12815 19TH AVE SE Geotech Report 2022-10-25

Silver Lake Elementary School Subsurface Exploration, Geologic Hazard, Building Additions, Service Drive, and Water Line Installation and Geotechnical Engineering Report Everett, Washington Pro'ect and Site Conditions engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. 2.0 PROJECT AND SITE DESCRIPTION The project site consists of the existing Silver Lake Elementary School property located at 12815 19'h Avenue SE in Everett, Washington. We understand that current plans call for a new 8,205-square-foot building addition at the east end of Building C, a smaller, 1,000-square- foot building addition east of the cafeteria, a new water line loop along the south, east, and north edges of the property, and a new service drive north and east of the existing buildings. Site topography within the proposed improvement areas is relatively flat to gently sloping. The area planned for the larger building addition is surfaced with asphalt concrete. The smaller building addition location is surfaced with grass. The areas where the service drive and water line will be constructed are surfaced with either asphalt or grass. 3.0 SUBSURFACE EXPLORATION Our field study included advancing five new exploration borings (EB-5 through EB-10) to gain subsurface information within the proposed development areas. Logs from EB-1 through EB-4 from our 2003 report have also been included in this report. The various types of sediments, -.. as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in the Appendix. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. Our explorations were approximately located in the field by measuring from known site features shown on the Site and Exploration Plan, Figure 2. The conclusions and recommendations presented in this report are based on the exploration borings completed for this and the previous study. The number, locations, and depths of the explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. November 8, 2006 ASSOCIATED EARTH SCIENCES, INC. SOB/id-KE02599B2-Projeas120020S991KELWP Page 2