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• Soil Profile and Geologic Information The Site is mapped on the Preliminary geologic map of the Tracy quadrangle, San Joaquin County, California (Diblee, 1981). It is depicted within a map unit of Holocene alluvium (Plate 7). The surface and near surface soils located at the Site are reported by the Web Soil Survey (USDA, 2017) to be composed of Stomar clay loam (Plate 8). 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 (in) Classification mmhos/cm Reaction ability absorption Symbol pH (in/hr) fields Stomar clay 0-17 Clay loam; CL <2 6.6-7.3 0.2-0.6 Severe: loam, 0-2% 17-47 Clay loam, clay; CL, CH <2 6.6-8.4 0.06-0.2 peres slowly slopes, 252 47-60 Clay loam, silty clay <2 7.4-8.4 0.2-0.6 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. Soil Borings • On July 16, 2018, Live Oak excavated shallow soil borings on the proposed new parcels of the Site for the purpose of conducting percolation tests. The borings were four inches in diameter, 3.05 and 3.25 feet deep, and were excavated by hand auger. Because the resulting percolation tests did yield acceptable percolation rates, Live Oak returned to the Site on July 23, 2018; at this time, shallow and deep borings were excavated on Parcel 1, and a deep boring was excavated on Parcel 2. These additional borings were four inches in diameter, 3.35, 9.65, and 13.68 feet deep, and were excavated by hand auger. Details of the borings are presented in Table 2; their locations are indicated on Plate 9. The soil in the borings was similar to that described by the Soil Survey. Sandy clay was encountered to a depth of approximately 10 feet below ground surface, followed by gravelly, sandy clay to the full depth of the hole. Live Oak drilled exploratory borings in several additional locations across the Site and found the soil conditions to be uniform. The soil log is presented in Plate 10. Discussion of Soil Lithology Based on the soil observed in the borings, it appears that there is limited potential for percolation in the shallow and deep soil zones at the test locations. Sandy soils generally have a much greater potential for percolation than fine-grained or cemented soils. However, a percolation test is the only accepted method for determining the • LOGE 1825 Page 4