6801 SEAWAY BLVD Geotech Report 2025-08-19

Seaway Commercial Center Subsurface Exploration, Geologic Hazard, 7007 Seaway Boulevard and Geotechnical Engineering Evaluation Everett, Washington Project and Site Conditions 2.0 SITE AND PROJECT DESCRIPTION The project site is located at 7007 Seaway Boulevard (Snohomish County Parcel No. 28040200300500) in Everett, Washington. The site has an area of about 29 acres and is bounded by the Narbeck Wetland Sanctuary to the south, Seaway Boulevard to the southwest, and various commercial facilities to the west, north, and east. The site is comprised of a vacant lot that is moderately to heavily wooded with several wetland areas that span along the western and northern ends of the property. The site also contains a few smaller isolated wetland areas located along the eastern and southern ends of the property. The site generally slopes down gently to the north with an overall vertical relief of about 20 to 30 feet over a distance of about 1,000 feet. We understand that the project consists of constructing a new distribution center containing approximately 193,630 square feet of warehouse space. Employee parking will be located along the south, west, and north ends of the facility. The north end of the facility will also contain approximately 21 truck docks. We understand the northwest corner of the property will remain undeveloped. Based on the current grading plan prepared by David Evans and Associates, Inc., titled "Seaway Blvd Industrial Site, Grading Site Plan," dated March 30, 2021, we understand the warehouse currently has a proposed finished floor elevation of 522 feet, corresponding to maximum cuts of about 10 feet and maximum fills of about 16 feet across the site. A retaining wall with a maximum height of about 18 feet will be required at the north end of the parking lot to achieve final grade near an existing wetland area and eastern property line. The wall type is not known at this time. 3.0 SUBSURFACE EXPLORATION Our field study included performing eight exploration pits (EP-1 through EP-8) and one exploration boring (EB-1) to gain subsurface information about the site. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in Appendices A and B. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. If changes occurred between sample intervals in our explorations they were interpreted. Our explorations were approximately located in the field using a hand-held GPS device and by referencing known site features shown on an aerial photograph of the site. The site, topography, and the approximate locations of the explorations referenced in this report are presented on Figures 2 and 3. The conclusions and recommendations presented in this report are based, in part, on the exploration pits and boring completed for this study. The number, locations, and depths of the explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, interpolation of subsurface conditions between field December 17,2021 ASSOCIATED EARTH SCIENCES,INC. PEL/Id-20200319E001-002 Page 2