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CALCULATED NITRATE-NITROGEN LOADING <br /> NLS§3.3,3.4,3.5,3.6. The calculated nitrate-nitrogen impact to the soil and potentially to the <br /> groundwater is difficult to determine due to the large number of variables involved and variables <br /> unknown at this time. These include: 1.) Impact from upgradient agricultural and septic system <br /> sources, 2.) Variability in wastewater flows, nitrogen concentrations and dilution effects from <br /> stormwater recharge, 3.) Changes in groundwater directional flow and elevation, 4.) <br /> Denitrification potential within the loam and clay soil fractions, and within confined and/or <br /> unconfined aquifers. <br /> The Hantzsche/Finnemore Formula is used in this report to predict the average resultant <br /> concentration of nitrate-nitrogen in effluent recharge water. As calculated below,the property has <br /> been assessed on a total areal loading basis correlated with the total projected yearly wastewater <br /> flow volumes calculated above. These two factors primarily estimate the average resultant <br /> concentration of nitrate-nitrogen in the recharge water. This concentration should not exceed 10 <br /> ppm nitrate-nitrogen(45 ppm as nitrate). <br /> Calculated nitrate-nitrogen loading: <br /> IN„0 -d)+RNb <br /> Nr= (I+R) <br /> Where: <br /> Nr = Resultant average concentration of nitrate-nitrogen in recharge water-(ppm NO,-N) <br /> I = Volume rate of wastewater entering the soil averaged over the gross developed area in inches per yr <br /> Nw = Total nitrogen concentration of wastewater in mg N/L <br /> d = Fraction N)of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate of rainfall-inches per yr NLS§3.2 <br /> Nb = Background nitrate-nitrogen concentration of rainfall recharge,exclusive of wastewater influences <br /> (ppm NO3-N)- <br /> Values and Assumptions: <br /> I=840 x 365 d/yr=306,600 gals=total WW/Yr=40,989 cu ft =7.73 in/yr <br /> 46 Ac x 43,560 sq ft/Ac x (1 ft/12 in) <br /> Nw=62 mg /L <br /> d = Assume 15%from the fine-grained loam fraction of the soil. <br /> R = 11 in/yr. <br /> Nb= Assumed to be 0.1 ppm NO3-N <br /> 7.74 in/yr(62 mg N/L) (1 -0.15)+(11 in/yr x 0.1 me/L) <br /> Nr = (7.73 in/yr+ 11 in/yr) <br /> Nr = 21.8 ppm as nitrate-nitrogen (NO3-N)or 98.3 ppm as nitrate (NO3) <br /> Page -6- <br /> Chesney Consulting <br />