HomeMy WebLinkAboutD_ERC_Report_wExhibits_WSADA_Parking_Lot_180803.pdf
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
SIGNATURES:
Gregg Zimmerman, Administrator
Public Works Department
Date Rick M. Marshall, Administrator
Renton Regional Fire Authority
Date
Kelly Beymer, Administrator
Community Services Department
Date C.E. Vincent, Administrator Date
Department Of Community & Economic Development
ENVIRONMENTAL (SEPA) DETERMINATION OF
NON-SIGNIFICANCE (DNS)
PROJECT NUMBER: LUA18-000384, ECF, SPR-A
APPLICANT: Vicki Giles Fabre, 621 SW Grady Way, Renton, WA 98057
PROJECT NAME: Washington State Auto Dealers Association Parking Lot
PROJECT DESCRIPTION: The applicant is requesting an Environmental Threshold Determination (SEPA) for
the construction of a standalone surface parking lot on a vacant site at 620 SW 12 th St (APN 3340404805). The 14,500
square foot property is zoned Medium Industrial (IM) and is located within the Automall Overlay District B. The property
has a Comprehensive Plan Land Use designation of Employment Area. The new parking stalls would be used by visitors of
the Washington State Auto Dealers Association building located directly north of the project site. The proposed surface
parking lot would consist of 32 parking spaces, an underground stormwater vault, a bio-retention area, and one landscape
island. Twelve (12) stalls on the north side of the site would have direct access to the alley. Access to the other 21 stalls
would be via existing curb cuts on SW 12th St and the public alley to the north of the site. A High Seismic Hazard is mapped
on the project site. The applicant has proposed the removal of one (1) significant tree. The applicant submitted a
Geotechnical Report, a Drainage Report, and an Arborist Report with the application.
PROJECT LOCATION: 621 SW Grady Way, Renton, WA 98057
LEAD AGENCY: City of Renton
Environmental Review Committee
Department of Community & Economic Development
The City of Renton Environmental Review Committee has determined that it does not have a probable significant adverse
impact on the environment. An Environmental Impact Statement (EIS) is not required under RCW 43.21C.030(2)(c). This
Determination of Non-Significance is issued under WAC 197-11-340. Because other agencies of jurisdiction may be
involved, the lead agency will not act on this proposal for fourteen (14) days.
Appeals of the environmental determination must be filed in writing on or before 5:00 p.m. on August 17, 2018.
Appeals must be filed in writing together with the required fee with: Hearing Examiner, City of Renton, 1055 South Grady
Way, Renton, WA 98057. Appeals to the Examiner are governed by RMC 4-8-110 and more information may be obtained
from the Renton City Clerk’s Office, (425) 430-6510.
PUBLICATION DATE: August 3, 2018
DATE OF DECISION: July 30, 2018
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
8/1/2018 | 4:25 PM PDT
7/31/2018 | 3:50 PM PDT
8/1/2018 | 3:37 PM PDT
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
ERC REPORT 18-000384 Project Location Map
ENVIRONMENTAL REVIEW COMMITTEE REPORT
ERC MEETING DATE: July 30th, 2018
Project Name: Washington State Auto Dealers Association Parking Lot
Project File Number: PR18-000313
Land Use File Number: LUA18-000384, ECF, SPR-A
Project Manager: Alex Morganroth, Associate Planner
Owner: WSADA Property LLC, 621 SW Grady Way, Renton, WA 98057
Applicant/Contact: Vicki Giles Fabre, 621 SW Grady Way, Renton, WA 98057
Project Location: 621 SW Grady Way, Renton, WA 98057
Project Summary: The applicant is requesting an Environmental Threshold Determination (SEPA) for the
construction of a standalone surface parking lot on a vacant site at 620 SW 12th St (APN
3340404805). The 14,500 square foot property is zoned Medium Industrial (IM) and is
located within the Automall Overlay District B. The property has a Comprehensive Plan
Land Use designation of Employment Area. The new parking stalls would be used by
visitors of the Washington State Auto Dealers Association building located directly
north of the project site. The proposed surface parking lot would consist of 32 parking
spaces, an underground stormwater vault, a bio-retention area, and one landscape
island. Twelve (12) stalls on the north side of the site would have direct access to the
alley. Access to the other 21 stalls would be via existing curb cuts on SW 12th St and
the public alley to the north of the site. A High Seismic Hazard is mapped on the project
site. The applicant has proposed the removal of one (1) significant tree. The applicant
submitted a Geotechnical Report, a Drainage Report, and an Arborist Report with the
application.
Site Area: 14,500 sq. ft. (0.33 acres)
STAFF
RECOMMENDATION:
Staff Recommends that the Environmental Review Committee issue a Determination
of Non-Significance - Mitigated (DNS-M).
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
City of Renton Department of Community & Economic Development Environmental Review Committee Report
WSADA PARKING LOT LUA18-000384, ECF
Report of July 30, 2018 Page 2 of 4
ERC REPORT 18-000384
PART ONE: PROJECT DESCRIPTION/BACKGROUND
The applicant is requesting Environmental (SEPA) Review for the construction of a surface parking lot on a vacant
parcel of land. The parking lot would include 32 stalls (two of which are van-accessible ADA stalls) and the associated
landscaping. The parking lot would be used by visitors to the Washington State Auto Dealers Association headquarters
located directly north of the project site. WSADA expects the lot to be primarily utilized during the mid -day hours
when they offer trainings at the facility.
PART TWO: ENVIRONMENTAL REVIEW
In compliance with RCW 43.21C.240, the following environmental (SEPA) review addresses only those project impacts
that are not adequately addressed under existing development standards and environmental regulations.
A. Environmental Threshold Recommendation
Based on analysis of probable impacts from the proposal, staff recommends that the Responsible Officials:
Issue a DNS-M with a 14-day Appeal Period.
B. Mitigation Measures
1. Full frontage improvements shall be constructed along SW 12th St. in compliance with the City of Renton
Street Standards, RMC 4-6-060. The frontage improvements shall be shown on the construction permit
application for review and approval prior to construction permit issuance.
C. Exhibits
Exhibit 1 Environmental Review Committee Report
Exhibit 2 Neighborhood Detail Map
Exhibit 3 Site Plan
Exhibit 4 Plan Set (Sheets S503-1, C601-2)
Exhibit 5 Construction Mitigation Description
Exhibit 6 Geotechnical Report prepared by Migizi Group, Inc (dated May 18, 2018)
Exhibit 7 Technical Information Report (TIR) prepared by Sitts & Hills Engineers, Inc (dated May of 2018
and revised in June of 2018)
Exhibit 8 Advisory notes to Applicant
D. Environmental Impacts
The proposal was circulated and reviewed by various city departments and divisions to determine whether the
applicant has adequately identified and addressed environmental impacts anticipated to occur in conjunction with
the proposed development. Staff reviewers have identified that the proposal is likely to have the following probable
impacts:
1. Earth
Impacts: The subject site is located in an area of a known seismic hazard. As such, the applicant submitted a
Geotechnical Report, prepared by Migizi Group, Inc and dated May 18th, 2018 (Exhibit 6). Surface conditions
on the site primarily consists of sparse grass and bushes, with a row of trees along the eastern property line.
Migizi Group, Inc dug three test pits with a mini-excavator at depths ranging from three to ten feet in order
to analyze the soil characteristics of the site.
