HomeMy WebLinkAboutDrainage Report -Revision - PLN General - 10/30/2018 Drainage Report
RECEIVED Belfair Park and Ride
NOV 16 2018 Mason Transit Authority
615 W. Alder street Mason County
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SCJ ALLIANCE
CONSULTING SERVICES
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Drainage Report
Proiect Information
Project: Mason Transit Authority Belfair Park and Ride
Prepared for: Mason Transit Authority
Reviewing Agency
Jurisdiction: Mason County
Project Representative
Prepared by: SO Alliance
8730 Tallon Lane NE,Suite 200
Lacey,WA 98516
360.352.1465
scjalliance.com
Contact: Whitney Holm, PE
Project Reference: SO#0738.05
Path:N:\Projects\0738 Mason Transit Authority\0738.05 MTA Park and Ride
Development\Phase 9-Design Development\Belfair\Drainage\2018-1016
Drainage Report.docx
SO Alliance November 2018
L�
Page 1 of 1
Michael MacSems -Re: Mason Transit Authority Stormwater Review
From: Patrick Holm patrick.holm@scjalliance.com
To: <mms@co.mason.wa.us>
Date: 11/16/2018 9:30 AM
Subject: Re: Mason Transit Authority Stormwater Review
Attachments: 2018-1116 Drainage Report(signed).pdf
Michael,
We made a revision to the drainage report in the SWPPP regarding required element 13. The revised
drainage report is attached. That was the only change.
On Fri,Nov 16, 2018 at 9:29 AM Patrick Holm<patrick.holm(t�r�,scjalliance.com>wrote:
Michael,
I'm attaching the SWPPP Checklist.
On Wed,Nov 7, 2018 at 3:24 PM Michael MacSems<mms&o.mason.wa.us>wrote:
Hello Patrick Holm,
I'm the forest practice reviewer for Mason County and today I began reviewing the FPA application
for the MTA park and ride in Belfair. I noted that your submittal included a Drainage Report,but did
not include the required submittal checklist that we use to determine that such plans are complete.
Please complete the attached checklist,complete it and return it to me (PDF is fine).
Thank you,
Michael MacSems
FPA Reviewer
Patrick Holm,PE
SG Alliance
Project Manager
o.360.352.1465
m.909.644.5315
www.scoalliance.com
This communication may contain privileged or other confidential information.If you have received it in error,please advise the sender by reply email and immediately
delete the message and any attachments without copying or disclosing the contents.Thank you.
Patrick Holm,PE
SG Alliance
Project Manager
o.360.352.1465
m.909.644.5315
www.scoalliance.com
This communication may contain privileged or other confidential information.If you have received it in error,please advise the sender by reply email and immediately
delete the message and any attachments without copying or disclosing the contents.Thank you.
file:///C:/Users/mms/AppData/Local/Temp/XPgrpwise/5BEE8E53Masonmail l 00161346... 11/19/2018
TABLE OF CONTENTS
1. Project Overview........................................................................................................1
1.1 Site Data ................................................................................................................................ 1
1.2 Project Overview...................................................................................................................1
2. Existing Condition Summary.......................................................................................2
2.1 Site Description .....................................................................................................................2
3. Offsite Analysis Report...............................................................................................2
3.1 Upstream Analysis.................................................................................................................2
3.2 Downstream Analysis............................................................................................................2
4. Permanent Stormwater Control Plan..........................................................................2
4.1 Existing Site Hydrology..........................................................................................................2
4.2 Developed Site Hydrology.....................................................................................................3
4.3 Flow Control System..............................................................................................................3
4.4 Performance Standards and Goals........................................................................................3
4.5 Water Quality System............................................................................................................4
4.6 Conveyance System Analysis and Design..............................................................................5
4.7 Minimum Requirements.......................................................................................................5
5. Construction Stormwater Pollution Prevention Plan ...................................................6
5.1 Objective of the Stormwater Pollution Prevention Plan.......................................................6
5.2 Summary of Elements...........................................................................................................6
6. Special Reports and Studies......................................................................................11
7. Other Permits...........................................................................................................11
8. Operation and Maintenance Manual........................................................................12
8.1 Overview..............................................................................................................................12
8.2 Required Maintenance........................................................................................................12
LIST OF APPENDICES
Appendix A—Basin Map
Appendix B—Construction Plans
Appendix C—Drainage Calculations
Appendix D—Geotechnical Report
SG Alliance November 2018
Page i
PROJECT
1.1 SITE DATA
Project Proponent: Belfair Park and Ride
Total Site Area: 4.0 acres
Required Permits: Grading,Special Use,Construction, Building, NPDES
Parcel Numbers: - - -
ItJZI - L1I 6ocv
1.2 PROJECT OVERVIEW
Currently,there is undeveloped forestland at the southwest corner of State Route 3 and Log Yard Road.
The site is owned by Mason Transit Authority.They plan on constructing a park and ride, including
parking stalls, a bus turnaround,a bus shelter,and an MTA building.
Figure 1. Project Location
r
1
Stormwater currently infiltrates on site.The proposed site will have three basins. Basin 1 includes the
offsite access road; Basin 2 includes the main parking lot;and Basin 3 includes the bus parking,
turnaround area,and the building.See attached Basin Map.
The runoff from Basin 1 and Basin 2 will be collected and treated in a bioretention facility and then
piped to an infiltration pond on site. Basin 3 will sheet flow into a biofiltration Swale for treatment and
conveyance to the onsite infiltration pond.
SCJ Alliance November 2018
Page 1
The proposed stormwater will infiltrate 100%,matching the predeveloped patterns. See the Drainage
Basin Exhibits in Appendix A.
The proposed project follows the new development requirements stated in the Department of Ecology's
2005 Stormwater Management Manual for Western Washington (SMMWW). From Figure 2.4.1—Flow
Chart for Determining Requirements of New Development of the SMMWW minimum requirements#1-
#10 need to be applied to the new and replaced impervious surfaces.
EXISTING CONDITION SUMMARY
2.1 SITE DESCRIPTION
The existing site is heavily forested. It is generally flat in the areas of proposed improvements,although
some portions of the site slope as much as approximately 15%down to the northwest.There are no
storm drainage systems on site.The stormwater infiltrates on site.
Landau Associates completed a geotechnical report in September 2017. Landau tested 10 pits between
12.5 and 16.3 feet below ground surface.The tests found that the area was covered in 0.75 to 2.5 feet
of forest duff and topsoil. Forest duff consisted of leaves,fir needles,and other decomposed organics.
The topsoil was typically a brown, loose to medium dense,silty sand with variable gravel and organic
content. Below the forest duff/topsoil layer was ice-contact deposits.This layer consisted of brown to
gray, medium dense to very dense sand with variable silt,gravel, and cobble content or brown to gray,
dense to very dense gravel with variable silt, sand,and cobble content. Landau's preliminary factored
infiltration rates range from 0.1 inches per hour to 1.8 inches per hour. See the Geotechnical
Engineering Report in Appendix D.
• REPORT
3.1 UPSTREAM ANALYSIS
The surrounding properties are heavily forested area. No runoff appears to flow onto the site.
3.2 DOWNSTREAM ANALYSIS
All runoff will infiltrate. No downstream effects are anticipated. See the stormwater analysis in Appendix
C.
PERMANENT STORMWATER • ■ •
4.1 EXISTING SITE HYDROLOGY
See Section 2.1 for the hydrology of the existing site.
SCJ Alliance November 2018
Page 2
4.2 DEVELOPED SITE HYDROLOGY
The site has three basins.The stormwater system is designed using the SMMWW and WWHM2012.
Basin 1 includes the offsite improvements, Basin 2 includes the parking lot area,and Basin 3 includes the
bus parking and turnaround area. See the Basin Area Exhibits in Appendix A.
Table 4.1 Developed Conditions Summary
Impervious Pervious Total Basin
Area (acres) Area(acres) Area(acres)
Basin 1 0.52 0.37 0.89
Basin 2 0.98 0.91 1.89
Basin 3 1.68 1.71 3.39
The runoff from Basin 1 will be collected and conveyed to the bioretention facility. Infiltration is
anticipated in the bioretention facility,and an infiltration rate of 1.0 inch per hour was used in modeling.
The infiltration rate was averaged from two of the closest test pits to the bioretention facility Landau
dug to assume 1.0 inch per hour. Runoff from Basin 2 will sheet flow to a conveyance ditch and then
flow into the bioretention facility. Overflow from the bioretention facility will be collected in a beehive
catch basin and conveyed to an infiltration pond on site. Runoff from Basin 3 will sheet flow to a
biofiltration swale for treatment and be conveyed to the onsite pond.The pond is designed to infiltrate
100%of all the runoff from all three basins. Based on the Geotechnical Report,an infiltration rate of 0.4
inches per hour was used for the infiltration pond.
See Figure 2 and Table 5 in the Geotechnical Report (Appendix D)for field-measured infiltration rates.
4.3 FLOW CONTROL SYSTEM
Flow control has been designed to handle the 100-year event. Runoff will infiltrate in the bioretention
facility and the infiltration pond. Using an infiltration rate of 0.4 in/hr. a 14,000 square-foot pond with
5.5 feet of depth will adequately infiltrate the 100-year storm for all three basins.The 5.5 feet of depth
includes 1.0 feet of freeboard.
See Appendix C for drainage calculations.See Figure 2 and Table 5 in the Geotechnical Report
(Appendix D)for field measured infiltration rates.
4.4 PERFORMANCE STANDARDS AND GOALS
The proposed park and ride is considered a new development project.The basic treatment menu has
been selected for this project, and oil control and phosphorous control are not required. Flow control
has been designed per the Standard's 100-year, 24-hour storm,and the conveyance system was
designed to handle a 25-year, 24-hour storm.
SCJ Alliance November 2018
Page 3
4.5 WATER QUALITY SYSTEM
Treatment of stormwater runoff from Basins 1 and 2 will be provided by a bioretention facility.
Stormwater runoff treatment for Basin 3 will be provided by a biofiltration swale.They were designed
using the SMMWW.
Using an approved continuous runoff model to infiltrate 91%of the site's runoff,2,500 square feet of
bioretention area is required to treat both Basin 1 and Basin 2.The bioretention facility includes 1.5 feet
of amended soils,0.5 feet of ponding,and 0.5 feet of freeboard.
Basin 3 will be treated using a biofiltration swale.The biofiltration swale is designed according to BMP
T9.10 and the design calculation steps in Volume 5 Section 9.4 of the SMMWW.The swale is designed to
be 4.1-feet wide with a 1.5%longitudinal slope.The swale will be one-foot deep with four inches of
ponding.The required length is 465-feet long.The project site uses a 640-foot-long swale. See the
Proposed Conditions Exhibit in Appendix A for treatment areas.
Below is a summary of the analysis.
EQUATIONS UNITS LEGEND
2.5Qn b = bottom width of swale(ft) = 4.1
b _ 1.49y1 67s0 5 -Zy Q = 6-month, 24-hour storm event(cfs) _ .2405
n = Manning's roughness coefficient = 0.24
=Q y = depth of flow(ft) _ .33
V = A s = slope parallel to direction of flow = 0.015
(ft/ft)
Z = swale side slopes(ft:ft) = 3:1
L = V(t)(60) V = design flow velocity(fps) = unknown variable
A = swale flow area ff) = 1.68
L = required swale length(ft) = unknown variable
Ratio of peak 10-minute flow
k = predicted by SBUH to the water = 3 0
quality design flow rate estimate using
WWHM
t = 9 minutes or 18 minutes for = 18
continuous inflow
Length of flow requirements for biofiltration swale
2.5Qn
b = 1.49y167s0 s -Zy
b — 1.49(0032)067(00015)05 -(3)(0.33) = 4.04 b=4.1 ft
SCJ Alliance November 2018
Page 4
V = kQ = (3.0)(0.2405) = 0.43 0.43 fps< 1.0 fps
A 1.68
L = Vt(60) = 0.43(18)(60) = 464.4 ft Minimum Swale
length=465 ft
See Appendix C for drainage calculations.
4.6 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The SMMWW requires the system to be able to convey the 25-year storm,2.33 cfs. However,the
conveyance system is large enough to handle 4.28 cfs,which is larger than the 100-year storm for the
entire site, 3.15 cfs.The designed system allows for high flow capacity so that runoff does not flood a
the bioretention area or swale.
See Appendix C for flow control calculations.
4.7 MINIMUM REQUIREMENTS
The stormwater design complies with all ten minimum requirements as follows:
Minimum Requirement#1—Preparation of Stormwater Site Plans—This summary is contained within
the stormwater site plan.
Minimum Requirement#2—Construction Stormwater Pollution Prevention—A pollution prevention plan
has been included within the stormwater site plan,which describes the 12 required elements. Further,
an erosion control plan has been prepared and is part of the engineering plan set.
Minimum Requirement#3—Source Control of Pollution—The project owner has been made aware of
the requirements for source control for pollution prevention.
Minimum Requirement#4—Preservation of Natural Drainage Systems and Outfalls—Runoff from the
project site currently infiltrates on site. Stormwater runoff from the developed site will infiltrate
completely on site as well.
Minimum Requirement#5—Onsite Stormwater Management—Runoff from Basin 1 and Basin 2 will
convey to a bioretention facility for water quality treatment and Basin 3 will sheet flow to a biofiltration
Swale for treatment. Runoff is conveyed from both facilities to an infiltration pond where runoff will
completely infiltrate on site.
Minimum Requirement#6—Runoff Treatment—Runoff treatment is provided by a bioretention facility
and a biofiltration swale.
Minimum Requirement#7—Flow Control—Runoff from the site will be conveyed to an infiltration pond
and infiltrated 100%.
Minimum Requirement#8—Wetlands Protection—There are no known wetlands on site.
SCJ Alliance November 2018
Page 5
Minimum Requirement#9—Basin/Watershed Planning—There is no additional basin/watershed for this
area.
Minimum Requirement#10—Operation and Maintenance—An operation and maintenance manual is
included with this stormwater site plan. Refer to Section 8 for additional information.
CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN
5.1 OBJECTIVE OF THE STORMWATER POLLUTION PREVENTION PLAN
The purpose of a construction Stormwater Pollution Prevention Plan(SWPPP) is to describe the
potential for pollution problems on a construction project.The SWPPP also explains and illustrates the
measures to be taken on the construction site to control these problems.The SWPPP is a guideline for
the contractor to follow during construction to prevent erosion and sedimentation. Erosion control
measures are not limited to those shown in this SWPPP or on the temporary erosion and sediment
control (TESL) plans. Measures shall be installed as necessary to meet the DOE guidelines for
construction stormwater pollution prevention and the requirements of the DOE NPDES permit. Further,
the SWPPP shall be updated by the contractor as required by the requirements of the DOE NPDES
permit.
This SWPPP is prepared according to the guidance of the Stormwater Management Manual for Western
Washington—Washington State Department of Ecology(DOE).The DOE manual describes 12 necessary
elements of construction stormwater pollution prevention.These 12 elements include: mark clearing
limits,establish construction access,control flow rates, install sediment controls,stabilize soils, protect
slopes, protect drain inlets,stabilize channels and outlets,control pollutants, control dewatering,
maintain BMPs, and manage the project.These elements have been addressed as follows:
5.2 SUMMARY OF ELEMENTS
The Best Management-Practices(BMPs) listed in this report, or their equivalent, are required.Any
revisions by the contractor to the BMPs listed in the SWPPP shall be approved by the Engineer in
writing.Therefore, if the contractor does not require a BMP or needs to modify a BMP,the contractor
shall document the reasons and present the documentation to the Engineer for approval.
ELEMENT#1:MARK CLEARING LIMITS
Prior to beginning land disturbing activities, including clearing and grading, clearly mark all clearing limits
including trees that are to be preserved within the construction area. Fences shall be constructed as
shown on the TESC Plans and per the details in the landscape plans. In addition,the following BMPs will
be implemented where appropriate:
• BMP C101: Preserving Natural Vegetation
• BMP C103: High Visibility Plastic or Metal Fence
• BMP C104: Stake and Wire Fence
SCJ Alliance November 2018
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ELEMENT#2:ESTABLISH CONSTRUCTION ACCESS
A stabilized construction entrance shall be constructed to minimize the tracking of sediment onto any
public road.The stabilized construction entrance shall be constructed as shown on the TESC plans and in
accordance with the requirements of BMP C105.
ELEMENT#3:CONTROL FLOW RATES
Properties and waterways downstream from development sites shall be protected from erosion due to
increases in the volume,velocity, and peak flow rate of stormwater runoff from the project site.The
following BMP will be implemented where appropriate:
• BMP C240: Sediment Trap
ELEMENT#4:INSTALL SEDIMENT CONTROLS
Prior to leaving a construction site or prior to discharge into an infiltration facility,stormwater runoff
must pass through a sediment pond or other appropriate sediment removal BMP. Silt fence barriers
shall be constructed as shown on the Temporary Erosion Control Plans and in accordance with BMP
C233. In addition,the following BMPs will be implemented where appropriate:
• BMP C230: Straw Bale Barrier
• BMP C231: Brush Barrier
• BMP C232: Gravel Filter Berm
• BMP C234: Vegetated Filter Strip
• BMP C235: Straw Wattles
• BMP C240: Sediment Trap
• BMP C241: Temporary Sediment Pond
• BMP C251: Construction Stormwater Filtration
ELEMENT#5:STABILIZE SOILS
All exposed and unworked soils shall be stabilized by application of effective BMPs,which protect the
soil from the erosive forces of raindrop impact and flowing water, and from wind erosion. From October
1 through June 30, no soils shall remain exposed and unworked for more than 15 days. From July 1 to
September 30, no soils shall remain exposed and unworked for more than 30 days.This condition
applies to all onsite soils,whether at final grade or not.
In areas where the soils will remain unworked for more than the limits stated above or have reached
final grade,seeding and mulching shall be used in accordance with BMPs C120 and C121. Sod shall be
used in accordance with BMP C124 for disturbed areas that require immediate vegetative cover. Dust
control shall be used as needed to prevent wind transport of dust from disturbed soil surfaces and in
accordance with BMP C140.
In addition,the following BMPs will be implemented where appropriate:
SCJ Alliance November 2018
Page 7
• BMP C123: Plastic Covering
• BMP C125: Topsoiling
ELEMENT#6:PROTECT SLOPES
Slopes shall be constructed in a manner that will minimize erosion.This shall include, but is not limited
to, placing excavated material on the uphill side of trenches,collecting drainage at the top of slopes, etc.
Slopes will be stabilized as indicated in Element#5. In addition,the following BMPs will be implemented
where appropriate:
• BMP C130—Surface Roughening
• BMP C131—Gradient Terraces
• BMP C200—Interceptor Dike and Swale
• BMP C201—Grass-Lined Channels
• BMP C205—Subsurface Drains
• BMP C204—Pipe Slope Drains
• BMP C206—Level Spreader
• BMP C207—Check Dams
ELEMENT#7.PROTECT DRAIN INLETS
All storm drain inlets made operable during construction as well as all existing structures within the
project limits shall be protected so that stormwater runoff shall not enter the conveyance system
without first being filtered or treated to remove sediment. Install catch basin sock filters as shown on
the TESC plans and in accordance with BMP C220.
ELEMENT#8:STABILIZE CHANNELS AND OUTLETS
All temporary onsite conveyance channels shall be constructed and stabilized to prevent erosion.
Stabilization, including armoring material, adequate to prevent erosion of outlets,adjacent to stream
banks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems.The
following BMPs will be implemented where appropriate:
• BMP C202—Channel Lining
• BMP C209—Outlet Protection
ELEMENT#9:CONTROL POLLUTANTS
All pollutants, including waste materials and demolition debris,that occur on site during construction
shall be handled and disposed of in a manner that does not cause contamination of stormwater.
Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain
down,solvent and de-greasing cleaning operations,fuel tank drain down and removal,and other
activities that may result in discharge or spillage of pollutants to the ground or into stormwater runoff
must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be
cleaned immediately following any discharge or spill incident. Emergency repairs may be performed on
SCJ Alliance November 2018
Page 8
site using temporary plastic placed beneath and, if raining,over the vehicle.Application of agricultural
chemicals, including fertilizers and pesticides,shall be conducted in a manner and at application rates
that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations shall be
followed for application rates and procedures.
Three source control BMPs will apply to this project:
• A Spill Prevention Plan (prepared by Contractor)
• Maintenance of Storm Drainage Facilities(by Contractor during construction; by City following
construction)
• Street Sweeping(as needed during construction by Contractor)
ELEMENT#10:CONTROL DE-WATERING
All foundation,vault,and trench de-watering water,which have similar characteristics to stormwater
runoff at the site, shall be discharged into a controlled conveyance system prior to discharge to a
sediment pond.
Clean, non-turbid de-watering water,as determined by the Certified Professional in Erosion and
Sediment Control,can be discharged to systems tributary to state surface waters, provided the de-
watering flow does not cause erosion or flooding of receiving waters.These clean waters should not be
routed through stormwater sediment ponds.
Highly turbid or otherwise contaminated de-watering water,such as from construction equipment
operation,clamshell digging,concrete tremie pour,or work inside a cofferdam,shall be handled
separately from stormwater at the site. Some disposal options,depending on site constraints, may
include: 1)transport off site in vehicle,such as a vacuum flush truck,for legal disposal in a manner that
does not pollute state waters, 2)onsite treatment using chemical treatment or other suitable treatment
technologies,or 3)sanitary sewer discharge with local sewer district's approval if there is no other
option.
ELEMENT#11:MAINTAIN BMPs
All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as
needed to ensure continued performance of their intended function. All maintenance and repair shall be
in accordance with BMPs.
Sediment control BMPs shall be inspected weekly or after a runoff-producing storm event during the dry
season and daily during the wet season.
All temporary erosion and sediment control BMPs shall be removed within 30 days after final site
stabilization is achieved or after the temporary BMPs are no longer needed.Trapped sediment shall be
removed or stabilized on site. Disturbed soil areas resulting from removal of BMPs or vegetation shall be
permanently stabilized.
SCJ Alliance November 2018
Page 9
ELEMENT#12:MANAGE THE PROJECT
• Phasing of Construction
The project shall be phased where feasible to prevent,to the maximum extent practicable,the transport
of sediment from the site during construction. Revegetation of exposed areas and maintenance of that
vegetation shall be an integral part of the clearing activities for each phase.
• Seasonal Work Limitations
From October 1 through April 30,clearing,grading,and other soil disturbing activities shall only be
permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be
prevented from leaving the construction site.
The following activities are exempt from the seasonal clearing and grading limitations:
1. Routine maintenance and necessary repair of erosion and sediment control BMPs;
2. Routine maintenance of public facilities or existing utility structures that do not expose the soil or
result in the removal of the vegetative cover to the soil; and
3. Activities where there is 100%infiltration of surface water runoff within the site in approved and
installed erosion and sediment control facilities.
• Inspection and Monitoring
All BMPs shall be inspected, maintained, and repaired as needed to ensure continued performance of
their intended function.
The Certified Professional in Erosion and Sediment Control for this project is
shall be on site or on call at all times during
construction.The role of the Certified Professional is to identify problems or failures of erosion control
measures in the field and to promptly initiate corrective measures.The Certified Professional and the
contractor will be paid by contractor.
Sampling and analysis of the stormwater discharges from the construction site may be necessary to
ensure compliance with standards.
Whenever inspection and/or monitoring reveals that the BMPs identified in the construction SWPPP are
inadequate due to the actual discharge of or potential to discharge a significant amount of any
pollutant,the construction SWPPP shall be modified,as appropriate, in a timely manner.
• Maintenance of the SWPPP
The construction SWPPP shall be retained on site or within reasonable access to the site.The
construction SWPPP shall be modified whenever there is a significant change in the design,construction,
operation,or maintenance of any BMP.
SC-7 Alliance November 2018
Page 10
ELEMENT#13:PROTECT LOW IMPACT DEVELOPMENT BMPS
. Protect all Bioretention and Rain Garden BMPS :
1. Bioretention and Rain Garden BMPS will be protected from sedimentation through installation and
maintenance of erosion and sediment control BMPS on portions of the site that drain into the
Bioretention and/or Rain Garden BMPs. BMPS will be restored to their fully functioning condition if
they accumulate sediment during construction. Restoration will include removal of sediment and
any sediment-laden Bioretention/Rain Garden soils and replacement with soil that meets the design
specification.
2. Compaction will be prohibited in Bioretention and Rain Garden BMPS by excluding construction
equipment and foot traffic. Completed lawn and landscaped areas will be protected from
compaction due to construction equipment.
3. Heavy vehicles will not be allowed on existing soils under LID facilities that have been excavated to
final grade to retain infiltration rate of the soil.
• BMP C103: High Visibility Plastic or Metal Fence
• BMP C230: Straw Bale Barrier
• BMP C231: Brush Barrier
• BMP C232: Gravel Filter Berm
• BMP C233: Silt Fence
• BMP C234: Vegetated Filter Strip
• BMP C235: Straw Wattles
. BMP C240: Sediment Trap
• BMP C241: Temporary Sediment Pond
• BMP C251: Construction Stormwater Filtration
SPECIAL ' • '
Landau Associates completed a Geotechnical Engineering Report in September 2017. It can be found in
Appendix D.
OTHER
No other permits are anticipated at this time.
SO Alliance November 2018
Page 11
OPERATION
8.1 OVERVIEW
Onsite drainage facilities such as pipes, bioretention areas, biofiltration swales,and infiltration ponds
will require routine maintenance.The owner is responsible for performing regular maintenance of the
storm drainage facilities. Mason County will provide technical assistance at the owner's request.
Maintenance of private storm drainage facilities will be performed by the owner and/or their
representative.
8.2 REQUIRED MAINTENANCE
Facility-specific maintenance standards contained in this section are intended to be conditions for
determining if maintenance actions are required as identified through inspection. Based upon inspection
observations,the inspection and maintenance schedules shall be adjusted to minimize the length of time
that a facility is in a condition that requires a maintenance action.
The jurisdiction may be called for technical assistance. Please do not hesitate to call,especially if it is
unclear whether a particular situation may be a problem.
SCJ Alliance November 2018
Page 12
APPENDIX A
BASIN MAP
LEGEND. �
o _ ! BASIN
TOTAL
AREA.In ACRES -,\
0 _ PERVIOUS AREA.1.74 ACRES \
IMPERVIOUS AREA 0.15 ACRES
BASH 1'.OFFSITE RUNOFF _ n,
TOTAL AREA 0.89 ACRES
I PERVIOUS AREA:OM ACRES
MPERVIOUS AREA:OAS ACRES
I T
I
l�
j L-P-ARKING LOT RUNOFF
I TOTAL AREA 0.39 ACRES
j PERVIOUS AREA O.IS ACRES rid
iIMPERVIOUS AREA:0.21 ACRES
f
,
---------------- - ------------ - - - - - = -
e
�i BELFAIR PARK AND RIDE EK-1
SCJ ALLIANCE
S EXISTING CONDITIONS EXHIBIT
1
i
I
LEGEND:
eAsx l:an'srt xlxnr e.As.AxA �.
O 919xke Ailt
j BASIN I.OFFSITE RUNOFF
TOTAL AREA.019 ACRES
PERVIOUS AREA.O37 ACRES
IMPERVIOUS AREA:0.52 ACRES I 1— ———-
N!
` BASIN 2:PARKING LOT RUNOFF
i TOTAL AREA.1.89 ACRES
PERVIOUS AREA:0.91 ACRES
l i 9.1PERVIOIS AREA:0M ACRES
I
`B10FILTRATION S'N LE
i
j I si I I
BASH 3.BUS PARIRM LOT RUNOFF
TOTAL AREA 3.39 ACRES
PERVIOUS AREA III ACRES
IMPERVIOUS AREA 1.68 ACRES 'IKg
PGIS:1.16 ACRES
`INFILTRATION POND NG�-0.19 ACRES y
I Pow:0M ACRES \ /
t
l t ,
t
BELFAIR PARK AND RIDE EX-1
SC..I/MJJANcC '
PROPOSED CONDfiIONS EXLIBR
1
i
it
I
APPENDIX B
CONSTRUCTION PLANS
T.23 N.,R.01 W.,S.21,W.M.
LEGEND i. •. ��.. _ '
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_nra max \ `R cs�n,,,mlflr �'t dcw.,a iastar 'vaBf'7 mRs
I(Iq i ulao rleq '` .ryur rvet iz An � •• � � B
i
->♦-sm.IK P.al 'd+d4Pr,1a'n �... ..: 6 . .4 ��� � ,..�i j `��
■ cA,a msN rm i
GRADING NOTES. v \. •.)
r.�rcr ns¢ars ra s,ae rw xn.ax (I - B- ','4 }''. i� .. 'fi � I ,�,`•,`•.
x Wirv.cla aru FMBII[MERE 6 RLYrzt 1 • ` _ r. � 1'•
Rn,ranawxN sArxr a nxxmsr uc �I � € � I ..
a sror f1LWnaS ARMSFNr Ia9tD Q4h 1r
ne.a(auss Bnms Norm I I� . � �:, r •rt
7F
Am... _ !
au.
.art mm it m)
a11Er I?
rb 57U 6-Rr I1 ,,,• .MMPa 4aaE J':4 I 7.i
y ,mrm q%3iiriu'M
sM�ar ..._
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L u
(
1 1
MASON TRANSIT AUTHORITY �S0.1
QQ v�"aET $GJ II WRA�NC6 BELFAIRIDE
"� . � PARK AND RIDE DEVELOPMENT
.• GR OW AND DRAINAGE PLAN 1 of 3
123 N.,R.01 W.,S.21,W.M.
o
oo y ......�.. YI n
o
OO HK
Rm-WR
��� rcrw.w eoe..vl as
AdELLble
L I �{ YAYYA[NfY.¢MC imiCM.IIC
T-L---ID'I il'�.I- YAIWAL-¢KIIL POI ASTI ISb.¢m-n-a .rwaw .�.r.�.a
.Ytvmurt Yoar Im as r�rlYem�s
PA[I rp 9tl®I .w.a...w
BEEHIVE GRATE FOR USE WITH SAI60 30'X3/'REV FRAME
¢IgsaP< ¢Igsm
YA.goo
>w. ........... ......:..R run aml
... 45 iNFF[0/li ®YL W1F
Y Ann
A�
i i ♦r ru ...._ _._
¢5
uy ........... ........................:..NYC............. ....... a• ............... ... ......
I[PN
y .............. .:...................:... .............. ........ y ' '
g
SECTION A-A ... ...a
SECTION B-B
' wynu[Y�tous � MASON TRANSIT AUTHORITY 4 SD-2
f ,�� sllowl MiEFI S+w AdJJ^NCE BELFAIR
PARK AND RIDE--L-.ENT 91`
GRADING AND DRAINAGE DETAILS 2 of 3
T.23 N.,R.01 W.,S.21,W.M.
—T-2)
i66. . ........................
----- -------------
----------------- - .............b.
fw"wff. ......... . .........
_T ..........
