10627 19TH AVE SE COOLEY SMILES DENTISTRY 2019-03-18

° Geotechnical Engineering Evaluation Cooley Smiles Commercial Development 10627, 10709, and 10711 — 19th Avenue SE Everett, Washington INTRODUCTION This report presents the results of our geotechnical engineering investigation and evaluation of the planned commercial development project located at 10627, 10709, and 10711 — 19th Avenue SE in Everett,Washington, as shown on the Vicinity Map in Figure 1. The proposed development consists of three separate parcels. The ground surface within each of the properties is generally level to gently sloping. The northern parcel is occupied by an existing single- family residence. The central parcel is occupied by an existing commercial business structure. The southern parcel is occupied by an existing garage structure. We understand that the proposed development will likely include removal of all of the site structures and construction of two new commercial structures along the western portions of the properties along with associated pavement parking areas and underground utilities. For our use in preparing this report,we were provided with a site plan titled"Cooley Smiles Dental Clinic-Everett," dated June 15, 2017,prepared by Gabbert Architects, showing the proposed site conditions. Specific grading and stormwater handling plans were not available at the time this report was prepared. However, we do understand that stormwater generated within the property may be directed to onsite infiltrations systems, if feasible. The existing and proposed site conditions are shown on the Site Plan in Figure 2. SCOPE The purpose of this study was to explore and characterize the site surface and subsurface conditions, evaluate infiltration capacity of the on-site soils, and provide general recommendations for the planned development. Specifically,our scope of services included the following: 1. Review available soil and geologic maps of the area. 2. Explored the subsurface soil and groundwater conditions within the site with trackhoe excavated test pits. Trackhoe was subcontracted by NGA. 3. Perform grain-size sieve analysis on soil samples, as needed. 4. Provide recommendations for earthwork,foundation support, and slabs-on-grade. 5. Provide recommendations for retaining walls. 6. Provide recommendations for temporary and permanent slopes. NELSON GEOTECHNICAL ASSOCIATES, INC.