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

z- NELSON GEOTECHNICAL � ► ASSOCIATES, INC. GEOTECHNICAL ENGINEERS&GEOLOGISTS Main Office Engineering-Geology Branch 17311-135t'Ave NE,A-500 5526 Industry Lane,#2 Woodinville,WA 98072 East Wenatchee,WA 98802 (425)486-1669•FAX(425)481-2510 (509)665-7696-FAX(509)665-7692 October 3, 2017 Mr. Brandon Cooley EPC Holdings 908,LLC 18031 —67th Avenue NE Kenmore,Washington 98028 Geotechnical Engineering Evaluation Cooley Smiles Commercial Development 10627, 10709,and 10711 -19t'Avenue SE Everett,Washington NGA File No. 1008917 Dear Mr. Cooley: We are pleased to submit the attached report titled "Geotechnical Engineering Evaluation— Cooley Smiles Commercial Development— 10627, 10709, and 10711 —19th Avenue SE— Everett, Washington." This report summarizes the existing surface and subsurface conditions within the site and provides general recommendations for the proposed site improvements. Our services were completed in general accordance with our proposal signed by you on September 1,2017. 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. Specific grading and stormwater plans were not available at the time this report was prepared. However,we understand that stormwater generated within this site may be directed to on-site infiltration systems,if feasible. We explored the subsurface soil and groundwater conditions on September 15, 2017 with six trackhoe- excavated test pits, and three small-scale pilot infiltration tests (PITs). In general, the test pits encountered medium dense to very dense silty fine to medium sand with gravel that we interpreted as native glacial till soils to the depths explored. It is our opinion that the proposed site development is feasible from a geotechnical engineering standpoint, provided that our recommendations for site development are incorporated into project plans. In general,the native glacial till soils underlying the site should adequately support the planned structures. Foundations should be advanced through the loose soils down to the competent glacial material interpreted to underlie the site, for bearing capacity and settlement considerations. These soils should generally be encountered approximately one to three feet below the existing ground surface,based on our explorations. If undocumented fill is encountered in unexplored areas of the site, it should be removed and replaced with structural fill for foundation and pavement support.