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 the subject site is underlain by Vashon lodgement till. Our interpretation of the sediments encountered in our explorations is in general agreement with the geologic map. 4.3 Hydrology Groundwater seepage was not encountered in any of our exploration pits or exploration boring. Although not encountered, in areas underlain by lodgement till it is common for shallow perched groundwater to accumulate seasonally at the base of the weathered till horizon. This perched seepage, known as "interflow" occurs when stormwater infiltrates through the relatively permeable, weathered till horizon and becomes perched atop the underlying, dense, low-permeability, unweathered till. Areas of perched groundwater can be anticipated in areas containing low depressions and are generally indicated by the mapped wetlands onsite. It should be noted that the presence or depth to groundwater below the site likely varies in response to such factors as changes in season, precipitation, site use, and other factors. It should be noted that our field exploration was conducted in late October and early November when groundwater levels are typically near their seasonal low. December 17,2021 ASSOCIATED EARTH SCIENCES,INC. PEL/Id-20200319E001-002 Page 5