Laserfiche WebLink
28 September 2022 AdvancedGeo <br />Project No. 22-6994 An Employee Owned Compony <br />Page 14 of 15 -" <br />EXISTING AND PROPOSED HOME CALCULATIONS: <br />Nr= I x Nw(1-d)+Rx Nb=(I+R) <br />Assumptions: <br />I = 127,750 gallons = 17,079 cubic feet wastewater _ [(0.979 acres x 43,560 feet2) - 12 <br />inches] = 17,079 - 3,554 = 4.81 inches/year <br />NW = 45 mg/L-N <br />d = 40 percent denitrification <br />R = 3.54 inches/year <br />Nb = 1.0 milligram per liter <br />Nr = [4.81 inches/year x 45 mg/L-N (1-0.40)] + (3.54 inches/year x 1.0 milligram per liter) <br />(4.81 inches/year + 3.54 inches/year) <br />Nr= 133.41 =8.35= 15.97 <br />Nr = 15.97 ppm nitrogen (NO3_N) <br />9.7. IMPACT OF NITROGEN LOADING FROM SITE PROJECT TO <br />DOWNGRADIENT WATER SOURCES <br />The recharging of groundwater is the most likely potential feature that could impact future <br />nitrogen loading. Since the subject property is flat, AGI does not anticipate percolating <br />effluent will affect any nearby water sources. Based on the volume of wastewater to be <br />generated and the depth to groundwater (110-120 feet bsg), the potential vertical <br />migration would not likely degrade the local groundwater. A total of 15.97 ppm of <br />additional nitrogen is estimated to be added to the site over the long term through <br />wastewater recharge from the proposed septic system. The nitrogen loading value is <br />above the desired value of 10 ppm. <br />10.0. TOTAL NITRATE IMPACT FROM PROPOSED PROJECT <br />Based on the method and assumptions described, proposed NO3_N mass of wastewater <br />and the calculations of the NO3_N loading predicted, the proposed development may <br />negatively impact NO3_N loading rates within the aquifer. The soil at the site appear to <br />be adequate for nitrate degradation and proper leaching of wastewater. A total of <br />15.97 ppm of additional nitrogen is estimated to be added to the site over the long term <br />through wastewater recharge from the proposed septic system. <br />11.0. MITIGATION METHODS PROPOSED <br />To mitigate any known or potential future impacts of nitrate to soil and groundwater from <br />the proposed septic system, the following mitigations could be implemented: <br />