HomeMy WebLinkAboutRS_Earthwork_Observation_221103_v115365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
November 3, 2022
ES-3220.09
MainVue WA, LLC
121 – 3rd Avenue
Kirkland, Washington 98033
Attention: Ms. Allison Rothstein
Subject: Stormbrixx Stormwater Facility Final Report
Earthwork Observation and Consulting Services
Sumpter Short Plat
14204 – 156th Avenue Southeast
Renton, Washington
Reference: Earth Solutions NW, LLC
Geotechnical Engineering Study
ES-3220.03, dated November 12, 2018
Dear Ms. Rothstein:
In accordance with your request, Earth Solutions NW, LLC (ESNW) representatives provided
earthwork observation and consulting services at the subject site. ESNW provided the referenced
geotechnical engineering study for the project. Our representative observed the Stormbrixx stormwater facility installation on July 18, 2022.
The subgrade for the facility was observed to consist of poorly graded sand. A sieve analysis of
the soil exposed at the subgrade elevation indicated the fines content of the soil was 1.1 percent.
Our representative observed Stormbrixx modules bedded in pea gravel, backfilled with clean
sand and 1-1/4-inch clean crushed rock, and wrapped with filter fabric. Based on our
observations, the stormwater facility was installed in accordance with the project plans and
our geotechnical recommendations. Based on observation of the infiltration surface, in our
opinion there are no mounding concerns for the installed stormwater facility.
MainVue WA, LLC ES-3220.09
November 3, 2022 Page 2
Earth Solutions NW, LLC
We trust this letter meets your current needs. If you have any questions, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
Lewis A. Conklin Kyle R. Campbell, P.E.
Construction Services Manager Principal Engineer
11/03/2022