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20 July 2021 AdvancedGeo Project No. 21-6486 An Employee-Owned Company Page 8 of 15 ' 5.2. SOIL LITHOLOGY AS RELATED TO FUTURE ONSITE SEPTIC USES The soil was visually described in accordance with the Unified Soil Classification System (USCS) by a representative of AGI under the supervision of a California Professional Geologist. The soil collected from the percolation test hole boring consisted of dry silty sand from surface grade to 42 inches bsg. The soil type is considered semi-permeable and should be sufficient for liquid waste disposal and treatment. 6.0. PERCOLATION TEST INFORMATION A percolation soil suitability test was performed at the site under EHD permit No. SR0083893 using a four-inch diameter soil boring established to a depth of 42 inches bsg. A site map showing the approximate location of the percolation test hole is illustrated in Figure 2. A precise description of the location and construction of the percolation test hole is included in Appendix D (EHD form 42-03 revised 11/02/2009). The soil suitability study was conducted within the area of the proposed septic system leach field. 6.1 . NUMBER OF PERCOLATION TESTS PERFORMED One shallow percolation test was performed at the site. The appropriate percolation test procedure established by the EHD was followed for the test (Procedure #3). The percolation test hole was pre-soaked overnight for 24 hours followed by a one-hour percolation testing period. 6.2. CONSTRUCTION OF PERCOLATION TEST HOLE On 30 June 2021, one boring was advanced for a shallow percolation test. The boring was advanced using a four-inch diameter hand auger to a depth of 42 inches bsg. Following borehole advancement, the sides of the boring were scraped, and loose material was removed from the borehole. Once the borehole was cleared of loose material, two inches of fine gravel was added to the bottom of the borehole and a two- inch diameter polyvinyl chloride (PVC) casing with 0.020-inch slots was installed in the borehole to perform the test. Gravel was added to the annulus of the borehole, between the borehole and the casing. The borehole was then filled with water to a depth of 12 inches above the gravel at the time of 0800. The test hole was then covered for 24 hours to allow for complete saturation of the borehole. 6.3. DESCRIPTION OF THE PERCOLATION TEST HOLE - POST SOAK On 01 July 2021, the boring was found to be completely dry, intact and in good condition.