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{� 1 n <br /> CONCLUSIONS AND RECOMMENDATIONS <br /> In summary, the soil conditions examined near the location of the septic system drain <br /> field appear to be suitable. A satisfactory soil percolation rate of 24 minutes per inch <br /> was observed near the drain field area. <br /> The depth of ground water based on recent aquifer levels is relatively deep and <br /> approximately 80 to 90 feet below the ground surface. The ground water flow direction <br /> is to the south-southeast at a rate of 10 to 20 feet per mile. <br /> The on-site domestic water well was tested for nitrate and DBCP. The nitrate <br /> concentration in ground water was found to be 7.1 mg/L-NO3, which is well below the <br /> maximum contaminant drinking water limit of 45 mg/L-NO3. DBCP was detected at 0.60 <br /> pg/L, significantly above the MCL set by the US EPA of 0.2 pg/L. It is recommended <br /> that the owner of the Site consult with the San Joaquin County Environmental Health <br /> Department regarding the best methods to mitigate the DBCP. <br /> The use of on-site septic tanks and drain field systems on the Site is not expected to <br /> cause a buildup of nitrate in the aquifer above 3.84 mg/L-N, which is well below the US <br /> EPA drinking water recommendation of 10 mg/L-N. In fact, the actual impact to the <br /> aquifer will be much less since the equation is conservative and overestimates impacts. <br /> We believe the Site suitable for development with the use of standard septic systems. <br /> We do not anticipate that the ground water quality will be negatively impacted, primarily <br /> due to the low calculated nitrate level. No nitrate mitigation is recommended. <br /> LOGE0911 Page 14 <br />