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
City of Renton Department of Community & Economic Development Environmental Review Committee Report
WSADA PARKING LOT LUA18-000384, ECF
Report of July 30, 2018 Page 3 of 4
ERC REPORT 18-000384
The boring results indicated that the subsurface conditions at the site includes structural fill and construction-
related debris at depths between two and half feet to four and a half feet across the site. The material overlays
native alluvial flood plain deposits compromised of fine and silty silt and sand mixed with gravel. Groundwater
seepage was encountered at a depth of four to four and a half feet below existing grade. Due to the
completion of the borings only a few weeks after the rainy season, Migizi Group, Inc does not anticipate that
the groundwater would rise higher than the level observed in the test pits.
According to the City of Renton Critical Areas Maps, the project site is located in a seismic hazard area. The
submitted geotechnical report concluded that the project site is located in an area of high liquefaction
potential. The geotechnical report would be required to be submitted with the construction permit application
for the parking lot and compliance with the report would be reviewed at that time.
The applicant has indicated the project would result in approximately 10,875 sq. ft. of new impervious area.
Overall the project would not increase the imperious coverage on-site.
Mitigation Measures: No further mitigation required.
Nexus: Not applicable
2. Water
Impacts: The applicant submitted a Technical Information Report (TIR) prepared by Sitts & Hills Engineers,
Inc, dated May of 2018 and revised in June of 2018 (Exhibit 7). Based on the updated TIR, the project contains
greater than 2,000 sq. ft. of new impervious surface and therefore a Full Drainage Review is required pursuant
to the 2017 City of Renton Surface Water Design Manual (RSWDW). Based on the City’s flow control map, this
site falls within the Peak Rate Flow Control Standard matching Existing Site Conditions. The project site is
located within the Black River Drainage basin. A Full Drainage Review was included in the report.
All nine core requirements and the six special requirements were discussed in the report. The project does
not propose a flow control facility since the increase of peak flow rate during a potential 100-year rain event
is less than 0.15 cubic feet per second (cfs). The project is required to provide enhanced basic water quality
treatment prior to discharge. The applicant has proposed the use of two Filterra units in order to provide the
required treatment. On-site BMPs will be required to help mitigate the new runoff created by the proposed
improvements. The applicant has proposed limited infiltration in order to meet Core Requirement #9 for on-
site BMPs. The final drainage report submitted at the time of construction permit application should address
the implementation of on-site BMPs.
Mitigation Measures: No further mitigation required.
Nexus: Not applicable
3. Trees and Vegetation
Impacts: The applicant submitted an arborist report prepared by Sitts and Hill Engineers, Inc. The applicant
has proposed the removal of two (2) non-significant trees on the site, including a 6-inch caliper Hawthorn and
a 3-inch caliper Alder located on the east side of the site. In addition, sparse native grasses and non-native
shrubs including blackberry and butterfly bush are proposed for removal as part of the grading process. As
part of the landscaping proposed for the perimeter and island landscaping associated with the parking lot, the
applicant has proposed the installation variety of native shrubs and native ground cover plants. In addition,
the applicant has proposed the installation of nine (9) 2-inch caliper shade trees.
Mitigation Measures: No further mitigation required.
Nexus: Not applicable
4. Transportation
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
City of Renton Department of Community & Economic Development Environmental Review Committee Report
WSADA PARKING LOT LUA18-000384, ECF
Report of July 30, 2018 Page 4 of 4
ERC REPORT 18-000384
Impacts: The applicant submitted a parking and traffic analysis prepared by Heath & Associates, Inc. The
report concludes that there would be little to no increase in vehicle trips within the AM and PM expected as
a result of the new parking lot. This conclusion is based on the fact new services are not being offered by
WSADA as the parking lot is designed to handle the existing overflow parking based on the existing services
at the facility. However, the provided report did not evaluate expected pedestrian trips from the parking lot
to nearby auto dealers and businesses. The addition of a parking lot is expected to produces pedestrian traffic
along public streets. The frontage along SW 12th Street is currently unimproved and does not provide a public
sidewalk to allow for safe pedestrian mobility along SW 12th to existing auto dealerships or to Grady Way
where a more robust sidewalk system exists to access nearby business and public transit. Due to the
expectation of an increase in pedestrian traffic as a result of the new parking lot, staff recommends as a
mitigation measure that frontage improvements are installed along SW 12th Street. Development
Engineering staff have reviewed the provided traffic analysis and concur with the applicants assertion that
traffic impacts would not be significant within the AM and PM peak times and conclude that the construction
of frontage improvements along SW 12th street and the payment of impact fees transportation impacts for
the subject project would provide adequate mitigation.
Mitigation Measures: Full frontage improvements shall be constructed along SW 12th St. in compliance with
the City of Renton Street Standards, RMC 4-6-060. The frontage improvements shall be shown on the
construction permit application for review and approval prior to construction permit issuance.
Nexus: SEPA Environmental Review; RMC 4-6-060 Street Standards
E. Comments of Reviewing Departments
The proposal has been circulated to City Department and Division Reviewers. Where applicable, their comments
have been incorporated into the text of this report and/or listed under Exhibit 8 “Plan Review Comments to
Applicant.”
Copies of all Review Comments are contained in the Official File and may be attached to this report.
The Environmental Determination decision will become final if the decision is not appealed within the 14-day
appeal period (RCW 43.21.C.075(3); WAC 197-11-680).
Environmental Determination Appeal Process: Appeals of the environmental determination must be filed in writing
together with the required fee to: Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057, on
or before 5:00 p.m. on August 17th, 2087. RMC 4-8-110 governs appeals to the Hearing Examiner and additional
information regarding the appeal process may be obtained from the City Clerk’s Office, Renton City Hall – 7th Floor,
(425) 430-6510.
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
CITY OF RENTON
DEPARTMENT OF COMMUNITY AND ECONOMIC DEVELOPMENT
STAFF REPORT TO THE ENVIRONMENTAL REVIEW COMMITTEE
EXHIBITS
Project Name:
Washington State Auto Dealers Association
Parking Lot
Project Number:
LUA18-000384, ECF, SPR-A
Date of Meeting
July 30th, 2018
Staff Contact
Alex Morganroth
Associate Planner
Project Contact/Applicant
Vicki Giles Fabre
WSADA Property LLC
621 SW Grady Way
Renton, WA 98057
Project Location
621 SW Grady Way
Renton, WA 98057
The following exhibits are included with the ERC Report:
Exhibit 1: Environmental Review Committee (ERC) Report
Exhibit 2: Neighborhood Detail Map
Exhibit 3: Site Plan
Exhibit 4: Plan Set (Sheets S503-1, C601-2)
Exhibit 5: Construction Mitigation Description
Exhibit 6: Geotechnical Report prepared by Migizi Group, Inc (dated May 18, 2018)
Exhibit 7: Technical Information Report (TIR) prepared by Sitts & Hills Engineers, Inc (dated
May of 2018 and revised in June of 2018)
Exhibit 8: Advisory notes to Applicant
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
SW Grady WaySW Grady WaySW Grady WayRaymond Ave SWSW 12th StSW 12th StSW 12th StLind Ave SWSeneca Ave SWSW 13th StLind Ave SWLind Ave SWSW 10th StSW 10th StRECEIVED06/27/2018amorganrothPLANNING DIVISIONExhibit 2DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
TPN 3340404805
S.W. 12TH
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
SURFACING AND DIMENSION PLAN
RECEIVED
06/27/2018
amorganroth
PLANNING DIVISION
Exhibit 3 DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
ENGINEERS, INC.
