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NITRATE LOADING CALCULATIONS <br />According to the articles by Hantzsche & Finnemore 1992, “Predicting Ground-Water <br />Nitrate-Nitrogen Impacts” (see Appendix E References) the expression for the resultant <br />average concentration, nr, of nitrate-nitrogen in recharge water is given by: <br />nr = I nw (1 – d) + R nb <br />(I + R) <br />I = volume rate of wastewater entering the soil averaged over the gross developed <br />area, in inches per year <br />nw = total nitrogen concentration of wastewater, in milligrams per liter <br />d = fraction of nitrate-nitrogen loss due to denitrification in the soil <br />R = average recharge rate of rainfall, in inches per year <br />nb = background nitrate-nitrogen concentration of rainfall recharge at the water table, <br />exclusive of waste-water influences, in milligrams per liter <br />I = Q / A multiplied by a conversion factor of 0.01344 acre • inch • day <br /> year • gallon <br />Using the values presented in Table 3 – Assumptions for Nitrate Loading Calculations, <br />the resulting calculation follows: <br />I = 250.0 gpd x 0.01344 acre-inch-day = 5.895 inches per year <br />0.57 acres year-gallon <br />nr = 5.895 • 35 ( 1 – 0.25 ) + 10.98 ( 1.00) = 9.819 mg per L-N <br /> (5.895 + 10.98) <br />BAEZ GEOTECI-INICAL GROUP <br />PLATE 3