WCH SECTION DC DITCH SECTION D-0 DRAINAGE SWALE SECTION E-E
sic
POND MAINTENANCE ACCESS ROAD
�DRCNSKM MASON TRANSIT AuniDRITY SD-3
�NRET SCJ ALLIANCE NVAIR
PARK AND RUE DEVELOPUFNT
DRAINAGE DETAILS 3 of 3
APPENDIX C
DRAINAGE CALCULATIONS
SMMWW Minimum Requirements
Start Here
1
Does the site have See Redevelopment
35/o or more of Yes Minimum
existing impervious --
Requirements and
coverage? Flow Chart
No Does the project convert (Figure 3.3)
%acres or more of
Does the project vegetation to lawn or
result in 5,000 landscaped areas,or
square feet,or No convert 2.5 acres or more
greater,of new plus of native vegetation to
replaced hard pasture?
surface area?
Does the project
Yes Yes No result in 2,000 square
IF feet, or greater,of
new plus replaced
All Minimum hard surface area?
Requirements apply
to the new and
replaced hard surfaces
and converted YefDoes
No
vegetation areas. IF
Minimum Requirements e project have
#1 through#5 apply to disturbing
the new and replaced ties of 7,000
hard surfaces and the Yefeet or greater?
land disturbed.
No
Minimum
Requirement#2
applies.
Figure 2.4.1 -Flow Chart for Determining Requirements for New Development
Volume 1-Minimum Technical Requirements-August 2012
2-10
WWHM: Treatment and Flow Control
Predeveloped Basins
n Basin 1 Predeveloped 04 p Basin 2 Nedeveloped
Subbasin Name:l Su66esin Nnme:'Baair 2 �
Surlace Inlerflow Group inalm Surface Irsedbw Broundweles
Flows To: _-. I� Flows To: r..----
Area in Basin r-show Dry seieded Area in Basin r Show Ony sabaed
ilable
Ames
vailable
le
xw
r�/B—aFp-si.orissi,S iesta,Mod
eep-Pervious r AROnD55 r- RaADSEEP Impervious Acre r FI moue Acres r AROODWWaS/bSTDEEImpervious
� �
rA�idit,Fk ] r ROOFTOPsh7AT ,'r AR,Paue.FW _'0 r TOPS/FIAT
o r AYS
r AR, adua,Mod r DRIVEWAYS/FI.AT 'r -� F
Sam r DRNswnYs/KIOD ---- rA/B,Pmtua� 0 r DITIVEWAYSAM _ r_r-AR.Palsss.
f-A/B,Lawn.Flat r DRNEWAYs/STEEP-� r�•u .TW 1 0 r oRNEwAYSK P _ C
r 1 r SIDEWALKS/FIAT r AM.Lawn Mod p r SIDEWALKSAUT
�rAB,Lawn.Steep b -� r SIDEWAL AQ
r Ars.l.wn seep r siDEWAucsn�oo
r C,Fxd Flat r SIDEwALKSKTEEP r C Fwed Fld r SIDEWALKSKiEEP
r C ForeM Mad r- PARNOAW C� Ir
Ir C.Padw p r FMRKINGS EEP_ - _,�-1
ir
r c F«w steep r PARMK]NGAAOD
r C Pat Flat r PARKING/STEEP
r C Padua Mod r POND - r C,Paraw,Mod b r POND
r C Padua Steep -1 r PaousPavwnws Ir L. anus,sleep �D r P.-F,vemers
--- " Ir C.Lawn,Flat
r-C.Lawn,Fla r C Law Mod -J
r C,Lawn pod —� r C Lwwb t.p
r C,Lawn sleep -
r SAT.F-1-Flat- -,07 1 r SAT,FONSILMod
r SAT,Fosd Mad C� J r SAT.Farad,step 4-
r SAi,Faed.Step ---I
Pervious Tad ®A-
P—Tdd —J Apses Impetuous Total Aaes
Imperous Tall An Sa ToIN A-
B-Tdd Aon
C Basin 3Predevebped
Subbasin Name:.Bati 3
Surface Inlerllrrw Groursdwaasse
Flows To: I
Are.in Basin r Shav Orysdedad
Available Pervious Acres Available Im ervious Acres
p kv:Fnesl.F1M _�09�-- r ROADS/FLA _
--J7 r A/B,Feed Mad_ r ROADSMOD __._]
r A/B.F-L Stop I r ROADS/STEEP
r AR,Pawn,Flat r ROOF TOPSMAT l
F- ,Partue.Mod r DfINEWAYSMAT
r A/B,Padua, tap I� r NEWAYSAAOD 0�_ �
r-fJ6_Lawri,_Fld__�� r DIiNEVWAYSKTEEP OL_ _�
r SIDEWALKSNIAT
r i✓e.Law�.steeo � r sawmAw
r C.Faec Flat __� r&MKT EP -i 0.
r C,Forest.Mod ---� r PARKm*uT ;l
r C FwnL Steep—�1 r PARKNIGMOD --
r C.PaAn� r PARFJNG/STEW
r C.Phase,Mad _ r POND -�
_ -----
C,C,.Padua,steep r Parous Pawsiwa_
- C,Le..n.Flat _-
C.L Mod __t
- C-L-awn.Seep
SAT.Forest Fie 0
SAT,Forest,Mod j p
-.`-SAT.Feed Stems �I
Panes Tdd Aces
Impwviour Tdd Acm
BasilTad ------- A-
Developed Basins
M Basin 1 Maigaed 4 Basin 2Mitigated
Subbasin Name:: J r Daipnate as Bypass la POC Subbasin Nama[,�__ __.__��Desytaem Bypaafor POC:
Surface Intedlow 6—ndwata Surface IMafbw Groundwater
Flows To: Gravel irerchOedT GuwdT—.hBedl F— Flows To: (Gravel Tronch Bedt 7 ravel Tronch Bedt C__ ___ �
Area in Basin rShowo*sa6cted Area in Basin ( Show OrAVSelected
Available Pervious Acres Available Im ervious Acres
A�1 F i Mod
o r m. aee,SteepF-
A -- -- ---p-
Available Pervious Acres ll Available Irrt envious Acres _ 77 _
J � � �J F- R�SM D
rJ ROADS 4
A+B F d,Mod ( r ROADSMOD
rE F esl Steep I f 55TEEP ROOFT EP
i"AR Pauda Fld r r ROOF TOPS/FIAT r� ta
AM. Flat I' ROOF TO
r MB Paaae,Mod f r DRNEWAYS/FLAT__� _ Ir A B,Pmaae,Mod 0 r ORNEWAYS/FIAT
r AAB Pat4ae_S1aep r r DRNEWAYSMOD r aB.Pag te,seeap p� r DRNEWAYSMOD
p A/B.lawn,Flal 37- r DRNEWAYSSTEEP F- DRNEWAYS jF AIB.Lawn.Fla LAT I
rAR,LanMod 4 _� r SIDEWALKS/FLAi �.r A/B,Lawn.Mod r SIDEWALKS/FIAi
--r AN.Lawn.Slaep r. _ r SIDEWALKSMOD 00 rA/B.Lawn,slaec r SID WALK4MOD 7
r C.bored Fla r $IDEWALKS/STEEP r C.Faw Fls ]FO r PARS NGh1AT
r C, awl t modr PPAKING/FlAT r C.Fa esL Mod
r C,F00d.Steev — C r PARKING/MOD r CFme-Lhnro — 0 r r PARKINGAW
r ;�0 "�^1
r PARIONG rC,P.O—,FW C STEEP
C,Padua,Flat U
r C,Padua.Nod A POND C.Pave.Mod D r POND
r C_Patlue.Steep r Poous Pavement __J r C.Paa Bleep r Porous Parenterit
r C.Lawn.Fla J r C.Lewrt.Fla 0
r C,Lawn,Mad
r C Levi,Mod
eep
r C L wn SIM 4r SAT,F-C. ,St,Flat
r SAT Freest Flat r SAT,Forest.Fla
r SAT,Forest.Mod
ae 0 --
('SAT,Fa,Mod
___-----. �r SAT.Focal Steep
llt a Tad A—
PaviousTI,W Aaa lnpwiw,Tad Area
Irnperviout Tad r0.2B l Acra Bash Tad Acrot
Basin Total J Area
4 Basin i Mrtigated
Subbasin Neme:� _ Designate as Bypass la POC:
Sufsce IMedlaw G—adwatd
Flows To: L�lurd 1 I[LTaeta t J
Area in Basin r Show Dry Seleded
Available Pervious Acres Available Impervious Acres _
�W A/B Faed,Fla J A ROADS/FIAT
r A B Freed.Mad r ROADSMOD 10
r 0 r ROAf)S/STEEP �[0
r-A/B P-*-.F_at _ 0 r_ROOFTOPS/FLAT
r Are PaBae.Mod � r DRNEWAYS/FLAAT�L�
r-AA,Paaue,sue_j p� r DRNEWAYSMOD�
p A/B.L—,Fla �1—.71 ___� r DRNEWAYS/STEEP �',
rA/B,Lamt,Mod 110 r SIDLWALXSRIAT
r A/B,Laws,Steep 0�� r SIDEWALKSMOD
r C.Faed Fla r SIDEWAI KS/S EP
lr C,FaedN���0 �—j r PARKING/RAT
r C_Fgt LStw _ C J r PAAKMGMOD
r C_PmWe_Flat_ r PARKNGSTEEP
r C.Patfu M
e,Mod �0 r, POND ,33
r C.Paraae,S_ r Paous Pa a wM
r C,Lewn.Fla
r C,Laws Mod 1
r C,Lawn,Steap I—
r SAT.Freed Flat r
r SAT.Freed Mod_—
�f-SAT.Faedsleep J L�
Pervious Tad 1i-Acres
Inpervious Taa Acres
Basin Total PIN
it i
Treatment and Flow Control
• S<F—bm -_ a Grehcl T—h Bed 1 MRigned -
-- _._.. �...SCENARIOS_ -... FacilityName IG,"Treads Bed
.. _-- _
I - Outlet __Outletet
2 Outlet 3
❑RedeM Facility a dnedion Iupexndel�1-1 _- J D
rdoped G �_ .. ._.--
0 ragatad F A to F«aiy Ou Ck Tree
,___
Rrn Scerorio r KraPaalon_Avded to Facely -._Fntality Dimension Dinaram
BaacEM®�ts --- --
Facility Dimensions Outlet Structur ate
Tench l.erghlltl alp J
I Torch Batam Wdh(nl 10 Rna Hegv Inl r—
®�■® Rea Drenhaer lnl 12 J
En«o-a loss,Depth Ift)
®�®® Too ardbatan—(HA9 Reel Tip �—
Len Sde S hp J
MM Notch Type
.-- -------_ _-- --`--___ RgHSde Slope MM
Pro Ek'ner" Material Layers for Trendy/Bed
® 1-0111 TI-.1,—(e) ,1.5 Ofilice Diameter Heigh
Lare.lpaps#,10-1) JW4 I Number con) M
�® Lme,2 Ttaceneri In) t 1 Fo=Fo-.4
Lays 2 oaoss,10-11 L 2 )0 -H(0 -
-- lge.3Th'elness Ul) 3 F0—'` 0-I.'I
Lays 3 porous,IDl)
TrrrhVdeea Rise Head l«al 111
InfiHration F-.—
Carnnercid Tooboa _.___ _
------!, Measuad lrlsbam Rae lMvl
Redcean Fad"tun Wador) F,—-II Show Trench OoenTrie -`
Um Waned Sur«e Au-eder.ahl Yer '.� Ine"Staee(ft)
TdaVd.ro lr&W d1.4t) 337.607 TadvoLane TIoughF�350.216
R T.WVd+ee ThroughFi-j chl laws Pane,lrAnaed 964
M—Elrawee Size lnfilbetion Trench
In Channel 1 Mitigated 13•Trapaoidal Pord 1 Mitigated 651
Facility Name Charnel t - ----- Facility Nestle LTrapzdda Patel �' Facility Type
----_-- -l --__ Outlet 1 Outlet 2 Outlet 3
OWlel i UWlet T Outlet 3 _
--- - Downstream Connections
Downstream Connection T.�w add Pend 1 0 0 -
- F-Preci As Appted to Facity Auto Pond Quick Pond
FeGiliy,Type Charnel _ Use X-Sections Uwdc Channel rLvaposabon Appiedm Facsty Facility Dimension Diagram
(User Dared r ___.___... _.-� Outlet Structure Dar-
Fedf Dimensions I
I Feciry Baron Ele•.awn(Itl Rea Hdgr(nl 4.5 J
Channel Dimensions Bonn Lerghlnl Rea Duman(nI 12
Browse Ior file. I
General Channel Data Batanwdnlnl R1ter Trios r-�
Chard Bonam width lit( 1.1 EBeceve Depth Ik] Notch Type -
Claud Lerpth(n) Left Sde Slope(HN)
Bottom Side Shp(HM
Marrnp n codlicieN 24 Rigs Side Slope B1M
Slope of(hard(nM) O15
Left Side Slope(HNI 3 Top Sale lHM 3 Orifice Diameter Height
Infiltration Number Cin) 00
Riga Side Slope Meewed lrAhaim Rae(eJhl D.a _•� 1 r—�Fp�Tnn:ry.'
Mataam CharnelDWIt[ft) 1 _ _.—__ Redcbon F-tgwlelact"I Il---H 2 Fo--s?ro---`I
Infiltration Ye, -]
umWehed Sulaa Areafuslewats) va--t; 3 Fo---H(D..y
Measured lrAtration RalefnMl 0.3 -!d TaaVdnelnMated(«d) 255628
Taa Velure TFswgh Ric IacAl 0 Pond Vohs a Rio Heed(«a) 1.617
Reduction Factor fruHleda) _ Tots Volare Though Facity(«Jtl 255 f3 _J
Use Wetted Sort—Arse lsdewalH) es -� Show Pond Table Opah Tebb
" Paces Mrheted 100 mild �
Total Volume 1,.%at d(«-It) 116 412
Size Infiltration Pond
Total VaLme Though Riser(acil) 240642
Target X:100 -•.{
Total Vclme Though F«iry(«It) 357.054
Pram Infiltrated 326
Tide Gate I Time Series I Demand
Show Channel Table Open Tede Determine Outlet WM Tide Gate
Sue Infiltration Channel I --- r Use Tide Gate
L Target ye: 100 j Tide Gate Elevation(II) FO Downstream Connection
Overfl w Elevation(0) !0 fteretions FO
SWALE: Treatment
Biofiltration Swale Calculation Notes:
The bioswale was sized following the Manual's"Design Calculations for Biofiltration Swale"steps.
See section 4.5:Water Quality System for all calculations.
• For Step D-4:
o From WWHM,the 15 min.Water Quality Design Flow(Q) =0.2405 cfs(see below).The swale is
designed to treat the pollution-generation impervious area, 1.16 acres.
.w. .+rr. .�..+. I 11
-iwF'— Oin_._ewA
N..i O..'r r Mu.Or05�rre MwY__.
MO.kN F.rvb..Ao.. AraYekl.4FaNw.M..
r LM-P9kTH--1 r1H�L ANOL W 1WFb 5sCwfln WO�� SI.LL�dFW RaM W+I'4137
r �
r �_7 ripr=�
!ram -.) ` tio: _.,��'-� Sk..n P,erckm DuYm 11D OuYm ibri wAv Du 16do n
ir�_._J W�.W Valm, LDP U.�im Md,.P R.d•,.�c.d,' .dw Mb+.d
�r MxUa.I,bn.r C-WWDM( Dditsw d r MaftR
J si POC,vrd...eo.dla
4iwTW I�R`=�J^. MD!w fls E1.Y. Fai Ew IOCI
M1./fi0o�l0dMd
Figure 1
• For Step D-6:
o To compute the flow velocity at design flow rate:
V = kQ
o K=a ratio of the peak 10-minute flow predicted by SBUH to the water quality design flow rate estimate
using the WWHM.
SUN f..kFAWN 0MW 15w WO Flay RMbn
04WO FwMptrWm 1.,0%W 100%k00.Mw.A—
u
•.0 ---
■ 3.5
3.0
l 2.5
00 2.0
1.5
1.0
0.5
0.0
00 0.5 to 1.0 2.0 2.0 0.0 35 00
6-0.fun p.... . px%W E-E..r1,b
Mg—5.EO-fd05o of SUIT F..MINIG FMw
Figure 2
o The 2-year, 24-hr precipitation =0.2076 acre-feet(See Figure 1)
■ 72%of the 2-year, 24-hr precipitation, inches:
1 12 inches
0.2076 acrefeet x x = 2.15 inches
1.16 acres 1 f 00t
o Using Figure 2,K=3.0
CONVEYANCE
Flow frequencies for the project site - Required Pipe Capacity
W Analysis �h
® _ Flow Frequency A
10.o Cumulative Probability 100 Flow(cfa) 0701 15m
2 Year C.9216
5 Year 1.4383
10 Year 1.8151
+ 25 Year - 2.3264
++ + + 50 Year - 2.7308
+r+++++ 100 Year a 3.1544
10. y Annual Peaks
� �HrM-,'d� + 701 1956 0.7016
+ + +++++�+ 1957 2.2173
+ 1958 0.5069
1959 C.8040
1960 1.3698
1961 0.5588
0.1 0.1 1962 0.4585
0.5 1 2 5 10 20 30 50 70 80 90 95 98 99 99,5 100 1963 1.8496
1964 1.1827
SUeam Protection Duration LID Duation Flow Freq.iency L Water quaky Hydogaph I 1965 1.3742
WetlandlnputVolumes I LIOReport I RechargeDuation Rechargehedeveloped Rechargek!60ed I 1966 0.4494
r Mo ec FF �-- -y -967 0.9512
Analyze datasets Compact WDM Delete Seeded I J 1968 0.6614
1969 0.4467
i PUYALLUP DAILY EVAP W/JENSEN-HATS 197 .
2 Shepon � 1971 1.0665
665
501 POC 1 hedeveloped lbw 1972 1.3817
r - _ 1973 0.5974
801 POC 1 Mitigated flow 1974 0.6243
1000 Trapezoidal Pond 1 ALL OUTLETS Mitigated 1975 0.7521
1001 Trapezoidal Pond 1 OUTLET 1 Mitigated 1976 0.9866
1002 TrapezokW Pond 1 OUTLET 2Mhgated
1977 0.7944
AlDalasets� +'_.(Stage !Pr^ecip Evap POC1 j 1978 1.2668
-- Flood Frequ--y Method
1979 1.6420
r:Lop Peamon Type 81178 1900 0.7229
r WebA 1981 1.1480
Gma w 1982 1.2692
Grngorten 1983 1.5395
v
CONVEYANCE
Pipe Capacity
PIPE CAPACITY ANALYSIS
PROJECT NAME: Belfair Park and Ride DESIGN STORM:25 Year Event
PROJECT NUMBER: 738.05 DESIGN BASIS: 2005 WSDOE
DATE: 10/17/2018 PREPARED BY: Maddie Knecht
PIPE PIPE HYDRAULIC PIPE PIPE DRAINAGE CUMULATIVE
FROM TO DIAMETER SLOPE MANNING'S RADIUS AREA CAPACITY AREA AREA
(IN) (FT/FT) n R (SF) (CFS) (SF) (SF)
Ditch Bioretention 12 0.013 0.011 0.250 0.785 4.81
Bioretention Pond 12 0.010 0.011 0.250 0.785 4.28
Swale Pond 12 0.103 0.011 0.250 0.785 13.54
Swale Pond 12 0.093 0.011 0.250 0.785 12.88
1 of 1
CONVEYANCE
BiVSvVa|e Capacity
Swale Conveyance for 6'monthstorm:
P6|l 1.16acres
Flow,To
.
� , , A:
r 'SImWWo�",�/
r r
r ,
,, M"GIM
r F-
r
r
,
�F-
r m�~�__z@���
P.~~'� b ��~ ^~ |
Basin3 Flow Frequencies:
Flow Frequency
Uoo Year - 1.0192
Kzov Year ~ 1.0985
° 6'mnnth' I4'hour storm =72Y& ofZ'ycar, Z4'hourstorm
o 72 (0.5798) =0.417ds
Swale Flow Capacity:
�=R- C�d��,°_9- M-�
��e". ��� ' � "--W�� M ~~—W .
it
0.417cis < O.53Ocfs 171
CONVEYANCE
Bioswale Capacity
Swale Conveyance for 100-year storm:
Impervious Surface: 1.35 acres
n—,T.
M.H.— r
_��Ail P,M... A— �M.bp—. A.
F
r RDM_SA*D__
r lkwsi
KA:F7 no WFT60S 1
J
E�� r
r
r
VG E77 ---------
r c AaW-hfw
r t7aWliw—,k— *R..�
,
rtAw..i4-- r
Basin 3 Flow Frequencies:
Flow Frequency
Flow(cfs) 0801 15m
2 Year = 0.6748
5 Year = 0.8503
10 Year = 0.9595
125 Year = 1.0914
50 Year = 1.1862
100 Year = 1.2784
Swale Flow Capacity:
W Wwk,',d:T,,P idl Cb,..A I
Lhk_Rc Gadwb Ve P_ Menyea
SF_
WR
a Hyft B A—
L.ft on(H.V) T"W
R*W Sd,SbD:
-- �S�
8 WR
D..._ W"ty aft
WWtlYNW. F-!W =■
5ft E.W
Q12
F..TM
10 ca,-J-
1.2784 cfs <4.17 cfs r7l
APPENDIX D
GEOTECHNICAL REPORT
Draft
Geotechnical Engineering Report
Mason Transit Authority
Park and Ride Site Improvements
Belfair Site
September 18, 2017
II
Prepared for
SO Alliance
8730 Tallon Lane NE, Suite 200
Lacey, Washington
i
I
I
LANDAU
ASSOCIATES
955 Malin Lane SW,Suite B
Tumwater,WA 98501
(360)791-3178
DRAFT Landau Associates
Geotechnical Engineering Report
Mason Transit Authority
Park and Ride Site Improvements
Belfair Site
This document was prepared by,or under the direct supervision of, the undersigned,whose seal is
affixed below.
Name: Lance Levine
Washington/No.45853
Date: September 18, 2017
Document prepared by: Lance Levine, PE
Project Manager
Document reviewed by: Steven R. Wright, PE
Quality Reviewer
Date: September 18,2017
Project No.: 1174015.010.012
File path: Y:\1174\015.010\R\Belfair Site\Signature Page.docx
Project Coordinator: MCS
LANDAU
ASSOCIATES
l
DRAFT Landau Associates
TABLE OF CONTENTS
Page
1.0 INTRODUCTION..............................................................................................................................1-1
1.1 Project Understanding........................................................................................................1-1
1.2 Scope of Services................................................................................................................1-1
2.0 EXISTING CONDITIONS...................................................................................................................2-1
2.1 Surface Conditions..............................................................................................................2-1
2.2 Geologic Review.................................................................................................................2-1
2.3 Subsurface Explorations.....................................................................................................2-1
2.3.1 Soil Conditions ...............................................................................................2-1
2.3.2 Groundwater Conditions ................................................................................2-2
3.0 CONCLUSIONS AND RECOMMENDATIONS....................................................................................3-1
3.1 Earthwork...........................................................................................................................3-1
3.1.1 Wet Weather Considerations..........................................................................3-1
3.1.2 Site Preparation Activities ..............................................................................3-2
3.1.3 Subgrade Preparation.....................................................................................3-2
3.1.4 Structural Fill .................................................................................................3-2
3.1.4.1 General....................................................................................................3-2
3.1.4.2 Imported Fill.............................................................................................3-3
3.1.4.3 Onsite Soil................................................................................................3-3
3.1.4.4 Recycled Materials ...................................................................................3-3
3.1.4.5 Fill Placement and Compaction.................................................................3-4
3.1.5 Temporary and Permanent Slopes ..................................................................3-4
3.2 Site Utilities.........................................................................................................................3-4
3.2.1 Trench Excavation and Support.......................................................................3-5
3.2.2 Construction Dewatering................................................................................3-5
3.2.3 Pipe Foundation Support................................................................................3-5
3.2.4 Pipe Bedding and Initial Backfill......................................................................3-6
3.2.5 Trench Backfill and Compaction......................................................................3-6
3.3 Structures...........................................................................................................................3-6
3.3.1 Seismic Design Considerations........................................................................3-7
3.3.2 Bearing Capacity ............................................................................................3-7
3.3.3 Settlement.....................................................................................................3-7
3.3.4 Resistance to Lateral Loads.............................................................................3-8
3.3.5 Footing Overexcavations ................................................................................3-8
3.3.6 Foundation Drainage Considerations ..............................................................3-8
3.3.7 Slabs-On-Grade..............................................................................................3-8
3.3.8 Illumination Pole Foundations ........................................................................3-9
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3.4 Pavement Design................................................................................................................3-9
3.5 Stormwater Infiltration Feasibility...................................................................................3-10
4.0 CONSTRUCTION SUPPORT.............................................................................................................4-1
5.0 USE OF THIS REPORT......................................................................................................................5-1
6.0 REFERENCES...................................................................................................................................6-1
FIGURES
Figure Title
1 Vicinity Map
2 Site and Exploration Location Plan
TABLES
Table Title
1 Summary of Design Parameters
2 2015 International Building Code Seismic Design Parameters
3 Recommended Asphalt Pavement Design Section
4 Recommended Portland Cement Concrete Section
5 Preliminary Factored Infiltration Rates
APPENDICES
Appendix Title
A Field Explorations
B Laboratory Testing
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LIST OF ABBREVIATIONS AND ACRONYMS
AASHTO.................American Association of State Highway and Transportation Officials
ASTM.................................................................................................ASTM International
bgs.................................................................................................below ground surface
CBR.............................................................................................California Bearing Ratio
CSBC.................................................................................crushed surfacing base course
ESAL...................................................................................... equivalent single-axle load
ft........................................................................................................................foot/feet
GDM................................................................................... Geotechnical Design Manual
H:V..................................................................................................horizontal to vertical
IBC........................................................................................ International Building Code
LAI...............................................................................................Landau Associates, Inc.
MDD.............................................................................................. maximum dry density
MTA...........................................................................................Mason Transit Authority
PCC......................................................................................... Portland cement concrete
pcf.................................................................................................pounds per cubic foot
PIT....................................................................................................pilot infiltration test
psf.............................................................................................. pounds per square foot
SCJ.................................................................................................................SCJ Alliance
SWMMWW........................Stormwater Management Manual for Western Washington
WAC............................................................................ Washington Administrative Code
WSDOT............................................... Washington State Department of Transportation
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1.0 INTRODUCTION
This report presents the results of our field investigation and provides geotechnical engineering
conclusions and recommendations for Mason Transit Authority's(MTA's) proposed Park and Ride
Improvements project, located near the Mason County—Kitsap County border, southeast of the
intersection of Log Yard Road and State Highway 3 near Belfair,Washington (site). The purpose of our
investigation was to compile and review available subsurface information for the project area,
complete site investigations to characterize subsurface soil and groundwater conditions, and develop
geotechnical conclusions and recommendations for design of the proposed improvements.
The general project location is shown on Figure 1. Figure 2 shows some of the site features and the
approximate locations of the explorations completed for this study. Appendix A includes a description
of our field explorations and summary logs of the conditions observed during our field investigation.
Test results and a description of our laboratory testing program are provided in Appendix B.
This report has been prepared based on conversations with and information provided by SCJ Alliance
(SCJ),data collected during our field investigation,the results of our laboratory testing program, our
familiarity with geologic conditions in the vicinity of the project area, and our experience with similar
projects.Our services were provided in accordance with amendment number one to the
subconsultant agreement for professional services, issued by SCJ on July 28, 2017 and authorized on
August 1, 2017.
1.1 Project Understanding
We understand a park and ride will be constructed on an undeveloped,4-acre site in a future
commercial/industrial development near the Mason County—Kitsap County border. Proposed
improvements include a 1,500-square-foot MTA office building,two bus shelters, illumination (i.e.,
light poles), paved parking and drive lanes, and stormwater management facilities.The proposed site
layout is subject to minor changes and will be finalized during design.
1.2 Scope of Services
The objective of our services was to explore subsurface soil and groundwater conditions at the site as
a basis for developing geotechnical recommendations in support of the proposed improvements. Our
scope of services includes the following tasks:
• reviewing available published geologic maps and geotechnical reports for the project area;
• coordinating public and private utility locates;
• completing a subsurface exploration program by advancing a series of exploratory test pits;
• collecting representative soil samples and completing laboratory testing to aid in the
classification and determination of certain engineering soil properties;
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• providing seismic spectral acceleration coefficients for the proposed structures using map-
based methods in accordance with International Building Code (IBC) criteria. We also assessed
the risk for seismically induced soil liquefaction and lateral spreading;
• providing recommendations for earthwork and grading, including stripping depth, subgrade
preparation, utility trench excavation, construction dewatering,the reuse of onsite materials
and structural fill, and structural fill placement and compaction;
• providing geotechnical recommendations for shallow foundation support of the proposed bus
shelters and MTA office building, including allowable soil bearing capacity, minimum footing
width and depth, lateral resistance criteria,and elastic settlement estimates;
• providing geotechnical recommendations for design of foundations for new illumination in
accordance with section 17.2.1 of the Washington State Department of Transportation's
Geotechnical Design Manual(WSDOT GDM;WSDOT 2015);
• providing recommendations for pavement sections using assumed traffic loading conditions;
• assessing the feasibility of infiltrating stormwater on site, including feasible infiltration
locations, depth-to-groundwater, and a design infiltration rate estimated by correlation to
grain size characteristics; and
• preparing this geotechnical engineering report, summarizing the results of our field
investigation and laboratory testing program and presenting our conclusions and
recommendations along with supporting data.
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2.0 EXISTING CONDITIONS
The following sections describe the surface conditions observed during our field explorations,the
results of our geologic review,our subsurface exploration program, and the subsurface soil and
groundwater conditions observed in our explorations.
2.1 Surface Conditions
The site includes undeveloped forestland with several trails and primitive gravel roads.Topography is
generally flat in the areas of the proposed improvements,though the eastern portion of the site
slopes gently down to the west with a vertical relief of about 10 feet(ft). The site is vegetated with
mostly trees and some brush. Evidence of surface water or ponding was not observed during our
August 2017 site visits.
2.2 Geologic Review
The geology of the area is described on the Geologic Map of the Belfair 7.5-minute Quadrangle,
Mason, Kitsap, and Pierce Counties, Washington (Polenz 2009). Vashon glacial ice-contact deposits
(Qgic) are mapped at the project site,with Vashon till (Qgt) mapped to the east. Ice-contact deposits
are described as sand, gravel, lodgment till, and flow till with minor silt and clay beds.This unit is light
brown to gray, loose to compact, and massive to well stratified. The unit was formed in the presence
of meltwater alongside ice, generally near the end of the glaciation, and commonly is accompanied by
stagnant-ice features,such as kettles, eskers, and subglacial outwash channels. The soils observed in
our explorations are consistent with the mapped geology.
