7505 SEAWAY BLVD Geotech Report 2022-10-25

November 11, 2016 HWA Project No. 2014-117-21 1.3 SURFACE CONDITIONS The subject property comprises a vacant portion of a 4.2-acre parcel located within a commercial and industrial area of Everett, Washington, at the southeast corner of Seaway Boulevard and 75th Street SW. The parcel is bordered by 75th Street SW and an undeveloped wooded area on the north and east sides, PUD facilities along the south, and Seaway Boulevard and Boeing industrial facilities on the west. The parcel is currently un-developed and vegetated with grass and small bushes. There are several trees along the southern border, near the PUD power transmission lines. The eastern half of the property is currently covered with a 10-to 15-foot high mound of fill material. The purpose of the fill mound is undocumented,but aerial photographs indicate it was placed on the site sometime between 1975 and 1990. The western portion of the property is relatively flat, but the property appears to have a natural, gentle to moderate slope,rising from east to west. However, the presence of the fill mound makes it difficult to determine the natural contour of the property prior to mound placement. The northeastern portion of the site is bordered by 75th Street SW. A significant wetland area exists on the opposite side of 75th Street SW near the southeastern corner of the subject property. Archived aerial photographs indicate the wetland previously extended 500 to 1,000 feet south of its present southern border; possibly directly beneath the current commercial facilities immediately east of the PUD access driveway. That southern extent of the wetland was likely filled sometime between 1952 and 1968. Photographs also indicate a small sliver of the southwestern portion of the wetland was filled in preparation for site development during the same period. This southwestern portion is on the opposite side of 75th Street SW from the subject property. The western portion of the site is bordered by Seaway Boulevard. Our explorations indicate fill material was placed in some areas in this section. This undocumented fill is possibly of different origin than the fill mound, but this was not verified. The extent of this fill layer was not determined,but we expect it is on the order of 2 to 5 feet thick. 2. FIELD INVESTIGATION HWA's field exploration programs were conducted in two phases. Phase I explorations were completed in August 2014 in support of a feasibility study to evaluate the practicality of constructing a transit facility at the subject location. Phase II explorations were completed in February and November 2016 in support of design of the aforementioned transit facility. Further details associated with both exploration programs are provided below. 2014-117 Final Geotechnical Report 2 HWA GEOSCIENCES INC.