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Nelson Geotechnical17311-135" Ave. N.E. Suite A-500 NELSON GEOTECHNICAL Woodinville, WA 98072 (425) 486-1669 ASSOCIATES, INC. www.nelsongeotech.com April 2, 2021 Mr. Garth Hitchens 3380 — 126`h Avenue NE Bellevue, Washington 98005 c/o Mr. Robin Kearsley — Kearsley Homes Dry Season Grading Extension Letter Hitchens Residence Development 17901 Vista Del Mar Drive Edmonds, Washington NGA File No. 1065318 Dear Mr. Hitchens: This letter presents our opinions and recommendations regarding wet -season earthwork construction at the Hitchens Residence development project located at 17901 Vista Del Mar Drive in Edmonds, Washington. We understand that grading activities on this site will take place during the wet season (October 1, 2020 to April 30, 2021) and therefore, you plan to apply for a dry season grading extension. We were provided a copy of the site development plans and the proposed construction schedule during the wet season. We understand we will be retained to monitor construction activities on a part-time basis including verification of erosion and sedimentation control measures. We understand demolition of the existing infrastructure is currently planned for April 12, 2021 and drilled pier installation on April 19, 2021, provided relief from wet weather grading activities is granted. Based on our review of the provided plans and grading activity description, all construction equipment will remain on site, all exposed surface soils will be covered with straw or similar erosion control material, and that silt fences and other erosion control materials will be installed and regularly maintained to minimize soil and or muddy water movement from the site. Based on the grading activity schedule provided by you, we understand that earthwork and significant grading activities will begin approximately 11 days prior to the sanctioned dry grading months. In our opinion, the above -mentioned erosion control measures should provide adequate protection 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. Dry Season Grading Extension Letter Hitchens Residence Development Edmonds, Washington NGA File No. 1065318 April 2, 2021 Page 2 In our opinion, provided the planned construction activities are completed in general accordance with the project plans and our daily recommendations during construction, beginning grading activities prior to April 30, 2021 for this project should not result in adverse impacts or environmental harm to the surrounding vicinity. ••• NELSON GEOTECHNICAL ASSOCIATES, INC. Dry Season Grading Extension Letter Hitchens Residence Development Edmonds, Washington NGA File No. 1065318 April 2, 2021 Page 3 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, NELSON GEOTECHNICAL ASSOCIATES, INC. Alex B. Rinaldi, LG Project Geologist Khaled M. Shawish, PE Principal ABR:KMS:dy NELSON GEOTECHNICAL ASSOCIATES, INC.