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geotech wet season plan.pdf September 29, 2016 Mr. Derek Abbott th Place SW 221–185 Bothell, Washington98012 Dry Season Extension Letter Abbott Residence Place West 16404–75 th Edmonds, Washington NGA File No. 9175B16 Dear Mr.Abbott: This letter presents our opinionsand recommendations regarding wet-season earthwork construction atthe th Place West in Edmonds, Washington.We understand that Abbott Residenceproject located at 16404-75 grading activities on this site willtake place during the wet season(September30, 2016 through April 30, 2017), and therefore, you plan to apply for a dry seasongradingextension.Wewere provideda copy of the site TESC plan and theproposed construction schedule during the wet season. We have reviewed the providedTESCplan andthe proposedwet-season grading activity scheduleand concluded that the proposed scope for dry-season extension isappropriate for this project. Based on our review of thesite TESC planand grading activity description, we understand that all exposed cuts and soil stockpiles will be covered with plastic, all constructionequipment will remain on site, all exposed surface soils will be covered with strawor similar erosion control material, and that silt fences and other erosion control materials will beinstalledand regularly maintained to minimize soiland or muddy watermovement from the site.Tall cut excavations will also be supported with soldier pile shoringwalls where temporary slope excavations cannot be sloped, as recommended in our previous report. Based on the grading activity schedule provided by your contractor, we understand that grading activities will take approximately ten to twelveweeks upon grading beginning. Dry Season Extension Letter NGA File No. 9175B16 Abbott ResidenceSeptember 29, 2016 Edmonds, WashingtonPage 2 _______________________________________________________________________________________ In our opinion, these erosion control measures should provide adequateprotection during the wet season. NGA should be retained to observe erosion control measures and provide recommendations for additional erosion control measures as needed during construction.Also, all recommendations provided in our previous report should be strictly followed during construction. In our opinion, provided the planned construction activities are completed in general accordance with the project plans and our daily recommendations during construction, extending grading activities beyond September 30, 2016for this project should not result in adverse impacts or environmental harm to the surrounding vicinity. We appreciate the opportunity to provide service to you on this project. If you have any questions or require further information,please contact us. Sincerely, N ELSON GEOTECHNICAL ASSOCIATES, INC. Khaled M. Shawish, PE Principal LSB:KMS:dy NELSON GEOTECHNICAL ASSOCIATES, INC.