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Water and Land Resources Division
Department of Natural Resources and Parks
King Street Center
201 South Jackson Street, Suite 600
Seattle, WA 98104-3855
206-477-4800 Fax 206-296-0192
TTY Relay: 711
M E M O R A N D U M
DATE: December 5, 2019
TO: Jill Ding, Senior Planner
FROM: Monica Walker, Project Manager
CC: Amanda Pierce, Surface Water Utility Engineer
SUBJECT: Cedar River Trail Embankment Subsurface Exploration
The Cedar River Trail Embankment Subsurface Exploration Project is proposed to take place
within the City of Renton requiring a Critical Areas Exemption and Shoreline Exemption. As part
of the exemption process, certain application materials are required and attached.
Project Narrative
King County is conducting a feasibility study to analyze existing flood and landslide hazards and
risks, and their interactions on the left bank of the Cedar River Trail Site A (CRT-A). The feasibility
study will characterize existing and potential future hazards, identify risks to infrastructure and
public safety, and develop alternatives to address potential risks. In order to characterize
subsurface soil conditions, the project proposes to drill up to four borings to collect soil data for
analysis. Boring holes will be backfilled according to Washington State regulations using
bentonite pellets; the excavation and backfilling is less the 500 CY of material.
The site is located on the north shoulder of the Cedar River Trail and the South bank of the Cedar
River across from the southeastern corner of the Riviera Apartments (2201 SE Maple Valley
HWY). The feasibility study area encompasses approximately 75,000 SF. The project is petitioning
for exemption on the basis of watershed restoration. The anticipated dates of work are
December 9 thru December 20, 2019.
The project is located on land used for public parks and trails. Coordination with City of Renton
Parks Department has been made to obtain a right-of-entry permit.
Page 2
The area is also located within the following critical areas: Moderate Coal Mine Hazard Area, High
Erosion Hazard Area, Moderate Land Slide Area, Protected Slopes, Urban Conservancy Regulated
Shoreline, and Wellhead Protection Zone 2. The assessment area is not located within a wetland,
unclassified stream, floodplain, or critical habitat. The work to be conducted is a geotechnical
study and is to get a better understanding of the geologic risk of the area. The work does not
impact drainage or require re-grading, as surface will be returned to existing conditions. The soil
and drainage conditions are to be assessed based on the feasibility study to mitigate potential
hazards. As this project is a feasibility study and not a construction project there is no
construction or market value associated. The borings and site exploration will not require the
removal of any trees or land clearing. The distance from the closest area of work to the Ordinary
High Water Mark of the shoreline is 20-feet. The existing shoreline is defined as Urban
Conservancy which is suitable for public or private access.
Attachments
Land Use Permit Master Application Form
Waiver Form
Neighborhood Detail Map
Site Plan
Critical Areas Exemption
Shoreline Exemption