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PHYSICAL SETTING Topography The elevation of the Site, according to a United States Geological Survey topographic map, is approximately 75 feet above mean sea level (Plate 3). The Site is relatively flat. Geology The Site is mapped on the Geologic map of the San Francisco-San Jose quadrangle, California (Wagner, et al., 1991). It is depicted within a map unit of alluvial fan deposits (Plate 4). Soil Analysis Chemical and Physical Properties of the Soil The surface and near surface soils located at the Site are reported by the Web Soil Survey (USDA, 2020) to be composed of Capay clay (Plate 5). The table below presents some selected properties of this soil type: Table 1. Selected Properties of On-Site Soils (USDA, 1992) Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank and Map Reaction ability absorption Symbol (in) Classification mmhos/cm pH (in/hr) fields Capay Clay, 0-20: Clay; CH, CL <4 6.6 - 8.4 0.06 - 0.2 Severe: wet, 0-2% 20-44: Clay, silty clay: CH, CL <4 6.6 - 8.4 0.06 - 0.2 peres slowly slopes, 121 44-60: Silty clay loam, clay <4 6.6 - 8.4 0.06 - 0.2 loam: CL 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. The soil encountered on the Site was similar to that described by the Soil Survey. On May 18, 2020, Live Oak collected a sample of surface soil near the proposed leach field area; the soil was found to be silty clay. Mass Transport Soil Properties The soil type will allow limited infiltration of water through the surface soils. The longer the effluent remains near the surface, the more biologic treatment may occur. In a situation where permeable soils exist to the depth of the aquifer, it is possible that any remaining surface contaminants may be transported to the first saturated zone of the aquifer. LOGE 20-21 Page 2