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Geotechnical Engineering Evaluation NGA File No. 1014317 <br /> Zerzura Townhome Development November 9,2017 <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 one small-scale pilot infiltration test (PIT) within the property. The subsurface <br /> soils generally consisted of silty sand with varying amounts of gravel and cobbles that we interpreted as <br /> native glacial till soils. Based on our field testing results and the relatively silty nature of the native <br /> glacial soils encountered at depth within our explorations, it is our opinion that the site conditions are not <br /> conducive to traditional infiltration systems. However shallow infiltration systems such as bio-swales, <br /> rain gardens and pervious pavements with suitable overflow components could be feasible. These types <br /> of systems should be further discussed with the civil engineer. <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 on final 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 />