SITTS & HILL
DEALERS ASSOCIATION
WASHINGTON STATE AUTO
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WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
COVER SHEET
Exhibit 4 DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
TPN 3340404805
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LEGEND
HORIZONTAL DATUM
VERTICAL DATUM
SITE DATA
NOTES
LEGAL DESRIPTION
REFERENCES
IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
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PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
TOPOGRAPHIC SURVEY DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
TPN 3340404805
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A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
DEMOLITION, EROSION AND
SEDIMENTATION CONTROL DETAILS DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
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A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
DEMOLITION, EROSION AND
SEDIMENTATION CONTROL DETAILS DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
DEMOLITION, EROSION AND
SEDIMENTATION CONTROL DETAILS DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
TPN 3340404805
S.W. 12TH
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
SURFACING AND DIMENSION PLAN DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
SURFACING AND DIMENSION NOTES DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
SURFACING AND DIMENSION DETAILS DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
TPN 3340404805
S.W. 12TH
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GRADING AND DRAINAGE PLAN
LEGEND
PROPOSED FEATURES-
GENERAL NOTES
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ALLEY
S.W. 12TH ST
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PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
WSADA PARKING LOT
A-NNNNNNN
PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
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DATE:CHECKED:DRAWN:############P:\17600\17668\DRAWINGS\17668-C3.2.DWG 6/14/2018 6:46 PMThe design and information shown on this drawing is provided as a service to the project owner, engineer and contractor by CONTECH Engineered Solutions LLC or one of its affiliated companies ("CONTECH"). Neither this drawing, nor any part thereof, may be used, reproduced or modified in any
manner without the prior written consent of CONTECH. Failure to comply is done at the user's own risk and CONTECH expressly disclaims any liability or responsibility for such use. If discrepancies between the supplied information upon which the drawing is based and actual field conditions are
encountered as site work progresses, these discrepancies must be reported to CONTECH immediately for re-evaluation of the design. CONTECH accepts no liability for designs based on missing, incomplete or inaccurate information supplied by others.
FILENAME:800-338-1122 513-645-7000 513-645-7993 FAX
9025 Centre Pointe Dr., Suite 400, West Chester, OH 45069
www.ContechES.com
FILTERRA THROAT OPENING DETAILS
FILTERRA THROAT OPENING DTL
PRECAST
TOP SLAB TYP
4" MIN.
OPENING
4" MIN.
OPENING
CROWNED FLUME REVERSE FLUME - SLOPED
TOWARDS FILTERRA THROAT
CURB
DOWEL
PRECAST
TOP SLAB
CAST-IN-PLACE
FLUME AND GUTTER
(SLOPED TOWARD
THROAT)
PRECAST
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FLUME AND GUTTER
(CROWNED AND SLOPED
TOWARD FILTERRA THROATS)
THROAT
OPENING
TYP
SECTION VIEWS OF TYPICAL FLUME APPLICATIONS
SEE ABOVE FOR DETAILS NOT SHOWN
4" MIN.
OPENING
THROAT
OPENING
TYP
DOWELPRECAST
VAULT WALL
PRECAST
TOP SLABSTANDARD 90° NOSING
(OTHER NOSING AVAILABLE
UPON REQUEST)
CAST-IN-PLACE GUTTER
AND THROAT OPENING
(BY CONTRACTOR PER
LOCAL STANDARDS)#4 DOWEL BARS @ 12" O.C. BY
CONTECH TO BE BENT AS
NECESSARY BY CONTRACTOR
PRIOR TO INSTALLATION OF
CAST-IN-PLACE GUTTER
THROAT PROTECTION DEVICE
DO NOT REMOVE - LEAVE IN
PLACE UNTIL SITE IS STABILIZED
AND FILTERRA IS ACTIVATED
PRECAST VAULT WALL
SECTION VIEW
STANDARD THROAT OPENING
4"-6" CLEAR
THROAT
OPENING
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PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/
GRADING AND DRAINAGE DETAILS DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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IN COMPLIANCE WITH CITY OF RENTON STANDARDSAAANNNNNNN
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PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
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LANDSCAPING NOTES
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4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
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PHONE: (253) 474-9449 | FAX: (253) 474-0153
4815 CENTER STREET | TACOMA, WA. 98409
SITTS & HILL
ENGINEERS, INC.
CIVIL STRUCTURAL SURVEYING
http://www.sittshill.com/RAY M O N D J. JOH N S
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NN O. 4 4 9 E X P. 0 3 / 2 0 /1 9L A N D S C A P E A R C H I T E C TTREE RETENTION PLAN DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
SITTS & HILL ENGINEERS, INC.
Professional Engineers and Planners BRENT K. LESLIE, P.E.
4815 Center Street, Tacoma, WA 98409 KATHY A. HARGRAVE, P.E.
www.sitts-hill-engineers.com LARRY G. LINDELL, P.E.
(253) 474-9449 MICHAEL A. McEVILLY, P.L.S.
Civil, Structural and Surveying
May 22nd, 2018
WASHINGTON STATE AUTO DEALERS ASSOCIATION (WSADA)
621 Southwest Grady Way
Renton, Washington 98057
To: City of Renton
Subject: Construction Mitigation Description
Renton Parking Lot for WSADA
This project proposes construction dates per permit approval, in anticipation for construction in August
2018 to September 2018.
The proposed construction hours of operation for this parking lot are to be 6AM-4PM Monday through
Friday.
Proposed hauling/transportation routes shall be limited to accessing and leaving the site via the
designated construction entrance on 12th Street Southwest. Completed hauling and transportation routes
shall be made by the contractor.
The project proposes to minimize dust by sweeping the adjacent streets (alley and 12th Street
Southwest) at the end of each business day or as necessary. Traffic and transportation impacts will be
mitigated by allowing construction to occur and end earlier than typical business hours. Erosion shall be
mitigated via implementing BMPs such as silt fencing and catch basin protection. Noise shall be
minimized by limiting construction to the hours of construction.
Thank you again for giving us the opportunity to present our proposal for engineering services for the
Washington State Auto Dealers Association parking lot improvements.
Sincerely,
SITTS & HILL ENGINEERS, INC.
Kathy A. Hargrave, P.E.
Principal
P:\17600\17668\Applications and Permits\2018-05-22 Construction Mitigation Description.docx
RECEIVED
06/27/2018
amorganroth
PLANNING DIVISION
Exhibit 5
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
Geotechnical Engineering Report
Washington State Auto Dealers Association
621 SW Grady Way
Renton, Washington 98057
May 18, 2018
prepared for:
Sitts & Hill Engineers, Inc.
Attention: Kathy Hargrave
4815 Center Street
Tacoma, Washington 98409
prepared by:
Migizi Group, Inc.
PO Box 44840
Tacoma, Washington 98448
(253) 537-9400
MGI Project P1258-T18
Exhibit 6
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
i
TABLE OF CONTENTS
Page No.
