1210 W MARINE VIEW DR Geotech Report 2022-10-25

Proposed Port Gardner Substation a �F�(" Project No. 1779.01 ` Geo eoprofessional Consultants 15 November 2017 G the south,west,and north by developed industrial properties and to the east by West Marine View Drive. The project site is shown on the Site and Exploration Plan, Figure 1. SITE CONDITIONS Surface Conditions The project site served as a parking lot at the time we completed our evaluation and was completely asphalt paved. The site is level and at approximately elevation 14 feet. The site contains an underground natural gas main,storm sewer,sanitary sewer,and apparent wiring for overhead lighting. The commercial boat yard to the south and southwest is about 2 feet higher than the site, while the balance of the adjoining properties are at or very near the site grade. Subsurface Conditions The site is located along the Everett waterfront, east of Port Gardner. The former shoreline was located about 200 feet to the east, and the site and surrounding area were filled over the years to create the current waterfront topography. The site and vicinity have a history of industrial land uses dating back to the 1800s. The publication Distribution and Description of the Geologic Units in the Everett Quadrangle, Washington (USGS Open File Report 81-248,dated 1981)describes the bluff to the east of the site as containing Vashon lodgement glacial till,underlain by advance outwash deposits and Vashon glacial to pre-Fraser non-glacial deposits. The native soils are mantled by fill material that is prevalent along the waterfront. ZGA completed two exploratory borings (B-1 and B-2) and six direct-push probes(GP-1 through GP-6) in April 2017. The soil descriptions presented below have been generalized for ease of report interpretation. Please refer to the boring logs in Appendix A for detailed soil descriptions at the exploration locations. Variations in subsurface conditions may exist between the exploration locations and the nature and extent of variations between the explorations may not become evident until construction. If variations then appear,it may be necessary to reevaluate the recommendations of this report. Subsurface conditions at specific locations are summarized below. ZGA borings B-1 and B-2 both disclosed approximately 3 to 4 inches of asphalt pavement above fill material consisting of medium dense gravelly sand to depths of approximately 2 feet and 1 foot, respectively. The pavement section was underlain by fill material that typically consisted of very loose to loose fine sand with a variable silt and gravel content and lenses of very soft silt with fine sand. Most of the gravel-size material was shell fragments. Wood fibers were also observed intermittently throughout the fill. The fill extended to a depth of approximately 21 feet at both boring locations. The fill was underlain by medium dense to dense fine to medium sand with a variable silt and gravel content(advance outwash) to approximately 48.5 feet. Pre-Fraser deposits of hard silt and very dense silty fine sand extended to boring B-1's termination depth of approximately 54 feet. The advance outwash observed at Page 12