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CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the project Site has been found suitable for the use of standard septic <br /> systems. A satisfactory soil percolation rate of 6.76 min/in was observed in the shallow <br /> soil zone at the test location. The soil in the test location was found to be silty clay and <br /> silty clay with fine sand. <br /> The depth of ground water based on recent aquifer levels is approximately 68 to 90 feet <br /> below ground surface. The ground-water flow beneath the Site is to the east or <br /> northeast at a rate of approximately 12 to 17 feet per mile. <br /> Because the percolation rates encountered fall between 5.0 and 30.0 min/in, the San <br /> Joaquin County Environmental Health Department will require an eight-foot separation <br /> from the bottom of the dispersal system to ground water. Based on the anticipated <br /> depth to water beneath the Site, this requirement should not necessitate any <br /> modification to standard systems. <br /> No wells are on the Site; no water sample was collected as part of this investigation. <br /> Based on the method and assumptions described, the nitrate loading calculation <br /> indicates that the use of on-site septic tanks and drain field systems on the Site has the <br /> potential to cause a buildup of nitrate in the aquifer up to 9.9 mg/L-N, below the US EPA <br /> drinking water recommendation of 10 mg/L-N. Because of the favorable result of the <br /> nitrate loading calculation, no nitrate mitigation is recommended. <br /> LOGE 20-44 Page 12 <br />