1209 MADRONA AVE 2016-10-05 - Laserfiche WebLink

NELSON GEOTECHNICAL --00'0* N , A ASSOCIATEs, GEOTEOE-Itr icAL ENGINEERS a GE®LOGISTE Main Office Engineering-Geology Branch 17311—135'Avenue NE,A-500 437 East Penny Road Woodinville,WA 98072 Wenatchee,WA 98801 (425)486-1669 FAX(425)481-2510 (509)665-7696 FAX(509)665-7692 (425)337-1669 Snohomish County March 11,2013 Mr.and Mrs.Robert and Heidi Packer 1209 Madrona Avenue Everett,Washington 98203 Geotechnical Engineering Evaluation Packer Property Retaining Walls and Steep Slope Evaluation Everett,Washington NGA Pile No. 870113 Dear Mr. and Mrs.Packer: We are pleased to submit the attached report titled "Geotechnical Engineering Evaluation — Packer Property—Retaining Wails and Steep Slope Evaluation—Everett, Washington." This report summarizes the existing surface and subsurface conditions within the vicinity of the existing block retaining walls and recent slope failure, and provides recommendations for improving slope conditions. Our services were completed in general accordance with the proposal signed by you on January 18,2013. The property is currently occupied by a single-family residence within the southern portion.of the site. A steep northwest-facing slope is located to the north of the residence. The portion of the steep slope along the western property line appears to be an old ravine area. The neighboring property to the west slopes steeply down to your western property line and appears to share the steep slope area within the old ravine. Several tiers of short block retaining walls were constructed on the steep slope within the northern portion of your property over the past 10 years or so. In general, these walls appear to have experienced little to no movement since they have been constructed starting in the early 2000's. However, a small section of one of the walls that is not in the direct vicinity of the slide has experienced some settlement which you are in the process of repairing. We understand that drains have been installed behind all of the retaining walls, and the residence drains have also been tightlined into corrugated pipes that descend down the steep slope and discharge near the toe of the slope. A landslide recently occurred on the steep slope below the retaining walls on your property and your neighbor's property to the west at the end of November 2012. This Iandslide included the steep slopes on the neighbor's property above the ravine and the portion of the ravine directly below your second lowest retaining wail. The slide debris travelled toward the railroad tracks below. You informed us that landslides have occurred a few times within this area since you purchased the property in 1996. We understand that the largest landslide occurred in 1996. before any retaining walls were built or vegetation disturbed.