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Soil Borings On June 16, 2021, Live Oak excavated a shallow soil boring near the proposed septic disposal area of the Site for the purpose of conducting a percolation test. The boring was four inches in diameter, 2.13 feet deep, and was excavated by hand auger (Table 2). The location of the boring is indicated on Plate 10. The soil in the boring was similar to that described by the Soil Survey. Silty sand was encountered to the full depth of the hole. Gravel and plastic sheeting were observed in the test hole as well; these may be due to backfill from past environmental remediation activities. The soil log is presented on Plate 11. Discussion of Soil Lithology Based on the soil observed in the boring, there appears to be moderate potential for percolation in the shallow soil zone at the test location. 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 suitability of the soils for a septic disposal area. Percolation test results are discussed in the following section. Percolation Test A shallow percolation test was conducted in the proposed septic disposal area of the Site. The soil boring discussed above was used for the percolation test hole. Percolation test procedures conformed to San Joaquin County Environmental Health Department policy. Preparation and Presaturation of Percolation Test Holes After the boring was advanced by hand auger and the soil logged, the test hole was completed for the percolation testing. Approximately two inches of pea gravel were placed in the bottom of the open soil boring, followed by a 2.0-inch diameter PVC pipe with perforations on the bottom. Pea gravel was then used to backfill a few inches of the annular space. Live Oak presaturated the percolation test hole approximately 24 hours prior to the percolation testing. The hole was filled with water to a height of 12 inches above the bottom of the boring for the presaturation. On the day of testing, the hole was found to be intact and dry. LOGE 2130 Page 5