9702 19TH AVE SE Geotech Report 2024-03-28

Pacific Ridge — DRH, LLC ES-7829.01 August 26, 2021 Page 6 Based on the results of our study, there are no seismic or liquefaction hazard areas identified within 200 feet of the subject site. DISCUSSION AND RECOMMENDATIONS General In our opinion, construction of the proposed residential development is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed project include earthwork, temporary excavations, structural fill requirements, subgrade preparation, foundations and soil bearing capacity, slab-on-grade support, utility support and trench backfill, and drainage. The site is proposed to be developed with townhome building pads, access drives, and a stormwater detention vault. Mass grading activities will include cuts and fills of up to 18 feet and constructing Lock and Load retaining walls. New structural fill should be placed on competent soil. Given the condition of the existing fill on the site, remedial measures will be necessary where existing fill underlies new development. Such remedial measures will likely consist of reworking and compacting the existing fill and/or excavation and replacement with structural fill. If earthwork activities occur during wet weather, additional drainage measures, cement treatment of native soil, and/or the use of select fill material will likely be necessary. After completing earthwork activities in accordance with recommendations in this report, the proposed structures can be supported on conventional spread and continuous foundations bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. This study has been prepared for the exclusive use of Pacific Ridge — DRH, LLC and its representatives. A warranty is neither expressed nor implied. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Site preparation activities should consist of installing temporary erosion control measures and performing site stripping (as necessary) within the designated clearing limits. Subsequent earthwork activities may involve additional mass grading and infrastructure and utility installations. Earth Solutions NW, LLC