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, <br /> , <br /> Geologically Hazardous Areas: Geotechnical Letter <br /> Kennedy Single Family Residence <br /> 3815 Shore Avenue <br /> March 23, 2018 <br /> RN File No, 3279-001A <br /> Page 2 <br /> of the site. A single-family residence with an attached garage currently sits within the central <br /> portion of the site, with an approximately 70 foot offset from the steep slope. The gently <br /> sloping portion of the site is vegetated <br /> mostlywith a lawn, with a concrete °'Y <br /> swimming pool adjacent to the existing ,,- <br /> residence on the northwestern side of the 4' <br /> structure. We observed a small concrete !��� `' <br /> and masonry underground cellar-like ,. <br /> structure with ventilation on the northwest t ,�� - ^', -ff <br /> side of the lot within 15 feet from the edgeto, _" <br /> of the steep slope. Above ground and <br /> adjacent to this structure is a slab-on-grade " '" ` <br /> and masonry fire pit area that we observed <br /> settling and breaking along the edge of the .-.- <br /> steep slope, see Photo 1. The landscaping � � <br /> on the south side of the lot was previously <br /> removed in preparation for demolition of " ` <br /> the existing residence. Photo 1 <br /> We observed the steep slope area (as <br /> classified and mapped by a slope >15%) '. .11.: _� <br /> and found the slope to be partially : 'fir' <br /> vegetated with deciduous trees, bushes, ,,,,, •-',.` . ,t , .l <br /> and blackberry brambles. The crest of the1$14 ,` i ` i. <br /> slope is mostly vegetated with lawn. It , . ', a< , <br /> - �< <br /> appears some surface water flows over the8 - <br /> x'S4 <br /> top of slope and onto the steep slope. This <br /> has caused some erosion and toss of .;% <br /> - <br /> vegetation along the northeastern and '- <br /> southwestern property lines. We observed m. � �� '. .. <br /> a BNSF debris wall has been installed �I �, � <br /> within the last several years at the base of 1 <br /> the slope. We observed a portion of the <br /> very steep bluff face has exposed face _ <br /> without vegetation, see Photo 2. A drain Photo 2 <br /> pipe was observed descending the slope <br /> near the southwestern property line. <br /> Geology <br /> Most of the Puget Sound Region was affected by past intrusion of continental glaciation. The <br /> last period of glaciation, the Vashon Stade of the Fraser Glaciation, ended approximately 14,000 <br /> years ago. Many of the geomorphic features seen today are a result of scouring and overriding <br /> by glacial ice. During the Vashon Stade, areas of the Puget Sound region were overridden by <br /> over 3,000 feet of ice. Soil layers overridden by the ice sheet were compacted to a much <br /> Robinson Noble, Inc. <br />