B
Laboratory Testing and Results
SSGC
Geotechnical Engineering Report S S GC
ICE Facility Expansion
Yelm, Washington
SSGC Project No. 17042
June 12, 2017
Laboratory Testing
Select soil samples were tested for organic content and cation exchange capacity (CEC) by Northwest
Agricultural Consultants of Kennewick, Washington. Results of the laboratory testing are included in this
appendix.
Northwest Agricultural
1/0 Consultants
2545 W Falls Avenue
Kennewick, WA 99336
509.783.7450
www.nwag.com
lab @nwag.com
South Sound Geotechnical Consulting
PO Box 39500
Lakewood, WA 98496
PAP - Accredited
Report: 41589 -1
Date: June 5, 2017
Project No: 17042
Project Name: ICE
Sample ID
Organic Matter
Cation Exchange Capacity
IT -1, S -1 @ 3.5'
4.07%
6.0 meq /100g
IT -2, S -1 @ 3.5'
1.34%
8.3 meq /100g
Method
ASTM D2974
EPA 9081
UNIFIED SOIL CLASSIFICATION SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests"
Soil Classification
l
Group
.`x0
'
m
Symbol
Group Name'
Coarse Grained Soils
Gravels
Clean Gravels
Cu >_ 4 and 1 < Cc < 3E
GW
Well- graded gravel'
More than 50% retained
More than 50% of coarse
Less than 5% fines'
Cu < 4 and /or 1 > Cc > 3E
GP
Poorly graded gravel'
fraction retained on
Vertical at LL =16 to PI =7,
G
on No. 200 sieve
No. 4 sieve
Gravels with Fines
Fines classify as ML or MH
GM
Silty grave l'1 "
More than 12% fines
Fines classify as CL or CH
GC
Clayey grave l'1"
Goo
Sands
Clean Sands
Cu >_ 6 and 1 < Cc < 3E
SW
Well- graded sand'
50% or more of coarse
Less than 5% fines'
Cu < 6 and /or 1 > Cc > 3E
SP
Poorly graded sand'
fraction passes
CL - h4L
ML or OL
I
No. 4 sieve
Sands with Fines
Fines classify as ML or MH
SM
Silty sand "'
More than 12% fines'
Fines Classify as CL or CH
SC
Clayey sand"'
Fine - Grained Soils
Silts and Clays
inorganic
PI > 7 and plots on or above "A" line'
CL
Lean claylL
50% or more passes the
Liquid limit less than 50
PI < 4 or plots below "A" line'
ML
SiltKL M
No. 200 sieve
organic
Liquid limit - oven dried
Organic clay"`"'"
< 0.75
OIL
Liquid limit - not dried
Organic siltKLN10
Silts and Clays
inorganic
PI plots on or above "A" line
CH
Fat clay KLM
Liquid limit 50 or more
PI plots below "A" line
MH
K,L,M
Elastic Silt
organic
Liquid limit - oven dried
Organic clayKLMI
< 0.75
OH
Liquid limit - not dried
Organic siltKLN1I
Highly organic soils
Primarily
organic matter, dark in
color, and organic odor
PT
Peat
ABased on the material passing the 3 -in. (75 -mm) sieve
B If field sample contained cobbles or boulders, or both, add "with cobbles
or boulders, or both" to group name.
Gravels with 5 to 12% fines require dual symbols: GW -GM well - graded
gravel with silt, GW -GC well - graded gravel with clay, GP -GM poorly
graded gravel with silt, GP -GC poorly graded gravel with clay.
°Sands with 5 to 12% fines require dual symbols: SW -SM well - graded
sand with silt, SW -SC well - graded sand with clay, SP -SM poorly graded
sand with silt, SP -SC poorly graded sand with clay
ECU = D60/Djc Cc = (D3o )2
Dio x D6o
F If soil contains >_ 15% sand, add "with sand" to group name.
GIf fines classify as CL -ML, use dual symbol GC -GM, or SC -SM.
60
50
a
Lu 40
z
30
U_
Q 20
J
a
10
7
4
0
a
"If fines are organic, add "with organic fines" to group name.
1 If soil contains >_ 15% gravel, add "with gravel" to group name.
J If Atterberg limits plot in shaded area, soil is a CL -ML, silty clay.
