3301 SEAWAY BLVD WHOLE SITE 2025-10-30

TERRA ASSOCIATES Inc. Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences January 18, 2017 Project No. T-7342 Mr. Greg Bertch Bertch Capital Partners 8210 —164th Avenue NE, Suite 200 Redmond, Washington 98052 Subject: Geotechnical Engineering Evaluation Seaway Center 36th Avenue West and Seaway Boulevard Everett, Washington References: 1. Letter, Response to City of Everett Comments, Seaway Center, Everett, Washington, Project No. T-7342, prepared by Terra Associates, Inc., dated August 5, 2016 2. Geotechnical Report, Seaway Center, 36th Avenue West and Seaway Boulevard, Everett, Washington, Project No. T-7342, prepared by Terra Associates, Inc., dated May 11, 2016 3. Civil Drawings, Seaway Center, 3301 Seaway Blvd., Everett, Washington, prepared by Barghausen Consulting Engineers, dated February 19, 2016 revised January 10, 2017 Dear Mr. Bertch: As requested, we have completed an additional geotechnical engineering evaluation of the revised stormwater detention pond location for the subject project. We had originally addressed the stability of the original pond location and presented our findings in the referenced letter and geotechnical report. The original pond location was setback a distance of 10 to 40 feet from the crest of an adjacent east facing steep slope. As we understand, the City of Everett stormwater design manual requires the pond be setback from the slope crest a distance equal to the slope height. In this case, the required _setback distance would be on the order of 100 feet. After some discussion the City indicated they would consider allowing a reduced setback of 50 feet provided a slope stability analysis is completed demonstrating the pond would not negatively impact the" stability of the steep slope. We were provided with the referenced updated civil drawings from Barghausen Consulting Engineers, dated January 10, 2017 showing the revised pond location and design. To establish the required pond storage volume without encroaching into the 50-foot setback the eastern pond containment will be provided by a cast -in -place concrete retaining wall instead of a soil berm. Lining the pond with a flexible membrane liner (FML) to prevent excessive infiltration losses as recommended in the referen,qtd„geytechnical report will still be completed. q/ 12220 113th Avenue NE, Ste. 130, Kirkland, Washington 98034 Phone (425) 821-7777 a Fax (425) 821-4334