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Soil Profile and Geologic Information The Site is depicted on the Preliminary geologic map if the Bellota quadrangle, California (Marchand and Bartow, 1979). The Site is depicted within a map unit of the Modesto formation lower member, described as "arkosic alluvium forming Mokelumne River terraces and alluvial fan; chiefly sand; probably glacial outwash" (Plate 8). The surface and near surface soils located at the Site are reported by the USDA Web Soil Survey to be composed of San Joaquin loam, thick surface (Plate 9) (USDA, 2020). The table below presents some selected properties of this soil: Table 1. Selected Properties of On-Site Soils (USDA, 1992) Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank and Map (in) Classification mmhos/cm Reaction ability absorption Symbol pH (in/hr) fields San 0-12: Loam; CL-ML, ML <2 5.6-6.5 0.6-2.0 Severe: Joaquin 12-26: Sandy clay loam; SC <2 6.1-7.3 0.2-0.6 cemented loam, thick 26-35: Clay loam, clay; CL <2 6.1-7.8 <0.06 pan, peres surface, 0- 35-60: Indurated --- --- --- slowly 2% slopes 240. Note: The table descriptions do not necessarily reflect site-specific soil properties. See description of the map unit for composition and behavior characteristics of the map unit. Soil Borings On April 26, 2021, Live Oak excavated shallow and deep soil borings near the proposed septic disposal area of the Site for the purpose of conducting a percolation test. The borings were four inches in diameter, 3.29 and 6.31 feet deep, and were excavated by hand auger (Table 2). The location of the borings is indicated on Plate 10. The soil in the borings was similar to that described by the Soil Survey. Clayey silt with sand was encountered to approximately 1.0 feet below ground surface, followed by clay to approximately 3.0 feet, cemented sandy silt to 5.5 feet, sand with silt to 6.0 feet, and sand with clay to the full depth of the hole. The soil log is presented on Plate 11. Discussion of Soil Lithology Based on the soil observed in the borings, there appears to be limited potential for percolation in the shallow soil zone, but some potential for percolation in the deeper soil zone at the test location. Sandy soils generally have a much greater potential for percolation than fine-grained or cemented soils. However, a percolation test is the only LOGE 2125 Page 5