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D. CALCULATED IMPACT FROM NITRATE-NITROGEN LOADING <br /> The calculated or estimated nitrate impact to the soil and ultimately to the groundwater is extremely <br /> difficult to determine due to the number of variables involved. For example, the number of people to <br /> inhabit the primary residence and possible second unit dwelling is unknown and variable. A value of <br /> four people per household has been used, which incorporates a safety factor. <br /> The nitrate-nitrogen loading will be calculated below under two different conditions: First, only the <br /> two acres of proposed Parcel 1, with the primary residence and a second unit dwelling will be <br /> assessed. With the second calculation, the total area of Parcel 1 and the Designated Remainder will <br /> both be taken into consideration. The nitrate loading will be quantified and compared with the <br /> current nitrate concentration in the groundwater in the Conclusions section of this Report. <br /> HANTZSCHE/FINNEMORE EQ UA TION TAKING INTO CONSIDERA TION THE <br /> PRIMARYRESIDENCE ALONG WITH SECOND UNIT DWELLING ON PARCEL 1, <br /> AND EXCLUDING THE DESIGNATED REMAINDER AREA OF 4.5 ACRES: <br /> INW(1 -d. +RNb <br /> Nr (I(I+R) <br /> Where: <br /> Nr= Resultant average concentration of nitrate-nitrogen in recharge water -(ppm NO3-N) <br /> I = Volume rate of wastewater entering the soil averaged over the proposed Parcel 1 area in inches per yr <br /> Nw= Total nitrogen concentration of wastewater in N mg/L(66 mg N/L/day) <br /> d = Fraction (%)of nitrate-nitrogen loss due to denitrification in the soil <br /> R = Average recharge rate,of rainfall -inches per yr(9 in.) <br /> Nb= Background nitrate-nitrogen concentration of rainfall recharge, exclusive of wastewater influences <br /> (ppm NO3-N) <br /> Values and Assumptions: <br /> 68 gals/person/day x 4 people per household.x 21 ouses=2.00 Ac x 365 d/yr= 3.6 in/yr <br /> I— 43,560 cu ftlAc ft x 7.48 gal/cu ft z_(11ft/12 in) <br /> Nw= 66 mg/L - 10%reduction in each of 2 setic ta ks i�series 0%reduction total_53_rng/L N <br /> d = 10%from biomat and 25% from clay soil under leachlines and from the observed nitrogen decrease. <br /> Nb = Assumed to be 0.1 ppm NO3-N <br /> 3.6 in/�(53 ma NIL) (1 -0.35)+(9.0 in/yr x 0.1 mg/L) <br /> Nr = (3.6 iri/yr+9.0 in/yr) C' i-I/y/) <br /> Nr 9.9 ppm as NO3-N o 4.1�pp�s NO3 <br /> Page -9- <br /> Chesney Consulting <br />