2.3 Subsurface Explorations
We explored subsurface conditions at the site on August 15,2017 by advancing 10 test pits (TP-1
through T-10) between 12.5 and 16.3 ft below ground surface (bgs).The test pits were advanced by
Howard's Construction & Excavating of Olympia,Washington, under subcontract to Landau
Associates, Inc. (LAI).The apprdximate locations of the test pits are shown on Figure 2.The fohowing
sections summarize the subsurface conditions observed in our explorations. More detailed
information, including summary exploration logs, is provided in Appendix A.
2.3.1 Soil Conditions
We categorized the soils observed in our explorations into two general units.
• Forest duff/topsoil:A forest duff/topsoil layer was observed in all the explorations, except
test pit TP-1, where the forest duff was removed at the time the primitive gravel road was
constructed.The combined thickness of the forest duff and topsoil ranged from 0.75 to 2.5 ft.
Forest duff detritus observed typically included leaves, fir needles, and other non-
decomposed organics above the soil surface. Where observed in our explorations,the
thickness of the forest duff layer ranged from 3 to 12 inches.The topsoil observed at the
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surface in test pit TP-1 and below the forest duff at the remaining test pit locations was
typically a brown, loose to medium dense, silty sand with variable gravel and organic content.
• Ice-contact deposits: Ice-contact deposits were observed below the forest duff/topsoil unit to
the depths explored.This unit typically consists of brown to gray, medium dense to very dense
sand with variable silt,gravel, and cobble content or brown to gray, dense to very dense
gravel with variable silt, sand, and cobble content.
Although not observed in all of our explorations, cobbles and boulders are often present in glacial
deposits and may be present throughout the site.The contractor should be prepared to handle
oversized material.
2.3.2 Groundwater Conditions
During our August 2017 explorations,groundwater was not observed in the test pits to 16.3 ft bgs,the
maximum depth explored. No evidence of mottling was observed. The groundwater conditions
reported herein and on the exploration logs in Appendix A are for the specific locations and date
indicated and may not be indicative of other locations and/or times. Furthermore,we anticipate
groundwater conditions will vary depending on local subsurface conditions,weather conditions,and
other factors. Groundwater levels in the project area are expected to fluctuate seasonally, with
maximum groundwater levels occurring during late winter and early spring.
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3.0 CONCLUSIONS AND RECOMMENDATIONS
Based on the results of our field explorations, laboratory testing, and engineering analyses, it is our
opinion that subsurface conditions at the project site are suitable for the proposed improvements. We
interpret the ice-contact deposits to be suitable for onsite infiltration of stormwater, provided the
base of the infiltration facility is situated below restrictive layers.The ice-contact deposits observed in
our explorations are also suitable for shallow foundation support of structures(e.g., bus pad,shelters,
MTA office building, and light poles), provided the recommendations in Section 3.1 of this report are
followed.
The following sections of this report provide geotechnical conclusions and recommendations
pertaining to earthwork; underground utilities;structures, including seismic design criteria, allowable
bearing capacity,foundation settlement, resistance to lateral loads,footing overexcavations, and
slabs-on-grade; illumination; pavement design; and stormwater infiltration.
3.1 Earthwork
To accommodate construction of the proposed improvements,earthwork likely will include clearing,
grubbing, and stripping of areas where improvements are planned; cuts and fills;subgrade
preparation for structures and pavement areas; and construction of temporary and permanent slopes.
3.1.1 Wet Weather Considerations
Some of the onsite soils contain up to about 16 percent fines (material passing the U.S. Standard No.
200 sieve, by weight) and are considered moisture sensitive. Imported fill also could be moisture
sensitive. When the moisture content of soil is more than a few percent above or below the optimum
moisture content,the soil may become unstable,and meeting the required compaction criteria may
be difficult. Optimum moisture content is the moisture content at which the greatest compacted dry
density can be achieved. Disturbance of near surface soils should be expected if earthwork is
completed during periods of wet weather or under wet conditions.
The wet weather season in the project area generally begins in late October and continues through
June. However, periods of wet weather may occur throughout the year. If wet weather earthwork is
unavoidable, we recommend:
• the ground surface be sloped so that surface water is collected and directed away from the
work area to an approved collection/dispersion point;
• excavation of temporary drywells to expose cleaner underlying soils;
• earthwork activities not take place during periods of heavy precipitation;
• measures are taken to prevent onsite soil and soil stockpiles from becoming wet or unstable;
• structural fill materials used during periods of wet weather should be limited to imported, all-
weather fill;
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• a smooth-drum roller is used to seal the surface prior to periods of precipitation to reduce the
extent to which the soil becomes wet or unstable;
• construction traffic is restricted to specific areas of the site, preferably areas surfaced with
materials that are not susceptible to wet weather disturbance;
• a minimum 1-ft-thick layer of 4-to 6-inch quarry spalls is used in high-traffic areas to protect
the subgrade soil from disturbance; and
• contingencies are included in the project schedule and budget to allow for the above
elements.
3.1.2 Site Preparation Activities
Site preparation activities are expected to include clearing,grubbing, and stripping of the existing
vegetation, duff, and topsoil and removal of pavement and utilities, if present.Sod,topsoil, and
organic-rich soils or fill located within the bus pad shelter or pavement areas should be stripped. We
estimate an average stripping depth of approximately 20 inches for removal of forest duff and near
surface topsoil. If the forest duff is removed during logging activities,the remaining topsoil will range
from 0.5 to 1.5 ft thick.These estimates do not include the removal of existing tree roots or debris, if
present.
All incidental excavations associated with site preparation activities should be backfilled in accordance
with the recommendations set forth in Section 3.1.4 of this report.
3.1.3 Subgrade Preparation
Prior to placing structural fill,the prepared subgrade should be proof-rolled in the presence of a
qualified civil or geotechnical engineer,who is familiar with the site conditions and can check for any
soft and/or disturbed areas.Areas of limited access that cannot be proof-rolled can be evaluated
using a steel T-probe. Loose and/or disturbed subgrades identified during the proof-roll should be
repaired by overexcavating the disturbed soil and replacing it with compacted structural fill, meeting
the requirements described in Section 3.1.4 of this report. Unsuitable soils also can repaired with
additional scarification, moisture conditioning, and recompacting. Repaired subgrades should be
recompacted in accordance with Section 3.1.4.5 of this report.
3.1.4 Structural Fill
The following sections provide recommendations for the use of onsite soils, imported fill, and recycled
materials as structural fill and structural fill placement and compaction.
3.1.4.1 General
The suitability of excavated or imported soil for use as structural fill will depend on the gradation and
moisture content of the soil when it is placed. As the amount of fines increases,the soil becomes
increasingly sensitive to small changes in moisture content, and adequate compaction may become
more difficult to achieve.Soil containing more than about 5 percent fines cannot be compacted
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consistently to a dense, non-yielding condition when the water content is more than about 2 to 3
percent above or below optimum moisture content.
During dry,warm weather(generally July through early October), structural fill should consist of
well-graded sand and gravel with a maximum particle size of 6 inches and at least 75 percent of the
material passing the 3-inch sieve. The material should contain less than 30 percent fines and be
maintained at a moisture content near optimum. If wet weather construction is anticipated,the
amount of fines should not exceed 5 percent, based on the minus%-inch fraction. Structural fill
should be free of debris, organic material, and rock fragments larger than 6 inches.
3.1.4.2 Imported Fill
During dry,warm weather(generally July through early October), imported structural fill should
consist of well-graded sand and gravel with a maximum particle size of 6 inches and at least 75
percent of the material passing the 3-inch sieve.The material should contain less than 30 percent
fines and be maintained at a moisture content near optimum. Imported structural fill should be free
of debris, organic material, and rock fragments larger than 6 inches.
During wet weather conditions, imported all-weather fill should consist of well-graded sand and
gravel or crushed rock with a maximum particle size of 4 inches and less than 5 percent passing a
U.S. Standard No. 200 sieve, based on the minus%-inch fraction. Organic matter, debris, or other
deleterious material should not be present. Gravel Borrow, as described in Section 9-03.14(1)of the
Washington State Department of Transportation's 2016 Standard Specifications for Road, Bridge, and
Municipal Construction (2016 WSDOT Standard Specifications), is a suitable source of imported
all-weather fill, provided the requirements set forth in this paragraph are satisfied.
3.1.4.3 Onsite Soil
The ice-contact deposits observed in our explorations contain up to about 16 percent fines and are
generally well suited for use as structural fill during dry weather. If onsite soils are reused as structural
fill,they will require significant moisture conditioning to satisfy the compaction criteria recommended
herein. We recommend a representative of LAI is present to review onsite material for use as
structural fill prior to placement.
3.1.4.4 Recycled Materials
If practical, recycled concrete materials can be considered for use as structural fill. Recycled concrete
materials used as structural fill should meet the requirements set forth in Section 9-03.21 of the 2016
WSDOT Standard Specifications;the materials also must meet the minimum gradation criteria for
Select Borrow,outlined in Section 9-03.14(2) of the 2016 WSDOT Standard Specifications. In all
instances, use of recycled concrete should comply with current environmental policies.
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3.1.4.5 Fill Placement and Compaction
Structural fill should be placed on an approved subgrade that consists of uniformly firm and
unyielding, inorganic native soils or compacted structural fill prepared as described in Section 3.1.3 of
this report. Structural fill should be compacted at a near-optimum moisture content. Optimum
moisture content varies with the soil gradation and should be evaluated during construction.
In structure and pavement areas,structural fill should be placed and compacted in accordance with
Section 2-03.3(14)C, Method C of the 2016 WSDOT Standard Specifications. Method A of the 2016
WSDOT Standard Specifications is appropriate for non-structural areas,such as landscaping. Structural
fill should be placed in loose, horizontal lifts, not exceeding 12-inch thickness,and thoroughly
compacted. Compaction and moisture control tests should be completed in accordance with Section
2-03.3(14)D of the 2016 WSDOT Standard Specifications. Alternatively,the maximum dry density
(MDD)and optimum moisture content can be determined using ASTM International test method
D1557 (i.e., modified Proctor).
3.1.5 Temporary and Permanent Slopes
Based on the soil conditions observed in our explorations,the maximum inclination for temporary
excavation slopes less than 20 vertical ft in height, and in the absence of groundwater seepage, is 1%
horizontal to 1 vertical(1%H:1V). If groundwater is present, unstable conditions may develop in the
temporary slope, and flatter slopes or shoring will be necessary.Temporary excavation slopes should
be covered with plastic sheets, straw, or other materials to prevent erosion. In addition, the
contractor should implement measures to prevent surface water runoff from entering excavations.
Temporary excavation slopes should be the responsibility of the contractor. All applicable local,state,
and federal safety codes should be followed. Open cuts should be monitored by the contractor during
excavation for evidence of instability. If instability is detected,the contractor should flatten the side
slopes or install temporary shoring.If groundwater or groundwater seepage is present and the
excavation is not properly dewatered,the soil may be prone to caving, channeling, and running.
Permanent cut-or-fill slopes constructed as recommended in this report should be sloped no steeper
than 2HAV.This ratio is not intended for use in the design of stormwater pond slopes;these slopes
are typically 3H:1V or flatter and should be designed in compliance with local stormwater code
requirements. Permanent slopes should be protected from erosion (see the preceding
recommendations for protecting temporary excavations) and seeded or vegetated as soon as
practical.
3.2 Site Utilities
The following sections provide geotechnical recommendations for design and construction of new site
utilities. Geotechnical recommendations include trench excavation and support, construction
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dewatering, pipe foundation support, pipe bedding and initial backfill, and trench backfill and
compaction criteria.
Please note for any new utilities within the public right-of-way, local standards may supersede the
following recommendations.
3.2.1 Trench Excavation and Support
We anticipate excavations for underground utilities will be primarily within the ice-contact deposits.
Conventional construction equipment with sufficient reach should be able to excavate the proposed
trenches to the expected depth of 12 ft bgs. Upon reaching the trench bottom,we suggest that a
smooth-bladed bucket be used to remove any loose and/or disturbed soil.The final trench bottom
should be firm and free of loose and disturbed soil.
Trench configurations and maintenance of safe working conditions, including temporary excavation
stability,should be the responsibility of the contractor.All applicable local, state, and federal safety
codes should be followed.Temporary excavations for utilities should be sloped no steeper than
1%H:1V, based on the governing regulations for safe excavation practice in the State of Washington
(Washington State Department of Labor and Industries,Chapter 296-155 Washington Administrative
Code [WAC]). If groundwater seepage is present,flatter slopes,temporary shoring, and/or dewatering
may be required.
Trench boxes should provide adequate support for shallow excavations, provided the trench is
properly dewatered and settlement-sensitive structures and utilities are not situated immediately
adjacent to the excavation.Trench boxes should meet the requirements in Safety Standards for
Construction Work, Part N (WAC Chapter 296-155).
3.2.2 Construction Dewatering
We anticipate underground utilities at the site can be installed without encountering significant
groundwater. However, localized zones of perched groundwater may be encountered within the
trench zone, particularly during the winter and spring months. If perched,water-bearing zones are
encountered, construction dewatering using conventional sumps and pumps within the excavations
should be sufficient to handle groundwater inflow. If dewatering is necessary,the contractor should
be responsible for design and implementation of the dewatering system.
3.2.3 Pipe Foundation Support
Based on the conditions observed in our explorations, medium dense to very dense granular soils are
expected to be present at the base of utility trenches. This soil type typically will provide adequate
foundation support for utilities, provided the foundation soil remains in a relatively undisturbed
condition. If the bottom of the trench becomes disturbed due to excavation and/or foot traffic during
the laying of the pipe,the disturbed material should be overexcavated to expose undisturbed
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foundation soil. The overexcavation should be backfilled with suitable foundation material to provide
a firm trench bottom. Foundation material should be free of roots,topsoil, lumps of silt and clay,
cobbles, and debris.
3.2.4 Pipe Bedding and Initial Backfill
Pipe zone bedding material should consist of crushed, processed, or naturally occurring granular
material,free of organic matter and other deleterious material, and should meet the gradation
requirements of Gravel Backfill for Pipe Zone Bedding outlined in Section 9-03.12(3)of the 2016
WSDOT Standard Specifications.
Pipe bedding material should extend at least 6 inches below the invert of the pipe and be compacted
to a relative density of at least 90 percent of the MDD (ASTM test method D1557).The initial pipe
backfill should be brought up evenly around the pipe in relatively horizontal lifts, not exceeding 6
inches, and worked under the haunches of the pipe by slicing with a shovel,vibration, or other
approved procedure. Pipe zone backfill should extend 6 inches above the crown of the pipe. In order
to prevent damage to the pipe,the initial backfill directly over the pipe should be compacted with
hand-operated compaction equipment. Specific material and compaction requirements provided by
pipe manufacturers may supersede the recommendations provided in this report.
3.2.5 Trench Backfill and Compaction
Granular portions of the ice-contact deposits may be utilized for trench backfill, provided all soil
particles greater than 4 inches in diameter are removed and the soil is properly moisture conditioned
and compacted to the required density. Trench backfill should be compacted as described in Section
3.1.4.5 of this report.
3.3 Structures
The following sections provide geotechnical engineering conclusions and recommendations for
foundation design of structures. Recommendations are provided for seismic design, allowable bearing
capacity,settlement, resistance to lateral loads,footing excavations, drainage considerations,
slabs-on-grade, and illumination pole foundations.
Table 1 provides a summary of design parameters for the structural engineer.The design parameters
should be used in conjunction with the complete recommendations provided in this report.
Table 1.Summary of Design Parameters
Allowable soil bearing pressure=3,500 pounds per square foot
Friction coefficient(factored,)-=0.35
Passive resistance(factored)=280 pounds per cubic foot
Minimum foundation width=18 inches(continuous),24 inches(isolated)
Maximum foundation width(for settlement considerations)=5 feet(continuous),10 feet(isolated)
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3.3.1 Seismic Design Considerations
We understand that seismic design will be performed using the 2015 IBC standards (ICC 2014).The
parameters listed in Table 2 can be used to compute seismic base shear forces.
Table 2.2015 International Building Code Seismic Design Parameters
Spectral response acceleration at short periods(Ss)=1.483g
Spectral response acceleration at 1-second periods(Sl)=0.586g
Site class=C
Site coefficient(Fa)=1.0
Site coefficient(FJ=1.3
g=force of gravity
The site is underlain by medium dense to very dense glacial deposits, and the groundwater table is
relatively deep. On this basis, it is our opinion that there is a low risk for seismically induced soil
liquefaction or lateral spreading at the site. Considering the location of the site with respect to the
nearest known active crustal faults and the presence of a relatively thick layer of glacial deposits, it is
our opinion that the risk of ground rupture due to surface faulting is low.
3.3.2 Bearing Capacity
We recommend an allowable soil bearing pressure of 3,500 pounds per square foot (psf)for shallow
foundations that are established on medium dense to very dense glacial soils or structural fill
extending to such soils.This allowable soil bearing pressure applies to long-term dead and live loads,
exclusive of the weight of the footing and any overlying backfill.The allowable soil bearing pressure
can be increased by one-third when considering total loads, including transient loads,such as those
induced by wind and seismic forces.
The bus pad slab-on-grade foundation may utilize a thickened-edge slab design. For that reason,we
recommend a minimum width of 18 inches for continuous footings. For settlement considerations, we
have assumed a maximum width of 5 ft for continuous footings. For frost protection,footings should
be embedded at least 12 inches below the lowest adjacent grade where the ground is flat adjacent to
the footing.
3.3.3 Settlement
Settlement of shallow foundations will depend on the foundation size and bearing pressure as well as
the strength and compressibility characteristics of the underlying bearing soil.Assuming construction
is accomplished as previously recommended,we estimate the settlement of continuous or isolated
spread footings will be on the order of 1 inch or less. Differential settlement between similarly loaded
foundation elements may be assumed to be on the order of%inch or less.
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3.3.4 Resistance to Lateral Loads
Resistance to lateral loads can be provided by friction acting on the base of footings and by passive
lateral earth pressures acting against the sides of footings.An allowable coefficient of sliding
resistance of 0.35, applied to the vertical dead loads only, may be used to compute frictional
resistance.The allowable coefficient of sliding resistance includes a factor of safety of 1.5 on the
calculated ultimate value. For design purposes,the passive resistance of properly compacted
structural fill placed against the sides of foundations may be considered equivalent to a fluid with a
density of 280 pounds per cubic foot(pcf).The foundation passive earth pressure has been reduced
by a factor of 1.5 to limit deflections to less than 2 percent of the embedded depth. In addition,the
recommended foundation passive earth pressure assumes drained conditions within the depth of the
foundation.
The passive earth pressure and friction components can be combined, provided the passive
component does not exceed two-thirds of the total. The top foot of soil should be excluded when
calculating passive resistance unless the foundation perimeter area is covered by a slab-on-grade or
pavement.
3.3.5 Footing Overexcavations
We do not anticipate that appreciable overexcavations will be required for the proposed
improvements. Medium dense to very dense ice-contact deposits soils should be present at or within
about 2 ft of the ground surface. However, overexcavations could be required if the soils become
saturated or disturbed by foot traffic. If overexcavations are required,the overexcavation zone should
extend a horizontal distance equal to at least one-half of the overexcavation depth on each side of the
footing. For example, a 2-ft-wide footing with a 2-ft-deep overexcavation should have a 4-ft-wide
overexcavation zone. All footing overexcavations should be backfilled with structural fill. Alternatively,
the depth of the footing could be increased to bear on the base of the overexcavation. The base of the
overexcavation should be evaluated by a qualified civil or geotechnical engineer prior to placement of
structural fill or concrete.
3.3.6 Foundation Drainage Considerations
We recommend installing a footing drain around the perimeter of the proposed MTA office building.
The drain should consist of a minimum 4-inch-diameter, perforated pipe surrounded by clean drain
rock,wrapped in filter fabric. The drain pipe should be connected to a positive outlet and should
include cleanouts. Roof drains should not be connected to footing drain.
3.3.7 Slabs-On-Grade
Slabs-on-grade should be established on a subgrade that consists of uniformly firm and unyielding
soil. A modulus of vertical subgrade reaction (subgrade modulus) can be used to design the slab. The
subgrade modulus varies based on the dimensions of the slab and the magnitude of applied loads on
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 3-8 September 18,2017
DRAFT Landau Associates
the slab surface;slabs with larger dimensions and loads are influenced by soil to a greater depth.We
recommend a subgrade modulus value of 225 pounds per cubic inch for the design of on-grade floor
slabs with floor loads up to 500 psf.This subgrade modulus is for a 1-ft by 1-ft square plate and is not
the overall modulus of a larger area. We are available to provide alternate recommendations during
design, based on specific loading information available at that time.
3.3.8 Illumination Pole Foundations
Illumination structures (i.e., light poles) are proposed at the site. In our test pits,we observed medium
dense to very dense soils with an estimated allowable lateral bearing pressure of 3,500 psf.The lateral
bearing pressure provided was developed in general accordance with the methods described in
Section 17.2.1 of the WSDOT GDM.
3.4 Pavement Design
Pavement sections should be constructed on a subgrade that consists of 1 ft of uniformly firm and
unyielding, compacted native subgrade or imported structural fill as described in Section 3.1 of this
report.The structural fill should be prepared as described in Section 3.1.4 of this report.The design
pavement sections were developed using the American Association of State Highway and
Transportation Officials' (AASHTO's) Guide for Design of Pavement Structures (AASHTO 1993).The
standard duty asphalt pavement section recommendations provided in Table 3 assume a 20-year
design life, a maximum equivalent single-axle load (ESAL) of 100,000, and an assumed California
Bearing Ratio (CBR) of 12 percent for the section. The heavy-duty asphalt pavement section assumes
at least 65 buses per day, a 20-year design life, a loading of 2,000,000 ESALs, and an assumed CBR of
12 percent for the section. The assumed CBR value is estimated to correspond to a subgrade soil with
a density equal to 90 percent of the MDD, determined by ASTM test method D1557.
For any new pavement installed within the public right-of-way, local standards may supersede the
recommendations below.
Table 3.Recommended Asphalt Pavement Design Section
Pavement Section Type Asphalt Concrete Crushed Surfacing Base Compacted Native or
Pavement Thickness Course Thickness Structural Fill Thickness
Standard duty 3 inches 4 inches 12 inches
Heavy duty 4 inches 4 inches 12 inches
Asphalt concrete should be Class B aggregate material or hot-mix asphalt class%2 inch, PG64-22,
conforming to Section 5-04 of the 2016 WSDOT Standard Specifications.The asphalt should be
compacted to at least 91 percent of the Rice density. Base course material should be compacted to at
least 95 percent of the MDD(ASTM test method D1557)and should meet the requirements for
crushed surfacing base course (CSBC) in Section 9-03.9(3) of the 2016 WSDOT Standard Specifications.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 3-9 September 18,2017
DRAFT Landau Associates
The upper 2 inches of crushed surfacing could consist of crushed surfacing top course to facilitate fine
grading of the surface.
For our Portland cement concrete (PCC) pavement design,we assumed a design life of 20 years. For
bus turnarounds, 2,000,000 ESALs were assumed in our rigid pavement design.A reliability of 85
percent, a terminal serviceability index of 2.5, a design serviceability loss of 2,and load transfer
coefficient of 3.2 (assumes continuous reinforcement and tied shoulders)were used in the design.
The design assumed a CBR of 12 percent(equates to a resilient modulus of 12,533) and at least 4
inches of CSBC placed below the PCC pavement. The following table summarizes the PCC pavement
section for the bus turnarounds.
Table 4.Recommended Portland Cement Concrete Pavement Design Section
Pavement Section Type Portland Cement Concrete Crushed Surfacing Base Compacted Native or
Pavement Thickness Course Thickness Structural Fill Thickness
Heavy Duty 8 inches i 4 inches 12 inches
Base course material should be compacted to at least 95 percent of the MDD determined using ASTM
test method D1557 and should meet the requirements for CSBC in Section 9-03.9(3) of the 2016
WSDOT Standard Specifications. PCC pavement should meet the requirements in Section 5-05 of the
2016 WSDOT Standard Specifications.The pavement edges should be fully supported with either a
thickened edge or an integral curb,and the joint spacing should be no more than 15 ft apart.To
provide load transfer across the joints between panels,the panels should be fully doweled. Dowels
should be placed at a depth of one-half the slab thickness and spaced 12 inches on center.The dowel
bar diameter should be 1.5 inches and should have a minimum embedment of 9 inches on each side
of the joint.
Prevention of road base saturation is essential for pavement durability.Thus,efforts should be made
to limit the amount of water entering the base course.
3.5 Stormwater Infiltration Feasibility
Stormwater improvements may include ponds or underground infiltration facilities. Site soils suitable
for stormwater infiltration were observed in our explorations but vary with depth and location.
Groundwater was not observed during our site investigation in August 2017 to a maximum depth of
16.3 ft bgs. Groundwater levels in the project area are expected to fluctuate seasonally,with
maximum groundwater levels occurring during the late winter and early spring months.
Long-term preliminary infiltration rates are provided in Table 5 and are based on the soil grain size
infiltration rate determination methods in the Washington State Department of Ecology's 2005
Stormwater Management Manual for Western Washington (2005 SWMMWW) and on the results of
our laboratory tests (Appendix B). Appendix III-A of the 2005 SWMMWW provides the method and
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 3-10 September 18,2017
DRAFT Landau Associates
recommended correction factors to be used to estimate the infiltration rates.The following assumed
correction factors were used to account for pond size (CFsize= 1.0), biofouling and siltation effects for
ponds (CFsilt/bio=0.9), and aspect ratio correction factor(CFaspect= 1.0). We also assumed a
ponded water depth of 4 ft and a depth-to-groundwater of 20 ft.These assumptions should be
verified or modified in final design to calculate final infiltration rates.
The preliminary(factored) infiltration rates using the correction factors mentioned above are
provided in Table 5.The highest estimated infiltration rates are for soils located in the vicinity of test
pits TP-2,TP-3,TP-6, and TP-9 site. The rates assume at least 10 ft of separation to seasonal high
groundwater.
Table 5.Preliminary Factored Infiltration Rates
Preliminary Factored
Exploration Designation Infiltration Rate(a)
Depth Interval
(inches/hour) (ft)
TP-2 0.9 1.0—12.5
TP-3 0.7 1.5—13.5
TP-4 0.3 2.0—14.0
_._.__— . __...._._..--.....__...... _
TP-5 0.3 1.7—14.0
TP-6 0.4 2.0—13.0
TP-6 1.0 14.0—15.0
TP-9 1.8 2.5—14.0
TP-10 0.3 0.75—10.0
TP-10 0.1 10.0—14.0
(a)=Assumes bottom of infiltration facility is 4 ft bgs from current site grades.
ft=feet
TP=test pit
It is our opinion that the collection of seasonal high groundwater information is not warranted, given
the site conditions. Final design infiltration rates should be confirmed by pilot infiltration test (PIT)
evaluations at the specific locations and depths of the proposed facilities. Typically,the infiltration
rates provided in Table 5 can be increased through the completion of onsite infiltration testing.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 3-11 September 18,2017
DRAFT Landau Associates
4.0 CONSTRUCTION SUPPORT
Landau Associates, Inc. (LAI) should be asked to review the geotechnical portions of the plans and
specifications for the proposed project in advance of project bidding.The purpose of the review is to
verify that the recommendations presented in this geotechnical report have been properly
interpreted and implemented in the design and project specifications.
We recommend that monitoring,testing, and consultation be provided during construction to confirm
that the conditions observed are consistent with those indicated by our explorations,to provide
expedient recommendations should conditions be revealed during construction that differ from those
anticipated, and to evaluate whether geotechnical activities comply with the project plans,
specifications, and the recommendations contained in this report. Such geotechnical activities include
but are not limited to observation of foundation subgrades, compaction testing of structural fill, and
observation of the prepared slab and pavement subgrades.The purpose of these services would be to
observe compliance with the design concepts, specifications, and recommendations in this report. In
the event subsurface conditions differ from those anticipated before the start of construction, LAI can
provide revised recommendations appropriate to the conditions revealed during construction. LAI
would be pleased to provide these services for you.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 4-1 September 18,2017
DRAFT landau Associates
5.0 USE OF THIS REPORT
Landau Associates, Inc. prepared this report for the exclusive use of Mason Transit Authority and SO
Alliance for the proposed Belfair Park and Ride Improvements project, located southeast of the
intersection of Log Yard Road and State Highway 3 near Belfair,Washington. Within the limitations of
scope,schedule, and budget, our services have been conducted in accordance with generally
accepted practices of the geotechnical engineering profession; no other warranty, express or implied,
is made as to the professional advice included in this report.
The conclusions and recommendations contained in this report are based on the conditions
observed/interpreted in the explorations advanced for this study and on our experience in the project
area.There may be some variation in subsurface soil and groundwater conditions, and the nature and
extent of the variations may not become evident until construction.Accordingly, a contingency for
unanticipated conditions should be included in the construction budget and schedule.
If variations in subsurface conditions are encountered during construction, LAI should be notified for
review of the recommendations in this report and revision of such if necessary. If there is a substantial
lapse of time between submission of this report and the start of construction,we recommend that we
review this report to determine the applicability of the conclusions and recommendations contained
herein.
We appreciate the opportunity to be of service to you on this project. Please contact us at
(360)791-3178 if you have questions or require additional information.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 5-1 September 18,2017
DRAFT Landau Associates
6.0 REFERENCES
AASHTO. 1993. AASHTO Guide for Design of Pavement Structures. American Association of State
Highway and Transportation Officials.
ASTM. 2003. Annual Book of ASTM Standards. In:Soil and Rock(I). West Conshohocken, PA: ASTM
International.
Ecology. 2005.Stormwater Management Manual for Western Washington: Volume lll—Hydrologic
Analysis and Flow Control Design/BMPs. Washington State Department of Ecology.
[CC. 2014. 2015 International Building Code. International Code Council. May 30.
Polenz M., K. Alldritt, N.J. Hehemann, I.Y. Sarikhan, and R.L. Logan. 2009. Geologic Map of the Belfair
7.5-minute Quadrangle, Mason, Kitsap, and Pierce Counties, Washington. Open File Report 2009-
7. Washington State Department of Natural Resources.
Washington State Department of Labor and Industries. 2016. Construction Work. Chapter 296-155
WAC; Part N. Excavation,Trenching, and Shoring. Washington State Department of Labor and
Industries.
WSDOT. 2015. Geotechnica/Design Manual. Washington State Department of Transportation.
WSDOT. 2016.Standard Specifications for Road, Bridge, and Municipal Construction 2016. M 41-10.
Washington State Department of Transportation. Amended April 4.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 6-1 September 18,2017
D AF 3
Bremerton
National
Airport
Project Location
i
fai
eek
Project Q
Location
Everett
N 0 0.5 1 Seattle
Spokane*
Tacoma
Miles Olympia
Washington
Data Source:Esri 2012
Mason Transit Authority Figure
Park and Ride Improvements
LANDAU Belfair Site Vicinity Map 1
ASSOCIATES Belfair,Washington
Legend
/ TP-1 l9 Approximate Test Pit Location and Designation
LOT 20
,
Project Limits
r
/ LOT 1 ` ,'/ LOT 16
1.0 inches/hour assumed I/TP-11W
for bioretention facility. No / \
oO'data from TP 8 provided, \
so averaged rates from
TP-6 and TP-9 1_ 0.0
(.4+1.8)/2 = 1.1 1.0 used.
