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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, shallow septic system utilizing leach lines or a <br /> filter bed. <br /> A satisfactory soil percolation rate of 5.56 min/in was observed in the shallow soil zone <br /> at the test location. The soil in the test location was found to be silty sand and silty <br /> organic clay. <br /> Based on maps reviewed, depth to ground water at the Site is anticipated to be less <br /> than 10 feet below ground surface; the Site is beyond the mapped area for both years <br /> reviewed. Ground water depth and flow direction in the Delta area are highly dependent <br /> on seasonal pumping and irrigation. <br /> Because of the percolation rate between 5.0 and 30.0 min/in encountered in the test <br /> hole, the San Joaquin County Environmental Health Department will require an eight- <br /> foot separation from the bottom of the dispersal system to ground water. <br /> A water sample was collected from the domestic well on the Site as part of this <br /> investigation. No nitrate or DBCP was detected in the sample. <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 5.8 mg/L, well below the MCL <br /> of 10 mg/L-N. No nitrate mitigation is recommended. <br /> LOGE 20-36 <br /> Page 13 <br />