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Table 5. Result of Nitrate Loading Calculations <br />Variable Value Units Description <br />Nc (Parcel 1) 3.1 mg/L-N Long-term average concentration of percolating effluent, <br />Parcel 1 (potential future houses) <br />Nc (Parcel 2) 3.2 mg/L-N Long-term average concentration of percolating effluent, <br />Parcel 2 (potential future houses) <br />Nc (Parcel 3) 2.9 mg/L-N Long-term average concentration of percolating effluent, <br />Parcel 3 (existing houses) <br />Nc (Parcel 4) 3.2 mg/L-N Long-term average concentration of percolating effluent, <br />Parcel 4 (potential future houses) <br />Based on the method and assumptions described, the existing homes on Parcel 3 result <br />in a calculated buildup of nitrates in the aquifer up to 2.9 mg/L-N. <br />Were two houses to be placed in the future on each currently vacant parcel, the <br />maximum buildup of nitrates in the aquifer from the use of septic systems is predicted to <br />be 3.1 mg/L-N for Parcel 1 and 3.2 mg/L-N for Parcels 2 and 4. For any parcel <br />remaining undeveloped, the predicted nitrate loading will be equivalent to the nitrate <br />concentration of rainwater, 0.15 mg/L-N; this calculation has been presented in previous <br />reports. <br />The US EPA recommended MCL for nitrate in drinking water is 10 mg/L-N. The results <br />of the nitrate loading calculation for each parcel are well below maximum drinking water <br />standard. <br />Discussion of Nitrate Loading Results <br />Total Nitrate Impact <br />Based on the method and assumptions described, the results of the nitrate loading <br />estimates indicate that the proposed development on the Site should not cause a <br />buildup of nitrates in the aquifer over 10 mg/L-N. Because of the favorable result of the <br />nitrate loading calculations, no nitrate mitigation is recommended at this time. <br />LOGE 2153 Page 14 <br />