0.4 inches/hour used ,
for infiltration pond. TP 7 \�
TP 9 /
i
1.8
/ TP-6N \ i
0.3
o \ LOT 13 TP-2'�
\ TP-5
0.3 Z vr,)
0
/ \
o TP-4
2 0.0
0.3 inches/hour used 0.3
for biofiltration swale.
0
}
LOT 12 - DRAFT
v
0
0 150 300
a
Source:SO Alliance,2017 Scale in Feet
a
c
Mason Transit Authority Figure
LANDAU Park and Ride Improvements Site and Exploration Location Plan
14ASSOCIATES Belfair Site
Belfair,Washington
APPENDIX A
Field Explorations
DRAFT Landau Associates
APPENDIX A
FIELD EXPLORATIONS
Subsurface conditions at the site were explored on August 15, 2017 by advancing 10 test pits (TP-1
through TP-10) between 12.5 and 16.3 feet below ground surface.The approximate locations of our
explorations are shown on Figure 2. The test pits were advanced by Howard's Construction&
Excavating of Olympia,Washington, under subcontract to Landau Associates, Inc.
The field explorations were coordinated and monitored by a representative of Landau Associates, Inc.,
who also obtained representative soil samples, maintained a detailed record of the subsurface soil
and groundwater conditions observed, and described the soil encountered by visual and textural
examination. In general accordance with ASTM International test method D2488,Standard Practice
for Description and Identification of Soils(Visual-Manual Procedure), each representative soil type
observed was described using the soil classification system shown on Figure A-1. Logs of our
explorations are presented on Figures A-2 through A-6.These logs represent our interpretation of
subsurface conditions identified during the field explorations.The stratigraphic contacts shown on the
individual logs represent the approximate boundaries between soil types; actual transitions may be
more gradual. A further discussion of the soil and groundwater conditions observed is contained in
the main text of this report.
Soil samples obtained from the test pits were taken to our laboratory for further examination and
testing.The test results and a discussion of our testing procedures are presented in Appendix B. Upon
completion of excavation and sampling,the test pits were backfilled with the excavated material. The
backfill material was compacted using the bucket of the backhoe.
Appendix A 1174015.010.012
MTA—Belfair Park and Ride A-1 September 18,2017
Soil Classification System
uscs
MAJOR GRAPHIC LETTER TYPICAL
DIVISIONS SYMBOL SYMBOL!" DESCRIPTIONS t2N3d
GRAVEL AND CLEAN GRAVEL :�'Q p o: GW Well-graded gravel;gravel/sand mixture(s);little or no fines
GRAVELLY SOIL
.19
" (Little or no fine') o°o°o. GP Poorly graded gravel;gravel/sand mixture(s);little or no fines
O m (More than 50%Of GRAVEL WITH FINES GM Silty gravel;gravellsand/silt mixture(s)
W E'y coarse fraction retained (Appreciable amount of
Z`o N on No.4 sieve) fines) GC Clayey gravel;gravevsand/clay mixture(s)
0 Ln z° SAND AND CLEAN SAND $W
u1 Well graded sand;gravely sand;little or no fines
m c SANDY SOIL (Little or no fines)
X t 10 $P Poorly graded sand;gravely sand;little or no fines
o d (More than 50%of SAND WITH FINES $M Silty sand;sand/silt mixture(s)
OU W coarse fraction passed (Appreciable amount of
through No.4 sieve) fines) $C Clayey sand;sand/clay mixture(s)
Inorg r
anic sift and ve v fine sand;rock flour,silty or clayey fine
O w r^m SILT AND CLAY ML sand or clayey sift with slight plasticity
C o 'u CL Inorganic clay of low to medium plasticity,gravelly clay;sandy
mw day,silty day,lean clay
W CS%m (Liquid limit less than 50)
Z r m m OL Organic sift;organic,silty day of low plasticity
sv'aN SILT AND CLAY MH Inorganic silt;micaceous or diatomaceous fine sand
C0 o•r
e J��6 (;H Inorganic clay of high plasticity,fat clay
Z E (Liquid limit greater than 50)
LL OH Organic day of medium to high plasticity;organic sift
HIGHLY ORGANIC SOIL PT Peat;humus;swamp soil with high organic content
GRAPHIC LETTER
OTHER MATERIALS SYMBOL SYMBOL TYPICAL DESCRIPTIONS
PAVEMENT JJ7RK
or PC Asphalt concrete pavement or Portland cement pavement
- ROCK --- - Rock(See Rock Classification)
WOOD WD Wood,lumber,wood chips
DEBRIS DB Construction debris,garbage
Notes: 1. USCS letter symbols correspond to symbols used by the Unified Soil Classification System and ASTM classification methods.Dual letter symbols
(e.g.,SP-SM for sand or gravel)indicate soil with an estimated 5-15%fines.Multiple letter symbols(e.g.,MUCL)indicate borderline or multiple soil
classifications.
2. Soil descriptions are based on the general approach presented in the Standard Practice for Description and Identification of Soils(Visual-Manual
Procedure),outlined in ASTM D 2488.Where laboratory index testing has been conducted,soil classifications are based on the Standard Test
Method for Classification of Soils for Engineering Purposes,as outlined in ASTM D 2487.
3. Soil description terminology is based on visual estimates(in the absence of laboratory test data)of the percentages of each soil type and is defined
as follows:
Primary Constituent: >50%-"GRAVEL,""SAND,""SILT,""CLAY,"eta
Secondary Constituents: >30%and<50%-"very gravelly,""very sandy,""very silty,"etc.
>15%and<30"/,-"gravelly,""sandy,""silty,"etc.
Additional Constituents: > 5%and<15%-"with gravel,""with sand,"Vth silt,"etc.
< 5%-Vth trace gravel,""with trace sand,"Vth trace silt,"etc.,or not noted.
4. Soil density or consistency descriptions are based on judgement using a combination of sampler penetration blow counts,drilling or excavating
conditions,field tests,and laboratory tests,as appropriate.
Drilling and Sampling Key Field and Lab Test Data
SAMPLER TYPE SAMPLE NUMBER&INTERVAL
Code Description Code Description
a 3.25-inch O.D.,2.42-inch I.D.Split Spoon PP=1.0 Pocket Penetrometer,tsf
b 2.00-inch O.D.,1.50-inch I.D.Split Spoon Sample Identification Number TV=0.5 Torvane,tsf
c Shelby Tube PID=100 Photoionization Detector VOC screening,ppm
d Grab Sample Recovery Depth Interval W=10 Moisture Content,%
e Single-Tube Core Barrel D=120 Dry Density,pU
f Double-Tube Core Barrel If 1
f— Sample Depth Interval -200=60 Material smaller than No.200 sieve,%
g 2.50-inch O.D.,2.00-inch I.D.WSDOT Portion of Sample Retained GS Grain Size-See separate figure for data
h 3.00-inch O.D.,2.375-inch I.D.Mad.California for Archive or Analysis AL Atterberg Limits-See separate figure for data
i Other-See text if applicable GT Other Geotechnical Testing
1 300-lb Hammer,304nch Drop CA Chemical Analysis
2 140-lb Hammer,30-inch Drop Groundwater
3 Pushed
4 Vibroobre(Rotosonic/Geoprobe) Approximate water level at time of ddling(ATD)
5 Other-See text if applicable 1 Approximate water level at time other than ATD
Mason Transit Authority Figure
Park and Ride Improvements Soil Classification System and Key /�
LANDAU Belfair Site A_
ASSOCIATES Belfair, Washington
TP- 1
SAMPLE DATA SOIL PROFILE GROUNDWATER
a 0 � o Excavation Method: Excavator
i z'm ~ m Ground Elevation(ft):
Not Measured
o m Z `m m o N
a U
o w `ma as U3 F2 0 � Logged By: BJM
0 SM Brown,silty,fine to coarse SAND with gravel
SP and organics(medium dense,dry to moist)
SM (TOPSOIL) Groundwater not encountered.
S-1= d Brown,fine to coarse SAND with gravel and sift
5 (medium dense,moist)
(ICE CONTACT)
-Grades to light brown and dense at 2.5 ft bgs
S-2= d
10
S-2 d
15 S 4 d o:o. GP Light brown,sandy,fine to coarse GRAVEL
cobbles(dense,moist)
Test Pit Completed OB/15117
Total Depth of Test Pit=15.5 ft.
20
TP- 2
SAMPLE DATA SOIL PROFILE GROUNDWATER
o a a> o E n Method:. vator
z'_ > @ E vation( Not Measured
o mZ d 6 Cl)
w n« a ❑ o.
n >
I
p 0 W N as l� FF U' 0
t 0 of forest duff
N (FOREST DUFF) Groundwater not encountered.
w - W S Brov tfty fine to coarse SAND with organics
a S 1= d (loose,dry to moist)
5 (TOPSOIL)
o S-2= d Brown,gravelly,fine to coarse SAND with sift
o - (dense,moist)
(ICE CONTACT)
10 -Grades to gray at 5.5 ft bgs
m
E S-3 d
Test Pit Completed 08/15/17
m Total Depth of Test Pit=12.5 ft.
F 15
'o
vi
0
'a
20
i -
zz
m
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
n 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
3. Refer to"Soil Gassification System and Key'figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits
LANDAU Belfair Site A-2
ASSOCIATES Belfair, Washington
TP-3
SAMPLE DATA SOIL PROFILE GROUNDWATER
_ o Excavation Method: Excavator
E n E
c z cg a) >, Ground Elevation(ft):
o (D Z a`> m to
L c6 aN d 0 d U)
o > cn m 0 � Lo99ed By: BJM
0
sM 6 inches of forest duff
SP_ (FOREST DUFF) Groundwater not encountered.
SM Brown,silly,fine to coarse SAND with gravel
5 S-1= d GS 3 (loose,dry to moist)
(TOPSOIL)
Gray,very gravelly,fine to coarse SAND with
S-2= d silt and cobbles(dense,moist)
(ICE CONTACT)
10 -Grades to very dense at 8 ft bgs
S-3 d -Grades to gravelly at 11 ft bgs _
Test Pit Completed 08/15/17
15 Total Depth of Test Pit=13.5 ft.
20
TP-4
SAMPLE DATA S GROUNDWATER
o c E n Meth vato
>a z— E" vation Not Measured
J .O a) Z (0 U U)
w L � n m 0. a
3 m a2i ca m atei m rn
0
O O W p)cif Cl)) H (5 7
C 0 'I 4W
of forest duff
CL
F (FOREST DUFF) Groundwater not encountered.
co
F S-1= d S Br illy,fine to coarse SAND with gravel
a and organics(loose,dry to moist)
5 (TOPSOIL)
d W=5
N S 2= d GS Brown,very gravelly,fine to coarse SAND with
b silt and cobbles(dense,moist)
1 (ICE CONTACT)
ru 10 I
r W_6 1 -Grades to gray at 3.5 ft logs /
� S 3= d GS 1 -Grades to light brown and very dense at 6 ft I
1 I
a logs
S-4 d 1------- -------/
°W° 15 Test Pit Completed 08/15/17 Light brown,silty,very gravelly,fine to coarse
F Total Depth of Test Pit=14.0 ft. SAND with cobbles(very dense,mast)
ui
0
s
20
N
OI
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
$ 3. Refer to"Soil Classification System and Key"figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits /�/-�_�
LANDAU Belfair Site
ASSOCIATES Belfair, Washington
TP-5
SAMPLE DATA SOIL PROFILE GROUNDWATER
m -6 Excavation Method: Excavator
E a E E
c z H co Ground Elevation(ft): Not Measured
o a) Z d m o
a o rA
0 w i)ca co FT ? Logged By: BJM
0
SM 8 inches of forest duff
SM (FOREST DUFF) Groundwater not encountered.
S 1= d GS6 Broom,silly,fine to coarse SAND with gravel
and organics(loose,dry to moist)
5 (TOPSOIL)
Light reddish brown,silty,very gravely,fine to
S-2= d W=6 coarse SAND(dense,moist)
GS (ICE CONTACT)
10 -Grades to gray and gravelly at 5 ft bgs
-Grades to with cobbles at 7.5 ft bgs
S-3 d
15 Test Pit Completed 08/15/17
Total Depth of Test Pit=14.0 ft.
120
TP- 6
SAMPLE DATA SOIL .PROFILE GROUNDWATER
z a a) o E n Method: E vato
a = �' T E Not Measured
c Z H U) vation
W t m nm n n
3 n m E c E n N
0 0 W Mad CO) H C7
0
t 0 of forest duff
y (FOREST DUFF) Groundwater not encountered.
S-1= d G B illy,fine to coarse SAND with gravel
a and organics(loose,dry to moist)
q 5 (TOPSOIL)
d _ W_6
S 2= d GS Broom,very sandy,fine to coarse GRAVEL with
silt(very dense,moist)
(ICE CONTACT)
10 -Grades to gray at 6 ft bgs
co
z
w S-3= d o:o. GP Gray,very sandy,fine to coarse GRAVEL
0 15 S-4 d4 Q GP- \ (dense,moist) —————J_
o GS
Test Pit Comple GM Gray,very sandy,fine to coarse GRAVEL with
Total Depth of Test Pit=16.0 ft. sift
(dense,moist)
9
20
i�
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
3. Refer to"Soil Gassification System and Key"figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits /� _�
LANDAU Belfair Site /-�
ASSOCIATES Belfair, Washington
TP-7
SAMPLE DATA SOIL PROFILE GROUNDWATER
a E a Excavation Method: Excavator
z m a to >, Ground Elevation(ft): Not Measured
.2 CD Ca m (3 u)
£ co o.d n n to
o ch
w `cn°-a co H Logged By: BJM
0
SM 8 inches of forest duff
(FOREST DUFF) Groundwater not encountered.
SP-
S 1= d SM Brown,silty,fine to coarse SAND with gravel
and organics(loose,dry to moist)
5 (TOPSOIL)
Gray,fine to coarse SAND with gravel and sift
S 2= d 377—
o.a. GP \ (dense,moist) —
0. \ (ICE CONTACT) /
10 °O -----------
q 0 Light brown,sandy,fine to coarse GRAVEL
0..0 (dense,moist)
15
S-3 d °
Test Pit Completed 08/15/17
Total Depth of Test Pit=15.0 ft.
20
TP-8
SAMPLE DATA S GROUNDWATER
EE o
o _ n E a Excavation Methot): vato
a 3 T E Not Measured
w v Z m m tq > round Elevation(ft):
J B
w
m m m av'i BA
0 o ur U).8 cn 1— Cq _ogged By: _
J -
F- 0 inches of forest duff
(FOREST DUFF)
ro _ Groundwater not encountered.
F- S-1= d S ilty,fine to coarse SAND with gravel
IL and organics(loose,dry to moist)
o
5 (TOPSOIL)
c g Light brown,gravelly,fine to coarse SAND with
\ silt(very dense,moist) /
\ (ICE CONTACT) /
_J
10 S-2= d Brown to gray,fine to coarse SAND with gravel
N (dense,moist)
rr
LL -Grades to with cobbles at 10 ft bgs
J
m 15 S-3 d
o Test Pit Completed 08/15/17
o Total Depth of Test Pit=15.0 ft.
6
0
a
20
n
rn
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
ui 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
v - 3. Refer to"Soil Gass cation System and Key"figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits
LANDAU
14 Belfair Site A-5
ASSOCIATES Belfair,Washington
TP-9
SAMPLE DATA SOIL PROFILE GROUNDWATER
a0 o Excavation Method: Excavator
E n E E Not Measured
c z m Cl) Ground Elevation(ft):
o m Z m m uJ
n am a E Cl)
o w cn as rn c7 j Logged By: BJM
0
12 inches of forest duff
SM (FOREST DUFF)
Groundwater not encountered.
4:
a. Gw Brown,silly,fine to coarse SAND with gravel
S 1= d W=3 i...Q_ and organics(medium dense,dry to moist)
5 GS a Q (TOPSOIL)
o:°) Light brown,very sandy,fine to coarse
0�: GRAVEL(very dense,moist)
S-2= d a, (ICE CONTACT)
10 6 Q
o.... -Grades to brown to gray,with cobbles,and
p:o: dense at 8.5 ft bgs
Q:
15 SP- Brown,gravely,fine to coarse SAND with sift
S-31W d SM (dense,moist)
Test Pit Completed 08/15/17
Total Depth of Test Pit=16.3 ft.
-20
TP-10
SAMPLE DATA SOIL PROFILEGROUNDWATER
o n d .0 o E in MethyA* Excavator
n
Z_ @ C0 T Not Measured
W � vation
o Z d m 9 rn
W L 6 D.M d 0 r-
n n
3 a� E c E (D m
0 0 liJ (0-a ram/) l U �
0
tz _ o of forest duff
N W=5 (FOREST DUFF) Groundwater not encountered.
F S 1= d Brov iffy,fine to coarse SAND with gravel
SP and organics(loose,dry to moist) Ir
-5 S 2 d (TOPSOIL) I
o _ I
Brown,very gravely,fine to coarse SAND with I
Ilsilt(dense,moist) I
(ICE CONTACT) I
------------------
F 10 SM \ Gray,fine to coarse SAND with gravel(dense, /r
m _ S-3 d \moist)
a S4 d ML \ -------------------//
J \ Gray,silty,fine to coarse SAND with gravel
W S 5 d SP \\(dense,moist)
F -15 Test Pit Completed 08/15/17 \------------------ f
s \Gray,sandy SILT(hard,moist) /
o Total Depth of Test Pit=14.8ft. `-----------------J
Gray,fine to coarse SAND with gravel and trace
sift(dense,moist)
20
i
rn
b Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
$ 3. Refer to"Soil Gassif cation System and Key"figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits /�
LANDAU Belfair Site A_6
ASSOCIATES Belfair,Washington
APPENDIX B
Laboratory Testing
i
DRAFT Landau Associates
APPENDIX B
LABORATORY TESTING
Natural moisture content determinations and grain size analyses were performed on select samples to
aid in soil classification and estimation of infiltration rates. Laboratory testing was performed in
general accordance with the ASTM International (ASTM)standard test methods described below.The
samples were checked against the field log descriptions and updated where appropriate in general
accordance with ASTM standard D2487,Standard Practice for Classification of Soils for Engineering
Purposes.
Natural Moisture Content
In general accordance with ASTM test method D2216, natural moisture content determinations were
performed on select soil samples obtained from the explorations.The natural moisture content is
shown as W=xx(i.e., percentage of dry weight)at the respective sample depth in the column labeled
"Test Data" on the summary exploration logs presented in Appendix A.
Grain Size Analyses
To provide an indication of the grain size distribution of the onsite soil,grain size analyses were
conducted on representative soil samples obtained from the explorations. Analyses were performed
in accordance with ASTM test method D422. Samples selected for grain size analyses are designated
with a "GS" in the column labeled "Test Data" on the summary exploration logs in Appendix A.The
results of the grain size analyses are presented in the form of grain size distribution curves on Figures
B-1 and B-2 in this appendix.
Appendix B 1174015.010.012
MTA—Belfair Park and Ride B-1 September 18,2017
117401501 WW17 YA11741015.01UTBELFAIRSRF1174015.010.GPJ GRAINSIZEFIGURE
U.S.Sieve Opening in Inches I U.S.Sieve Numbers Hydrorneter
6 4 3 2 1 314 1/2 3I8 3 4 6 8 10 14 16 20 30 40 5060 100 140 2W
100
so
80
70
L
3 60
T
a
m 50
c
iL
C
�$ 40
Q.
a
30
20
10
0
100 10 0.1 0.01 0.001
n In Millimeters
Cobbles Gravel Sand Silt or Clay
Coarse Fine Medium IFine
Symbol Exploration Sample Depth Natural Soil Description Unified Soil
Number Number (ft) Moisture(%) Gassification
• TP-2 S-1 3.5 4 Gravelly,fine to coarse SAND with sift SPSM
m TP-3 S-1 4.0 3 Very gravelly,fine to coarse SAND with silt SPSM
♦ TP-4 S-2 6.0 5 Very gravelly,fine to coarse SAND with silt SPSM
* TP-4 S-3 11.0 6 Silty,very gravelly,fine to coarse SAND SM
O TP-5 S-1 3.0 6 Silty,very gravelly,fine to coarse SAND SM
Mason Transit Authority Figure
Park and Ride Improvements Grain Size Distribution
LANDAUBelfair Site B-1
ASSOCIATES Belfair,Washington
1174015.01 0,6117 YA11741015.0101TtaELFAIR Sr1E11174015.010.GPJ GRAIN SIZE FIGURE
U.S.Sieve Opening in Inches U.S.Sieve Numbers Hydrometer
6 4 3 2 U 1 314 112 W8 3 4 6 8 10 14 16 20 30 40 5060 100 140 200
100
90
80
70
L
3 60
T
50
i�
c
40
m
a
30
20
10
0
100 10 0.1 0.01 0.001
in In Millimeters
Cobbles Gravel Sand Sift or Clay
Coarse Fine Medium Fine
Symbol Exploration
tural Unified Soil
nDepthtN Number Number ( Moisture Soil Description Classification
49 TP-5 S 2 7.5 6 Silty,very ,grsvelty,fine to coarse SAND SM
m TP-6 S-2 6.0 6 Very sandy,fine to coarse GRAVEL with silt GP-GM
♦ TP-6 S-4 15.5 4 Very sandy,fine to coarse GRAVEL with silt GP-GM
* TP-9 S-1 4.0 3 Very sandy,fine to coarse GRAVEL GW
O TP-10 S-1 2.5 5 Very gravelly,fine to coarse SAND with silt SPSM
Mason Transit Authority Figure
Park and Ride Improvements Grain Size Distribution
LANDAU Belfair Site B-2
ASSOCIATES Belfair,Washington
MASON COUNTY
DEPARTMENT of PUBLIC WORKS
100 W PUBLIC WORKS DRIVE
1V SHELTON, WASHINGTON 98584
MEMORANDUM
DATE: July 15, 2019
TO: Ron Buckholt, Senior Planner
Trish Woolett, Building Inspector
FROM: ��7oretta Swanson, Director
Cc: Patrick Holm, PE, SCJ Alliance
SUBJECT: Mason Transit Authority— Belfair Park and Ride Stormwater Plan
Mason County Public Works received a stormwater plan for the proposed Belfair Park and Ride facility to
be located on tax parcel 12321-41-00000 located east of SR 3 and just south of Log Yard Road.
REVIEW
Public Works reviewed the following information:
■ Drainage Report dated October 2018 prepared by SCJ Alliance;
■ Hydraulic Report dated April 2019 prepared by SCJ Alliance; and
■ Civil plan sheets dated October 31, 2018 prepared by SCJ Alliance.
COMMENTS
1. The stormwater plan was developed based on the 2005 Stormwater Management Manual for Western
Washington (SWMMWW)and found to be acceptable. All ten minimum requirements are addressed and
low impact development objectives achieved through 100%infiltration on site.
2. Performance standards are identified in section 4.4, page 3. and staff concurs.
3. Minimum Requirements are summarized in section 4.7, page 5. Minimum Requirement 44 is to preserve
natural drainage systems and outfalls. The plans show construction of a shallow swale near the east
property line (sheets 11,13 of 24;section F-F). The Swale bottom appears to be at elevation 350.5'. The
offsite analysis on page 2 states "no runoff appears to flow onto the site". What purpose does the Swale
serve then? If run-on is anticipated to be collected in the swale and directed to the north and future Log
Yard Road, please either contain on site or quantify runoff anticipated to leave the site by the swale.
Page 1 of 2
4. An infiltration pond is to be constructed on the property. The infiltration facility is designed with a
r maximum ponding depth of 4.5'with 3:1 side slopes and does not appear to warrant fencing. The owner
may decide to fence for other reasons, however, and III-3.2.1 of the Manual may provide guidance to help
with the decision on whether to fence.
5. Infiltration pond rates are to be confirmed by PIT evaluations at the specific facility location and depth.
6. Prior to beginning work on-site,the contractor shall provide a copy of the SWPPP and identify the project
Certified Erosion and Sediment Control Lead for the project.
7. Prior to final project approval and occupancy, an Operation and Maintenance Covenant shall be recorded
and copy provided to Mason County.
8. Building plans are to be reviewed to ensure roof and footing drains are not connected, per Geotechnical
Engineering Report prepared by Landau and dated September 18, 2017.
Thank you for the opportunity to review and comment. Please do not hesitate to call (360) 427-9670 ext
769 or email if there are any questions or clarification required.
Page 2 of 2
Page 1 of 1
Michael MacSems -Re: MCTA Project
i
From: Patrick Holm< atrick.holm sc'alliance.com>
p J @
To: Michael MacSems<mms@co.mason.wa.us>
Date: 1/25/2019 1:58 PM
Subject: Re: MCTA Project
I believe the stormwater report was in your court for review. As a part of the Log Yard Road roundabout
project we are using a combined pond system so the report will change slightly. I recommend waiting on
reviewing until we are done with the roundabout design and the full system can be reviewed.
We did go out there and write a quick Wetland/Stream Memo for our records. I will submit it as part of
the updated SEPA information.
On Thu, Jan 24, 2019 at 1:28 PM Michael MacSems<mms@co.mason.wa.us>wrote:
Patrick,
I'm just checking in with you as it has been a while since we last talked. I know that we are waiting
for more information before issuing a SEPA determination,but what is your understanding of where
the status of the stormwater review?I'm sorry, but I'm struggling to remember who is waiting for
what in that regard and I'm hoping that you can jog my memory.
Hope all is well.
Thanks,
Michael MacSems
Patrick Holm,PE
SO Alliance
Project Manager
o.360.352.1465
m.909.644.5315
www.sc*alliance.com
This communication may contain privileged or other confidential information.If you have received it in error,please advise the sender by reply email and immediately
delete the message and any attachments without copying or disclosing the contents.Thank you.
file:///C:/Users/mms/AppData/Local/Temp/XPgrpwise/5C4B 15E9Masonmail 1001613462... 1/28/2019
Page 1 of 1
Michael MacSems - GRD2018--00015 (Mason Transit)
From: Ronald Buckholt
To: patrick.holm@scjalliance.com
Date: 12/19/2018 11:05 AM
Subject: GRD2018--00015 (Mason Transit)
CC: MacSems, Michael; Swanson, Loretta
Attachments: Buckholt, Ronald.vcf
Dear Applicant,
I am Ron Buckholt, planner with Mason County, reviewing permit GRD2018-00015 for the Belfair Mason Transit project.
Unfortunately,the subject building permit is being placed on HOLD, due to the following reason(s):
1. Note: It appears that a draft SEPA checklist was provided in conjunction with a previously submitted forest practice permit
application and that the proponent is attempting to update the SEPA checklist to address all aspects of the development. In
order for the subject grading permit application to be reviewed, the quantity of the cut and fill needs to be identified in terms
of cubic yards within the SEPA checklist. Please address.
2. The square footage of all proposed individual structures need to be identified within the SEPA checklist and corresponding
site plans, i.e.including bus shelters,etc.
3. As discussed in the pre-application notes,there are wetlands and streams within proximity of the project site, therefore,
the SEPA checklist and accompanying site plan shall quantify the distances from all aspects of the proposed development,
e.g.including clearing/grading boundaries from the subject wetlands and streams. These distances are needed in order to
confirm that the development does not encroach into any regulated streams or wetlands nor any associated buffers and
setbacks related to the aforementioned wetlands and streams. Please address with a report or narrative from a certified
wetlands biologist on the classification or regulatory status of the wetlands and streams,and delineation, if warranted, in
order to demonstrate that the proposed development does not infringe upon the Mason County's adopted codes
for prescribed buffers and setbacks from regulated wetlands and streams.
4. Commercial site plan application is required, in order to verify zoning, landscaping, parking standards are being satisfied.
Please provide clarification, if the proponent is wishing to incorporate a commercial site plan review concurrent with the SEPA
review process. Please note,that if the full scope of work is not disclosed within the SEPA checklist to address the size and
quantity of all building elements,the SEPA may have to be re-addressed at the time of commercial site plan and building
permit application review(which may cause delay). Please advise on how the proponent would like to proceed in terms of
building permit, commercial site plan and zoning review.
5. A geo-technical report was provided (dated December 12, 2018). What was the intent of the geo-report? Was it
required as part of Michael MacSems review for the forest practice permit?or intended to coincide with a future building
permit or stormwater plan submittal? Please provide clarification.
Please address these issues in order for the review process to proceed.Thank you in advance.
Ron Buckholt
Senior Planner
Mason County
Community Services Department
615 W. Alder St., Bldg 8
Shelton,WA 98584
360.427.9670 x287
rbuckholtCcbco.mason.wa.us
file:///C:/Users/mms/AppData/Local/Temp/XPgrpwise/5C 1 A25EAMasonmai1100161346... 12/24/2018
Drainage Report
Belfair Park and Ride
Mason Transit Authority
Mason County
�F
4`tr1EY G.
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wa
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October 2018
s��01VA ECG 1�l��ad
SCJ ALLIANCE
CONSULTING SERVICES
Drainage Report
Proiect Information
Project: Mason Transit Authority Belfair Park and Ride
Prepared for: Mason Transit Authority
Reviewing Agency
Jurisdiction: Mason County
Proiect Representative
Prepared by: SO Alliance
8730 Tallon Lane NE, Suite 200
Lacey, WA 98516
360.352.1465
scjalliance.com
Contact: Whitney Holm, PE
Project Reference: SO #0738.05
Path:N:\Projects\0738 Mason Transit Authority\0738.05 MTA Park and Ride
Develop ment\Phase 9-Design Develop ment\Belfair\Drainage\2018-1016
Drainage Report.docx
SG Alliance October 2018
TABLE OF CONTENTS
1. Project Overview........................................................................................................1
1.1 Site Data ................................................................................................................................ 1
1.2 Project Overview................................................................................................................... 1
2. Existing Condition Summary.......................................................................................2
2.1 Site Description .....................................................................................................................2
I Offsite Analysis Report...............................................................................................2
3.1 Upstream Analysis.................................................................................................................2
3.2 Downstream Analysis............................................................................................................2
4. Permanent Stormwater Control Plan..........................................................................2
4.1 Existing Site Hydrology..........................................................................................................2
4.2 Developed Site Hydrology.....................................................................................................3
4.3 Flow Control System..............................................................................................................3
4.4 Performance Standards and Goals........................................................................................3
4.5 Water Quality System............................................................................................................4
4.6 Conveyance System Analysis and Design..............................................................................5
4.7 Minimum Requirements.......................................................................................................5
S. Construction Stormwater Pollution Prevention Plan ...................................................6
5.1 Objective of the Stormwater Pollution Prevention Plan.......................................................6
5.2 Summary of Elements ...........................................................................................................6
6. Special Reports and Studies......................................................................................11
7. Other Permits...........................................................................................................11
8. Operation and Maintenance Manual ........................................................................11
8.1 Overview.............................................................................................................................. 11
8.2 Required Maintenance........................................................................................................ 11
LIST OF APPENDICES
Appendix A—Basin Map
Appendix B—Construction Plans
Appendix C—Drainage Calculations
Appendix D—Geotechnical Report
SCJ Alliance October 2018
Page i
1. "PROJECT OVERVIEW
1.1 SITE DATA
Project Proponent: Belfair Park and Ride
Total Site Area: 4.0 acres
Required Permits: Grading, Special Use, Construction, Building, NPDES
Parcel Numbers: 12321-41-00000, 12321-44-00000
1.2 PROJECT OVERVIEW
Currently,there is undeveloped forestland at the southwest corner of State Route 3 and Log Yard Road.
