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Geotechnical Engineering Evaluation NGA File No. 1008917 <br /> Cooley Smiles Commercial Development October 3,2017 <br /> Everett,Washington Summary-Page 2 <br /> We also performed on-site infiltration testing in accordance with the Department of Ecology 2012 <br /> Stormwater Management Manual for Western Washington, as amended in 2014. Our on-site testing <br /> consisted of performing three small-scale pilot infiltration tests (PITs) within each of the properties. The <br /> subsurface soils generally consisted of silty sand with varying amounts of gravel and cobbles that we <br /> interpreted as native glacial till soils. Based on our field testing results and the relatively silty nature of <br /> the native glacial soils encountered at depth within our explorations, it is our opinion that the site <br /> conditions are not conducive to traditional infiltration systems. However shallow infiltration systems <br /> such as bio-swales, rain gardens and pervious pavements with suitable overflow components could be <br /> feasible. These types of systems should be further discussed with the civil engineer. We also include <br /> recommendations for erosion control, site preparation and grading, structural fill, foundations, retaining <br /> walls and site drainage in this report. <br /> In the attached report, we have also provided general recommendations for site grading, slabs-on-grade, <br /> structural fill placement, retaining walls, erosion control, and drainage. We should be retained to review <br /> and comment onfinal development plans and observe the earthwork phase of construction. We also <br /> recommend that NGA be retained to provide monitoring and consultation services during construction to <br /> confirm that the conditions encountered are consistent with those indicated by the explorations,to provide <br /> recommendations for design changes should the conditions revealed during the work differ from those <br /> anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with <br /> contract plans and specifications. <br /> We appreciate the opportunity to provide service to you on this project. Please contact us if you have any <br /> questions regarding this report or require further information. <br /> Sincerely, <br /> NELSON GEOTECHNICAL ASSOCIATES, INC. <br /> Khaled M. Shawish,PE <br /> Principal <br />