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10 May 2021 <br />Project No. 21-6390 <br />Page 6 of 14 <br />was utilized to advance three (3) percolation test holes to 42 inches bsg (P-1 and P-3) <br />and 36 inches bsg (P-2) in the proposed septic system disposal field area. <br /> <br />A plan of the specific site features including the percolation test hole locations <br />(i.e., structures, drives, wells, septic systems, large trees, pastures, pools, natural <br />drainage courses, ponds, waterways, etc.) is illustrated in Figures 2 through 6. <br /> <br /> <br />5.1. SOIL PROFILE PIT INCLUDING DEPTH AND DIMENSIONS <br /> <br />The percolation test holes were all located in the disposal field area of the proposed septic <br />system. The initial percolation test hole (P-1) was advanced to a depth of 42 inches bsg <br />and the subsequent percolation test holes were advanced to total depths of 36 inches <br />bsg (P-2) and 42 inches bsg (P-3) using a four-inch diameter hand auger (Figure 6). <br /> <br /> <br />5.2. SOIL LITHOLOGY AS RELATED TO FUTURE ONSITE SEPTIC USES <br /> <br />The soil was visually described in accordance with the Unified Soil Classification System <br />(USCS) by a representative of AGI under the supervision of a California Professional <br />Geologist. The soil collected from the percolation test hole borings consisted of dry, very <br />compacted, silty sand from surface grade to approximately 42 inches bsg. The soil type <br />is considered semi-permeable to impermeable and is not sufficient for liquid waste <br />disposal and treatment. <br /> <br /> <br />6.0. PERCOLATION TEST INFORMATION <br /> <br />A percolation soil suitability test was attempted at the site under EHD permit No. <br />SR0083519 using a four-inch diameter soil boring established to a depth of 36 inches <br />bsg. Initially, one soil boring (P-1) was established to a depth of 42 inches bsg on 21 April <br />2021 to perform a percolation soil suitability test. On 22 April 2021, two additional borings <br />were established to depths of 36 inches (P-2) and 42 inches bsg (P-3) to perform a <br />percolation soil suitability test. A site map showing the approximate location of the <br />percolation test holes is presented in Figure 6. A precise description of the location and <br />construction of the percolation test hole is included in Appendix D (EHD form 42-03 <br />revised 11/02/2009). The soil suitability study was conducted within the area of the <br />proposed septic system leach field. <br /> <br /> <br />6.1. NUMBER OF PERCOLATION TESTS PERFORMED <br /> <br />One shallow percolation test was performed at the site using test hole P-2. The <br />appropriate percolation test procedure established by the EHD was followed for the test <br />(Procedure #2). The percolation test hole was pre-soaked overnight for 24 hours followed