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Nitrate Loading Estimate <br />A nitrate loading analysis was performed to determine the impact of using treated effluent for Project <br />irrigation on local ground water. The Uniform wastewater loading value (W) could be reduced to <br />account for transpiration, but was not adjusted to reflect this factor. Thus, the calculated nitrate <br />concentration (Nc) is conservative. The analysis uses assumptions as previously discussed. <br />Table 3.1 provides a summary of assumptions used for the nitrate loading calculations. A more detailed <br />review of assumptions and calculations is provided in Appendix E, Summary of Calculations. <br />The results of the nitrate loading, or long term average concentration of percolating effluent, Nc, as <br />calculated using the Hantzsche and Finnemore equation, are presented in Table 3.2. <br />Table 3.2 - Result of Nitrate Loading Calculation <br />✓ariable <br />Table 3.1- Assumptions for Nitrate Loading Calculation <br />Units <br />Variable <br />Value <br />Units <br />Description <br />Long-term average concentration of percolating <br />Q <br />46,110 <br />gpd <br />Sewage effluent flow rate <br />Nw <br />mg/L-N <br />Effluent nitrogen concentration <br />.1�1 <br />bUl 1(Ain ci <br />A <br />282 <br />acres <br />Watershed area <br />nG -�a Ca <br />Nb <br />1.0 <br />mg/L-N <br />Concentration of rain <br />d <br />25% <br />unitless <br />Denitrification factor <br />R <br />1.18 <br />inches per year <br />Deep percolation of rain water <br />W <br />2.20 <br />inches per year <br />Uniform waste water loading for calculation <br />The results of the nitrate loading, or long term average concentration of percolating effluent, Nc, as <br />calculated using the Hantzsche and Finnemore equation, are presented in Table 3.2. <br />Table 3.2 - Result of Nitrate Loading Calculation <br />✓ariable <br />Value <br />Units <br />Description <br />Nc <br />5.24 <br />mg/L-N <br />Long-term average concentration of percolating <br />Conclusion and Recommendations <br />The US EPA Primary Drinking Water Standards set the maximum contaminant level (MCL) for nitrate in <br />drinking water at 10 mg/L as nitrogen (45 mg/I NO3). According to the calculations based on the <br />Hantzsche and Finnemore equation, nitrate concentrations due to the proposed project are projected to <br />be approximately 5.24 mg/L as N. Actual nitrate loading is expected to be lower due to transpiration and <br />nutrient absorption from plants, grasses, and trees. <br />71Paee <br />M <br />