Laserfiche WebLink
CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the soil conditions examined near the proposed septic system drain field <br /> were found to be suitable for a standard septic system utilizing leach lines and seepage <br /> pits. <br /> A satisfactory soil percolation rate of 17.86 min/in was observed in the deep soil zone at <br /> the test location. The soils in the test location were found to include strata of clay, silt, <br /> and sand. The percolation test is considered representative of soils within a 100-foot <br /> radius of the test location. <br /> Based on maps reviewed, ground water is anticipated to be encountered approximately <br /> 80 to 90 feet below ground surface at the Site. The ground-water gradient beneath the <br /> Site is to the northeast at a rate of approximately 8 to 10 feet per mile. <br /> Because of the percolation rate between 5.0 and 30.0 min/in encountered in the deep <br /> test hole, the San Joaquin County Environmental Health Department will require an <br /> eight-foot separation from the bottom of the dispersal system to ground water. Based <br /> on the anticipated depth to ground water, no modifications to standard septic systems <br /> should be required. <br /> A water sample was collected from the domestic well on the Site. Nitrate was detected <br /> at a concentration of 4.1 mg/L-N, well below the MCL of 10 mg/L-N. DBCP was not <br /> detected in the sample. Neither nitrate nor DBCP appears to be a significant problem in <br /> nearby wells, according to water testing maps reviewed. <br /> Based on the methods 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 4.5 mg/L, well below the MCL <br /> of 10 mg/L-N. As a result, no nitrate mitigation is recommended. <br /> LOGE 20-56 Page 13 <br />