1.0 SITE AND PROJECT DESCRIPTION............................................................................................... 1
2.0 EXPLORATORY METHODS ............................................................................................................. 2
2.1 Test Pit Procedures ................................................................................................................ 2
3.0 SITE CONDITIONS ............................................................................................................................ 3
3.1 Surface Conditions ................................................................................................................. 3
3.2 Soil Conditions ....................................................................................................................... 3
3.3 Groundwater Conditions ...................................................................................................... 3
3.4 Seismic Conditions ................................................................................................................. 4
3.5 Liquefaction Potential ............................................................................................................ 4
4.0 CONCLUSIONS AND RECOMMENDATIONS ............................................................................ 4
4.1 Site Preparation ...................................................................................................................... 5
4.2 Asphalt Pavement .................................................................................................................. 7
4.3 Structural Fill .......................................................................................................................... 8
5.0 RECOMMENDED ADDITIONAL SERVICES ................................................................................ 9
6.0 CLOSURE ........................................................................................................................................... 10
List of Tables
Table 1. Approximate Locations and Depths of Explorations ............................................................................. 2
List of Figures
Figure 1. Topographic and Location Map
Figure 2. Site and Exploration Plan
APPENDIX A
Soil Classification Chart and Key to Test Data .................................................................................................. A-1
Logs of Test Pits TP-1 through TP-3 .......................................................................................................... A-2…A-4
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Page 1 of 10
MIGIZI GROUP, INC.
PO Box 44840 PHONE (253) 537-9400
Tacoma, Washington 98448 FAX (253) 537-9401
May 18, 2018
Sitts & Hill Engineers, Inc.
4815 Center Street
Tacoma, Washington 98409
Attention: Kathy Hargrave
Subject: Geotechnical Engineering Report
Washington State Auto Dealers Association
621 SW Grady Way
Renton, Washington 98057
MGI Project P1258-T18
Dear Ms. Hargrave:
Migizi Group, Inc. (MGI) is pleased to submit this report describing the results of our geotechnical
engineering evaluation for a proposed asphalt parking lot expansion to be located in a vacant lot
immediately south of the existing parking lot for the Washington State Auto Dealers Association
(WSADA) building in Renton, Washington. A previous Geotechnical Letter Report was prepared for
the existing facilities by E3RA, Inc. dated April 4, 2012.
This report has been prepared for the exclusive use of Sitts & Hill Engineers, Inc., and their
consultants, for specific application to this project, in accordance with generally accepted
geotechnical engineering practice.
1.0 SITE AND PROJECT DESCRIPTION
The project site is located along the south side of SW Grady Way in a commercial area just north of
I-405 in Renton, Washington, as shown on the enclosed Topographic and Location Map (Figure 1).
The project area is rectangularly-shaped, encompassing a total area of 0.33-acres. The site is
undeveloped and lies in the ancestral floodplain of the Black and Green Rivers before the partial
draining of Lake Washington in 1916. The site is bordered by SW 12th St to the south, asphalt
parking lots to the north and east, and Bell Electronics to the west.
It is our understanding that the project area will be stripped, paved, and connected to the existing
WSADA parking area to the north. The new parking lot will be at or near existing grade.
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018
Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 2 of 10
2.0 EXPLORATORY METHODS
We explored surface and subsurface conditions at the project site on April 27, 2018. Our exploration
and evaluation program comprised the following elements:
• Surface reconnaissance of the site;
• Three test pit explorations (designated TP-1, TP-2, and TP-3) advanced on April 27, 2018;
and
• A review of published geologic and seismologic maps and literature.
Table 1 summarizes the approximate functional locations and termination depths of our subsurface
explorations, and Figure 2 depicts their approximate relative locations. The following sections
describe the procedures used for excavation of the test pits.
TABLE 1
APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS
Exploration Functional Location
Termination
Depth
(feet)
TP-1
TP-2
TP-3
Roughly central to the western third of the property
Roughly the middle-most point of the property
Roughly central to the eastern third of the property
10
3
10
The specific numbers and locations of our explorations were selected in relation to the existing site
features, under the constraints of surface access, underground utility conflicts, and budget
considerations.
It should be realized that the explorations performed and utilized for this evaluation reveal
subsurface conditions only at discrete locations across the project site and that actual conditions in
other areas could vary. Furthermore, the nature and extent of any such variations would not
become evident until additional explorations are performed or until construction activities have
begun. If significant variations are observed at that time, we may need to modify our conclusions
and recommendations contained in this report to reflect the actual site conditions.
2.1 Test Pit Procedures
Our exploratory test pits were excavated with a rubber-tracked mini-excavator operated by an
excavation contractor under subcontract to MGI. An engineering geologist from our firm observed
the test pit excavations, collected soil samples, and logged the subsurface conditions.
The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in our
test pits, based on our field classifications. Where a soil contact was observed to be gradational or
undulating, our logs indicate the average contact depth. We estimated the relative density and
consistency of the in-situ soils by means of the excavation characteristics and the stability of the test
pit sidewalls. Our logs also indicate the approximate depths of any sidewall caving or groundwater
seepage observed in the test pits. The soils were classified visually in general accordance with the
system described in Figure A-1, which includes a key to the exploration logs. Summary logs of our
explorations are included as Figure A-2 through A-4.
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Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018
Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 3 of 10
3.0 SITE CONDITIONS
The following sections present our observations, measurements, findings, and interpretations
regarding surface, soil, groundwater, and infiltration conditions.
3.1 Surface Conditions
As previously indicated, the project site consists of a rectangularly-shaped, 0.33-acre commercial
property situated near the intersection of I-405 and WA-167 in Renton. The property lies in the
ancestral floodplain of the Black and Green Rivers before the partial draining of Lake Washington in
1916. The site is undeveloped and topographically flat, with the exception of a dry, empty pit in the
southeastern corner of the property approximately 4 feet deep and 20 feet in length.
Site vegetation is limited to sparse grass and spiky bushes lining the edges of the property, in
addition to a line of deciduous and evergreen trees on the eastern boundary near an existing
parking lot.
No hydrologic features were observed on site, such as seeps, springs, ponds and streams.
3.2 Soil Conditions
We observed subgrade conditions in three test pits across the property. These explorations revealed
structural fill and construction-related debris such as concrete, asphalt, and brick in a dense
condition down to approximately 2½ to 4½ feet below the surface. This material overlies dense
native alluvial flood plain deposits comprised of fine sand, silty sand, silt and gravel. Native soils
were all poorly consolidated and oversaturated. While excavating TP-2, a block of concrete
prevented further excavation beyond 3 feet deep and the test pit was terminated.
In the Geologic Map of the Renton Quadrangle, King County, Washington, as prepared by the
Department of the Interior United States Geological Survey (USGS) (1965), the project site is
mapped as containing Qaw, or Quaternary Alluvium associated with the flood plains of the White
and Green Rivers. The upper part of these deposits are mostly clayey silt and fine sand, locally
peaty, being 10 to 20 feet thick near Kent, thickening to 30 to 40 feet near Tukwila. The lower part of
these deposits are mostly medium and coarse sand and can reach thicknesses of up to 75 feet.
The National Cooperative Soil Survey (NCSS) for the King County Area classifies soils onsite as
Ur-Urban Land, surrounded by minor soil units of sand and silt loam. This soil series reportedly
formed along alluvial flood plains and is comprised of sandy loam, silt loam, silty clay loam and
sand. Our subsurface explorations generally correspond with the site classifications prepared by
the USGS and NCSS.
