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• Soil Profile and Geologic Information <br /> The Site is mapped on the Preliminary geologic map of Cenozoic deposits of the Bellota <br /> quadrangle, California (Marchand and Bartow, 1979). It is depicted within a map unit of <br /> the Modesto formation upper member, described as "arkosic alluvium forming <br /> Mokelumne River terraces and alluvial fan; chiefly sand with minor gravel and silt; <br /> probably glacial outwash" (Plate 7). <br /> The surface and near surface soils located at the Site are reported by the Web Soil <br /> Survey (USDA, 2017) to be Tokay fine sandy loam (Plate 8). The table below presents <br /> 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) Classification mmhos/cm Reaction ability absorption <br /> Symbol pH (in/hr) fields <br /> Tokay fine 0-19 Fine sandy loam; SM <2 6.1-7.8 2.0-6.0 Slight <br /> sandy loam, 19-45 Fine sandy loam, sandy <2 6.1-7.8 2.0-6.0 <br /> 0-2% loam; SM <br /> slopes, 45-60 Fine sandy loam, sandy <2 6.1-8.4 2.0-6.0 <br /> 256 loam, coarse sandy <br /> loam; SM <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 /> On September 8, 2017, Live Oak excavated a shallow soil boring on the proposed <br /> homesite parcel of the Site for the purpose of conducting a percolation test. The boring <br /> was four inches in diameter, 3.32 feet deep, and was excavated by hand auger (Table <br /> 2). The location of the boring is indicated on Plate 9. <br /> The soil in the boring was similar to that described by the Soil Survey. Sandy silt was <br /> encountered to the full depth of the hole. The soil log is presented on Plate 10. <br /> Discussion of Soil Lithology <br /> Based on the soil observed in the boring, there appears to be moderate potential for <br /> percolation in the shallow soil zone at the test location. 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 /> • I <br /> LOGE 1721 Page 5 <br />