The site is owned by Mason Transit Authority.They plan on constructing a park and ride, including
parking stalls, a bus turnaround, a bus shelter, and an MTA building.
Figure 1. Project Location
'Ace Pades Mx Outlel
LN—p,Supply
Stormwater currently infiltrates on site.The proposed site will have three basins. Basin 1 includes the
offsite access road; Basin 2 includes the main parking lot; and Basin 3 includes the bus parking,
turnaround area, and the building. See attached Basin Map.
The runoff from Basin 1 and Basin 2 will be collected and treated in a bioretention facility and then
piped to an infiltration pond on site. Basin 3 will sheet flow into a biofiltration swale for treatment and
conveyance to the onsite infiltration pond.
SCJ Alliance October 2018
Page 1
The proposed stormwater will infiltrate 100%, matching the predeveloped patterns. See the Drainage
Basin Exhibits in Appendix A.
The proposed project follows the new development requirements stated in the Department of Ecology's
2005 Stormwater Management Manual for Western Washington (SMMWW). From Figure 2.4.1—Flow
Chart for Determining Requirements of New Development of the SMMWW minimum requirements#1-
#10 need to be applied to the new and replaced impervious surfaces.
2. EXISTING CONDITION SUMMARY
2.1 SITE DESCRIPTION
The existing site is heavily forested. It is generally flat in the areas of proposed improvements, although
some portions of the site slope as much as approximately 15% down to the northwest.There are no
storm drainage systems on site.The stormwater infiltrates on site.
Landau Associates completed a geotechnical report in September 2017. Landau tested 10 pits between
12.5 and 16.3 feet below ground surface.The tests found that the area was covered in 0.75 to 2.5 feet
of forest duff and topsoil. Forest duff consisted of leaves,fir needles, and other decomposed organics.
The topsoil was typically a brown, loose to medium dense, silty sand with variable gravel and organic
content. Below the forest duff/topsoil layer was ice-contact deposits.This layer consisted of brown to
gray, medium dense to very dense sand with variable silt, gravel, and cobble content or brown to gray,
dense to very dense gravel with variable silt, sand, and cobble content. Landau's preliminary factored
infiltration rates range from 0.1 inches per hour to 1.8 inches per hour. See the Geotechnical
Engineering Report in Appendix D.
OFFSITE3. • • •
3.1 UPSTREAM ANALYSIS
The surrounding properties are heavily forested area. No runoff appears to flow onto the site.
3.2 DOWNSTREAM ANALYSIS
All runoff will infiltrate. No downstream effects are anticipated. See the stormwater analysis in Appendix
C.
i PERMANENT STORMWATER • •
4.1 EXISTING SITE HYDROLOGY
See Section 2.1 for the hydrology of the existing site.
SCJ Alliance October 2018
Page 2
4.2 DEVELOPED SITE HYDROLOGY
The site has three basins.The stormwater system is designed using the SMMWW and WWHM2012.
Basin 1 includes the offsite improvements, Basin 2 includes the parking lot area, and Basin 3 includes the
bus parking and turnaround area. See the Basin Area Exhibits in Appendix A.
Table 4.1 Developed Conditions Summary
Impervious Pervious Total Basin
Area (acres) Area (acres) Area (acres)
Basin 1 0.52 0.37 0.89
Basin 2 0.98 0.91 1.89
Basin 3 1.68 1.71 3.39
The runoff from Basin 1 will be collected and conveyed to the bioretention facility. Infiltration is
anticipated in the bioretention facility, and an infiltration rate of 1.0 inch per hour was used in modeling.
The infiltration rate was averaged from two of the closest test pits to the bioretention facility Landau
dug to assume 1.0 inch per hour. Runoff from Basin 2 will sheet flow to a conveyance ditch and then
flow into the bioretention facility. Overflow from the bioretention facility will be collected in a beehive
catch basin and conveyed to an infiltration pond on site. Runoff from Basin 3 will sheet flow to a
biofiltration swale for treatment and be conveyed to the onsite pond.The pond is designed to infiltrate
100%of all the runoff from all three basins. Based on the Geotechnical Report, an infiltration rate of 0.4
inches per hour was used for the infiltration pond.
See Figure 2 and Table 5 in the Geotechnical Report(Appendix D)for field-measured infiltration rates.
4.3 FLOW CONTROL SYSTEM
Flow control has been designed to handle the 100-year event. Runoff will infiltrate in the bioretention
facility and the infiltration pond. Using an infiltration rate of 0.4 in/hr. a 14,000 square-foot pond with
5.5 feet of depth will adequately infiltrate the 100-year storm for all three basins.The 5.5 feet of depth
includes 1.0 feet of freeboard.
See Appendix C for drainage calculations. See Figure 2 and Table 5 in the Geotechnical Report
(Appendix D)for field measured infiltration rates.
4.4 PERFORMANCE STANDARDS AND GOALS
The proposed park and ride is considered a new development project. The basic treatment menu has
been selected for this project, and oil control and phosphorous control are not required. Flow control
has been designed per the Standard's 100-year, 24-hour storm, and the conveyance system was
designed to handle a 25-year, 24-hour storm.
SCJ Alliance October 2018
Page 3
4.5 WATER QUALITY SYSTEM
Treatment of stormwater runoff from Basins 1 and 2 will be provided by a bioretention facility.
Stormwater runoff treatment for Basin 3 will be provided by a biofiltration Swale.They were designed
using the SMMWW.
Using an approved continuous runoff model to infiltrate 91%of the site's runoff, 2,500 square feet of
bioretention area is required to treat both Basin 1 and Basin 2.The bioretention facility includes 1.5 feet
of amended soils, 0.5 feet of ponding, and 0.5 feet of freeboard.
Basin 3 will be treated using a biofiltration Swale.The biofiltration swale is designed according to BMP
T9.10 and the design calculation steps in Volume 5 Section 9.4 of the SMMWW.The swale is designed to
be 4.1-feet wide with a 1.5% longitudinal slope.The swale will be one-foot deep with four inches of
ponding.The required length is 465-feet long.The project site uses a 640-foot-long swale. See the
Proposed Conditions Exhibit in Appendix A for treatment areas.
Below is a summary of the analysis.
EQUATIONS UNITS LEGEND
2.5Qn b = bottom width of swale (ft) = 4.1
b __ 1.49y1 67s0 5 -Zy Q = 6-month, 24-hour storm event(cfs) = .2405
n = Manning's roughness coefficient = 0.24
kQ y = depth of flow(ft) = .33
V = A s = slope parallel to direction of flow = 0.015
(ft/ft)
Z = swale side slopes (ft:ft) = 3:1
L = V(t)(60) V = design flow velocity(fps) = unknown variable
A = swale flow area(ft') = 1.68
L = required swale length (ft) = unknown variable
Ratio of peak 10-minute flow
predicted by SBUH to the water
k 3.0
quality design flow rate estimate using =
WWHM
t = 9 minutes or 18 minutes for = 18
continuous inflow
Length of flow requirements for biofiltration Swale
2.5Qn
b = 1.49y1.67s0.5 -ZY
b = 2.5(0.2405)(0.24)
1.49(0.33)'67(0.015)0 5 -(3)(0.33) = 4.04 b=4.1 ft
SCI Alliance October 2018
Page 4
V = k _ (3.0)(0.2405) — 0.43 0.43 fps < 1.0 fps 0
A 1.68
L = Vt(60) = 0.43(18)(60) = 464.4 ft Minimum Swale
length=465 ft
See Appendix C for drainage calculations.
4.6 CONVEYANCE SYSTEM ANALYSIS AND DESIGN
The SMMWW requires the system to be able to convey the 25-year storm, 2.33 cfs. However,the
conveyance system is large enough to handle 4.28 cfs,which is larger than the 100-year storm for the
entire site, 3.15 cfs.The designed system allows for high flow capacity so that runoff does not flood a
the bioretention area or swale.
See Appendix C for flow control calculations.
4.7 MINIMUM REQUIREMENTS
The stormwater design complies with all ten minimum requirements as follows:
Minimum Requirement#1—Preparation of Stormwater Site Plans—This summary is contained within
the stormwater site plan.
Minimum Requirement#2—Construction Stormwater Pollution Prevention—A pollution prevention plan
has been included within the stormwater site plan, which describes the 12 required elements. Further,
an erosion control plan has been prepared and is part of the engineering plan set.
Minimum Requirement#3—Source Control of Pollution—The project owner has been made aware of
the requirements for source control for pollution prevention.
Minimum Requirement#4—Preservation of Natural Drainage Systems and Outfalls— Runoff from the
project site currently infiltrates on site. Stormwater runoff from the developed site will infiltrate
completely on site as well.
Minimum Requirement#S—Onsite Stormwater Management—Runoff from Basin 1 and Basin 2 will
convey to a bioretention facility for water quality treatment and Basin 3 will sheet flow to a biofiltration
swale for treatment. Runoff is conveyed from both facilities to an infiltration pond where runoff will
completely infiltrate on site.
Minimum Requirement#6— Runoff Treatment—Runoff treatment is provided by a bioretention facility
and a biofiltration swale.
Minimum Requirement#7— Flow Control—Runoff from the site will be conveyed to an infiltration pond
and infiltrated 100%.
Minimum Requirement#8—Wetlands Protection—There are no known wetlands on site.
SCJ Alliance October 2018
Page 5
Minimum Requirement#9— Basin/Watershed Planning—There is no additional basin/watershed for this
area.
Minimum Requirement#10—Operation and Maintenance—An operation and maintenance manual is
included with this stormwater site plan. Refer to Section 8 for additional information.
5. CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN
5.1 OBJECTIVE OF THE STORMWATER POLLUTION PREVENTION PLAN
The purpose of a construction Stormwater Pollution Prevention Plan (SWPPP) is to describe the
potential for pollution problems on a construction project.The SWPPP also explains and illustrates the
measures to be taken on the construction site to control these problems.The SWPPP is a guideline for
the contractor to follow during construction to prevent erosion and sedimentation. Erosion control
measures are not limited to those shown in this SWPPP or on the temporary erosion and sediment
control (TESC) plans. Measures shall be installed as necessary to meet the DOE guidelines for
construction stormwater pollution prevention and the requirements of the DOE NPDES permit. Further,
the SWPPP shall be updated by the contractor as required by the requirements of the DOE NPDES
permit.
This SWPPP is prepared according to the guidance of the Stormwater Management Manual for Western
Washington—Washington State Department of Ecology(DOE).The DOE manual describes 12 necessary
elements of construction stormwater pollution prevention.These 12 elements include: mark clearing
ow a flow rates, install sediment controls stabilize soils
limits, establish construction access, control soils, protect
p
slopes, protect drain inlets, stabilize channels and outlets, control pollutants,control dewatering,
maintain BMPs, and manage the project.These elements have been addressed as follows:
5.2 SUMMARY OF ELEMENTS
The Best Management Practices (BMPs) listed in this report, or their equivalent, are required.Any
revisions by the contractor to the BMPs listed in the SWPPP shall be approved by the Engineer in
writing.Therefore, if the contractor does not require a BMP or needs to modify a BMP, the contractor
shall document the reasons and present the documentation to the Engineer for approval.
ELEMENT#1:MARK CLEARING LIMITS
Prior to beginning land disturbing activities, including clearing and grading, clearly mark all clearing limits
including trees that are to be preserved within the construction area. Fences shall be constructed as
shown on the TESC Plans and per the details in the landscape plans. In addition,the following BMPs will
be implemented where appropriate:
• BMP C101: Preserving Natural Vegetation
• BMP C103: High Visibility Plastic or Metal Fence
• BMP C104: Stake and Wire Fence
SCJ Alliance October 2018
Page 6
ELEMENT#2:ESTABLISH CONSTRUCTION ACCESS
A stabilized construction entrance shall be constructed to minimize the tracking of sediment onto any
public road.The stabilized construction entrance shall be constructed as shown on the TESC plans and in
accordance with the requirements of BMP C105.
ELEMENT#3: CONTROL FLOW RATES
Properties and waterways downstream from development sites shall be protected from erosion due to
increases in the volume,velocity, and peak flow rate of stormwater runoff from the project site.The
following BMP will be implemented where appropriate:
• BMP C240: Sediment Trap
ELEMENT#4:INSTALL SEDIMENT CONTROLS
Prior to leaving a construction site or prior to discharge into an infiltration facility, stormwater runoff
must pass through a sediment pond or other appropriate sediment removal BMP. Silt fence barriers
shall be constructed as shown on the Temporary Erosion Control Plans and in accordance with BMP
C233. In addition, the following BMPs will be implemented where appropriate:
• BMP C230: Straw Bale Barrier
• BMP C231: Brush Barrier
• BMP C232: Gravel Filter Berm
• BMP C234: Vegetated Filter Strip
• BMP C235: Straw Wattles
• BMP C240: Sediment Trap
• BMP C241: Temporary Sediment Pond
• BMP C251: Construction Stormwater Filtration
ELEMENT#5:STABILIZE SOILS
All exposed and unworked soils shall be stabilized by application of effective BMPs,which protect the
soil from the erosive forces of raindrop impact and flowing water, and from wind erosion. From October
1 through June 30, no soils shall remain exposed and unworked for more than 15 days. From July 1 to
September 30, no soils shall remain exposed and unworked for more than 30 days.This condition
applies to all onsite soils, whether at final grade or not.
In areas where the soils will remain unworked for more than the limits stated above or have reached
final grade, seeding and mulching shall be used in accordance with BMPs C120 and C121. Sod shall be
used in accordance with BMP C124 for disturbed areas that require immediate vegetative cover. Dust
control shall be used as needed to prevent wind transport of dust from disturbed soil surfaces and in
accordance with BMP C140.
In addition,the following BMPs will be implemented where appropriate:
SCJ Alliance October 2018
Page 7
• BMP C123: Plastic Covering
• BMP C125: Topsoiling
ELEMENT#6:PROTECT SLOPES
Slopes shall be constructed in a manner that will minimize erosion.This shall include, but is not limited
to, placing excavated material on the uphill side of trenches, collecting drainage at the top of slopes, etc.
Slopes will be stabilized as indicated in Element#5. In addition,the following BMPs will be implemented
where appropriate:
• BMP C130—Surface Roughening
• BMP C131—Gradient Terraces
• BMP C200—Interceptor Dike and Swale
• BMP C201—Grass-Lined Channels
• BMP C205—Subsurface Drains
• BMP C204—Pipe Slope Drains
• BMP C206—Level Spreader
• BMP C207—Check Dams
ELEMENT#7:PROTECT DRAIN INLETS
All storm drain inlets made operable during construction as well as all existing structures within the
project limits shall be protected so that stormwater runoff shall not enter the conveyance system
without first being filtered or treated to remove sediment. Install catch basin sock filters as shown on
the TESC plans and in accordance with BMP C220.
ELEMENT#8:STABILIZE CHANNELS AND OUTLETS
All temporary onsite conveyance channels shall be constructed and stabilized to prevent erosion.
Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent to stream
banks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems.The
following BMPs will be implemented where appropriate:
• BMP C202—Channel Lining
• BMP C209—Outlet Protection
ELEMENT#9: CONTROL POLLUTANTS
All pollutants, including waste materials and demolition debris, that occur on site during construction
shall be handled and disposed of in a manner that does not cause contamination of stormwater.
Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain
down, solvent and de-greasing cleaning operations,fuel tank drain down and removal, and other
activities that may result in discharge or spillage of pollutants to the ground or into stormwater runoff
must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be
cleaned immediately following any discharge or spill incident. Emergency repairs may be performed on
SC-7 Alliance October 2018
Page 8
site using temporary plastic placed beneath and, if raining, over the vehicle.Application of agricultural
chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates
that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations shall be
followed for application rates and procedures.
Three source control BMPs will apply to this project:
• A Spill Prevention Plan (prepared by Contractor)
• Maintenance of Storm Drainage Facilities(by Contractor during construction; by City following
construction)
• Street Sweeping(as needed during construction by Contractor)
ELEMENT#10:CONTROL DE-WATERING
All foundation,vault, and trench de-watering water,which have similar characteristics to stormwater
runoff at the site, shall be discharged into a controlled conveyance system prior to discharge to a
sediment pond.
Clean, non-turbid de-watering water, as determined by the Certified Professional in Erosion and
Sediment Control, can be discharged to systems tributary to state surface waters, provided the de-
watering flow does not cause erosion or flooding of receiving waters.These clean waters should not be
routed through stormwater sediment ponds.
Highly turbid or otherwise contaminated de-watering water, such as from construction equipment
operation, clamshell digging, concrete tremie pour, or work inside a cofferdam, shall be handled
separately from stormwater at the site. Some disposal options, depending on site constraints, may
include: 1)transport off site in vehicle, such as a vacuum flush truck, for legal disposal in a manner that
does not pollute state waters, 2) onsite treatment using chemical treatment or other suitable treatment
technologies, or 3) sanitary sewer discharge with local sewer district's approval if there is no other
option.
ELEMENT#11:MAINTAIN BMPs
All temporary and permanent erosion and sediment control BMPs shall be maintained and repaired as
needed to ensure continued performance of their intended function.All maintenance and repair shall be
in accordance with BMPs.
Sediment control BMPs shall be inspected weekly or after a runoff-producing storm event during the dry
season and daily during the wet season.
All temporary erosion and sediment control BMPs shall be removed within 30 days after final site
stabilization is achieved or after the temporary BMPs are no longer needed.Trapped sediment shall be
removed or stabilized on site. Disturbed soil areas resulting from removal of BMPs or vegetation shall be
permanently stabilized.
SCJ Alliance October 2018
Page 9
ELEMENT#12:MANAGE THE PROJECT
• Phasing of Construction
The project shall be phased where feasible to prevent,to the maximum extent practicable,the transport
of sediment from the site during construction. Revegetation of exposed areas and maintenance of that
vegetation shall be an integral part of the clearing activities for each phase.
• Seasonal Work Limitations
From October 1 through April 30,clearing, grading, and other soil disturbing activities shall only be
permitted if shown to the satisfaction of the local permitting authority that silt-laden runoff will be
prevented from leaving the construction site.
The following activities are exempt from the seasonal clearing and grading limitations:
1. Routine maintenance and necessary repair of erosion and sediment control BMPs;
2. Routine maintenance of public facilities or existing utility structures that do not expose the soil or
result in the removal of the vegetative cover to the soil; and
3. Activities where there is 100%infiltration of surface water runoff within the site in approved and
installed erosion and sediment control facilities.
• Inspection and Monitoring
All BMPs shall be inspected, maintained, and repaired as needed to ensure continued performance of
their intended function.
The Certified Professional in Erosion and Sediment Control for this project is
shall be on site or on call at all times during
construction.The role of the Certified Professional is to identify problems or failures of erosion control
measures in the field and to promptly initiate corrective measures.The Certified Professional and the
contractor will be paid by contractor.
Sampling and analysis of the stormwater discharges from the construction site may be necessary to
ensure compliance with standards.
Whenever inspection and/or monitoring reveals that the BMPs identified in the construction SWPPP are
inadequate due to the actual discharge of or potential to discharge a significant amount of any
pollutant, the construction SWPPP shall be modified, as appropriate, in a timely manner.
• Maintenance of the SWPPP
The construction SWPPP shall be retained on site or within reasonable access to the site.The
construction SWPPP shall be modified whenever there is a significant change in the design, construction,
operation, or maintenance of any BMP.
SCJ Alliance October 2018
Page 10
6. SPECIAL ' • '
Landau Associates completed a Geotechnical Engineering Report in September 2017. It can be found in
Appendix D.
7. OTHER PERMITS
No other permits are anticipated at this time.
8. OPERATION
8.1 OVERVIEW
Onsite drainage facilities such as pipes, bioretention areas, biofiltration swales, and infiltration ponds
will require routine maintenance.The owner is responsible for performing regular maintenance of the
storm drainage facilities. Mason County will provide technical assistance at the owner's request.
Maintenance of private storm drainage facilities will be performed by the owner and/or their
representative.
8.2 REQUIRED MAINTENANCE
Facility-specific maintenance standards contained in this section are intended to be conditions for
determining if maintenance actions are required as identified through inspection. Based upon inspection
observations,the inspection and maintenance schedules shall be adjusted to minimize the length of time
that a facility is in a condition that requires a maintenance action.
The jurisdiction may be called for technical assistance. Please do not hesitate to call, especially if it is
unclear whether a particular situation may be a problem.
SCJ Alliance October 2018
Page 11
APPENDIX A
BASIN MAP
LEGEND:
BASIN 1 �- --------------------------------
BASIN 2 BASIN 2
TOTAL AREA:1.89 ACRES \_
BASIN 3 PERVIOUS AREA: 1.74 ACRES
IMPERVIOUS AREA:0.15 ACRES \
,��, IMPERVIOUS AREA
I
I
BASIN 1:OFFSITE RUNOFF-
TOTAL AREA:0.89 ACRES
PERVIOUS AREA:0.83 ACRES
IMPERVIOUS AREA:0.06 ACRES
I
I
1
I
I
I I
I I
I
I
I
1
I
I
1
I
I
I
I
I
I
I
I
o I
I I
BASIN 3:BUS PARKING LOT RUNOFF
_ TOTAL AREA:3.39 ACRES ,
PERVIOUS AREA:3.18 ACRES
IMPERVIOUS AREA:0.21 ACRES
I ,
-ORZOATAL SCALE
I ,
g
EX-1
OCTOBER2018 BELFAIR PARK AND RIDE
SCJ ALLIANCE
la CONSULTING SERVICES 073e_05 EXISTING CONDITIONS EXHIBIT - --
y 8730 TALLON LANE NE,SUITE 200,LACEY,WASHINGTON 98516
k9' P:360-352-1465 F:360-352-1509 °w'YMOG FREA.- 1
SCIALUANCE.COM MTA PAWAND RIDE
LEGEND:
BASIN 1: OFFSITE RUNOFF BASIN AREA ' \ -------------
��-
BASIN 2: PARKING LOT RUNOFF BASIN AREA
2 00 23+00 8 24+00 25+00 26+00 27+00 28+00
�- 1---- -----------------------
BASIN 3: BUS LOT RUNOFF BASIN AREA _-- —
55
IMPERVIOUS AREA r '
-- ------------- -- --
'1 \'
BIORETENTION \
BASIN 1:OFFSITE RUNOFF-
TOTAL AREA:0.89 ACRES I
PERVIOUS AREA:0.37 ACRES __ __- _ __'"�____ _ _' I `�
IMPERVIOUS AREA:0.52 ACRES i i� _
,
� BASIN 2:PARKING LOT RUNOFF
TOTAL AREA: 1.89 ACRES
PERVIOUS AREA:0.91 ACRES
IMPERVIOUS AREA:0.98 ACRES
I i
,
BIOFILTRATION SWALE
,
' I BASIN 3:BUS PARKING LOT RUNOFF '
i
TOTAL AREA:3.39 ACRES i I
i
PERVIOUS AREA:1.71 ACRES
s , IMPERVIOUS AREA:1.68 ACRES
PGIS: 1.16 ACRES j! i
� INFILTRATION POND
NGPIS:0.19 ACRES !� ! '��• I '
i POND:0.33 ACRES
i
� I � �•J '�.�✓ i� I II
g
3
m HOROWAL Wove: �w�art
EX-i
DUE
CTOBB2018 BELFAIR PARK AND RIDE
SCJ ALLIANCE
CONSULTING SERVICES "��05 PROPOSED CONDITIONS EXHIBIT s"EET"°.
i� 8730 TALLON LANE NE,SURE 200,LACEY,WASHINGTON 98516 1
&9 P:360-352-1465 F:36D-352-1509 ORMWFLE N.;
SCIALUANCE.COM WTA PARK AND RIDE
APPENDIX B
CONSTRUCTION PLANS
T. 23 N.1 R. 01 W., S. 21 ) W.M.
LEGEND
: - .
X---- EXISTING MAJOR CONTOUR
1
........_-.XX -.- EXISTING MINOR CONTOUR _
PROPOSED MAJOR CONTOUR - 54+69 06 326:58 R[ \
a PROPOSED MINOR CONTOUR z3+ao 24+ao 25+00 { '.26+op 27+00 IE(SE) 340:70 5#+69IE(NW) _ 340 98
TLET 1 -
----------- GRADE BREAK - - C54+68.97, 10258'RT 1 '16 LF OF 6*PVC' 0 40 80
BIORETENTION FACILITY RIM:337.08 C54+6S.99,'165.53�-RT 47 \ SCALE IN FEET
- - - - - DITCH BOTTOM ELEV-- 335.0 .IE IN:335.00 12' (SE) IE OUT 335.82 12"_(NW)RIM:33e.32
��.� SPOT ELEVATION _ _ _ _ _ _ 1 _ -- 63 LF OF 12' PVC®1.307C - -- - -
/
339.
_ 5.6 �
0.00% 52
SLOPE LABEL 3396e
CO 2 3391 ...i
STORM LINE (HDPE) C54+68.97, 74.65 RT .. B 3- + - i 4! � :68
RIM:335.50 oe ;b ,
8 98 DITCH ITCH .71 344.9 .11
CATCH BASIN TYPE 1 1E OUT 330 00 12`(SW) N
W/BEEHIVE GRATE 1 w I 34
C D d I `
I I
.0 < -✓� - ^- �71-47
168 ^ .3GRADING NOTES: 3ee33916 y0 `• 4.6a .oa
9.1 - �j ... �45.63 345.
1. SEE'SD'SHEETS FOR STORM WATER INLET, PIPE I I --- - B 1� 339
AND DETENTION SYSTEM DETAILS.
213 LF OF 339.72'
�
2. CONTRACTOR SHALL ENSURE THERE IS POSITIVE I 8 �' 338 =u
DRAINAGE AWAY FROM BUILDING AT ALL TIMES. 5
_ SB S
3. EXISTING CONTOURS ARE BASED ON SEPTEMBER ( I N Z -�"-' 339 Jr 34370 fi
2017 TOPOGRAPHIC SURVEY BY MTN2COAST, LLC _ _ 3w•35 343.70
A.-BUILDING i
337.te
4. SPOT ELEVATIONS REPRESENT FINISHED GRADE AT I FOOTPRINT - -` ''
-
FLOW UNE UNLESS OTHERWISE NOTED. I ` Q 3905 1.70
FFE = 343.7 ._
.i9 a5:se
5. ALL LANDSCAPE AREAS SHALL BE STABILIZED. I Q I 3J664 3 ;q7
_ _ 344.
4 343.77991 345.36 545.68 \
34 3
Lu I 34 57 34149. 345.24
�IJJ 49_ OF tY P 0:1028x 4� �rJ 343.
- 3 .34 341.52 343.13
2.95
r �
`339:24 ,
CB
C53+05.71, 76.57'RT I Zb 338{5 - 344
RIM:336.35
IE OUT:332.85 12-(SW) :42 ` 0. / .45 11',
OUTLET 2 1
C52+57.03, 62.35'RT
RIM:330.38 1
E DRAINAGE SWALE
IE IN:327.80 12' (NE) �g.T I 337,57 4
C52+36.54,186.M RT I x x
C52+57.03, OUTLET8RT 73 I ' STORM POND RIM:338.73.
RIM:330.38 I 1 I R BOTTOM 3x.as IE OUT:333. 12'(W) I •24
f
IE IN:327.80 12'(NE) i I A I ELEV=327.8l A 64 LE OF 12'PVC 0 9 31x h 34A.41 r
I TLET 4 - 346.45 I .I
6 I 1 C52+10.26 128.38'RT
6 I 1 RIM:330.38 346.E 1
s I 8 I I i IE IN;321,80 1,2' (E) :3448 I'
--.. ``•ice ''' x � .�
s
J{3
� 0 rtensiau DATE By DESIGNED BY: ISSLIEDArE: =n:;.��•,nr•ir ,•._ ,
P H" MASON TRANSIT AUTHORITY SD-1
ALL DIMENSIONS DRAWN� �
� N.HAYFIELD 0738 OS
SHOWN INFEET SCJ ALLIANCE BELFAR
g UNLESS OTHERWISE CONSULTING SERVICES PARK AND RIDE DEVELOPMENT
R y" CHECKED BY DRAWING FILE No. DESIGNATED 8730 TALLON LANE NE,SUITE 200,LACEY,WASHINGTON 98516
g P:360-352-14Li5 F:3G0352-1509 GRADING AND DRAINAGE PLAN 1 of 3
3 0738.OSS61-B SUALLIANCE.COM
oa0
NOTES
y ALLOWANCES
1 As acceptable altematives to the mbar shown in me PRECAST BASE
O SECTION,fibers(placed accortlmg to the Standard Specifications),or
imum MA.. wire mesh having a min area of 0.12 square inches be,lo.11
IERIAL INSIDE be used with me minimum required raper shown in the ALTERNATIVE
O DIAMETER PRECAST BASE SECTION.Wine mesh shall not be placac in eta
¢ 0� a1t knockouts.
F- tT
N O 2. The knockout diameter shall not be greater than 20'.Knockouts shall
p have a wall thickness of 2'minimum to 2.5'maximum.Provide a 1.5'
0 tS m gap between the knockout wall and the outside of the pipe.
After the pipe is mstelled,fill the gap with joint narter m accordance
¢ 0 1z with Standard Specification 9-04.3.
9-M20)
CDO 3. The maximum depth from the finished grade to me lowest pipe invert
O ts. shall be 5'.
9-OS.12(1))
--► 4. The frame and grata may be installed with the flange down,or integrally
PVc tS Cast into me adjustment section with flange up.
9-D5.12(2))
I�a O D POLYEfNYIENE 5. The precast Base Section may have a rounded Moor,and the walls may
a m� oe sloped at a rate of 1.24 or steeper.
6. The opening shall be measured at the top of the Precast Base Section,
PLAT 7. All pickup holes shall be grouted full after the basin has been placed.
30" X
�10" x
1[-3
FF
L:-120"
CATCH BASIN TYPE 1
SEC
SHEET 1 OF 1 SHEET
•(SEE NOTE 1) 06-16-11
BEEHIVE GRATE I ALTERNATIVE PRECAST BASE SECTION
338.0
EXISTING GRADE
/
/
3:1 SIDE SLOPE /
336.0 /
3:1 SIDE SLOPE /
EEHIVE GRATE
JIM 335.50
334.0 ...................•.. .. ., .......... 336.0
/
332.0 ... . . ...... ........... .
o : /
�.1:5'A6tENDD.r
S01LS.,::
330.0 ............� ... .. ... . .. . . . .. . 334.0
b \
............ \/
328.0 • •• '
326.0 332.0
B
B-B
E
Q REVISIONS DATE BY DRAWING No..