The enclosed exploration logs (Appendix A) provide a detailed description of the soil strata
encountered in our subsurface explorations.
3.3 Groundwater Conditions
We encountered groundwater seepage in two of our three subsurface explorations, at a depth of 4 to
4½ feet below existing grade. Given the fact that our explorations were performed just outside of
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
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Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 4 of 10
what is generally considered the rainy season (November 1 to March 31), we do not anticipate that
groundwater will rise much higher than that which we observed. Groundwater levels will fluctuate
with localized geology and precipitation.
3.4 Seismic Conditions
Based on our analysis of subsurface exploration logs and our review of published geologic maps,
we interpret the onsite soil conditions to generally correspond with site class E, as defined by
Table 30.2-1 in ASCE 7, per the 2015 International Building Code (IBC).
Using 2015 IBC information on the USGS Design Summary Report website, Risk Category I/II/III
seismic parameters for the site are as follows:
Ss = 1.442 g SMS = 1.298 g SDS = 0.865 g
S1 = 0.538 g SM1 = 1.292 g SD1 = 0.862 g
Using the 2015 IBC information, MCER Response Spectrum Graph on the USGS Design Summary
Report website, Risk Category I/II/III, Sa at a period of 0.2 seconds is 1.30 g and Sa at a period of
1.0 seconds is 1.30 g.
The Design Response Spectrum Graph from the same website, using the same IBC information and
Risk Category, Sa at a period of 0.2 seconds is 0.86 g and Sa at a period of 1.0 seconds is 0.86 g.
3.5 Liquefaction Potential
Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength
caused by shear strains, as could result from an earthquake. Research has shown that saturated,
loose, fine to medium sands with a fines (silt and clay) content less than about 20 percent are most
susceptible to liquefaction. Poorly consolidated soils encountered below the water table (a depth of
4 to 4½ feet) present a moderate to severe risk for soil liquefaction. Recommendations for pavement
section design and construction contained within this report helps mitigate some of this risk, but the
risk for soil liquefaction and resultant post-construction settlement should still be considered
moderate across the project area in the instance of a large-scale seismic event.
4.0 CONCLUSIONS AND RECOMMENDATIONS
It is our understanding that the project area will be stripped, paved, and connected to the existing
WSADA parking area to the north. The new parking lot will be at or near existing grade. We offer
these recommendations:
• Feasibility: Based on our field explorations, research, and evaluations, the proposed
pavements appear feasible from a geotechnical standpoint.
• Pavement Sections: We recommend a conventional pavement section comprised of
an asphalt concrete pavement over a crushed rock base course over a properly
prepared (compacted) subgrade or a granular subbase.
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Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018
Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 5 of 10
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded
dump truck or heavy compactor. Any localized zones of yielding subgrade
disclosed during this proof-rolling operation should be over excavated to an
additional maximum depth of 12 inches and replaced with a suitable structural fill
material.
The following sections of this report present our specific geotechnical conclusions and
recommendations concerning site preparation, spread footings, slab-on-grade floors, asphalt
pavement, and structural fill. The Washington State Department of Transportation (WSDOT)
Standard Specifications and Standard Plans cited herein refer to WSDOT publications M41-10,
Standard Specifications for Road, Bridge, and Municipal Construction, and M21-01, Standard Plans for
Road, Bridge, and Municipal Construction, respectively.
4.1 Site Preparation
Preparation of the project site should involve erosion control, temporary drainage, clearing,
stripping, excavations, cutting, subgrade compaction, and filling.
Erosion Control: Before new construction begins, an appropriate erosion control system should be
installed. This system should collect and filter all surface water runoff through silt fencing. We
anticipate a system of berms and drainage ditches around construction areas will provide an
adequate collection system. Silt fencing fabric should meet the requirements of WSDOT Standard
Specification 9-33.2 Table 3. In addition, silt fencing should embed a minimum of 6 inches below
existing grade. An erosion control system requires occasional observation and maintenance.
Specifically, holes in the filter and areas where the filter has shifted above ground surface should be
replaced or repaired as soon as they are identified.
Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or
near-surface water within the construction zones before stripping begins. Because the selection of
an appropriate drainage system will depend on the water quantity, season, weather conditions,
construction sequence, and contractor's methods, final decisions regarding drainage systems are
best made in the field at the time of construction. Based on our current understanding of the
construction plans, surface and subsurface conditions, we anticipate that curbs, berms, or ditches
placed around the work areas will adequately intercept surface water runoff.
Clearing and Stripping: After surface and near-surface water sources have been controlled, sod,
topsoil, and root-rich soil should be stripped from the site. The proposed work area is currently
paved and no stripping will be necessary.
Site Excavations: Based on our explorations, we expect that excavations will encounter loose/soft to
medium dense/stiff silty, sandy alluvial soils which can be easily excavated using standard
excavation equipment.
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Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 6 of 10
Dewatering: We encountered groundwater seepage in two of three of our explorations at a depth of
4 to 4½ feet below existing grade. Given the fact that our explorations were performed just outside
of what is generally considered the rainy season (November 1 to March 31), we do not anticipate
that groundwater will rise much higher than that which we observed. If groundwater is
encountered in shallower excavations, we anticipate that an internal system of ditches, sumpholes,
and pumps will be adequate to temporarily dewater most excavations. For deeper excavations well
below the water table, expensive dewatering equipment, such as well points, may need to be
utilized in order to adequately dewater excavations.
Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should
be adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should
be no steeper than 1½H:1V, and should conform to Washington Industrial Safety and Health Act
(WISHA) regulations.
Subgrade Compaction: Exposed subgrades for the foundations of the planned additions should be
compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized
zones of looser granular soils observed within a subgrade should be compacted to a density
commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed
within a subgrade should be overexcavated and replaced with a suitable structural fill material.
Site Filling: Our conclusions regarding the reuse of onsite soils and our comments regarding wet-
weather filling are presented subsequently. Regardless of soil type, all fill should be placed and
compacted according to our recommendations presented in the Structural Fill section of this report.
Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent
(based on ASTM:D-1557).
Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as
structural fill:
• Fill: The fill that overlies the site contains construction debris and some organic
material, so is not reusable as structural fill. If areas of debris and organic-free fill
are encountered during the construction process and are thought to be reusable, we
recommend that MGI evaluate their potential for reuse.
• Alluvial Silt and Silty Sand: The alluvial silty sand that underlies the site is very
moisture sensitive and will be difficult or impossible to reuse during most weather
conditions. The majority of this soil type is currently above the optimum moisture
content and will not compact adequately unless extensively aerated.
• Alluvial Fine to Medium Sand with Gravel: Where encountered, and if properly
segregated from its siltier counterpart, the clean native fine sands are a possible
source of structural fill. This material type is relatively impervious to moisture
content variations and can be reused in most weather conditions.
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Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 7 of 10
Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce
long-term raveling, sloughing, and erosion. We generally recommend that no permanent slopes be
steeper than 2H:1V. For all soil types, the use of flatter slopes (such as 2½H:1V) would further
reduce long-term erosion and facilitate revegetation.
Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the
top edge of all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover
should be established as soon as feasible, to further protect the slopes from runoff water erosion.
Alternatively, permanent slopes could be armored with quarry spalls or a geosynthetic erosion mat.
4.2 Asphalt Pavement
Since asphalt pavements will be used across much of the project site, we offer the following
comments and recommendations for pavement design and construction.
