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project. The following table summarizes the assumptions for the nitrate loading <br /> calculation for the Site, as presented in Plate 16. <br /> Table 4. Assumptions for Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Q 350 gpd Effluent flow rate <br /> Nw 35 mg/L-N Effluent stream concentration <br /> A 2 acres Area <br /> Nb 0.103 mg/L-N Concentration of rain <br /> d 0.25 constant Denitrification factor <br /> R 8.75 inches per year Recharge rate of rainfall <br /> W 2.4 inches per year Uniform wastewater loading, calculated <br /> The details of the nitrate loading calculation are included in Plate 16. The result of the <br /> calculation is presented in the following table. <br /> Table 5. Result of Nitrate Loading Calculation <br /> Variable Value Units Description <br /> Nc 5.6 mg/L-N Long-term average concentration of percolating effluent <br /> The US EPA recommended MCL for nitrate in drinking water is 10 mg/L-N. In a worst- <br /> case situation, the maximum buildup of nitrate in the aquifer from the use of septic <br /> systems on the Site is predicted to be 5.6 mg/L-N. <br /> Discussion of Nitrate Loading Results <br /> Total Nitrate Impact <br /> Based on the method and assumptions described, the result of the nitrate loading <br /> estimate indicates that future development on the Site should not cause a buildup of <br /> nitrate in the aquifer over the MCL of 10 mg/L-N. Because of the favorable result of the <br /> calculation, no nitrate mitigation is recommended at this time. <br /> LOGE 2622 Page 12 <br />