KIf soil contains 15 to 29% plus No. 200, add "with sand" or "with
gravel," whichever is predominant.
L If soil contains >_ 30% plus No. 200 predominantly sand, add
"sandy" to group name.
M If soil contains >_ 30% plus No. 200, predominantly gravel,
add "gravelly" to group name.
"PI >_ 4 and plots on or above "A" line.
o PI < 4 or plots below "A" line.
P PI plots on or above "A" line.
PI plots below "A" line.
i
For classification of fine - grained
l
soils and fine - grained fraction
of coarse - grained soils
Equation of W- line
.`x0
'
m
Horizontal at PI =4 to LL =25.5.
then P1 =0.73 (LL -20)
'
O�
Equation of "U" - line
Vertical at LL =16 to PI =7,
G
then P1=0.9 (LL -8)
Goo
r'
MH or
OH
CL - h4L
ML or OL
I
10 16 20 30 40 50 60 70 80 96 100 110
LIQUID LIMIT (LL)
South Sound Geotechnical Consulting
June 28, 2017
International Construction Equipment (I.C.E.)
8101 Occidental Avenue S.
Seattle, WA 98108
Attention: Mr. Josh Angel
Subject: Geotechnical Engineering Addendum
ICE Facility Expansion
925 North Pacific Road SE
Yelm, Washington
SSGC Project Number: 17042
Mr. Angel,
We understand modifications are being considered to the entrance drive from North Pacific Road SE and
loading areas for the ICE facility expansion in Yelm, Washington. Specifically, these areas will not have
an asphalt (or concrete) surface as originally discussed in our geotechnical report for the site (dated June
12, 2017), but will be gravel covered.
We recommend the native subgrade in access drive and loading areas are prepared as described in our
June 12, 2017 report for gravel road sections. Native subgrades should be sloped to drain towards
planned stormwater treatment facilities. Proper grading and compaction of native subgrades will
significantly reduce the potential for precipitation infiltrating into lower native soils. Evidence of
standing water in low spots on the existing gravel drive was observed during the field evaluation for our
June 12, 2017 report, indicating limited vertical infiltration.
A minimum 12 inch section of ballast conforming to Section 9- 03.9(2) of the 2014 WSDOT "Standard
Specifications for Road, Bridge, and Municipal Construction Manual" (M -41) should be placed above the
prepared subgrade. It should be placed in two separate lifts with each lift compacted to at least 95 percent
of the maximum dry density (MDD) per ASTM D 1557 and to a firm and unyielding condition. Proper
compaction and the fines content (material passing the US No. 200 sieve) of the ballast will further reduce
infiltration potential of the gravel pavement section into native subgrades.
A working surface of crushed rock could be considered to level gravel sections. This layer should be at
least 6 inches thick and conform to Section 9- 03.9(3) of the 2014 WSDOT M -41 manual and compacted
to at least 95 percent of the MMD per ASTM D 1557. Top course or base course material could be used
for this purpose. It should be noted that the upper portion of the crushed surfacing material will likely
become looser with time. This is caused by loss of fines in the crushed rock from precipitation as well as
from short radius turns by vehicles. Alternatively, the ballast section described above could be increased
to 18 inches, placed in three separate lifts to facilitate reduction in infiltration potential.
P.O. Bog 39500, Lakewood, WA 98496 (253) 973 -0515
Geotechnical Engineering Addendum
ICE Facility Expansion
YeIm, Washington
SSGC Project No. 17042
June 28, 2017
SSCIC
Road Maintenance
The performance and lifespan of gravel roads are highly dependent on weather conditions
(freeze /thaw cycles, precipitation), loaded truck traffic volume, and drainage. Maintenance of
gravel roads should be anticipated to be much higher than conventional asphalt or concrete
surfaced pavements. Maintenance should include filling of low spots (pot holes) as quickly as
possible toaimit disturbance to subgrade soils.
Please contact us if additional information is required or we can be of further assistance.
Respectfully,
South Sound Geotechnical Consulting
Timothy H. Roberts, P.E., R.G.
Member /Geotechnical Engineer
J7
cc: AHBL, Inc. — Mr. Scott Kaul, RE,
2