Subgrade Preparation: We recommend a conventional pavement section comprised of an asphalt
concrete pavement over a crushed rock base course over a properly prepared (compacted) subgrade
or a granular subbase.
All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or
heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling
operation should be over excavated to an additional maximum depth of 12 inches and replaced
with a suitable structural fill material. All structural fill should be compacted according to our
recommendations given in the Structural Fill section. Specifically, the upper 2 feet of soils
underlying pavement section should be compacted to at least 95 percent (based on ASTM D-1557),
and all soils below 2 feet should be compacted to at least 90 percent.
Pavement Materials: For the base course, we recommend using imported crushed rock, such as
"Crushed Surfacing Top Course” per WSDOT Standard Specification 9-03.9(3). If a subbase course
is needed, we recommend using imported, clean, well-graded sand and gravel such as “Ballast” or
“Gravel Borrow” per WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively.
Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt
concrete pavement over a crushed rock base course. We recommend using the following
conventional pavement sections:
Minimum Thickness
Section Automobile Parking Areas Driveways and Areas Subject to
Truck Traffic
Asphalt Concrete Pavement 2 inches 3 inches
Crushed Rock Base 4 inches 6 inches
Compaction and Observation: All subbase and base course material should be compacted to at least
95 percent of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete
should be compacted to at least 92 percent of the Rice value (ASTM D-2041). We recommend that
an MGI representative be retained to observe the compaction of each course before any overlying
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018
Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 8 of 10
layer is placed. For the subbase and pavement course, compaction is best observed by means of
frequent density testing. For the base course, methodology observations and hand-probing are
more appropriate than density testing.
Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described
pavement sections present our minimum recommendations for an average level of performance
during a 20-year design life, therefore, an average level of maintenance will likely be required.
Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about
10 years. Thicker asphalt and/or thicker base and subbase courses would offer better long-term
performance but would cost more initially; thinner courses would be more susceptible to “alligator”
cracking and other failure modes. As such, pavement design can be considered a compromise
between a high initial cost and low maintenance costs versus a low initial cost and higher
maintenance costs.
4.3 Structural Fill
The term "structural fill" refers to any material placed under foundations, retaining walls, slab-on-
grade floors, sidewalks, pavements, and other structures. Our comments, conclusions, and
recommendations concerning structural fill are presented in the following paragraphs.
Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock,
crushed rock, well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit-
run"), and miscellaneous mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass,
which are derived from pulverizing the parent materials, are also potentially useful as structural fill
in certain applications. Soils used for structural fill should not contain any organic matter or debris,
nor any individual particles greater than about 6 inches in diameter.
Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be
placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be
thoroughly compacted with a mechanical compactor.
Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we
recommend that structural fill used for various onsite applications be compacted to the following
minimum densities:
Fill Application Minimum
Compaction
Asphalt pavement base
Asphalt pavement subgrade (upper 2 feet)
Asphalt pavement subgrade (below 2 feet)
95 percent
95 percent
90 percent
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
Sitts & Hill Engineers, Inc. – WSADA, 621 SW Grady Way, Renton, WA May 18, 2018
Geotechnical Engineering Report P1258-T18
Migizi Group, Inc. Page 9 of 10
Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill
should be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation
section of this report. The condition of all subgrades should be observed by geotechnical personnel
before filling or construction begins. Also, fill soil compaction should be verified by means of
in-place density tests performed during fill placement so that adequacy of soil compaction efforts
may be evaluated as earthwork progresses.
Soil Moisture Considerations: The suitability of soils used for structural fill depends primarily on
their grain-size distribution and moisture content when they are placed. As the "fines" content (that
soil fraction passing the U.S. No. 200 Sieve) increases, soils become more sensitive to small changes
in moisture content. Soils containing more than about 5 percent fines (by weight) cannot be
consistently compacted to a firm, unyielding condition when the moisture content is more than
2 percentage points above or below optimum. For fill placement during wet-weather site work, we
recommend using "clean" fill, which refers to soils that have a fines content of 5 percent or less (by
weight) based on the soil fraction passing the U.S. No. 4 Sieve.
5.0 RECOMMENDED ADDITIONAL SERVICES
Because the future performance and integrity of the structural elements will depend largely on
proper site preparation, drainage, fill placement, and construction procedures, monitoring and
testing by experienced geotechnical personnel should be considered an integral part of the
construction process. Subsequently, we recommend that MGI be retained to provide the following
post-report services:
• Review all construction plans and specifications to verify that our design criteria
presented in this report have been properly integrated into the design;
• Prepare a letter summarizing all review comments (if required);
• Check all completed subgrades for footings and slab-on-grade floors before concrete
is poured, in order to verify their bearing capacity; and
• Prepare a post-construction letter summarizing all field observations, inspections,
and test results (if required).
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DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
APPROXIMATE SITE
LOCATION
P.O. Box 44840
Tacoma, WA 98448
Location Job Number Figure
DateTitle
621 SW Grady Way
Renton, Washington
Topographic and Location Map
1
05/16/18
P1258-T18
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
APPENDIX A
SOIL CLASSIFICATION CHART AND
KEY TO TEST DATA
LOGS OF TEST PITS
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY
MIXTURES
SILTS AND CLAYSCOARSE GRAINED SOILSMore than Half > #200 sieveLIQUID LIMIT LESS THAN 50
LIQUID LIMIT GREATER THAN 50
CLEAN GRAVELS
WITH LITTLE OR
NO FINES
GRAVELS WITH
OVER 15% FINES
CLEAN SANDS
WITH LITTLE
OR NO FINES
MORE THAN HALF
COARSE FRACTION
IS SMALLER THAN
NO. 4 SIEVE
MORE THAN HALF
COARSE FRACTION
IS LARGER THAN
NO. 4 SIEVE
INORGANIC SILTS, MICACEOUS OR DIATOMACIOUS FINE
SANDY OR SILTY SOILS, ELASTIC SILTS
ORGANIC CLAYS AND ORGANIC SILTY CLAYS OF LOW
PLASTICITY
OH
INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR,
SILTY OR CLAYEY FINE SANDS, OR CLAYEY SILTS WITH
SLIGHT PLASTICITY
CH
SILTY GRAVELS, POORLY GRADED GRAVEL-SAND-SILT
MIXTURES
SANDS
SILTS AND CLAYS
Figure A-1
INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,
GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS,
LEAN CLAYS
R-Value
Sieve Analysis
Swell Test
Cyclic Triaxial
Unconsolidated Undrained Triaxial
Torvane Shear
Unconfined Compression
(Shear Strength, ksf)
Wash Analysis
(with % Passing No. 200 Sieve)
Water Level at Time of Drilling
Water Level after Drilling(with date measured)
RV
SA
SW
TC
TX
TV
UC
(1.2)
WA
(20)
Modified California
Split Spoon
Pushed Shelby Tube
Auger Cuttings
Grab Sample
Sample Attempt with No Recovery
Chemical Analysis
Consolidation
Compaction
Direct Shear
Permeability
Pocket Penetrometer
CA
CN
CP
DS
PM
PP
PtHIGHLY ORGANIC SOILS
TYPICAL NAMES
GRAVELS
ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY,
ORGANIC SILTS
WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES
MAJOR DIVISIONS
PEAT AND OTHER HIGHLY ORGANIC SOILS
WELL GRADED SANDS, GRAVELLY SANDS
POORLY GRADED SANDS, GRAVELLY SANDS
SILTY SANDS, POORLY GRADED SAND-SILT MIXTURES
CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES
POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES
SOIL CLASSIFICATION CHART AND KEY TO TEST DATA
GW
GP
GM
GC
SW
SP
SM
SC
ML
FINE GRAINED SOILSMore than Half < #200 sieveLGD A NNNN02 GINT US LAB.GPJ 11/4/05INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS
CL
OL
MH
SANDS WITH
OVER 15% FINES
Migizi Group, Inc.
