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CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the soil conditions examined near the proposed septic disposal area for the <br /> new home on the Site were found to be suitable for a septic system. A satisfactory soil <br /> percolation rate of 4.63 min/in was observed in the shallow soil zone at the test location. <br /> The soil in the test location was found to be silty clay. <br /> Based on maps of recent aquifer levels, the depth of ground water is approximately 70 <br /> to 130 feet below ground surface. Ground water flows generally northeast or northwest <br /> in the area at a rate of approximately 10 to 65 feet per mile. <br /> Because of the percolation rate between 1.0 and 5.0 min/in encountered in the test <br /> hole, the San Joaquin County Environmental Health Department will require a 20-foot <br /> separation from the bottom of the dispersal system to ground water. Based on the <br /> estimated depth to ground water, no modifications to septic systems should be <br /> necessary to comply with this requirement. <br /> The domestic well on the Site is not currently operational; no water sample was <br /> collected for this investigation. <br /> Based on the methods and assumptions described, the nitrate loading calculation <br /> indicates that the existing and proposed future on-site septic drain field systems have <br /> the potential to cause a buildup of nitrate in the aquifer up to 13.7 mg/L-N, over the MCL <br /> of 10 mg/L-N. It should be remembered that the Hantzsche and Finnemore equation is <br /> a conservative method for determining potential impacts. Ground water is deep in the <br /> area, and the clay soils may serve to limit the transportation of nitrate to the aquifer. <br /> Consequently, the actual nitrate loading experienced on the Site over time may be less <br /> than predicted. <br /> Although Live Oak cannot make engineering recommendations, we are aware that the <br /> San Joaquin County Environmental Health Department often allows the use of standard <br /> septic systems with oversized septic tanks in cases where a 30 percent reduction would <br /> bring the nitrate loading under the MCL; the subject Site's nitrate loading result meets <br /> this criterion. <br /> Future septic system construction should follow the San Joaquin County On-Site <br /> Wastewater Treatment Systems Standards (2017) where applicable. <br /> LOGE 2610 Page 14 <br />