MASON� TRANSIT AUTHORITY� I SD-2
BELFAIR
PARK AND RIDE DEVELOPMENT 5HEET No
--
x 2of3
GRADING AND DRAINAGE DETAILS
T. 23 N., R. 01 W., S. 21 , W.M.
344.0 344.0
HEAVY DUTY PAVEMENT
SECTION (SEE SHEET SP-2)
TRAFFIC CURB
346.0 346.0 342.0 342.0 342.0 .•. •• .........................•.•................. 342.0
roPsaL G 0.5' CLASS C TOPSOIL 7'00
———— - TRAFFIC CURB ---��--- --
TRAFFIC CURB —— ---------- 4.10
34to ....................... .`WHEEL'STOP '' 344.0 340.0 _._. �.—-.:-.—-.—-.— - ——..................... 340.0 340.0 .;. ............ 340.0
�20.04.00433420 ... `s: ...=r'` lAN ARD DUN' 342.0 338.0 ---------- '4^ ........... 338.0 338.a ........ .. ..................... 33&0
S U ;_. . STANDARD DUTY 0.5"CRUSHED'
PAVEMENT SECTION $
(SEE SHEET SP-2) PAVEMENT SECTION SURFACING BASE 0.5'CLASS C TOPSOIL
g o (� SHEET SP-2) COURSE. COMPACT TO
3400 340.0 336.0 336.0 336.0 95%MAX. DENSITY.
COMPACTED NATIVE SOIL
(95%OF ASTM 698) (95%OF ASTM 698)
DITCH SECTION C-C DITCH SECTION D-D DRAINAGE SWALE SECTION E-E
NTS NTS NTS
� 1
I
I 1
w
I I PAVED APRON FOR POND
MAINTENANCE ROAD
SWALE
SCALE
a
a '\
I
I
o -►____ .
____-F .tip
J a
u
0.5'(MIN)COMPACTED CSBC `
POND MAINTENANCE ROAD
a
0 10 20
b SCALE IN FEET
8 �
� 16
A`
POND MAINTENANCE ACCESS ROAD
Q ItEV SIONS DATE BY DESIGNED BY: ISSUE DATE: PROJECT NAME: DMONG No.:
! P.HOLM _ MASON TRANSIT AUTHORITY SD-3
SHOWN INFEET SC�I ALLIANCE
ALL DIMENSIONS BELFAIR
DRAW BBY. JOB No.:
+� N.MAYFIELD 0738.05
UNLESS OTHERWISE CONSULTING SERVICES MTA PARK AND RIDE DEVELOPMENT SHEETNo
.2 CHECKED BY: DRAWING FILE No.: DESIGNATED 8730 TALLON LANE NE,SUITE 200,LACEY,WASHINGTON 98516
= - 0738.05 SD3-B P:360-35w146S F:.OM52-1509
DRAINAGE DETAILS 3 of 3
APPENDIX C
DRAINAGE CALCULATIONS
SMMWW Minimum Requirements
Start Here
V
Does the site have
35% or more of See Redevelopment
existing impervious Yes 110. Minimum
Requirements and
coverage? Flow Chart
No (Figure 3.3)
Does the project convert
3/4 acres or more of
Does the project vegetation to lawn or
result in 5,000 landscaped areas, or
square feet, or No convert 2.5 acres or more
greater, of new plus of native vegetation to
replaced hard pasture?
surface area?
Does the project
Yes Yes No result in 2,000 square
feet, or greater, of
new plus replaced
All Minimum hard surface area?
Requirements apply
to the new and
replaced hard surfaces
and converted Yes No
vegetation areas. V 'I
Minimum Requirements Does the project have
#1 through #5 apply to land disturbing
the new and replaced activities of 7,000 !
hard surfaces and the Yes square feet or greater?
land disturbed.
No
Minimum
Requirement#2
applies.
Figure 2.4.1 —Flow Chart for Determining Requirements for New Development
Volume I—Minimum Technical Requirements—August 2012
2-10
WWHM: Treatment and Flow Control
Predeveloped Basins
It Basin 1 Predr:eloped B.Basin 2Predev6oped
Subbasin Name_ _ Subbasin Name:Bate 2
Surface Interflow Groudwalm Srafaoe Irtwtbw Groutdwatm
Flows To: �_. J I Flows To: I
Area in Basin r Slaw Orly Selected Area in Basin r Show Orly Selected
Available Pervious Acres Available Imperious Acres Available Pervious Acres Available Impervious Acres
W A/B.Forest,Flat ® r ROADS/FLAT 1 0 r A/B.Forest,Flat � r ROADS/FLAT 0
r A/B,FaW,Mod 0 r ROADS/MOD I0 r Are.Forest,Mod r ROADS/MOD 0
rA/B,Foram,StaW 0 r ROADSSTEEP 1 10 f�rA/B.Forest.Steep 0� r ROADS/STEEP 0�
r A/B,Padua,Flat 0 r ROOF TOPS/RAT 0 r A/B'P-tue,Flat 0 r ROOF TOPS/FLAT 0
r AM.Padura,Mod 0 r DRNEWAYS/FIAT 0 r A/B,Pasture,Mod r DRNEWAYS/FLAT 0
r AA.Pasture,Steep 0 r ORIVEWAYS/MOD 0 r Are,Pasture,Steep 0 r DRNEWAYS/MOD 0
r A/B,Lawn Fat 0 r DRNEWAYS/STEEP 0
r A/B,Lawn,Flat 0 r DRIVEWAYS/STEEP0 0
r A/B,Lawn,Mod 0 r SIDEWALKS/FLAT 0 r A/B,Lawn Mod 0 r SIDEWALKS/FIAT 0
r A/B,Lawn,Steep 0 r SIDEWALKS/MOD 0 r A/B,Law^'Steep 0 r SIDEWALKSAA00 0
r C,Faest.Flat 0 r SIDEWALKSSTEEP p r C,Faro,Flat 0 r SIDEWALKS/STEEPdl 0
r C,Fated,Mod 0 r PARKINGAUT r C,Feed Mod 0 r PARKING/ 0
'r C,Feed,Steep 0 r PARKING/MOD 0
r C,Forest.Steep 0 r PARKING/MOD 0 r C,Padua,Flat 0 r PARKING/STEEP 0
r C,Padue,Flat 0 r PAAKINGMEEP r C,Pastue,Mod r POND =0
r C.Pasture,Mod 0 r POND 10 r C.Pmtue,Steep 0 r Pears Pamnert 0
r C,pasture,Steep 0 r Porous Pavement r C,Lawn.Flat 0
r C,Lawn,Flat p
r-CLVAILMod
r C.Lawn,Mad 0� r C.Lawn,Steep
r C,Lawn,Steep 0 r SAT,Forest,Flat 0
r SAT,Faest.Flat 0 r SAT.Food,Mod 0
r SAT,Faes,Mad 0 J r SAT.Farm,Steep 0
r SAi,Faint Steep 0
P.—Total Apes
Pervious Taal -�Aam Impmvious Tad Aam
Impmvious Tad Aam Bash Total Aorm
Barn Total ®Aam
C-Basin 3 Predc:eloped
Subbasin Name:jBase 3
Surara Interflow Groudwatm
Flows To: 1 1
Area in Basin r Show O*Selected
Available Pervious Acres Available Impervious Ames
�r A/B,Forest,Flat r ROADSMAT 10
r AA,FaesLMod p� r ROADS/MOD p�
rA/B,Foed.Steep 0 r ROADS/STEEP 0�
r A/B,Padue,Flat r ROOF TOPS/FLAT 0�
r AID,Paste,Mad r DRNEWAYShUT J
r A/B,Padue,Steep r DRIVEWAYS/MOD
r AM,Lawn Had � r DRNEWAYSSTEEP 0
r A/B,Lawn,Mod 0� r SIDEWALKS/FLAT
r AA.La—,Stay p� r SIDEWALKS/MOD 0
r C,F—*L Fla p� r SIDEWALKS/STEEP 0
r C.Feed,Mod a r PARKINSNLAT
r 0
C,FwetLSMwp 0 r PARKING/KIOD
r C.Pattul.Fie 0 r PARKINGSTEEP
r C,Padua,Mod 0 r POND I��
r C.Padua,Steep r Paou Pav-wt
r C,Lawn,Flat 0
r C,Lawn Mod D�
r C.Lawn Steep 0
r SAT.FormL Fld 0�
r SAT.Feed Mod 0
-Jr SAT,Foal,Steep 0
Pan—s Tod 3.39 Aam
Impmvious Tad Aom
Bash Total 3.39 A—
Developed Basins
r3 8a— t Mitigated ® tS•Basin 2 Mitigated
Subbasin Name_! F Designate as Bypass for POC Subbasin Name Designate as Bypass for POC:
Surface Interlbw Groundwater Swlace Intwfbw Groundwates
--__-__--- Flows To: G L �1-1
Flows To: Gravd Ttaneh Bed_1 Gravel Trrnch Bed �� � rdd Trench Bedl Greed irerch Bedl
Area in Basin Show Only Sebded Area in Basin F Show Orly Sebded
Available Pervious Acres Available Impervious Acres Available Pervious Acres Available Impervious Acres
JW A/B.Feed.Flat p� .W ROADS/FLAT '.52 -- 7 W ALB.Fa ,ri ROADS/FIAT ®
J r A/B,Forest,Mod Q� ROADS/MOD 0 7 r Foal,Mod 0� r ROADS/MOD- 0�
F A/B,Forest,Steep 0 r ROADSISTEEP 0 A/B.Faed,Stsap 0 F ROADS/STEEP 0
F A/B,Pasture,Flat 0 F ROOF TOPSMAT 0 F A/B,Pasture.Flat 0 r ROOF TOPS/FAT 0
r A/B,Pasture,Mod 0 F DRIVEWAYSAIAT 0 F A5•Pasture,Mod 0 r DRNEWAYSMAT 0
F A/B,Pasture,Steep 0 F DRIVEWAYSMOD F AM.Pasture,Steep 0 F DRNEWAYS/MOD 0
r A/B,Lawn,Flat ® F DRIVEWAYS/STEEP 0 F'A/B,Lawn,Rat ® F DRNEWAY557EEP 0
F A/B.Lawn,Mod 0 r SIDEWALKS/Fl.AT 0 F A/B.Lawn,Mod 0 F SIDEWALKSh7AT 0
F A/B,Lawn,Steep 0 F SIDEWALKS/MOD p� F A5.Lawn,Steep 0� r SIDEWALKS/MOD 0�
F C,Forest,FW 0 r SIDEWALKSSTEEP 0 r C,Faed.Flat 0 F SIDEWALKSSTEEP 0
F C,Forest,Mad 0 r PARIONG/FLAT 0 F C.Forest.Mod 0 F PARKING/FLAT 0
F C,Food,Steep I J F PARKJNGAAOD p� F C,Forest.Steep 0� F PARKING/MOD 00
F C,Pasture,FW p� F PARKWGSTEEP 0 �F C,PaWae,FW 0 F PARKING/STEEP 0
F C,Pasture,Mod 0 F POND F C Pasture.Mod 0 Fii POND
0
F C,Pasture,Steep 0 F Paou Pavanert 0
F C.Pasture,Steep 0 r Paoli Pavemat 0 F C,La ,FW I0
F C,Lawn,Flat 0
F C.Lawn.Mod
F C,Lawn,Mad p 0
F C,Lawn.Steep 0 r SALT�FaesLesL FW
F SAT,Forest,Fla 0 F SAT,Fared.Mad 0
r SAT,Forest,Mod 0 j F SAT.Fa Steep 0
J F SAT,Faed,Steep 0�
Pervious Tad ®Apes
Pervious Total V37-- Apes Imps—o Tad ®Apes
Irnp.—Total ®Apes Basin Tdd 1F89 A.
Basin Total ®Apes
M Basin 3 Mrtigated
Subbasin Name:':. F Designate as Bypass for POC.
Surface Interns- Grourdwaler
Flows To: iCharrW 1 —� Charnel 1
Area in Basin F Show Only Selected
Available Pervious Acres Available Impervious Acres
W A5,Faed,Flat 0 r ROADSMAT j 11.35
F A/B.Faed Mod 0 F ROADS/MOD 0
F A/B,Forest,Steep 0 r ROADS/STEEP 0
F A/B,Pasture,Flat 0 F ROOF TOPSAUT
F A5,Pasture,Mod 0 r DRNEWAYS/F1AT 0
F A/B,Pasture,Steep 0 F DRNEWAYSAAOD 0
r A/B.Lawn,Fla 1.71 F DRIVEWAYSSTEEP 0
F A/B,Law t Mod 0 F SIDEWALKS/FLAT 0
F A/B,Lawn,Steep 0 r SIDEWALKS/MOD 0
F C.Forest,Flat 0 F SIDEWALKS/STEEP 0
F C,Fared.Mad 0 r PARKING/FLAT I 0
r C.Faed,Steep 0 F PARKING/MOD
F C.Pasture,Fiat 0 F PARKING/STEEP 0
F C.Pasture.Mod 0 ry POND 33
F C,Pastas,Steep 0 F Paow Pa+arrrw 0
r c,Lawn,Fiat 0
F C,Lawn,Mad 0
F C.Lawn.SStW 0
F SAT,Faed,Flat 0
r SAT,Faed,Mod 0
J F SAT,Faed,Steep 0
Pervious Total 1.71 Apes
Impervious Total 1.68 Apes
Basin Taal ®Apes
Treatment and Flow Control
a SChenatie 4 Grovel Trench Bed 1 Mitigated
Facility Name G—el Ttarcheadl
SCENARIOS Outlet 1 Outlet 2 Outlet 3
�EjPr Downstream Connection Tmpamidd Pond 1 10
FacilityType Greve)Trcrnh/Bad
Q Mtlteated Precplalm Appled to Fac Yy Quick Trench
Rill Stollen Evaporator Appledto FacAly FeciliN Dimension Diagram I
Facility Dimensions Outlet Structure Date I
Width WERE Trench Length Wi 250 _.
W®■® Trench Ronan hlNl .10 Rorer HeiDia ens F12 -H
i
Effect roTotal OWhlnl Ram Dheneta snit 12 �-
W®®® Top andbonan slope MNl 3 R—Tme IFlal J
Left Side Slope IHM 3 Notch Type
Rgh SEe Slope IHM 3
Pm Elm Material Layers for Trench/Bed
® ® - Layers Thick—lNl Ii.S - Orifice Diameter Height
Layer 1 paosry 1611 0.4 Number (in) (ft)
Layet 2 Thickness Ihl j t Fo---J Fo----H
Lays 2 paosly I0-1) 1 2 J J
Lays 3 Thick—(NJ G 3 F1J F--A
Lay.3 p—o ((all �0- _
Infiltration . J Ttmch Vokane at Rag Head(acltl 114
Commercial Tonbw - Measued I01Naeon Rate(i dhl F1----:1 J
Reduction Factor J Nathan F, Show Trench Open Table
U se Welled Suface A—(s*-hl F.— Iralial StapelNl
Total Vokme Infiltrated lac ttl 337607 Total Vokane Thoughl`&(ecJl) M216
i Total Valaro ThwghRim laces 12609 PmceN lNihated 961
Move Elm a Sue Infiltration Trends
Target%: 1Go J
M•Channel 1 Mitigated ' 1S-Trapezoidal Pond 1 Mitigated
Facility Name �Channel 1 Facility Name Trapezoidal Pard� Fatality Type
Outlet 1 Outlet 2 Outlet 3 Outlet 1 Outlet 2 Outlet 3
Downstream Connection Trapezadal Panel 1 0 0 Downstream Connections 10 0
r-Precoabm Applied to Fanny Auto Pond I Quick Pond
Facility Type ®F Use X-Sections Quick Channel I r£vapo,&-AppledtoFacit� FaciliyDimensionDiagram
J Faciliy Dimensions
Um Defiwd Outlet Structure Date I
Fanny Bottom Elevation(h) 0
Channel Dimensions Bottm Length(NI 100 Rim Haly/1[nit 45 J
Browse for file. I Rim Diameter f l 12
General Channel Data White Width lNl t40 RN-Ty" FFLat J
Charnel Bottom wkkh(N) 4.1 ENecb-Depth(N) is Nadi Type
Channel Length(NI ® Leh Side Slope(HM 3
Mamrg n coettloient 0.21 Bonan Side Slope(HNI 3
3
Slope ot Channel(ttn Righ Side Slope(HMtl D015
Lett Side Slope(HM 0 Top Side Slope(HM 0 Orifice Diameter Height
Right Side Slope[HN] Infiltration FR-4 Number Cn) (h)
Measued lNiralion Rate(:,nvl 0./ J 1 0 J p J sty
Ma�dram Chanel Depth(II) 1 - ro • _ '�
Redction Fada(iNe'fagal �� 2 �—- �J
Infiltration Yes Use Waned Suface Area[:idevsals) Yes J 3 Fo--J r—J
Measued)Natation Rat.(Whi) 0.3 --1 TotalVokmainfi ated(w4t) 255,628 .
TotalVokane Though Rise(achl 0 Pond Vol—al Rua Head Jana) 1.817
Reduction FaCa(a,"Naga) TotalVokme Though Facity(acal 255.63 ShdT J
Use Wetted Surface Area(Wential=) -� ow Ponable Open Tahh .
Pacers lrfltialed 100 Initial FO —
Taal Vokane Irlihated(ac-n) 116.412 Size Infiltration Pond
Total Vokane Through Riser(acN) 210.642
Total Vokane Though Facity(ac4t) 357.054 Tatsget%. too -i
Patent Infiltrated 326 Tide Gate I Time Senes I Demand
Size Infiltration Channel I
Show Channel Table IOpen Table - r-Use Tide Gate
Tide Gate
r Use Tide Gnte
Target%: 100 Tide Gate Elevation(tt) [10 Downstream Connection F
Overflow Elevation(ft) F0-- Notations (D
I
SWALE: Treatment
Biofiltration Swale Calculation Notes:
The bioswale was sized following the Manual's"Design Calculations for Biofiltration Swale" steps.
See section 4.5: Water Quality System for all calculations.
• For Step D-4:
o From WWHM,the 15 min. Water Quality Design Flow(Q) =0.2405 cfs (see below).The swale is
designed to treat the pollution-generation impervious area, 1.16 acres.
C Mre lMa'aea �NA-yfa.
S.bb..i.N. aad� _ _ 1r p.,vrme>w.wrroc Wale,Bu.W
sae... Run 1 On j=BMP OR4ie.BMP
Flow To r--
w..i.8—. r5yawpry_ L�,a = �
z4ha�,v.A..1«et azB7s
_ -
ba. A.oaDe4ml.^Impem.uc,.b I'm
�rh-iTwa�.s 1 rB�Oshxxr Slsdsd Row Rae;Idyl® Sladad Fi-RaIe Ids101367
r�:Yr��i � r ROOTiaysAu�-1
r�Iw-�I r n�eAf_—__�
r r 1isnue—1
raw riu�
r� r sc4Mwas�e�"�
r�� r
r�i � r +%,
r
r Sbeam Robxeon Duemn LID DuNnn Fkev Freoa.cy Wyn D�aBy Mydapeph
r� r Paa.P_a..we _
r� �—r� Wad dlrpulVWree UD RepM R«1wge Duamn Redwpe Rleaeveloped �R«Mpe M4pl.d
r A-11-detm.l. F--n WDM Ddd.Se l—I ' M-0N� .J
r —
r 1 PUYALLUP DAILY EVPP WIIENSEN+W S
as ---_- 2ShaAm
Jr srirr-s _�� � Sm Poc1 Red.wdo.alw
Bmn raaide 516�mn PlDdeuls Fbw StaOe R«q Ev POC1
Food Ree.a..v MOh d
Figure 1
• For Step D-6:
o To compute the flow velocity at design flow rate:
V = kQ
o K= a ratio of the peak 10-minute flow predicted by SBUH to the water quality design flow rate estimate
using the WWHM.
3BUH P.aFIW WHM On Jne 15+In WO Rwe ROft va
0411anth PreedpMelm for 0%W 100%Aapervivue Mea.
4.5 --
4.0
R 3.$
i 3.0
0
2.5
2.0
1%1
1.5
1.0
0.5
0.0
0.0 0.5 1.0 1.5 20 2.5 3.0 3.3 4.0
BwaWh 244m peacipltatl.n(72%of 2-year),Inch"
F4pm B.Ba-Ratio of SBUH Peak/WQ Flow
Figure 2
o The 2-year, 24-hr precipitation =0.2076 acre-feet (See Figure 1)
■ 72%of the 2-year, 24-hr precipitation, inches:
1 12 inches
0.2076 acrefeet x x = 2.15 inches
1.16 acres 1 foot
o Using Figure 2,K=3.0
CONVEYANCE
Flow frequencies for the project site - Required Pipe Capacity
Flow Frequency A
10.0 10.0 glor(efa) 0701 15m
2 Year - 0.9216
5 Year - 1.4383
10 Year = 1.8151
+ 25 Year - 2.3264
++ + + 50 Year - 2.7308
++++ 100 Year - 3.1544
1.0 - - __� _ Annsal Peaks
+ 701 1956 0.7016
+ + +t+++' 1957 2.2173
+ 1958 0.5869
1959 0.8040
1960 1.3698
1961 0.5588
O1 01 1962 0.4585
05 1 2 5 10 20 30 50 70 80 90 95 98 9999.51 CIO 1963 1.8496
1964 1.1827
Stream Protection Duation LID Duation Flow Frequency Water Quality Hydrograph 1965 1.3742
Welland lrputVohmas LID Report Recharge Duration RechargePredeveloped Recharge Mitigated 1966 0.4494
r Mond* 1967 0.9512
Analyze datasets Compact WDM I Delete Selected I =.1 FF 1968 0.6614
1969 0.4467
6079
1 PUYALLUP DAILY EVAPWJJENSEN+L41S A 1971 197 .1.0665665
2 Shelton
501 POC 1 Predevelo eel now 1972 1.3817
r a 1973 0.5974
8m POC 1 Mitigated flow 1974 0.6243
1000TrapezoidalPord 1 ALL OUTLETS Mitigated 1975 0.7521
1001 Trapezoidal Pord 1 OUTLET 1 Mitigated 1976 0.9866
1002 Trapezoidal Pond I OUTLET 2Mitigated 1977 0.7944
668
Al Datasets Flew Stage Precip Evap POC 1 Frequency1979 1.6420
Flood Method 197 1. 420
(: Log Pemon Type III 17B 1980 0.7229
Wei 1981 1.1480
Cunane 1982 1.2642
Grngarten 1983 1.5395
v
Pipe Capacity
PIPE CAPACITY ANALYSIS
PROJECT NAME: Belfair Park and Ride DESIGN STORM: 25 Year Event
PROJECT NUMBER: 738.05 DESIGN BASIS: 2005 WSDOE
DATE: 10/17/2018 PREPARED BY: Maddie Knecht
PIPE PIPE HYDRAULIC PIPE PIPE DRAINAGE CUMULATIVE
FROM TO DIAMETER SLOPE MANNING'S RADIUS AREA CAPACITY AREA AREA
(IN) (FT/FT) n R (SF) (CFS) (SF) (SF)
Ditch Bioretention 12 0.013 0.011 0.250 0.785 4.81
Bioretention Pond 12 0.010 0.011 0.250 0.785 4.28
Swale Pond 12 0.103 0.011 0.250 0.785 13.54
Swale Pond 12 0.093 0.011 0.250 0.785 12.88
1 of 1
-------------
CONVEYANCE
Bioswale Capacity
Swale Conveyance for 6-month storm:
PGIS: 1.16 acres
fb,emir 1 Mtigated
Subbasin Nams: rDedeste a.BM—b POC
Swf— I.w lon 6.audwalr
Flows To: 0 0� _]
Nee in Basin r Shw.Ory Sebated
Available Pervious Ades Available Im ervious Ades
J�A/0,Faek.Fist 0 A ROADSA-LAT 1.16
r yve.Fart Mal � r flOADSMOD �'I
r r k A/9,FaWm Flap 0 r ROADSSTEEP ��{
B.PMue,FW �� r fl00F TOPS/FIAT
r A/B.Padua,Mae 0 r DflNEWAVS/RAT
r A/9,Petlae,Steep pO r OflAfEWAYSMOD
ri A/ Lawn.rlal T 0 r DRNEWAIS/STEEP
r A B.Lwn Mae r SIDEWALKS flAT
r A/B,LwRstap r sIDEWAt1CSMOD
r C,Fae.t Fls r SfDEWAt1CS/STEEP
r C,FartMd 0� r PARK N6/RAT ��p. �7
r CFartS eep pO r PFV GMOD u
F-
r
C.Pews.Mad O r POND
r C,Padua.Steep r Paou Pa.arcn 0
r C.I.s F1d 0
r c.I.ann Mm °�
r c.Lawn.sta.p °� I
r sAr.FveM RM °�
r SAT.Foeri Mod _ pO I
Jr SAT.f'aea.SSteep
P—Taal A— Ili
trr a Tad .16 Aar
8mn Tad .16 Aria.
Basin 3 Flow Frequencies:
Flow Frequency
Flow(cfs) 0801 15M
2 Year = 0.5796
5 Year = 0.7306
10 Year = 0.8244
25 Year = 0.9378
50 Year — 1.0192
100 Year = 1.0985
• 6-month, 24-hour storm =72%of 2-year, 24-hour storm
o .72 (0.5798) =0.417 cfs
Swale Flow Capacity:
r Worbsheet:Trapezoidal Channel-1
WO"Row aaduall`vaned Row M...ag-
Solve For Dacharge .. Frkdbn Ustrd: M.-g F—Is vl
Roughness Coef4ent 02/0 ... Fbw A— 1.88 �or
Channel Slops. 0.01500 WR Yi~lh.indw 8.10 A
Normal DepN. 0.73 A My"WR&w OZr A
Left Sde Slope. 3.00 MB(X:V) Tep WWh: 8.00 0
Rgnt Sde Sblx: 3.00 eM 0tV) O.6ulOMM. 0.06 A
Bottom wdth 1.f0 A Clew Sbpr 2.00572 t811
D-harge' 0.57 Ash Vabuy: 0.]g Aa
Veboy Heat 0.00 A
S"ofiic Energy: g_ e
Froude Nuns-, 0.11
Fbw Type:
0.417 cfs <0.530 cfs 0
CONVEYANCE
Bioswale Capacity
Swale Conveyance for 100-year storm:
Impervious Surface: 1.35 acres
o B«�e l P,.de..loPea
Subbeoin Nema:B«�7
Since IMmlbw Giau.dwata '.
Flows T. - -
Area in Beeie sro,.a,y sekied
Aveileble Pervious Acres A-I,ble Impervious Acres
F-Flb 1 i5 RD41';.xLni 0
-li lv9,Faer1.MOE 0 . r POnI�SMOD B
F -S.
A/B aeY.Mq_ r POP➢55iEEP- ---_ p
r A/B Pews M 0 r-POOF TDPSATAT 0
r DPNEWAWPVU- �0
r n/o,ParNae,S�_.0 r DRNEWAVBA 0
FYI o r Dfl�WAI,sm D.
r AR,Leven.Mod 0 � r SIDEWNRS/FlAT_ i0 _
NB,Le�+n Steer, 0 r SDEWA1fSA10D J�
r C.F..,Flei 0 � r B EWAlR55TE P _
r C.Fa Mod _ 0 r AT OC
0 r Pal oC_
rC.Fawe,M 0 r EP
r C_Poaue Moe B r POND
r C_—,seep o -� r P-P—
rC.L F� o
rc.L-,Mae o
rEl-L-s- 0
rBA.f�aeKFIY 0
r 5�-Mad a
JrsA.F�a.t sl.:o _ a
P.Tdd
nea ov T- cU- hues
Bem Tad
Basin 3 Flow Frequencies:
Flow Frequency
Flow(cfs) 0801 15m
2 Year = 0.6748
5 Year = 0.8503
10 Year = 0e9595
25 Year = 1.0914
50 Year = 1.1862
100 Year = 1.2784
Swale Flow Capacity:
-W.O hee.:Trepaoidel Chennd-1 -
LW-Tow Gr.&,*Veeed Fbw M.esepee
SON.For: D..., v 2 Fretan K— Mennep F.rmIN
R..gn..»Coef0cen[ IO2ep 0J Fbw Aree T 10 _�R
Chenn.l sio. p,pT500 WR W.P.Permeter idp e2 - R
N.-,O P. t 00 R Nydreut P.- RM R
L.1 S-Sbpe ;.00 fnKV) Toe Wd 10.tl0 R
Rght Sd Sbpa D.pp fn(H:V) C-1 Depth ®■
Botlom W&h a t0 R Crbcel Sbpe'. i]0pN RM
D.O.rge. �dl Rh V.bcey p_y Rh
ven�n N..d- o.aT o
Speui�c Energy Tpd R
Fronde N-r.
Fbw Typ. C.crn cel
Q CNculehon SuccesshA _.. - _..-...
1.2784 cfs <4.17 cfs W
APPENDIX D
GEOTECHNICAL REPORT
Draft
Geotechnical Engineering Report
Mason Transit Authority
Park and Ride Site Improvements
Belfair Site
September 18, 2017
Prepared for
SO Alliance
8730 Tallon Lane NE, Suite 200
Lacey, Washington
LANDAU
ASSOCIATES
955 Malin Lane SW, Suite B
Tumwater,WA 98501
(360) 791-3178
DRAFT Landau Associates
Geotechnical Engineering Report
Mason Transit Authority
Park and Ride Site Improvements
Belfair Site
This document was prepared by, or under the direct supervision of, the undersigned, whose seal is
affixed below.
