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HomeMy WebLinkAbout990900016 Geotech Assessment (2007) Addendum GeoResources, LLC Ph.253-896-1011 5007 Pacific Hwy. E, Suite 20 Fx.253-896-2633 Fife, Washington 98424-2649 April 24, 2007 The Hinkies' ~~~~p c% Olympic Ridge Inc. 15940 Lindsay Lane Poulsbo, WA 98370 ,~ ~~0~ Attn: Mr. Joe Klinker JEffEOSON COI~N~ OCR Geotechnical Consultation Single-Family Residence 50 Montgomery Court (Lot 16) Jefferson County, Washington Job:Olym picRdg.Hinkie.Montgom ery.RG This report summarizes our site observations and reviews of the NWTI geotechnical report and Maclearnsberry Engineering Stormwater Site Plan for the proposed residential site development at 50 Montgomery Ct in the Port Ludlow area of Jefferson County. Our services are provided at your request. At the time of our April 10, 2007 site visit/meeting, the site was undeveloped but generally cleared of large vegetation with the exception of several large trees at or near the top of the shoreline bluff. The proposed layout of the site is illustrated on the Site Plan attached, Figure 1. The site is located in an area of established and newer shoreline residential development. The proposed new residence and garage will be setback a minimum of 50 feet from the top of the shoreline bluff. Stormwater runoff collected from the residence and driveway will be directed to an engineered HDPE pipe system that traverses the surface of the bluff slope to the shoreline area. Based on our review of the SWPPP, it is our opinion that the proposed engineered system will not have an adverse impact on slope stability provided it is constructed in accordance with the design and the standards of practice in the Puget Sound area. Relative to the location of the pipe on the slope, we understand that the pipe near the top of the slope may be relocated to the north. Either location will work provided the same engineered systems are utilized to anchor the pipe. Any areas disturbed during constructionrnstallation should be protected from erosion and revegetated as soon as practical. Based on our site observations and document review, it is our opinion that the vegetation on or near the shoreline bluff can be managed without any adverse impacts to stability provided the following guidelines are followed: • Large trees located within 5 feet of the top of the shoreline bluff should be removed. The stumps may be left in place or removed. Where the stump is removed, the depression should be backfilled with a clean structural fill compacted to a firm and unyielding condition. • Large deciduous trees (greater than 6 inches dbh) on the bluff slope may be trimmed or cut provided the stump and root wad remains. • Large evergreen trees (greater than 6 inches dbh) on the bluff slope may be limbed to create a view corridor and reduce the effects of "windsail". • Organic debris from vegetation management should be removed from the slope area. Accumulated debris will kill the underlying or low growing vegetation. K ~ -. Y C d a u c 3 O ~V ~~ /~ '/~ ~ Y~ / ~ ~~ ~~ ' Y~ ~ ` © 4 t„// ~ Y ~ ' ~ ~ '~ w-.~ ~ i ~~ J ~ ~~~ h % ~~ ~ ...~~ ~ ~: ar „ ~ ~f c °o w ~ ,~" ' ,'~ LL°,L ~/ ~. ac ~.~ ~ ,,. ~ ./ , a d~ o~ Etta .,~ o ~ !~ .y LJ~'b _O_-~ O t~c~ Z:s ~k oa ~as~9' J ~~~ ~I-V ~~~ ~~ ~`r.° °~ ~~ti 1 1 W .~ ~"' j