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Soil Profile and Geologic Information <br /> The Site is depicted on the Geologic and geophysical maps of the Stockton 30' x 60' <br /> quadrangle, California (Delattre, et al., 2023) as within a map unit of the Modesto <br /> Formation upper member, consisting of undivided alluvium (Plate 10). <br /> The surface and near surface soils located at the Site (Plate 11) are reported by the <br /> USDA Web Soil Survey to be composed of Tinnin loamy coarse sand (USDA, 2026). <br /> The table below presents some selected properties of this soil type: <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 /cm Reaction ability absorption <br /> Symbol (in) Classification mmhos pH (in/hr) fields <br /> Tinnin 0-28: Loamy coarse sand; SM <2 6.1-7.8 6.0-20 Severe: <br /> loamy 28-53: Loamy coarse sand, <2 6.1-7.8 6.0-20 poor filter <br /> coarse loamy sand; SM <br /> sand, 0-2% 53-75: Loamy coarse sand, <2 6.6-8.4 6.0-20 <br /> slopes, 255 loamy sand, sand; 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 April 7, 2026, Live Oak excavated a shallow soil boring near the future septic leach <br /> field area for the new house. The boring was four inches in diameter, 2.52 feet deep, <br /> and was excavated by hand auger. The location of the boring is indicated on Plate 12. <br /> The soil in the boring was similar to that described by the Soil Survey. Silty, fine sand <br /> was encountered to the full depth of the hole. The soil log is presented on Plate 13. <br /> Discussion of Soil Lithology <br /> Based on the soil observed in the boring, there appears to be good potential for <br /> percolation in the shallow soil zone. Sandy soils generally have a much greater <br /> potential for percolation than fine-grained or cemented soils. However, a percolation <br /> test is the only accepted method for determining the suitability of the soils for a septic <br /> disposal area. Percolation test results are discussed in the following section. <br /> LOGE 2618 Page 5 <br />