Name: Lance Levine
Washington/No. 45853
Date: September 18, 2017
Document prepared by: Lance Levine, PE
Project Manager
Document reviewed by: Steven R. Wright, PE
Quality Reviewer
Date: September 18,2017
Project No.: 1174015.010.012
File path: Y:\1174\015.010\R\Belfair Site\Signature Page.docx
Project Coordinator: MCs
LANDAU
ASSOCIATES
JI
DRAFT Landau Associates
TABLE OF CONTENTS
Page
1.0 INTRODUCTION..............................................................................................................................1-1
1.1 Project Understanding........................................................................................................1-1
1.2 Scope of Services................................................................................................................1-1
2.0 EXISTING CONDITIONS...................................................................................................................2-1
2.1 Surface Conditions..............................................................................................................2-1
2.2 Geologic Review.................................................................................................................2-1
2.3 Subsurface Explorations.....................................................................................................2-1
2.3.1 Soil Conditions ...............................................................................................2-1
2.3.2 Groundwater Conditions ................................................................................2-2
3.0 CONCLUSIONS AND RECOMMENDATIONS....................................................................................3-1
3.1 Earthwork...........................................................................................................................3-1
3.1.1 Wet Weather Considerations..........................................................................3-1
3.1.2 Site Preparation Activities ..............................................................................3-2
3.1.3 Subgrade Preparation.....................................................................................3-2
3.1.4 Structural Fill .................................................................................................3-2
3.1.4.1 General ....................................................................................................3-2
3.1.4.2 Imported Fill.............................................................................................3-3
3.1.4.3 Onsite Soil................................................................................................3-3
3.1.4.4 Recycled Materials ...................................................................................3-3
3.1.4.5 Fill Placement and Compaction .................................................................3-4
3.1.5 Temporary and Permanent Slopes ..................................................................3-4
3.2 Site Utilities.........................................................................................................................3-4
3.2.1 Trench Excavation and Support.......................................................................3-5
3.2.2 Construction Dewatering................................................................................3-5
3.2.3 Pipe Foundation Support................................................................................3-5
3.2.4 Pipe Bedding and Initial Backfill ......................................................................3-6
3.2.5 Trench Backfill and Compaction......................................................................3-6
3.3 Structures...........................................................................................................................3-6
3.3.1 Seismic Design Considerations........................................................................3-7
3.3.2 Bearing Capacity ............................................................................................3-7
3.3.3 Settlement.....................................................................................................3-7
3.3.4 Resistance to Lateral Loads.............................................................................3-8
3.3.5 Footing Overexcavations ................................................................................3-8
3.3.6 Foundation Drainage Considerations ..............................................................3-8
3.3.7 Slabs-On-Grade..............................................................................................3-8
3.3.8 Illumination Pole Foundations ........................................................................3-9
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride iii September 18,2017
DRAFT Landau Associates
3.4 Pavement Design................................................................................................................3-9
3.5 Stormwater Infiltration Feasibility ...................................................................................3-10
4.0 CONSTRUCTION SUPPORT.............................................................................................................4-1
5.0 USE OF THIS REPORT......................................................................................................................5-1
6.0 REFERENCES...................................................................................................................................6-1
FIGURES
Figure Title
1 Vicinity Map
2 Site and Exploration Location Plan
TABLES
Table Title
1 Summary g of Design Parameters
2 2015 International Building Code Seismic Design Parameters
3 Recommended Asphalt Pavement Design Section
4 Recommended Portland Cement Concrete Section
5 Preliminary Factored Infiltration Rates
APPENDICES
Appendix Title
A Field Explorations
B Laboratory Testing
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride iv September 18,2017
DRAFT Landau Associates
LIST OF ABBREVIATIONS AND ACRONYMS
AASHTO.................American Association of State Highway and Transportation Officials
ASTM.................................................................................................ASTM International
bgs.................................................................................................below ground surface
CBR............................................................................................. California Bearing Ratio
CSBC.................................................................................crushed surfacing base course
ESAL ...................................................................................... equivalent single-axle load
ft........................................................................................................................foot/feet
GDM................................................................................... Geotechnical Design Manual
H:V..................................................................................................horizontal to vertical
IBC........................................................................................ International Building Code
LAI ...............................................................................................Landau Associates, Inc.
MDD.............................................................................................. maximum dry density
MTA...........................................................................................Mason Transit Authority
PCC......................................................................................... Portland cement concrete
pcf.................................................................................................pounds per cubic foot
PIT....................................................................................................pilot infiltration test
psf.............................................................................................. pounds per square foot
SCJ.................................................................................................................SCJ Alliance
SWMMWW........................Stormwater Management Manual for Western Washington
WAC............................................................................ Washington Administrative Code
WSDOT............................................... Washington State Department of Transportation
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride v September 18,2017
DRAFT Landau Associates
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Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride vi September 18,2017
DRAFT landau Associates
1.0 INTRODUCTION
This report presents the results of our field investigation and provides geotechnical engineering
conclusions and recommendations for Mason Transit Authority's (MTA's) proposed Park and Ride
Improvements project, located near the Mason County—Kitsap County border, southeast of the
intersection of Log Yard Road and State Highway 3 near Belfair, Washington (site). The purpose of our
investigation was to compile and review available subsurface information for the project area,
complete site investigations to characterize subsurface soil and groundwater conditions, and develop
geotechnical conclusions and recommendations for design of the proposed improvements.
The general project location is shown on Figure 1. Figure 2 shows some of the site features and the
approximate locations of the explorations completed for this study. Appendix A includes a description
of our field explorations and summary logs of the conditions observed during our field investigation.
Test results and a description of our laboratory testing program are provided in Appendix B.
This report has been prepared based on conversations with and information provided by SCJ Alliance
(SCJ), data collected during our field investigation,the results of our laboratory testing program, our
familiarity with geologic conditions in the vicinity of the project area, and our experience with similar
projects. Our services were provided in accordance with amendment number one to the
subconsultant agreement for professional services, issued by SCJ on July 28, 2017 and authorized on
August 1, 2017.
1.1 Project Understanding
We understand a park and ride will be constructed on an undeveloped, 4-acre site in a future
commercial/industrial development near the Mason County—Kitsap County border. Proposed
improvements include a 1,500-square-foot MTA office building, two bus shelters, illumination (i.e.,
light poles), paved parking and drive lanes, and stormwater management facilities. The proposed site
layout is subject to minor changes and will be finalized during design.
1.2 Scope of Services
The objective of our services was to explore subsurface soil and groundwater conditions at the site as
a basis for developing geotechnical recommendations in support of the proposed improvements. Our
scope of services includes the following tasks:
• reviewing available published geologic maps and geotechnical reports for the project area,
• coordinating public and private utility locates;
• completing a subsurface exploration program by advancing a series of exploratory test pits;
• collecting representative soil samples and completing laboratory testing to aid in the
classification and determination of certain engineering soil properties;
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• providing seismic spectral acceleration coefficients for the proposed structures using map-
based methods in accordance with International Building Code (IBC) criteria. We also assessed
the risk for seismically induced soil liquefaction and lateral spreading;
• providing recommendations for earthwork and grading, including stripping depth, subgrade
preparation, utility trench excavation, construction dewatering, the reuse of onsite materials
and structural fill, and structural fill placement and compaction;
• providing geotechnical recommendations for shallow foundation support of the proposed bus
shelters and MTA office building, including allowable soil bearing capacity, minimum footing
width and depth, lateral resistance criteria, and elastic settlement estimates;
• providing geotechnical recommendations for design of foundations for new illumination in
accordance with section 17.2.1 of the Washington State Department of Transportation's
Geotechnical Design Manual(WSDOT GDM; WSDOT 2015);
• providing recommendations for pavement sections using assumed traffic loading conditions;
• assessing the feasibility of infiltrating stormwater on site, including feasible infiltration
locations, depth-to-groundwater, and a design infiltration rate estimated by correlation to
grain size characteristics; and
• preparing this geotechnical engineering report, summarizing the results of our field
investigation and laboratory testing program and presenting our conclusions and
recommendations along with supporting data.
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2.0 EXISTING CONDITIONS
The following sections describe the surface conditions observed during our field explorations, the
results of our geologic review,our subsurface exploration program, and the subsurface soil and
groundwater conditions observed in our explorations.
2.1 Surface Conditions
The site includes undeveloped forestland with several trails and primitive gravel roads.Topography is
generally flat in the areas of the proposed improvements, though the eastern portion of the site
slopes gently down to the west with a vertical relief of about 10 feet (ft). The site is vegetated with
mostly trees and some brush. Evidence of surface water or ponding was not observed during our
August 2017 site visits.
2.2 Geologic Review
The geology of the area is described on the Geologic Map of the Belfair 7.5-minute Quadrangle,
Mason, Kitsap, and Pierce Counties, Washington (Polenz 2009). Vashon glacial ice-contact deposits
(Qgic) are mapped at the project site, with Vashon till (Qgt) mapped to the east. Ice-contact deposits
are described as sand, gravel, lodgment till, and flow till with minor silt and clay beds.This unit is light
brown to gray, loose to compact, and massive to well stratified.The unit was formed in the presence
of meltwater alongside ice, generally near the end of the glaciation, and commonly is accompanied by
stagnant-ice features, such as kettles, eskers, and subglacial outwash channels. The soils observed in
our explorations are consistent with the mapped geology.
2.3 Subsurface Explorations
We explored subsurface conditions at the site on August 15, 2017 by advancing 10 test pits (TP-1
through T-10) between 12.5 and 16.3 ft below ground surface (bgs).The test pits were advanced by
Howard's Construction & Excavating of Olympia, Washington, under subcontract to Landau
Associates, Inc. (LAI).The approximate locations of the test pits are shown on Figure 2.The following
sections summarize the subsurface conditions observed in our explorations. More detailed
information, including summary exploration logs, is provided in Appendix A.
2.3.1 Soil Conditions
We categorized the soils observed in our explorations into two general units.
• Forest duff/topsoil:A forest duff/topsoil layer was observed in all the explorations, except
test pit TP-1, where the forest duff was removed at the time the primitive gravel road was
constructed. The combined thickness of the forest duff and topsoil ranged from 0.75 to 2.5 ft.
Forest duff detritus observed typically included leaves, fir needles, and other non-
decomposed organics above the soil surface. Where observed in our explorations,the
thickness of the forest duff layer ranged from 3 to 12 inches. The topsoil observed at the
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surface in test pit TP-1 and below the forest duff at the remaining test pit locations was
typically a brown, loose to medium dense, silty sand with variable gravel and organic content.
• Ice-contact deposits: Ice-contact deposits were observed below the forest duff/topsoil unit to
the depths explored. This unit typically consists of brown to gray, medium dense to very dense
sand with variable silt, gravel, and cobble content or brown to gray, dense to very dense
gravel with variable silt, sand, and cobble content.
Although not observed in all of our explorations, cobbles and boulders are often present in glacial
deposits and may be present throughout the site. The contractor should be prepared to handle
oversized material.
2.3.2 Groundwater Conditions
During our August 2017 explorations,groundwater was not observed in the test pits to 16.3 ft bgs, the
maximum depth explored. No evidence of mottling was observed. The groundwater conditions
reported herein and on the exploration logs in Appendix A are for the specific locations and date
indicated and may not be indicative of other locations and/or times. Furthermore, we anticipate
groundwater conditions will vary depending on local subsurface conditions, weather conditions, and
other factors. Groundwater levels in the project area are expected to fluctuate seasonally, with
maximum groundwater levels occurring during late winter and early spring.
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3.0 CONCLUSIONS AND RECOMMENDATIONS
Based on the results of our field explorations, laboratory testing, and engineering analyses, it is our
opinion that subsurface conditions at the project site are suitable for the proposed improvements. We
interpret the ice-contact deposits to be suitable for onsite infiltration of stormwater, provided the
base of the infiltration facility is situated below restrictive layers. The ice-contact deposits observed in
our explorations are also suitable for shallow foundation support of structures (e.g., bus pad, shelters,
MTA office building, and light poles), provided the recommendations in Section 3.1 of this report are
followed.
The following sections of this report provide geotechnical conclusions and recommendations
pertaining to earthwork; underground utilities; structures, including seismic design criteria, allowable
bearing capacity, foundation settlement, resistance to lateral loads, footing overexcavations, and
slabs-on-grade; illumination; pavement design; and stormwater infiltration.
3.1 Earthwork
To accommodate construction of the proposed improvements, earthwork likely will include clearing,
grubbing, and stripping of areas where improvements are planned; cuts and fills; subgrade
preparation for structures and pavement areas; and construction of temporary and permanent slopes.
3.1.1 Wet Weather Considerations
Some of the onsite soils contain up to about 16 percent fines (material passing the U.S. Standard No.
200 sieve, by weight) and are considered moisture sensitive. Imported fill also could be moisture
sensitive. When the moisture content of soil is more than a few percent above or below the optimum
moisture content, the soil may become unstable, and meeting the required compaction criteria may
be difficult. Optimum moisture content is the moisture content at which the greatest compacted dry
density can be achieved. Disturbance of near surface soils should be expected if earthwork is
completed during periods of wet weather or under wet conditions.
The wet weather season in the project area generally begins in late October and continues through
June. However, periods of wet weather may occur throughout the year. If wet weather earthwork is
unavoidable, we recommend:
• the ground surface be sloped so that surface water is collected and directed away from the
work area to an approved collection/dispersion point;
• excavation of temporary drywells to expose cleaner underlying soils;
• earthwork activities not take place during periods of heavy precipitation;
• measures are taken to prevent onsite soil and soil stockpiles from becoming wet or unstable;
• structural fill materials used during periods of wet weather should be limited to imported, all-
weather fill;
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• a smooth-drum roller is used to seal the surface prior to periods of precipitation to reduce the
extent to which the soil becomes wet or unstable;
• construction traffic is restricted to specific areas of the site, preferably areas surfaced with
materials that are not susceptible to wet weather disturbance;
• a minimum 1-ft-thick layer of 4-to 6-inch quarry spalls is used in high-traffic areas to protect
the subgrade soil from disturbance; and
• contingencies are included in the project schedule and budget to allow for the above
elements.
3.1.2 Site Preparation Activities
Site preparation activities are expected to include clearing,grubbing, and stripping of the existing
vegetation, duff, and topsoil and removal of pavement and utilities, if present. Sod, topsoil, and
organic-rich soils or fill located within the bus pad shelter or pavement areas should be stripped. We
estimate an average stripping depth of approximately 20 inches for removal of forest duff and near
surface topsoil. If the forest duff is removed during logging activities, the remaining topsoil will range
from 0.5 to 1.5 ft thick. These estimates do not include the removal of existing tree roots or debris, if
present.
All incidental excavations associated with site preparation activities should be backfilled in accordance
with the recommendations set forth in Section 3.1.4 of this report.
3.1.3 Subgrade Preparation
Prior to placing structural fill, the prepared subgrade should be proof-rolled in the presence of a
qualified civil or geotechnical engineer, who is familiar with the site conditions and can check for any
soft and/or disturbed areas. Areas of limited access that cannot be proof-rolled can be evaluated
using a steel T-probe. Loose and/or disturbed subgrades identified during the proof-roll should be
repaired by overexcavating the disturbed soil and replacing it with compacted structural fill, meeting
the requirements described in Section 3.1.4 of this report. Unsuitable soils also can repaired with
additional scarification, moisture conditioning, and recompacting. Repaired subgrades should be
recompacted in accordance with Section 3.1.4.5 of this report.
3.1.4 Structural Fill
The following sections provide recommendations for the use of onsite soils, imported fill, and recycled
materials as structural fill and structural fill placement and compaction.
3.1.4.1 General
The suitability of excavated or imported soil for use as structural fill will depend on the gradation and
moisture content of the soil when it is placed. As the amount of fines increases, the soil becomes
increasingly sensitive to small changes in moisture content, and adequate compaction may become
more difficult to achieve. Soil containing more than about 5 percent fines cannot be compacted
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consistently to a dense, non-yielding condition when the water content is more than about 2 to 3
percent above or below optimum moisture content.
During dry, warm weather(generally July through early October), structural fill should consist of
well-graded sand and gravel with a maximum particle size of 6 inches and at least 75 percent of the
material passing the 3-inch sieve.The material should contain less than 30 percent fines and be
maintained at a moisture content near optimum. If wet weather construction is anticipated, the
amount of fines should not exceed 5 percent, based on the minus%-inch fraction. Structural fill
should be free of debris, organic material, and rock fragments larger than 6 inches.
3.1.4.2 Imported Fill
During dry, warm weather(generally July through early October), imported structural fill should
consist of well-graded sand and gravel with a maximum particle size of 6 inches and at least 75
percent of the material passing the 3-inch sieve. The material should contain less than 30 percent
fines and be maintained at a moisture content near optimum. Imported structural fill should be free
of debris, organic material, and rock fragments larger than 6 inches.
During wet weather conditions, imported all-weather fill should consist of well-graded sand and
gravel or crushed rock with a maximum particle size of 4 inches and less than 5 percent passing a
U.S. Standard No. 200 sieve, based on the minus%-inch fraction. Organic matter, debris, or other
deleterious material should not be present. Gravel Borrow, as described in Section 9-03.14(1) of the
Washington State Department of Transportation's 2016 Standard Specifications for Road, Bridge, and
Municipal Construction (2016 WSDOT Standard Specifications), is a suitable source of imported
all-weather fill, provided the requirements set forth in this paragraph are satisfied.
3.1.4.3 Onsite Soil
The ice-contact deposits observed in our explorations contain up to about 16 percent fines and are
generally well suited for use as structural fill during dry weather. If onsite soils are reused as structural
fill,they will require significant moisture conditioning to satisfy the compaction criteria recommended
herein. We recommend a representative of LAI is present to review onsite material for use as
structural fill prior to placement.
3.1.4.4 Recycled Materials
If practical, recycled concrete materials can be considered for use as structural fill. Recycled concrete
materials used as structural fill should meet the requirements set forth in Section 9-03.21 of the 2016
WSDOT Standard Specifications; the materials also must meet the minimum gradation criteria for
Select Borrow, outlined in Section 9-03.14(2) of the 2016 WSDOT Standard Specifications. In all
instances, use of recycled concrete should comply with current environmental policies.
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3.1.4.5 Fill Placement and Compaction
Structural fill should be placed on an approved subgrade that consists of uniformly firm and
unyielding, inorganic native soils or compacted structural fill prepared as described in Section 3.1.3 of
this report. Structural fill should be compacted at a near-optimum moisture content. Optimum
moisture content varies with the soil gradation and should be evaluated during construction.
In structure and pavement areas, structural fill should be placed and compacted in accordance with
Section 2-03.3(14)C, Method C of the 2016 WSDOT Standard Specifications. Method A of the 2016
WSDOT Standard Specifications is appropriate for non-structural areas, such as landscaping. Structural
fill should be placed in loose, horizontal lifts, not exceeding 12-inch thickness, and thoroughly
compacted. Compaction and moisture control tests should be completed in accordance with Section
2-03.3(14)D of the 2016 WSDOT Standard Specifications. Alternatively,the maximum dry density
(MDD) and optimum moisture content can be determined using ASTM International test method
D1557 (i.e., modified Proctor).
3.1.5 Temporary and Permanent Slopes
Based on the soil conditions observed in our explorations, the maximum inclination for temporary
excavation slopes less than 20 vertical ft in height, and in the absence of groundwater seepage, is 1%
horizontal to 1 vertical (1%2H:1V). If groundwater is present, unstable conditions may develop in the
temporary slope, and flatter slopes or shoring will be necessary. Temporary excavation slopes should
be covered with plastic sheets, straw, or other materials to prevent erosion. In addition, the
contractor should implement measures to prevent surface water runoff from entering excavations.
Temporary excavation slopes should be the responsibility of the contractor. All applicable local, state,
and federal safety codes should be followed. Open cuts should be monitored by the contractor during
excavation for evidence of instability. If instability is detected, the contractor should flatten the side
slopes or install temporary shoring. If groundwater or groundwater seepage is present and the
excavation is not properly dewatered, the soil may be prone to caving, channeling, and running.
Permanent cut-or-fill slopes constructed as recommended in this report should be sloped no steeper
than 2H:1V.This ratio is not intended for use in the design of stormwater pond slopes; these slopes
are typically 3H:1V or flatter and should be designed in compliance with local stormwater code
requirements. Permanent slopes should be protected from erosion (see the preceding
recommendations for protecting temporary excavations) and seeded or vegetated as soon as
practical.
3.2 Site Utilities
The following sections provide geotechnical recommendations for design and construction of new site
utilities. Geotechnical recommendations include trench excavation and support, construction
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dewatering, pipe foundation support, pipe bedding and initial backfill, and trench backfill and
compaction criteria.
Please note for any new utilities within the public right-of-way, local standards may supersede the
following recommendations.
3.2.1 Trench Excavation and Support
We anticipate excavations for underground utilities will be primarily within the ice-contact deposits.
Conventional construction equipment with sufficient reach should be able to excavate the proposed
trenches to the expected depth of 12 ft bgs. Upon reaching the trench bottom,we suggest that a
smooth-bladed bucket be used to remove any loose and/or disturbed soil.The final trench bottom
should be firm and free of loose and disturbed soil.
Trench configurations and maintenance of safe working conditions, including temporary excavation
stability, should be the responsibility of the contractor. All applicable local, state, and federal safety
codes should be followed. Temporary excavations for utilities should be sloped no steeper than
1%H:1V, based on the governing regulations for safe excavation practice in the State of Washington
(Washington State Department of Labor and Industries, Chapter 296-155 Washington Administrative
Code [WAC]). If groundwater seepage is present, flatter slopes, temporary shoring, and/or dewatering
may be required.
Trench boxes should provide adequate support for shallow excavations, provided the trench is
properly dewatered and settlement-sensitive structures and utilities are not situated immediately
adjacent to the excavation. Trench boxes should meet the requirements in Safety Standards for
Construction Work, Part N (WAC Chapter 296-155).
3.2.2 Construction Dewatering
We anticipate underground utilities at the site can be installed without encountering significant
groundwater. However, localized zones of perched groundwater may be encountered within the
trench zone, particularly during the winter and spring months. If perched, water-bearing zones are
encountered, construction dewatering using conventional sumps and pumps within the excavations
should be sufficient to handle groundwater inflow. If dewatering is necessary, the contractor should
be responsible for design and implementation of the dewatering system.
3.2.3 Pipe Foundation Support
Based on the conditions observed in our explorations, medium dense to very dense granular soils are
expected to be present at the base of utility trenches. This soil type typically will provide adequate
foundation support for utilities, provided the foundation soil remains in a relatively undisturbed
condition. If the bottom of the trench becomes disturbed due to excavation and/or foot traffic during
the laying of the pipe, the disturbed material should be overexcavated to expose undisturbed
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foundation soil. The overexcavation should be backfilled with suitable foundation material to provide
a firm trench bottom. Foundation material should be free of roots, topsoil, lumps of silt and clay,
cobbles, and debris.
3.2.4 Pipe Bedding and Initial Backfill
Pipe zone bedding material should consist of crushed, processed, or naturally occurring granular
material, free of organic matter and other deleterious material, and should meet the gradation
requirements of Gravel Backfill for Pipe Zone Bedding outlined in Section 9-03.12(3) of the 2016
WSDOT Standard Specifications.
Pipe bedding material should extend at least 6 inches below the invert of the pipe and be compacted
to a relative density of at least 90 percent of the MDD (ASTM test method D1557). The initial pipe
backfill should be brought up evenly around the pipe in relatively horizontal lifts, not exceeding 6
inches, and worked under the haunches of the pipe by slicing with a shovel,vibration, or other
approved procedure. Pipe zone backfill should extend 6 inches above the crown of the pipe. In order
to prevent damage to the pipe, the initial backfill directly over the pipe should be compacted with
hand-operated compaction equipment. Specific material and compaction requirements provided by
pipe manufacturers may supersede the recommendations provided in this report.
3.2.5 Trench Backfill and Compaction
Granular portions of the ice-contact deposits may be utilized for trench backfill, provided all soil
particles greater than 4 inches in diameter are removed and the soil is properly moisture conditioned
and compacted to the required density. Trench backfill should be compacted as described in Section
3.1.4.5 of this report.
3.3 Structures
The following sections provide geotechnical engineering conclusions and recommendations for
foundation design of structures. Recommendations are provided for seismic design, allowable bearing
capacity, settlement, resistance to lateral loads, footing excavations, drainage considerations,
slabs-on-grade, and illumination pole foundations.
Table 1 provides a summary of design parameters for the structural engineer. The design parameters
should be used in conjunction with the complete recommendations provided in this report.
Table 1.Summary of Design Parameters
Allowable soil bearing pressure=3,500 pounds per square foot
Friction coefficient(factored)=0.35
Passive resistance(factored)=280 pounds per cubic foot
Minimum foundation width= 18 inches(continuous),24 inches(isolated)
Maximum foundation width(for settlement considerations)=5 feet(continuous), 10 feet(isolated)
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3.3.1 Seismic Design Considerations
We understand that seismic design will be performed using the 2015 IBC standards (ICC 2014).The
parameters listed in Table 2 can be used to compute seismic base shear forces.
Table 2.2015 International Building Code Seismic Design Parameters
Spectral response acceleration at short periods(SS)=1.483g
Spectral response acceleration at 1-second periods(Si)=0.586g
Site class=C
Site coefficient(Fa)=1.0
Site coefficient(F )= 1.3
g=force of gravity
The site is underlain by medium dense to very dense glacial deposits, and the groundwater table is
relatively deep. On this basis, it is our opinion that there is a low risk for seismically induced soil
liquefaction or lateral spreading at the site. Considering the location of the site with respect to the
nearest known active crustal faults and the presence of a relatively thick layer of glacial deposits, it is
our opinion that the risk of ground rupture due to surface faulting is low.
3.3.2 Bearing Capacity
We recommend an allowable soil bearing pressure of 3,500 pounds per square foot (psf)for shallow
foundations that are established on medium dense to very dense glacial soils or structural fill
extending to such soils. This allowable soil bearing pressure applies to long-term dead and live loads,
exclusive of the weight of the footing and any overlying backfill.The allowable soil bearing pressure
can be increased by one-third when considering total loads, including transient loads, such as those
induced by wind and seismic forces.
The bus pad slab-on-grade foundation may utilize a thickened-edge slab design. For that reason, we
recommend a minimum width of 18 inches for continuous footings. For settlement considerations, we
have assumed a maximum width of 5 ft for continuous footings. For frost protection, footings should
be embedded at least 12 inches below the lowest adjacent grade where the ground is flat adjacent to
the footing.
3.3.3 Settlement
Settlement of shallow foundations will depend on the foundation size and bearing pressure as well as
the strength and compressibility characteristics of the underlying bearing soil. Assuming construction
is accomplished as previously recommended, we estimate the settlement of continuous or isolated
spread footings will be on the order of 1 inch or less. Differential settlement between similarly loaded
foundation elements may be assumed to be on the order of% inch or less.
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3.3.4 Resistance to Lateral Loads
Resistance to lateral loads can be provided by friction acting on the base of footings and by passive
lateral earth pressures acting against the sides of footings. An allowable coefficient of sliding
resistance of 0.35, applied to the vertical dead loads only, may be used to compute frictional
resistance. The allowable coefficient of sliding resistance includes a factor of safety of 1.5 on the
calculated ultimate value. For design purposes, the passive resistance of properly compacted
structural fill placed against the sides of foundations may be considered equivalent to a fluid with a
density of 280 pounds per cubic foot (pcf). The foundation passive earth pressure has been reduced
by a factor of 1.5 to limit deflections to less than 2 percent of the embedded depth. In addition, the
recommended foundation passive earth pressure assumes drained conditions within the depth of the
foundation.
The passive earth pressure and friction components can be combined, provided the passive
component does not exceed two-thirds of the total. The top foot of soil should be excluded when
calculating passive resistance unless the foundation perimeter area is covered by a slab-on-grade or
pavement.
3.3.5 Footing Overexcavations
We do not anticipate that appreciable overexcavations will be required for the proposed
improvements. Medium dense to very dense ice-contact deposits soils should be present at or within
about 2 ft of the ground surface. However, overexcavations could be required if the soils become
saturated or disturbed by foot traffic. If overexcavations are required, the overexcavation zone should
extend a horizontal distance equal to at least one-half of the overexcavation depth on each side of the
footing. For example, a 2-ft-wide footing with a 2-ft-deep overexcavation should have a 4-ft-wide
overexcavation zone. All footing overexcavations should be backfilled with structural fill. Alternatively,
the depth of the footing could be increased to bear on the base of the overexcavation. The base of the
overexcavation should be evaluated by a qualified civil or geotechnical engineer prior to placement of
structural fill or concrete.
3.3.6 Foundation Drainage Considerations
We recommend installing a footing drain around the perimeter of the proposed MTA office building.
The drain should consist of a minimum 4-inch-diameter, perforated pipe surrounded by clean drain
rock, wrapped in filter fabric.The drain pipe should be connected to a positive outlet and should
include cleanouts. Roof drains should not be connected to footing drain.
3.3.7 Slabs-On-Grade
Slabs-on-grade should be established on a subgrade that consists of uniformly firm and unyielding
soil. A modulus of vertical subgrade reaction (subgrade modulus) can be used to design the slab. The
subgrade modulus varies based on the dimensions of the slab and the magnitude of applied loads on
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the slab surface; slabs with larger dimensions and loads are influenced by soil to a greater depth. We
recommend a subgrade modulus value of 225 pounds per cubic inch for the design of on-grade floor
slabs with floor loads up to 500 psf.This subgrade modulus is for a 1-ft by 1-ft square plate and is not
the overall modulus of a larger area.We are available to provide alternate recommendations during
design, based on specific loading information available at that time.
3.3.8 Illumination Pole Foundations
Illumination structures (i.e., light poles) are proposed at the site. In our test pits, we observed medium
dense to very dense soils with an estimated allowable lateral bearing pressure of 3,500 psf. The lateral
bearing pressure provided was developed in general accordance with the methods described in
Section 17.2.1 of the WSDOT GDM.
3.4 Pavement Design
Pavement sections should be constructed on a subgrade that consists of 1 ft of uniformly firm and
unyielding, compacted native subgrade or imported structural fill as described in Section 3.1 of this
report.The structural fill should be prepared as described in Section 3.1.4 of this report. The design
pavement sections were developed using the American Association of State Highway and
Transportation Officials' (AASHTO's)Guide for Design of Pavement Structures (AASHTO 1993). The
standard duty asphalt pavement section recommendations provided in Table 3 assume a 20-year
design life, a maximum equivalent single-axle load (ESAL) of 100,000, and an assumed California
Bearing Ratio (CBR) of 12 percent for the section. The heavy-duty asphalt pavement section assumes
at least 65 buses per day, a 20-year design life, a loading of 2,000,000 ESALs, and an assumed CBR of
12 percent for the section.The assumed CBR value is estimated to correspond to a subgrade soil with
a density equal to 90 percent of the MDD, determined by ASTM test method D1557.
For any new pavement installed within the public right-of-way, local standards may supersede the
recommendations below.
Table 3.Recommended Asphalt Pavement Design Section
Pavement Section Type Asphalt Concrete Crushed Surfacing Base Compacted Native or
Pavement Thickness Course Thickness Structural Fill Thickness
Standard duty 3 inches 4 inches 12 inches
Heavy duty 4 inches 4 inches 12 inches
Asphalt concrete should be Class B aggregate material or hot-mix asphalt class% inch, PG64-22,
conforming to Section 5-04 of the 2016 WSDOT Standard Specifications. The asphalt should be
compacted to at least 91 percent of the Rice density. Base course material should be compacted to at
least 95 percent of the MDD (ASTM test method D1557) and should meet the requirements for
crushed surfacing base course (CSBC) in Section 9-03.9(3) of the 2016 WSDOT Standard Specifications.
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The upper 2 inches of crushed surfacing could consist of crushed surfacing top course to facilitate fine
grading of the surface.
For our Portland cement concrete (PCC) pavement design, we assumed a design life of 20 years. For
bus turnarounds, 2,000,000 ESALs were assumed in our rigid pavement design. A reliability of 85
percent, a terminal serviceability index of 2.5, a design serviceability loss of 2, and load transfer
coefficient of 3.2 (assumes continuous reinforcement and tied shoulders) were used in the design.
