3610 W MUKILTEO BLVD Geotech Report 2022-10-25

Geotechnical Engineering Evaluation Zahler Residence Development 36XX West Mukilteo Boulevard Parcel No. 00433600004400 Everett, Washington INTRODUCTION This report presents the results of our geotechnical engineering investigation and evaluation of the planned Zahler Residence Development project in the Everett area of Snohomish County, Washington. The project site is located at the approximate address of 36XX West Mukilteo Boulevard in Everett, Washington, as shown on the Vicinity Map in Figure 1. The purpose of this study is to explore and characterize the site's surface and subsurface conditions and to provide geotechnical recommendations for the planned site development. For our use in preparing this report,we have been provided with a plan set titled "Edgewater Vista," prepared by Zahler Designs showing the proposed single-family residence structure. The site is currently undeveloped and vegetated with grass-covered areas and few young to mature trees bordering the property. The ground surface within the property is generally level to gently sloping. We understand that the proposed development will consist of constructing a single-family residence structure with associated driveway and underground utilities within the central portion of the property. Final development and grading plans have not been prepared at the time this report was issued. Final stormwater plans have also not been developed; however,we understand that stormwater may be directed to on-site infiltration systems, if feasible. The existing and proposed site layout is shown on the Site Plan in Figure 2. SCOPE The purpose of this study is to explore and characterize the site surface and subsurface conditions, and provide general recommendations for site development. Specifically, our scope of services included the following: 1. Review available soil and geologic maps of the area. 2. Explore the subsurface soil and groundwater conditions within the site with trackhoe- excavated test pits. NGA subcontracted the excavation services. 3. Provide long-term design infiltration rates based on on-site Small Pilot Infiltration Testing(PIT)per the 2014 SWMMWW, if feasible. One small-scale PIT was completed within`the site. 4. Complete grain size analysis laboratory testing on selected samples,as necessary. NELSON GEOTECHNICAL ASSOCIATES, INC.