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
GB
S-1
GP-
GM
SM
SP
ML
0.5
2.5
4.0
10.0
(GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill)
(SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill)
(SP) Blue/gray fine to medium sand with gravel (medium dense, moist) (Alluvium)
(ML) Blue/gray silt (very soft, wet) (Alluvium)
Moderate caving observed from 4 to 10 feet
Moderate groundwater seepage observed at 4 feet
The depths on the test pit logs are based on an average of measurements across the test pit and should be
considered accurate to 0.5 foot.
Bottom of test pit at 10.0 feet.
NOTES
LOGGED BY ZLL
EXCAVATION METHOD Rubber Tracked Mini Excavator
EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS:
CHECKED BY JEB
DATE STARTED 4/27/18 COMPLETED 4/27/18
AT TIME OF EXCAVATION 4.00 ft Moderate seepage
AT END OF EXCAVATION ---
AFTER EXCAVATION ---
TEST PIT SIZEGROUND ELEVATION
SAMPLE TYPENUMBERDEPTH(ft)0.0
2.5
5.0
7.5
10.0
PAGE 1 OF 1
Figure A-2
TEST PIT NUMBER TP-1
CLIENT Sitts & Hill Engineers, Inc.
PROJECT NUMBER P1258-T18
PROJECT NAME Washington State Auto Dealers Association
PROJECT LOCATION 621 SW Grady Way, Renton, WA
COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc.
PO Box 44840
Tacoma, WA 98448
Telephone: 253-537-9400
Fax: 253-537-9401
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
GP-
GM
SM
0.8
3.0
(GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill)
(SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill)
Refusal at a depth of 3 feet atop a large section of concrete
No caving observed
No groundwater seepage observed
The depths on the test pit logs are based on an average of measurements across the test pit and should be
considered accurate to 0.5 foot.
Bottom of test pit at 3.0 feet.
NOTES
LOGGED BY ZLL
EXCAVATION METHOD Rubber Tracked Mini Excavator
EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS:
CHECKED BY JEB
DATE STARTED 4/27/18 COMPLETED 4/27/18
AT TIME OF EXCAVATION ---
AT END OF EXCAVATION ---
AFTER EXCAVATION ---
TEST PIT SIZEGROUND ELEVATION
SAMPLE TYPENUMBERDEPTH(ft)0.0
2.5
PAGE 1 OF 1
Figure A-3
TEST PIT NUMBER TP-2
CLIENT Sitts & Hill Engineers, Inc.
PROJECT NUMBER P1258-T18
PROJECT NAME Washington State Auto Dealers Association
PROJECT LOCATION 621 SW Grady Way, Renton, WA
COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc.
PO Box 44840
Tacoma, WA 98448
Telephone: 253-537-9400
Fax: 253-537-9401
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
GP-
GM
SM
SM
ML
1.0
3.5
4.5
10.0
(GP-GM) Gray/brown gravel with silt and sand (dense, moist) (Fill)
(SM) Gray silty sand with gravel and concrete/asphalt/brick debris (dense, moist) (Fill)
(SM) Gray silty sand with gravel, wood, glass, plastic and other detritus (loose, wet) (Fill)
(ML) Blue/gray mottled silt (very soft, wet) (Alluvium)
Moderate caving observed from 4.5 to 10 feet
Moderate groundwater seepage observed at 4.5 feet
The depths on the test pit logs are based on an average of measurements across the test pit and should be
considered accurate to 0.5 foot.
Bottom of test pit at 10.0 feet.
NOTES
LOGGED BY ZLL
EXCAVATION METHOD Rubber Tracked Mini Excavator
EXCAVATION CONTRACTOR Paulman GROUND WATER LEVELS:
CHECKED BY JEB
DATE STARTED 4/27/18 COMPLETED 4/27/18
AT TIME OF EXCAVATION 4.50 ft Moderate seepage
AT END OF EXCAVATION ---
AFTER EXCAVATION ---
TEST PIT SIZEGROUND ELEVATION
SAMPLE TYPENUMBERDEPTH(ft)0.0
2.5
5.0
7.5
10.0
PAGE 1 OF 1
Figure A-4
TEST PIT NUMBER TP-3
CLIENT Sitts & Hill Engineers, Inc.
PROJECT NUMBER P1258-T18
PROJECT NAME Washington State Auto Dealers Association
PROJECT LOCATION 621 SW Grady Way, Renton, WA
COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 5/16/18 11:29 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1258-T18\P1258-T18 TEST PITS.GPJMigizi Group, Inc.
PO Box 44840
Tacoma, WA 98448
Telephone: 253-537-9400
Fax: 253-537-9401
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
Washington State Auto
Dealers Association (WSADA)
Renton Parking Lot
Technical
Information Report
Prepared for:
Washington State Auto
Dealers Association
621 SW Grady Way
Renton, WA 98057
Contact: Vicki Giles Fabré
Phone: (206) 433-6300
Prepared by:
Sitts & Hill Engineers, Inc.
4815 Center Street
Tacoma, Washington 98409
Contact: Kathy Hargrave, P.E.
Phone: (253) 474-9449
May 2018
Revised June 2018
S&H Job Number 17,668
Exhibit 7
Full document
available in
Laserfiche
Submittals Folder
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
DEPARTMENT OF COMMUNITY
AND ECONOMIC DEVELOPMENT
Page 1 of 4 LUA18-000384
ADVISORY NOTES TO APPLICANT
The following notes are supplemental information provided in conjunction with the administrative land use
action. Because these notes are provided as information only, they are not subject to the appeal process for
the land use action.
Planning:
(Contact: Alex Morganroth, 425-430-7219, amorganroth@rentonwa.gov)
1. RMC section 4-4-030.C.2 limits haul hours between 8:30 am to 3:30 pm, Monday through Friday unless
otherwise approved by the Development Services Division.
2. Commercial, multi-family, new single family and other nonresidential construction activities shall be
restricted to the hours between seven o’clock (7:00) a.m. and eight o’clock (8:00) p.m., Monday through
Friday. Work on Saturdays shall be restricted to the hours between nine o’clock (9:00) a.m. and eight
o’clock (8:00) p.m. No work shall be permitted on Sundays.
3. Within thirty (30) days of completion of grading work, the applicant shall hydroseed or plant an
appropriate ground cover over any portion of the site that is graded or cleared of vegetation and where
no further construction work will occur within ninety (90) days. Alternative measures such as mulch,
sodding, or plastic covering as specified in the current King County Surface Water Management Design
Manual as adopted by the City of Renton may be proposed bet ween the dates of November 1st and
March 31st of each year. The Development Services Division’s approval of this work is required prior to
final inspection and approval of the permit.
4. A National Permit Discharge Elimination System (NPDES) permit is required when more than one acre is
being cleared.
