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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 septic system utilizing leach lines with seepage <br />pits. A satisfactory soil percolation rate of 11.90 min/in was observed in the deep soil <br />zone at the test location. The soils in the test location were found to be a mixture of silt, <br />sand, and clay. <br />The depth of ground water based on recent aquifer levels is approximately 120 to 131 <br />feet below ground surface. The ground -water flow is to the south at a rate of <br />approximately 6 to 11 feet per mile in the vicinity of the Site. <br />A water sample was collected from the domestic well on the Site as part of this <br />investigation. Nitrate was detected in the sample at a concentration of 1.2 mg/L-N, well <br />below the MCL of 10 mg/L-N. The DBCP results have not yet been received from the <br />laboratory; they will be forwarded as soon as they are available. Based on maps <br />reviewed, neither nitrate nor DBCP appears to be a problem in nearby wells. <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 5.4 mg/L, well below the <br />maximum drinking water standard of 10 mg/L-N. Because of the favorable result of the <br />nitrate loading calculation, no nitrate mitigation is recommended at this time. <br />LOGE 2147 Page 15 <br />