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Table 5. Assumptions for Nitrate Loading Calculation, <br />Theoretical Future Houses <br />Variable Value Units Description <br />Q (A,B,C,D) 500 gpd Effluent flow rate (theoretical future houses), <br />Parcels A, B, C, D <br />Nw 35 mg/L-N Effluent stream concentration <br />A (A,B,C,D) 40 acres Site area, Parcel A, B, C, D <br />Nb 0.17 mg/L-N Concentration of rain <br />0.35 constant Denitrification factor <br />9.42 inches per year Recharge rate of rainfall <br />W (A,B,C,D) 0.2 inches per year <br />Uniform waste water loading (calculated), <br />Parcels A, B, C, D <br />The details of the nitrate loading calculations are included in Plates 17 through 19. The <br />results of the three calculations are presented in the following table. <br />Table 6. Result of Nitrate Loading Calculations <br />Variable Value Units Description <br />Nc <br />(Parcels ABC) 0.2 mg/L-N <br />Long-term average concentration of percolating effluent, <br />Parcels A,B,C (no development, Plate 17) <br />Nc (Parcel D) 0.3 mg/L-N <br />Long-term average concentration of percolating effluent, <br />Parcel D (existing modular home only, Plate 18) <br />Nc <br />(Parcels A,B,C,D) 0.6 mg/L-N <br />Long-term average concentration of percolating effluent, <br />Parcels A,B,C,D (theoretical future houses, Plate 19) <br />Based on the method and assumptions described, maintaining zero development on <br />Parcels A, B, and C would result in a buildup of nitrates in the aquifer up to 0.2 mg/L-N, <br />equivalent to the measured rainwater concentration. The existing modular home on <br />Parcel D results in a calculated buildup of nitrates in the aquifer up to 0.3 mg/L-N. <br />Were two houses to be placed on each parcel, the maximum buildup of nitrates in the <br />aquifer from the use of septic systems on the Site is predicted to be 0.6 mg/L-N for each <br />parcel. This calculation assumes future houses which are not planned for the Site. <br />LOGE 2062 Page 15