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• Soil Profile and Geologic Information <br /> The Site is depicted on the Preliminary geologic map of the Tracy Quadrangle, San <br /> Joaquin County, California (Diblee, 1981). The Site is depicted within a map unit of <br /> Holocene alluvium (Plate 7). <br /> The surface and near surface soils located at the Site are reported by the USDA Web <br /> Soil Survey to be composed of Capay clay, 0 to 2 percent slopes (Plate 8) (USDA, <br /> 2013). 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 Reaction ability absorption <br /> Symbol (in) Classification mmhos/cm pH (in/hr) fields <br /> Capay clay, 0-20: Clay: CH, CL <2 6.6 - 8.4 0.06 - 0.2 Severe: <br /> 0-2% 20-60: Clay, silty clay: CL, CH <2 6.6 - 8.4 0.06 - 0.2 peres slowly <br /> slopes, 118 <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 August 29, 2016, Live Oak excavated a shallow soil boring on the Site for the <br /> purpose of conducting a percolation test. The boring was four inches in diameter, 3.35 <br /> feet deep, and was excavated by hand auger. The location of the boring, approximately <br /> 150 feet north of the proposed septic disposal area, is indicated on Plate 9; this location <br /> is a result of changes in the location of the proposed septic disposal area over the <br /> course of the project. Because the Soil Survey reports the soils across the Site to be <br /> uniform, the percolation test is anticipated to represent soil conditions at the septic <br /> disposal area. <br /> The soil in the boring was within the range of what would be anticipated based on the <br /> Soil Survey data reviewed. At the percolation test location, sandy clay was encountered <br /> to the full depth of the boring. The log for the soil boring is presented in 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 of the surface soils. Sandy soils generally have a much greater potential for <br /> percolation than fine-grained or cemented soils. However, a percolation test is the only <br /> accepted method for determining the suitability of the soils for a septic disposal area. <br /> Percolation test results are discussed in the following section. <br /> • LOGE 1623 Page 4 <br />