1901 W MUKILTEO BLVD Geotech Report 2022-10-25

• Scriven Residence Improvements-REVISED NGA File No 974316 1901 West Mukilteo Boulevard November 29,2016 Everett,Washington Page 3 SITE CONDITIONS Surface Conditions The site consists of a roughly rectangular-shaped parcel covering approximately 0.26 acres. The site is occupied by a one-story, single-family residence with a partial daylight basement within the relatively level to gently sloping upper southern portion of the site. A level lawn area is located to the north and east of the residence along the top of a steep north-facing slope. The residence is currently setback approximately 20 feet from the top of the steep slope while the existing deck along the northwest corner of the residence extends from the residence to the top of the steep north-facing slope. The slope below the residence descends from the residence area to the railroad tracks below at gradients in the range of 20 to 35 degrees (36 to 70 percent). The overall height of the slope is approximately 80 feet. A profile of the existing ground surface and the interpreted subsurface conditions is presented in Cross Sections A-A' in Figure 3. The steep slope is generally vegetated with grass, thick underbrush, and blackberries. We did not observe significant signs of deep-seated slope movement during our site visit. We observed an overgrown railroad tie and concrete rubble wall along the top of the slope during our visit. It appears that fill was placed behind this wall and below the wall on the surface of the slope. We did observe some minor amounts of sloughing and movement of the undocumented fill on the slope immediately below the wall near the top of the slope. The railroad tie wall to the northeast of the residence also appeared to be leaning in a downhill direction. We did not observe surface water during our site visit on October 24, 2016. However, we did observe some significant groundwater seepage near the toe of the steep slope. Due to the dense vegetation along the surface of the steep slope we were unable to observe where the groundwater seepage was emitting from the slope area. The property is bordered to the north by the Burlington Northern and Santa Fe Railway railroad tracks and Puget Sound, to the east and west by residential properties, and to the south by West Mukilteo Boulevard. The site layout within the vicinity of the residence is shown on the Schematic Site Plan in Figure 2. We observed that drainage associated with the roof drains around the residence appear to be directed to underground pipes. We were unable to delineate where these pipes were being directed to during our site visit. We did observe a 4-inch diameter plastic pipe along the top of slope below the deck connected to a corrugated pipe that was directed down the slope. This pipe appears to daylight within the lower portion of the sloping area. NELSON GEOTECHNICAL ASSOCIATES, INC.