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

Pacific Ridge — DRH, LLC ES-7829.01 August 26, 2021 Page 2 Project Description The subject site is located at 9702 and 9620 — 19th Avenue Southeast in Everett, Washington, as depicted on Plate 1 (Vicinity Map). The proposed development area consists of two tax parcels (Snohomish County parcel numbers 2805180040-3000 and -3200) totaling approximately 4.93 acres. The site will be developed with 13 townhome building pads, a stormwater detention vault, access drives, and associated improvements is proposed. The proposed development area is located east of the existing stockpile, and is located approximately within the existing site improvement areas within the eastern portion of the site. Based on the referenced plans, mass grading will consist of cuts of up to about 2 to 4 feet and fills of up to about 16 to 18 feet. Lock and Load retaining walls up to about 16 to 18 feet in height will be constructed along the southwest side of the development and up to about 4 to 6 feet along the northwest side. At the time of report submission, specific building load values were not available for review; however, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads of about 1 to 2 kips per linear foot and slab-on-grade loading of 150 pounds per square foot (psf) will be incorporated into the final design. If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations provided in this report. ESNW should review the final design to confirm that our geotechnical recommendations have been incorporated into the final plans. SITE CONDITIONS Surface The site is currently developed with two commercial buildings, a maintenance shop, and associated improvements; the western portion of the site is lightly forested. The site topography gently descends to the west; a knoll feature is located within the northwestern portion of the site, comprised of stockpiled fill material. The site is bordered to the north and south by commercial buildings, to the east by 19th Avenue Southeast and to the west by Interstate 5. Subsurface As part of the subsurface exploration, five test pits and four borings were advanced at accessible locations of the site for the purpose of assessing the soil and groundwater conditions using an machines and operators retained by ESNW. The test pits were advanced to depths of approximately five to nine feet below the existing ground surface (bgs). The borings were advanced to a maximum exploration depth of 30.5 feet bgs. Please refer to the boring and test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Earth Solutions NW, LLC