The design assumed a CBR of 12 percent (equates to a resilient modulus of 12,533) and at least 4
inches of CSBC placed below the PCC pavement. The following table summarizes the PCC pavement
section for the bus turnarounds.
Table 4.Recommended Portland Cement Concrete Pavement Design Section
Pavement Section Type Portland Cement Concrete Crushed Surfacing Base Compacted Native or
Pavement Thickness Course Thickness Structural Fill Thickness
Heavy Duty 8 inches 4 inches 12 inches
Base course material should be compacted to at least 95 percent of the MDD determined using ASTM
test method D1557 and should meet the requirements for CSBC in Section 9-03.9(3) of the 2016
WSDOT Standard Specifications. PCC pavement should meet the requirements in Section 5-05 of the
2016 WSDOT Standard Specifications. The pavement edges should be fully supported with either a
thickened edge or an integral curb, and the joint spacing should be no more than 15 ft apart. To
provide load transfer across the joints between panels, the panels should be fully doweled. Dowels
should be placed at a depth of one-half the slab thickness and spaced 12 inches on center. The dowel
bar diameter should be 1.5 inches and should have a minimum embedment of 9 inches on each side
of the joint.
Prevention of road base saturation is essential for pavement durability. Thus, efforts should be made
to limit the amount of water entering the base course.
3.5 Stormwater Infiltration Feasibility
Stormwater improvements may include ponds or underground infiltration facilities. Site soils suitable
for stormwater infiltration were observed in our explorations but vary with depth and location.
Groundwater was not observed during our site investigation in August 2017 to a maximum depth of
16.3 ft bgs. Groundwater levels in the project area are expected to fluctuate seasonally, with
maximum groundwater levels occurring during the late winter and early spring months.
Long-term preliminary infiltration rates are provided in Table 5 and are based on the soil grain size
infiltration rate determination methods in the Washington State Department of Ecology's 2005
Stormwater Management Manual for Western Washington (2005 SWMMWW) and on the results of
our laboratory tests (Appendix B). Appendix III-A of the 2005 SWMMWW provides the method and
Geotechnical Engineering Report 1174015.010.012
VITA—Belfair Road Park and Ride 3-10 September 18,2017
DRAFT Landau Associates
recommended correction factors to be used to estimate the infiltration rates. The following assumed
correction factors were used to account for pond size (CFsize = 1.0), biofouling and siltation effects for
ponds (CFsilt/bio = 0.9), and aspect ratio correction factor (CFaspect = 1.0). We also assumed a
ponded water depth of 4 ft and a depth-to-groundwater of 20 ft. These assumptions should be
verified or modified in final design to calculate final infiltration rates.
The preliminary (factored) infiltration rates using the correction factors mentioned above are
provided in Table 5.The highest estimated infiltration rates are for soils located in the vicinity of test
pits TP-2,TP-3,TP-6, and TP-9 site. The rates assume at least 10 ft of separation to seasonal high
groundwater.
Table S.Preliminary Factored Infiltration Rates
Preliminary Factored
Exploration Designation Infiltration Rate(a)
Depth Interval
(inches/hour) (ft)
LTP-2 0.9 1.0—12.5
TP-3 0.7 1.5—13.5
I-
TP-4 0.3 2.0—14.0
TP-5 0.3 1.7—14.0
TP-6 0.4 2.0—13.0
i
TP-6 1.0 14.0—15.0
r -
TP-9 1.8 2.5—14.0
TP-10 0.3 0.75—10.0
TP-10 0.1 10.0—14.0
(a)=Assumes bottom of infiltration facility is 4 ft bgs from current site grades.
ft=feet
TP=test pit
It is our opinion that the collection of seasonal high groundwater information is not warranted, given
the site conditions. Final design infiltration rates should be confirmed by pilot infiltration test (PIT)
evaluations at the specific locations and depths of the proposed facilities. Typically, the infiltration
rates provided in Table 5 can be increased through the completion of onsite infiltration testing.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 3-11 September 18,2017
DRAFT Landau Associates
4.0 CONSTRUCTION SUPPORT
Landau Associates, Inc. (LAI) should be asked to review the geotechnical portions of the plans and
specifications for the proposed project in advance of project bidding. The purpose of the review is to
verify that the recommendations presented in this geotechnical report have been properly
interpreted and implemented in the design and project specifications.
We recommend that monitoring,testing, and consultation be provided during construction to confirm
that the conditions observed are consistent with those indicated by our explorations, to provide
expedient recommendations should conditions be revealed during construction that differ from those
anticipated, and to evaluate whether geotechnical activities comply with the project plans,
specifications, and the recommendations contained in this report. Such geotechnical activities include
but are not limited to observation of foundation subgrades, compaction testing of structural fill, and
observation of the prepared slab and pavement subgrades.The purpose of these services would be to
observe compliance with the design concepts, specifications, and recommendations in this report. In
the event subsurface conditions differ from those anticipated before the start of construction, LAI can
provide revised recommendations appropriate to the conditions revealed during construction. LAI
would be pleased to provide these services for you.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 4-1 September 18,2017
DRAFT Landau Associates
5.0 USE OF THIS REPORT
Landau Associates, Inc. prepared this report for the exclusive use of Mason Transit Authority and SO
Alliance for the proposed Belfair Park and Ride Improvements project, located southeast of the
intersection of Log Yard Road and State Highway 3 near Belfair, Washington. Within the limitations of
scope, schedule, and budget, our services have been conducted in accordance with generally
accepted practices of the geotechnical engineering profession; no other warranty, express or implied,
is made as to the professional advice included in this report.
The conclusions and recommendations contained in this report are based on the conditions
observed/interpreted in the explorations advanced for this study and on our experience in the project
area. There may be some variation in subsurface soil and groundwater conditions, and the nature and
extent of the variations may not become evident until construction. Accordingly, a contingency for
unanticipated conditions should be included in the construction budget and schedule.
If variations in subsurface conditions are encountered during construction, LAI should be notified for
review of the recommendations in this report and revision of such if necessary. If there is a substantial
lapse of time between submission of this report and the start of construction, we recommend that we
review this report to determine the applicability of the conclusions and recommendations contained
herein.
We appreciate the opportunity to be of service to you on this project. Please contact us at
(360) 791-3178 if you have questions or require additional information.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 5-1 September 18,2017
DRAFT Landau Associates
6.0 REFERENCES
AASHTO. 1993. AASHTO Guide for Design of Pavement Structures. American Association of State
Highway and Transportation Officials.
ASTM. 2003. Annual Book of ASTM Standards. In: Soil and Rock(I). West Conshohocken, PA: ASTM
International.
Ecology. 2005. Stormwater Management Manual for Western Washington: Volume Ill—Hydrologic
Analysis and Flow Control Design/BMPs. Washington State Department of Ecology.
ICC. 2014. 2015 International Building Code. International Code Council. May 30.
Polenz M., K. Alldritt, N.J. Hehemann, I.Y. Sarikhan, and R.L. Logan. 2009. Geologic Map of the Belfair
7.5-minute Quadrangle, Mason, Kitsap, and Pierce Counties, Washington. Open File Report 2009-
7. Washington State Department of Natural Resources.
Washington State Department of Labor and Industries. 2016. Construction Work. Chapter 296-155
WAC; Part N. Excavation,Trenching, and Shoring. Washington State Department of Labor and
Industries.
WSDOT. 2015. Geotechnical Design Manual. Washington State Department of Transportation.
WSDOT. 2016. Standard Specifications for Road, Bridge, and Municipal Construction 2016. M 41-10.
Washington State Department of Transportation. Amended April 4.
Geotechnical Engineering Report 1174015.010.012
MTA—Belfair Road Park and Ride 6-1 September 18,2017
DRAFT 3
Bremerton
National
Airport
t
1
Project Location
�l
fair
i
i
Ii
I
`tee Creek
?` f' CO
ICI
Project Q
Location
Everett
N 0 0.5 1 Seattle Spokane"
Tacoma
Miles Olympia
Washington
Data Source:Esri 2012
Mason Transit Authority
Park and Ride Improvements Figure
LANDAU Belfair Site Vicinity Map 1
ASSOCIATES Belfair,Washington
Legend
TP-1 N Approximate Test Pit Location and Designation
/ LOT 20 /
N /
/ Project Limits
100.0
/ LOT 1 \ ,, / LOT 16
1.0 inches/hour assumed /TP-1�
for bioretention facility. No/ / \,\
data from TP 8 provided,
so averaged rates from \
TP-6 and TP-9 j� 100.0
(.4+1 .8)/2 = 1.1, 1.0 used. TP s \
\ \ 1
0.4 inches/hour used /
for infiltration pond.
TP-7 \
TP-9 \
20.0
1.8
TP 3 /
/ TP-6 N
/ \ 0.4 TP 10
0.3
LOT 13 TP-2 •9
TP-5�
0.3 20.0
0
TP-4 N /
20.0 /
a 0.3 inches/hour used 0.3 -
for biofiltration swale.
LOT 12 - DRAF
- 0 150 300
0
Source:SO Alliance,2017 Scale in Feet
Mason Transit Authority Figure
LANDAU Park and Ride Improvements Site and Exploration Location Plan
ASSOCIATES Belfair Site
Belfair, Washington
APPENDIX A
Field Explorations
DRAFT Landau Associates
APPENDIX A
FIELD EXPLORATIONS
Subsurface conditions at the site were explored on August 15, 2017 by advancing 10 test pits (TP-1
through TP-10) between 12.5 and 16.3 feet below ground surface. The approximate locations of our
explorations are shown on Figure 2. The test pits were advanced by Howard's Construction &
Excavating of Olympia, Washington, under subcontract to Landau Associates, Inc.
The field explorations were coordinated and monitored by a representative of Landau Associates, Inc.,
who also obtained representative soil samples, maintained a detailed record of the subsurface soil
and groundwater conditions observed, and described the soil encountered by visual and textural
examination. In general accordance with ASTM International test method D2488, Standard Practice
for Description and Identification of Soils (Visual-Manual Procedure), each representative soil type
observed was described using the soil classification system shown on Figure A-1. Logs of our
explorations are presented on Figures A-2 through A-6. These logs represent our interpretation of
subsurface conditions identified during the field explorations. The stratigraphic contacts shown on the
individual logs represent the approximate boundaries between soil types; actual transitions may be
more gradual. A further discussion of the soil and groundwater conditions observed is contained in
the main text of this report.
Soil samples obtained from the test pits were taken to our laboratory for further examination and
testing.The test results and a discussion of our testing procedures are presented in Appendix B. Upon
completion of excavation and sampling, the test pits were backfilled with the excavated material. The
backfill material was compacted using the bucket of the backhoe.
Appendix A 1174015.010.012
MTA—Belfair Park and Ride A-1 September 18,2017
Soil Classification System
USCS
MAJOR GRAPHIC LETTER TYPICAL
DIVISIONS SYMBOL SYMBOL"' DESCRIPTIONS'2X3t
GRAVEL AND CLEAN GRAVEL o°o°o GW Well-graded gravel;gravel/sand mixture(s);little or no fines
d m N GRAVELLY SOIL (Little or ra fines) o 0
O M.N o 0 o GP Poorly graded gravel;gravel/sand mixture(s);little or no fines
(n c
O 2 a>, (More than 50%of GRAVEL WITH FINES GM Silty gravel;gravel/sand/sift mixture(s)
ZE.N coarse fraction retained (Appreciable amount of ��-50 on No.4 sieve) flnas) GC Clayey gravel;gravel/sarxi/day mbdure(s)
0 z° SAND AND CLEAN SAND SW Well-graded sand;gravelly sand;little or no fines
W c SANDY SOIL (Little or no fines) -
v)r a SP Poorly graded sand;gravelly sand;little or no fines
0 0 (More than 50%of SAND WITH FINES SM Silty sand;sand/sift mixture(s)
U coarse fraction passed (Appreciable amount of -
through No.4 sieve) fly) SC Clayey sand;sand/clay mixture(s)
ML Inor anic silt and veryfine sand;rock flour;silty or clayey fine
p o r SILT AND CLAY sand or clayey sift with slight plasticity
N Inorganic clay of low to medium plasticity;gravelly,clay;sandy CL
u clay;silty clay;lean clay
� En a ° (Liquid limit less than 50)
w ' E OL Organic silt;organic,silty clay of low plasticity
°m N SILT AND CLAY I MH Inorganic silt;micaceous or diatomaceous fine sand
W ° m Z Inorganic clay of high plasticity;fat clay
�d ° CH 9 Y 9 P ty; Y
Z E (Liquid limit greater than 50)
ty OH Organic clay of medium to high plasticity;organic silt
HIGHLY ORGANIC SOIL PT Peat;humus;swamp soil with high organic content
GRAPHIC LETTER
OTHER MATERIALS SYMBOL SYMBOL TYPICAL DESCRIPTIONS
PAVEMENT .. ,AC Or PC Asphalt concrete pavement or Portland cement pavement
ROCK RK Rock(See Rock Classification)
WOOD WD Wood,lumber,wood chips
DEBRIS O O O DB Construction debris,garbage
Notes: 1. USCS letter symbols correspond to symbols used by the Unified Soil Classification System and ASTM classification methods.Dual letter symbols
(e.g.,SP-SM for sand or gravel)indicate soil with an estimated 5-15%fines.Multiple letter symbols(e.g.,ML/CL)indicate borderline or multiple soil
classifications.
2. Soil descriptions are based on the general approach presented in the Standard Practice for Description and Identification of Soils(Visual-Manual
Procedure),outlined in ASTM D 2488.Where laboratory index testing has been conducted,soil classifications are based on the Standard Test
Method for Classification of Soils for Engineering Purposes,as outlined in ASTM D 2487.
3. Soil description terminology is based on visual estimates(in the absence of laboratory test data)of the percentages of each soil type and is defined
as follows:
Primary Constituent: >50%-"GRAVEL,""SAND,""SILT,""CLAY,"etc.
Secondary Constituents: >30%and<50%-"very gravelly,""very sandy,""very silty,"etc.
>15%and<30%-"gravelly,""sandy,""silty,"etc.
Additional Constituents: > 5%and<15%-"with gravel,""with sand,""with silt,"etc.
< 5%-"with trace gravel,"%vith trace sand,""with trace sift,"etc.,or not noted.
4. Soil density or consistency descriptions are based on judgement using a combination of sampler penetration blow counts,drilling or excavating
conditions,field tests,and laboratory tests,as appropriate.
Drilling and Sampling Key Field and Lab Test Data
SAMPLER TYPE_ SAMPLE NUMBER&INTERVAL _
Code Description Code Description
a 3.25-inch O.D.,2.42-inch I.D.Split Spoon PP=1.0 Pocket Penetrometer,tsf
b 2.00-inch O.D.,1.50-inch I.D.Split Spoon Sample Identification Number TV=0.5 Torvane,tsf
c Shelby Tube PID=100 Photoionization Detector VOC screening,ppm
d Grab Sample - Recovery Depth Interval W=10 Moisture Content,%
e Single-Tube Core Barrel j D=120 Dry Density,pcf
f Double-Tube Core Barrel 1 ♦ F Sample Depth Interval -200=60 Material smaller than No.200 sieve,%
g 2.50-inch O.D.,2.00-inch I.D.WSDOT Portion of Sample Retained GS Grain Size-See separate figure for data
h 3.00-inch O.D.,2.375-inch I.D.Mod.California for Archive or Analysis AL Atterberg Limits-See separate figure for data
i Other-See text if applicable GT Other Geotechnical Testing
1 300-lb Hammer,30-inch Drop CA Chemical Analysis
2 140-lb Hammer,30-inch Drop Groundwater
3 Pushed _
4 Vibrocore(Rotosonic/Geoprobe) Approximate water level at time of drilling(ATD)
5 Other-See text if applicable L Approximate water level at time other than ATD
Mason Transit Authority Figure
Park and Ride Improvements Soil Classification System and Key /�
LANDAU Belfair Site A_�f I
14 ASSOCIATES Belfair, Washington
TP- 1
SAMPLE DATA SOIL PROFILE GROUNDWATER
Excavator
E $ Excavation Method:
z'— r j E Ground Elevation(ft): Not Measured
0 0 m M U N
o t 0)a
U
o ElW od t10nCD 120 2) Logged By: BJM
0 SM Brown,silty,fine to coarse SAND with gravel
Sp- and organics(medium dense,dry to moist)
SM (TOPSOIL) Groundwater not encountered.
S-1 = d Brown,fine to coarse SAND with gravel and silt
5 (medium dense,moist)
(ICE CONTACT)
-Grades to light brown and dense at 2.5 ft bgs
S-2 �- d
10
S-2 d
15 S� d o o GP Light brown,sandy,fine to coarse GRAVEL with
cobbles(dense,moist)
Test Pit Completed 08/15/17
Total Depth of Test Pit=15.5 ft.
20
TP- 2
SAMPLE DATA S GROUNDWATER
a� o vato - - - -
0 n Meth
_� z'— rn E vation Not Measured
o m Z m m o CO)
w L 16 n m a 0 06
w 0 as 0) 1 Logged By: BJM — —-
0
0 6,(., es of forest duff
w (FOREST DUFF) Groundwater not encountered.
W S Bro silty,fine to coarse SAND with organics
'a S-1 I d (loose,dry to moist)
5 (TOPSOIL)
o _
,o S-2= d Brown,gravelly,fine to coarse SAND with silt
o (dense,moist)
(ICE CONTACT)
F 10 -Grades to gray at 5.5 ft bgs
rn
rr S-3 d
LL Test Pit Completed 08/15/17 - - - -
wW Total Depth of Test Pit=12.5 ft.
F 15
'o
0
vi
4
v
20
A
N
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
3. Refer to"Soil Classification System and Key'figure for explanation of graphics and symbols.
r
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits /�A_�
LANDAU Belfair Site
ASSOCIATES Belfair, Washington
TP- 3
SAMPLE DATA SOIL PROFILE GROUNDWATER
Excavator
E a� Excavation Method: - — —
z'— m rn Ground Elevation(ft):_ Not Measured
m — -
o CDZ y m a cn
t � a U
a > E c E (nn i m
o w cn as in Q c� � Logged By: _BJM- - - - --
SM 6 inches of forest duff
(FOREST DUFF)
SP- — Groundwater not encountered.
SM Brown,silty,fine to coarse SAND with gravel
5 S 1 1 d GS
(loose,dry to moist)
(TOPSOIL)
Gray,very gravelly,fine to coarse SAND with
silt and cobbles(dense,moist)
S-2= d (ICE CONTACT)
10 -Grades to very dense at 8 ft bgs -
S-3 T li d li -Grades to gravely at 11 ft bgs
Test Pit Completed 08/15/17
- 15 Total Depth of Test Pit=13.5 ft.
20
TP- 4
SAMPLE DATA SOIL PROFILE GROUNDWATER
z m $ Excavation Method: Excavator
o -
c Z m C E round Elevation(ft): Not Measured
o y Z y m 0 rn
w L '6 a Q a p o. rn
0 om w in 06 1 j Logged By: BJM
~ 0 12 inches ofa. forest duff
" (FOREST DUFF) Groundwater not encountered.
S-1 I d S Br iffy,fine to coarse SAND with gravel
a and organics(loose,dry to moist)
0 5 (TOPSOIL) -
W=5 - -- ——_-__3
S-2= d GS Brown,very gravelly,fine to coarse SAND with
v silt and cobbles(dense,moist)
(ICE CONTACT) �-
10 -Grades to gray at 3.5 ft bgs
55~ W=6
a 13-3= I d GS `t Grades to light brown and very dense at 6 ft
S-4 d - - - --- -- - -�
aWag1 15 Test Pit Completed 08/15/17 Light brown,silty,very gravelly,fine to coarse
o Total Depth of Test Pit=14.0 ft. SAND with cobbles(very dense,moist)
o
0
} 20
rn i
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
ui 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
a 3. Refer to"Soil Classification System and Key'figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits /�_�
LANDAU Belfair Site A
ASSOCIATES Belfair, Washington
TP- 5
SAMPLE DATA SOIL PROFILE GROUNDWATER
E a Excavator -
E n Excavation Method:_ _ __-
� F_ '' E Ground Elevation(ft): Not Measured
C Z (0 rA T - -- - -
N Z N (0 U C
a l to
U
o w Wad M c� Y Logged By: BJM--- -- -
0 8 inches of forest duff --- - ---
SM (FOREST DUFF)
W=6 SM - - -- Groundwater not encountered.
S-1 I d Brown,silty,fine to coarse SAND with ravel
GS g
and organics(loose,dry to moist)
5 (TOPSOIL)
Light reddish brown,silty,very gravelly,fine to
S-2= d W=6 coarse SAND(dense,moist)
GS (ICE CONTACT)
10 -Grades to gray and gravelly at 5 ft bgs
-Grades to with cobbles at 7.5 ft bgs
S-3_� d
15 Test Pit Completed 08/15/17 --- - -
Total Depth of Test Pit=14.0 ft.
-20
TP- 6
- - - -- - - - - - - - - -
SAMPLE DATA SOIL PROFILE GROUNDWATER
o n E a Excavation Meth vato
C z m j �, Ground Elevation _Not Measured
w
o Z y eo 9
a
3 d 2 m� cc m f0 U) By: BJM
(' o w rn 06 rn H c�
0
-0 --- - s of forest duff -- - - - -
N (FOREST DUFF) Groundwater not encountered.
Uj
S-1 T d G Brown, dty,fine to coarse SAND with gravel
and organics(loose,dry to moist)
5 (TOPSOIL)
W=g
q S-2= d GS Brown,very sandy,fine to coarse GRAVEL with
o silt(very dense,moist)
(ICE CONTACT)
r 10 -Grades to gray at 6 ft bgs -
<
w S-3= d o o GP Gray,very sandy,fine to coarse GRAVEL
Fo _ (dense,moist)
0 15 S-4 d GP-
GS GP- \ --
o Test Pit Comple ed-081T5T1 GM Gray,very sandy,fine to coarse GRAVEL with
0
Total Depth of Test Pit=16.0 ft. silt(dense,moist)
0
-20
i
N
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
0 3. Refer to"Soil Classification System and Key"figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits � /�
LANDAU Belfair Site _`r
ASSOCIATES Belfair, Washington
TP- 7
SAMPLE DATA SOIL PROFILE GROUNDWATER
° Excavator
m - o Excavation Method: - -
E a ----
oz' m r i E Ground Elevation(ft): Not Measured-
_ m Z co U <n m --
t m a CD ! CL a U
w
o w U)06 in U Logged Lo B BJM
y: --- - - - -
-0 - -- --_ - ---- - --_ __ - - -
6 inches of forest duff
I(� SM (FOREST DUFF) Groundwater not encountered.
SP- -- -- — - -- - --
S-1= d SM Brown,silty,fine to coarse SAND with gravel
and organics(loose,dry to moist)
-5 (TOPSOIL) -
Gray,fine to coarse SAND with gravel and sift
o GP \ (dense,moist) /—
S-2 i d o 0 \ (ICE CONTACT) /
10 0°o -- - - -- - - - --
°0 Light brown,sandy,fine to coarse GRAVEL
a0 (dense,moist)
00
o°
15 d S-3 i o
- --
Test Pit Completed 0 5/17
15
Total Depth of Test Pit=15.0 ft.
20
TP- 8
SAMPLE DATA SOIL PROFILE GROUNDWATER
o -- - - U Excav. nn M vator
=@ m cn E Ground ovation(ft):_Not Measured
O N y 6 U
W .t.+ a N a L U)
I a U
0 2 m� M I a f9 U) god 4- BJM
° o w U).6 rn 0
0 -- - - - i of forest duff -
(FOREST DUFF) Groundwater not encountered.
W = S Brown, iffy,fine to coarse SAND with gravel
a S-1 d and organics(loose,dry to moist)
q 5 (TOPSOIL)
o
g Light brown,gravelly,fine to coarse SAND with
b silt(very dense,moist)
(ICE CONTACT)
10 S-2= d Brown to gray,fine to coarse SAND with gravel
co (dense,moist)
� I
J -Grades to with cobbles at 10 ft bgs
15 ' S 3 j! d-
o Test Pit Completed 08/15/17
o Total Depth of Test Pit=15.0 ft.
0
'a
20
rn
S Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
ui 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
a 3. Refer to"Soil Classification System and Key'figure for explanation of graphics and symbols.
r
Mason Transit Authority Figure
Park and Ride Improvements Log of Test Pits A _�
LANDAU Belfair Site /`1
ASSOCIATES Belfair, Washington
TP- 9
SAMPLE DATA SOIL PROFILE GROUNDWATER
E 6 Excavation Method: _Excavator
a -
c z'— m cn E Ground Elevation(ft):_ -Not Measured
o w 2. cc L U
— ---
a aU a 0 L U
o w io ad U) H � I j Logged By: BJM ---0 --- - - -
12 inches of forest duff
SM (FOREST DUFF) Groundwater not encountered.
0 o GW Brown,silty,fine to coarse SAND with gravel
5 S-1 1 d GS3 101 and organics(medium dense,dry to moist)
0 0 (TOPSOIL)
°o
0 Light brown,very sandy,fine to coarse
0° GRAVEL(very dense,moist)
g_2 = d 0 0 (ICE CONTACT)
0
-10 0 0 -Grades to brown to gray,with cobbles,and -
0 0 dense at 8.5 ft bgs
0°
00
15 SP- Brown,gravelly,fine to coarse SAND with sift
S-3 d SM (dense,moist)
Test Pit Completed 08/15/17
Total Depth of Test Pit=16.3 ft.
-2040
TP-10
SAMPLE DATA SOIL PROFILE GROUNDWATER
o a CD 6 Excavation Method: Excavator
z_ round Elevation(tt Not Measured
o f0
w « .� d N a t co
d 12
0_ U
°o o w W Cd in F- c� Logged By: ZW
M
0 - - -I inches of forest duff - - --- - - — - - --
F W=5 SP_ (FOREST DUFF) Groundwater not encountered.
F S-1= d S g fifty,fine to coarse SAND with graveJI/1-
-10 SP and organics(loose,dry to moist)
S-2 d
Icv 5 TOPSOILd
Brown,very gravelly,fine to coarse SAND with
Wi silt(dense,moist)
(ICE CONTACT)
SM Gray,fine to coarse SAND with gravel(dense,
w S-3 d _ \ moist)
___/
LLS 4 d ML \\ Gray,silty,fine to coarse SAND with gravel /
W S-5 d SP \ \(dense,moist)15
Test Pit Completed 08/15/17 /
o Gray,sandy SILT(hard,moist)
S Total Depth of Test Pit=14.8 ft. _ _ J
1O Gray,fine to coarse SAND with gravel and trace
v silt(dense,moist)
20 - - - - --
Y -
r
N_
� I
o Notes: 1. Stratigraphic contacts are based on field interpretations and are approximate.
ui 2. Reference to the text of this report is necessary for a proper understanding of subsurface conditions.
a 3. Refer to"Soil Classification System and Key'figure for explanation of graphics and symbols.
Mason Transit Authority Figure
Park and Ride Improvements Log Of Test Pits
LANDAU Belfair Site A-6
ASSOCIATES Belfair, Washington
APPENDIX B
Laboratory Testing
DRAFT Landau Associates
APPENDIX B
LABORATORY TESTING
Natural moisture content determinations and grain size analyses were performed on select samples to
aid in soil classification and estimation of infiltration rates. Laboratory testing was performed in
general accordance with the ASTM International (ASTM) standard test methods described below. The
samples were checked against the field log descriptions and updated where appropriate in general
accordance with ASTM standard D2487,Standard Practice for Classification of Soils for Engineering
Purposes.
Natural Moisture Content
In general accordance with ASTM test method D2216, natural moisture content determinations were
performed on select soil samples obtained from the explorations.The natural moisture content is
shown as W= xx (i.e., percentage of dry weight) at the respective sample depth in the column labeled
"Test Data" on the summary exploration logs presented in Appendix A.
Grain Size Analyses
To provide an indication of the grain size distribution of the onsite soil, grain size analyses were
conducted on representative soil samples obtained from the explorations. Analyses were performed
in accordance with ASTM test method D422. Samples selected for grain size analyses are designated
with a "GS" in the column labeled "Test Data" on the summary exploration logs in Appendix A.The
results of the grain size analyses are presented in the form of grain size distribution curves on Figures
B-1 and B-2 in this appendix.
Appendix B 1174015.010.012
MTA—Belfair Park and Ride B-1 September 18,2017
1174015.01 9/6/17 Y.\1174\015.010\T\BELFAIR SITE\1174015.010.GPJ GRAIN SIZE FIGURE
U.S.Sieve Opening in Inches I U.S.Sieve Numbers Hydrometer
6 4 3 2 1 314 1/2 318 3 4 6 8 10 14 16 20 30 40 5060 100 140 200
100
90 --
70
L
3 60
50
c
°�' 40
m
a
30
20
10
— T+H+ 111 ___
1001 ,
10 1 1 11 0.1 0.01 0.001
in 1n Millimeters
Cobbles Gravel Sand Silt or Clay
L— Coarse Fine Medium Fine
Symbol Exploration
Sample Number Depth Natural Moisture(%) Soil Description Unified Soil
Classification
0 TP-2 S-1 3.5 4 Gravelly,fine to coarse SAND with silt SP-SM
m TP-3 S-1 4.0 3 Very gravelly,fine to coarse SAND with silt SP-SM
A TP-4 S-2 6.0 5 Very gravelly,fine to coarse SAND with silt SP-SM
* TP-4 S-3 11.0 6 Silty,very gravelly,fine to coarse SAND SM
O TP-5 S-1 3.0 6 Silty,very gravelly,fine to coarse SAND SM
Mason Transit Authority Figure
Park and Ride Improvements Grain Size Distribution
LANDAU Belfair Site B-1
ASSOCIATES Belfair, Washington
1174015.01 9/6117 Y:\1174\015.010\T\BELFAIRSITE\1174015.010.GPJ GRAIN SIZE FIGURE
U.S.Sieve Opening in Inches U.S.Sieve Numbers I Hydrometer
6 4 3 2 1 314 1/2 318 3 4 6 810 14 16 20 30 40 50 W 100 140 200
100
90
80
70
t
rn
3 60
T
50
LL
C
2 40
a�
a
30
20
10
HI 11 4 H E--L -
100 10 0.1 0.01 0.001
in in Millimeters
Cobbles Gravel Sand Silt or Clay
Coarse Fine Medium Fine
Symbol Exploration Sample Depth Natural o Soil Description Unified Soil
Number Number (ft) Moisture(h) Classification
• TP-5 S-2 7.5 6 Silty,very gravelly,fine to coarse SAND SM
m TP-6 S-2 6.0 6 Very sandy,fine to coarse GRAVEL with silt GP-GM
A TP-6 S-4 15.5 4 Very sandy,fine to coarse GRAVEL with silt_ GP-GM
* TP-9 S-1 4.0 3 Very sandy,fine to coarse GRAVEL GW
O TP-10 S-1 2.5 5 Very gravelly,fine to coarse SAND with silt SIP-SM
Mason Transit Authority Figure
Park and Ride Improvements Grain Size Distribution
LANDAU Belfair Site B_2
ASSOCIATES Belfair, Washington
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