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Soil Profile and Geologic Information <br /> The Site is depicted on the Preliminary geologic map showing Quaternary deposits of <br /> the Lodi Quadrangle, California (Marchand and Atwater, 1979). The Site is depicted <br /> within a map unit of the Modesto formation upper member, described as "arkosic <br /> alluvium forming Mokelumne River alluvial fan; chiefly sand, becoming finer-grained <br /> toward fan toe; probably glacial outwash" (Plate 11). <br /> The surface and near surface soils located at the Site are reported by the USDA Web <br /> Soil Survey to be composed primarily of Acampo sandy loam (Plate 12) (USDA, 2019). <br /> The table below presents some selected properties of this soil: <br /> Table 1. Selected Properties of On-Site Soils (USDA, 1992) <br /> Soil Name Depth Unified Soil Salinity Soil Perme- Septic tank <br /> and Map (in) Class <br /> Reaction ability absorption <br /> Symbol Classification mmhos/cm pH (in/hr) fields <br /> Acampo 0-19: Sandy loam; SM <2 6.1 - 7.8 2.0 - 6.0 Moderate: <br /> sandy loam, 19-47: Sandy loam, fine sandy <2 6.6 - 8.4 2.0 - 6.0 cemented <br /> 0-2% slopes, loam, coarse sandy pan <br /> 101 loam; SM <br /> 47-49: Indurated --- --- --- <br /> 49-60. Cemented --- --- --- <br /> Note: The table descriptions do not necessarily reflect site-specific soil properties. See description of the map unit for <br /> composition and behavior characteristics of the map unit. <br /> Soil Borings <br /> In 2010, TEST performed two percolation tests for the construction of the septic system <br /> for the California Islamic Center (Appendix 4). TEST advanced two soil borings on the <br /> Site for the purpose of percolation testing. The borings were eight inches in diameter <br /> and 3.3 to 14.7 feet deep. The locations of the borings are indicated on Plate 13. <br /> According to the TEST report, sandy silt and sandy clay were encountered in the test <br /> holes; drilling logs are included in the 2010 report. On August 7, 2019, Live Oak <br /> confirmed that the surface soils in the vicinity of the septic system are sandy silt. <br /> Discussion of Soil Lithology <br /> Based on the soil present in the septic system area, there appears to be limited to <br /> moderate potential for percolation in the test locations. Sandy soils generally have a <br /> much greater potential for percolation than fine-grained or cemented soils. However, a <br /> percolation test is the only accepted method for determining the suitability of the soils <br /> for a septic disposal area. Percolation test results are discussed in the following <br /> section. <br /> LOGE 1939 Page 6 <br />