4518 SEAHURST AVE Geotech Report 2022-10-25

GEOTECHNICAL ENGINEERING STUDY Proposed Single-Family Residence 45xx Seahurst Avenue Everett,Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed single-family residence to be located in Everett. We were provided with a topographic site plan, a basement floor plan, and elevation views of the proposed residence. Based on these plans, we understand that the building will consist of a two- story residence with a full basement that will daylight toward the west. The east side of the residence will be 35 feet from the east edge of the property and the building will be set back 5 feet from the north property line. We expect that a retaining wall on the order of 10 feet tall will be constructed on the east side of the residence. If the scope of the project changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this report are warranted. SITE CONDITIONS SURFACE The Vicinity Map, Plate 1, illustrates the general location of the trapezoidal-shaped site in Everett. The site is bordered to the east by Seahurst Avenue, and is otherwise surrounded with residences. The site is vegetated with young to mature evergreen and deciduous trees and brush. The eastern portion of the site has the shape of the upper portion of a small ravine which extends into the adjacent northern property and drains toward the west. The ground surface in the eastern 20 to 30 feet of the site slopes gently down toward the west to the top of a steep slope. The steep slope has a height of about 8 feet, and appears to have been created by the placement of fill for the adjacent Seahurst Avenue. West of the base of the steep slope, the ground surface declines gently to moderately toward the west. We expect that the steep eastern slope is considered landslide hazard area per City of Everett code due to the presence of uncontrolled fill and the height and inclination of the slope. An asphalt driveway is located along the south edge of the site, and provides access to residences to the west. In the eastern portion of the site, near the location of the proposed residence, the ground surface north of the driveway slopes moderately a few feet down toward the north, likely the result of fill that was placed to support the driveway. South of the driveway from about 60 to 130 feet west of Seahurst Avenue the ground slopes steeply down toward the north, likely caused by an excavation for the driveway. This steep slope extends into the adjacent property to the south. The ground surface immediately north of the east half of the site has a similar surface as the site, but about 10 to 20 feet north of the property line the ground slopes steeply about 10 to 15 feet upward to the north. This south-facing slope extends into the subject site near the midpoint of its northern edge, and extends as much as 40 feet into the west portion of the site. GEOTECH CONSULTANTS,INC.