3301 SEAWAY BLVD WHOLE SITE 2025-10-30

Sabrina Fandler ,- City of Everett Public Works Engineering /Permit Services Division-4- / February 15, 2017 a MWS unit, this review must occur for this site in addition to specific review of the location by the geotechnical engineer. In order to aid this review, two cross -sections of the unit must be provided, along its length and width, showing its location relative to the above grade and to the rockery between the unit and the NGPE boundary. The City must be provided a copy of MWS's written approval for the site grading and slope at the location of the proposed MWS system on -site. Response: The location of the MWS occurs near the top of the access road on a flat area. The closest edge of the MWS to the NGPE boundary is +/- 6.0 feet. An exhibit is included in this submittal that shows the cross sections of the MWS with existing grade, proposed grade, and the NGPE boundary marked. 3. Third Party Geotechnical Reviewer Comments (previous emailed to Barghausen on 10-17- 2016) a. We have reviewed the following documents you sent regarding the proposed development at 3301 Seaway Blvd: • Response to City of Everett Comments, Seaway Center, 36th Avenue West and Seaway Boulevard, Everett, Washington, prepared by Terra Associates, Inc., dated August 5, 2016. • Stormwater Site Plan, Proposed Seaway Center, NEC — 36th Avenue West and Seaway Boulevard, Everett, Washington, Prepared by Barghausen, revised date August 2, 106. Only Section 6.0 Special Reports and Studies was reviewed as it contains the original geotechnical report for the project site. • Plan Sheets Cl-C12 of the Site Development for Bertch Warehouses/Seaway Center, revised date 813116. • Lock and Load Retaining Wall Design, Seaway Center, Everett, Washington, reviewed and approved by Steve Miller, City of Everett 8110116. Response: Comment acknowledged. b. Regarding the slope stability calculations and factors of safety presented by Terra Associates, we ran slope stability analyses on Cross -Sections A -A' and B-B' as presented in the report using the program Slide V5.0. Using the soil parameters and geometries presented in the report, we calculated similar values of factors of safety. We do have concern with the following issues: • The stormwater pond sits at the crest of a steep slope. The slope is comprised of dense glacial till and advance outwash soils. If the pond were to leak, slope stability could be compromised and sliding could occur. Would an underdrain be feasible that could collect any leakage and direct it to an appropriate outlet? Is there a way to ensure the pond will not leak? Response: Please see the attached geotechnical engineer response letter prepared by Terra Associates, Inc.