1915 W MUKILTEO BLVD 2018-01-02 MF Import

NELSON GEOTECHNICAL N A ASSOCIATES, INC. GEOTECHNICAL ENGINEERS & GEOLOGISTS Main Office 17311 — 135" Avenue NE, A-500 Woodinville, WA 98072 (425) 486-1669 • FAX (425) 481-2510 (425) 337-1669 Snohomish County July 26, 2006 John and Dolores Robinson 1915 North Mukilteo Boulevard Everett, WA 98203 Geotechnical Engineering Evaluation and Slide Repairs 1915 Mukilteo Boulevard Everett, Washington NGA File No. 743206 Dear Mr. and Mrs. Robinson: Engineering -Geology Branch 112 Olds Station Road, Suite C Wenatchee, WA 98801 (509) 665-7696 (Phone/Fax) We are pleased to submit the attached report titled "Geotechnical --ngineering Evaluation and Slide Repairs — 1915 Mukilteo Boulevard - Everett, Washington." This report summarizes the existing surface and subsurface conditions within the site and provides recommendations for the repair and stabilization of the site's failing slopes. Our services were completed in general accordance with the proposal signed by Dolores Robinson on May 16, 2006. The site is situated on gently to steeply sloping ground on the north side of Mukilteo Boulevard overlooking Possession Sound. A single-family residence currently occupies the site. A moderate to steep slope is located within the site and wraps around the northern and eastern sides of the residence. The upper portion of the slope adjacent to the residence has experienced major slope movement during the past winter. As a result of slope movement, an exposed near vertical scarp has formed directly below the top of the slope along the northern side of the residence with tension cracks and subsidence developed above the scarp. The portion of the slope northeast and east of the residence is also showing signs of movement as evident by tension cracks and subsidence in these areas, although major scarps or exposed surfaces were not noted. We monitored the drilling of two geotechnical borings near the top of the slope. Our explorations indicated that the area near the top of the slope consisted of loose soil with competent native transitional beds material encountered at depth. We also observed the material on the slope below the affected areas and found loose debris that resulted from the recent slide along with older loose soils that might have resulted from past slope activity and/or grading operations above the slope. Based on our explorations and site observations, it is our opinion that permanent stabilization of the site slope and prevention of further slope movement would require massive retaining walls and/or major slope buttressing and regrading. Based on our discussions with you, we understand that you desire to improve the slope stability conditions using more feasible methods. Your goal is to reduce the potential and rate of future slope movement to lessen the adverse impacts on your backyard and residence, without incurring the major expenses that would otherwise be associated with the more elaborate stabilization `�� i