9606 19TH AVE SE PREMIER STORAGE Geotech Report 2022-10-25

Premier Storage Everett, LLC ES-2432 June 26, 2012 Page 3 Revised June 28, 2012 Subsurface An ESNW representative observed, logged and sampled two borings advanced within the proposed development envelope using drill rig and operator retained by our firm. ESNW also reviewed a boring log included in the referenced geotechnical report prepared by ADaPT. The approximate locations of the borings are depicted on the Boring Location Plan (Plate 2). Please refer to the test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Fill Fill was encountered at the boring locations extending to depths of between about four to six feet at boring locations B-1 and B-2, respectively. The fill consisted primarily of loose silty sand and silty sand with gravel (Unified Soil Classification SM) and silty gravel with sand (GM). Based on the topography at the site, and the surface conditions described in the referenced ADaPT report, the fill appears to have been placed some time after 1999 in order to increase level space on the site. Topsoil Topsoil was not observed at the boring locations; however topsoil may be present in areas which are not currently developed with asphalt pavement or gravel surfaced roadways. Native Soil Underlying the fill, native soils consisting primarily of medium dense to very dense silty sand and silty sand with gravel (SM) and silt with sand (ML) glacial till deposits were encountered extending to the maximum exploration depth of 16.5 feet below existing grades (ESNW) and 39.25 feet (ADaPT). Geologic Setting The referenced geologic map resource identifies glacial till (Qvt) and advance outwash (Qva) deposits across the site. The referenced NRCS soil survey identifies Alderwood Urban Land Complex (Map Unit 5) across the site. The Alderwood urban land complex soils represent modified areas which were part of regional grading operations. The native soil conditions observed at the test pit locations are generally consistent with glacially consolidated till or advance outwash deposits. Groundwater Minor perched groundwater was reported by ADaPT at boring location B-1 at a depth of about 38 feet below existing grade during the fieldwork (October 1999). Seepage should be expected in grading activities at this site, particularly during the winter, spring and early summer months. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the wetter, winter months. Earth Solutions NW, LLC