5. The applicant may not fill, excavate, stack or store any equipment, dispose of any materials, supplies or
fluids, operate any equipment, install impervious surfaces, or compact the earth in any way within the
area defined by the drip line of any tree to be retained.
6. The applicant shall erect and maintain six foot (6') high chain link temporary construction fencing around
the drip lines of all retained trees, or along the perimeter of a stand of retained trees. Placards shall be
placed on fencing every fifty feet (50') indicating the words, “NO TRESPASSING – Protected Trees” or on
each side of the fencing if less than fifty feet (50'). Site access to individually protected trees or groups
of trees shall be fenced and signed. Individual trees shall be fenced on four (4) sides. In addition, the
applicant shall provide supervision whenever equipment or trucks are moving near trees.
7. This permit is shall comply with the Bald and Golden Eagle Protection Act. The permitted is responsible
for adhering to the U.S. Fish and Wildlife Service National Bald Eagle Management Guidelines (2007) and
/or your U.S. Fish and Wildlife Service permit.
Development Engineering:
(Contact: Rohini Nair, 425-430-7298, rnair@rentonwa.gov)
1. See Attached Development Engineering Memo dated July 13, 2018
Building:
(Contact: Craig Burnell, 425-430-7290, cburnell@rentonwa.gov)
1. Recommendations of the geotechnical report must be followed as a condition of building permits.
Exhibit 8
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
ADVISORY NOTES TO APPLICANT
Page 2 of 4 LUA**-000***
DEPARTMENT OF COMMUNITY
& ECONOMIC DEVELOPMENT
M E M O R A N D U M
DATE: 7/13/2018
TO: Alex Morganroth, Planner
FROM: Rohini Nair, Civil Plan Reviewer
SUBJECT: Utility and Transportation Comments for WSADA Paarking Lot
Parcel 3340404805
LUA 18-000384
I have reviewed the application for the WSADA Paarking Lot parking lot Parcel ID 3340404805 and have the following
comments:
EXISTING CONDITIONS
The site is approximately 0.33 acres in size and is rectangular in shape. The site is currently vacant without ant buildings.
Water Water service is provided by City of Renton. The site is in the Valley service area in the 196 hydraulic pressure
zone. There is an existing 8-inch City water main located in SW 12th Street (see Water plan no. W-2798). The
approximate static water pressure is 73 psi at the elevation of 28 feet. The site is located outside of an
Aquifer Protection Area.
Sewer Wastewater service is provided by City of Renton. There is an existing 12-inch PVC gravity wastewater main
located in alley north of the site (see City plan no. S-0145).
Storm There is an existing 12–inch storm drainage conveyance in the alley north of the site (see City plan no. SW-
3657). The existing property does not contain stormwater facilities. There is no existing stormwater main
within SW 12th Street.
Streets SW 12th Street is a Collector Arterial with an existing right of way (ROW) width of 60 feet as measured using
the King County Assessor’s Map. The existing pavement width is about 24 feet without curb, gutter and sidewalk.
North of the site is a fully paved public alley with 16 feet ROW width.
CODE REQUIREMENTS
WATER
1. The information provided with the land use application of the proposed parking lot does not include any building
or any water service requirements.
2. If landscape irrigation is proposed, a separate meter will be required for landscape irrigation per COR Standard
Plan 320.1. A double check valve assembly (DCVA) is required behind the meter per COR Standard Plan 340.8.
SEWER
1. The information provided with the land use application of the proposed parking lot does not include any building
or any sewer service requirements.
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
ADVISORY NOTES TO APPLICANT
Page 3 of 4 LUA**-000***
SURFACE WATER
1. A geotechnical report, dated May 2018, completed by Migizi Group, Inc. for the site has been provided. Erosion
control measures will need to be in place prior to starting construction activities on the site. Geotechnical
recommendations need to be followed during construction.
2. A Preliminary Drainage Plan and Technical Information Report (TIR), revision date July 2018, was submitted by
Sitts & Hill Engineers, Inc. for the Land Use review. Based on the City of Renton’s flow control map, the site falls
within the Peak Rate Flow Control Standard area matching Existing Site Conditions and is within the Black River
Drainage Basin. The development is subject to Full Drainage Review in accordance with the 2017 Renton Surface
Water Design Manual (RSWDM). All nine core requirements and the six special requirements have been discussed
in the Technical Information Report.
3. The project does not propose a flow control facility since the increase of peak flow rate during the 100 year event
is less than 0.15 cfs.
4. The development is required to provide enhanced basic water quality treatment prior to discharge. The water
quality treatment is proposed by the use of two Filterra units.
5. Limited infiltration is proposed to meet the requirements of Core Requirement #9 on-site BMPS.
6. Stormwater facilities and on-site BMPS shall be designed in accordance with the RSWDM that is current at the
time of civil construction permit application. Final drainage plan and Technical Information Report (TIR) report
are required to be provided with the construction permit application.
7. Surface water system development fee is $0.687 per square foot of new impervious surface, but not less than
$1,718.00. This is payable prior to issuance of the construction permit.
TRANSPORTATION
1. The proposed development fronts SW 12th Street (a Commercial and Industrial access street) on the south and a
public alley on the north. The 4.5 feet wide dedication on SW 12th Street frontage shown in the plans is acceptable.
Based on the $100,000 project cost information provided by the applicant, the project meets the frontage
improvement exemption mentioned in RMC 4-6-060.D.1 which is the exemption for projects with valuation less
than $150,000. Therefore, the applicant is not proposing the construction of frontage improvements on SW 12th
Street.
2. The traffic memo for the project prepared by Heath & Associates mentioned that traffic impact analysis is not
triggered by the project.
3. Refer to City code 4-4-080 regarding driveway regulations.
a. The maximum width of any driveway shall not exceed 30-feet.
b. Driveways shall be located a minimum of 5-feet from property lines.
c. Maximum driveway slope is 8%.
4. Paving and trench restoration shall comply with the City’s Trench Restoration and Overlay Requirements.
GENERAL COMMENTS
1. Adequate separation between utilities as well as other features shall be provided in accordance with code
requirements.
a. 7-ft minimum horizontal and 1-ft vertical separation between storm and other utilities is required with
the exception of water lines which require 10-ft horizontal and 1.5-ft vertical.
b. The stormwater line should be minimum 5 feet away from any other structure or wall or building.
c. Trench of any utility should not be in the zone of influence of the retaining wall or of the building.
2. All civil construction permits for utility and street improvements will require separate plan submittals. All utility
plans shall confirm to the Renton Drafting Standards. A licensed Civil Engineer shall prepare the civil plans. Please
visit the Development Engineering Forms page for the most up-to-date plan submittal requirements:
http://rentonwa.gov/business/default.aspx?id=42473
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8
ADVISORY NOTES TO APPLICANT
Page 4 of 4 LUA**-000***
3. A landscaping plan shall be included with the civil plan submittal. Each plan shall be on separate sheets.
4. Fees quoted in this document reflect the fees applicable in the year 2018 only and will be assessed based on the
fee that is current at the time of the permit application or issuance, as applicable to the permit type. Please visit
www.rentonwa.gov for the current development fee schedule.
5. * An additional technology fee will be added to each fee marked with an asterisk (*).
DocuSign Envelope ID: A1A5CB90-0A7E-460D-AE8F-8B6BD4FFA2B8