5228 EAST DR Geotech Report 2022-10-25

COBALT GEOTECHNICAL INVESTIGATION GEOSCIENCES EVERETT,WASHINGTON December5,2019 to Introduction In accordance with your authorization, Cobalt Geosciences, LLC (Cobalt) has completed a geotechnical investigation for the proposed residential development located at 5xxx East Drive in Everett,Washington (Figure 1). The purpose_of-the-geotechnical-investigation was to identify subsurface conditions and to provide geotechnical recommendations for foundation design, stormwater management, earthwork, soil compaction,and suitability of the on-site soils for use as fill. The scope of work for the geotechnical evaluation consisted of a site investigation followed by engineering analyses to prepare this report. Recommendations presented herein pertain to various geotechnical aspects of the proposed development, including foundation support of the new buildings and new pavements. 2.o Project Description The project includes construction of six new single-family residences, utilities, roadways/driveways, and stormwater infrastructure. Anticipated building loads are expected to be light to moderate and site grading will include cuts and fills on the order of 4 feet or less. Stormwater management will include infiltration devices, if feasible. We should be provided with the final plans when they become available. • 3.o Site Description The site is located at 51= East Drive in Everett, Washington (Figure.). , The property consists of six irregularly shaped parcels with a total area of about 1.74 acres. The eastern portion of the property is developed with a residence and detached accessory structures. There is a driveway that extends onto the property from the east. The driveway extends north through a portion of the site (Figure 2). The remainder of the property is undeveloped and vegetated with grasses, bushes,and sparse trees. A majority of the site slopes downward ffrom•south tonorth at magnitudes of•5-to io percent and relief of about 15 to 20 feet. There are steep slopes along the west and north margins of the site area that extend downward to the west and north respectively. These slopes are part of ravine systems on adjacent properties. The slopes have variable magnitudes of 3o to 6o percent with local relief of 25 to 5o feet. The slope areas are well vegetated and locally developed with utility(sewer)infrastructure. The site is bordered to the north,west,and south by undeveloped land and residential properties, and to the east by East l PO Box 82243 Kenmore,WA 98a28 ,cobaltgeoPgmailxo 206-331-1097