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I E, `,. KLEINIFFLDER Ft EXPECT MORE Our calculation that includes both the proposed temple and the existing home is follows: = - 3x27(35)(1-0.2) + 8.0(0.5) = 8.48 mgll as N Nr_ (Y27 + 8.0) 1N�t,\k Given the above factors, we estimate that the proposed Grace Christian Church would require an average waste/sewage flow of 12,640 gal./week in order to exceed the state drinking water standard for nitrogen (N) of 10 mg/l in groundwater. We have also used the Hantzsche mass balance equation (source: Predicting -` Groundwater Nitrate-Nitrogen Impacts, Hantzsche and Finnemore (1992)), which is presented below, to help predict the nitrate loading taking into consideration a square mile of development around the proposed Grace Christian Church. •r C NC = __I(N,)(1-D) + R(Nb) + - AWN, (1-D) + R(Nb) (I+R) AW + R � d�J ` Where/ e rage calcu ed nitrate-nitrogen in groundwater resulting from leach field source and precipi 'on - mg/l, as N. Volume rate of waste watering e soil averaged over the gross developed a I - area = 3.27 Inches per ye ,r (talc laced as follows: ((9,800 gal/week x 52 ` weeks/year x 0.1337 cubic ft/g '1)1(5.74 cres x 43,560 sq ft/acre)) x 12 inches/ft) Nitrate concentration of nitrified leach-field effluent (mg/1) = 35 mg/1 (The Hantzsche Nw _ and Finnemore (1992) technical paper indicates that the average total nitrogen concentration in septic tank effluent ranges from 35 to 45 mg/l. This range was also reported in the 1996 Dames and Moore technical memorandum.) Fraction of nitrate-nitrogen loss due to dentrification of leach field effluent = 0.2 percent (Per Hantzsche and Finnemore (1992), 0.10 to 0.35 is typical). The 0.2 D = value was selected given that groundwater in the project area is relatively shallow and the subsurface soils are fine grained and will not easily allow infiltration of � effluent fluenf to the groundwater er year (representing 8o percent of1 Average recharge rate of rainfall = 8ir0 incyes p0 i inches. The remaining 20 percent the average annual rainfall o pp R = of rainfall is assumed to drain off-site into natural or manmade drainages or be lost to evapotranspiration-) Background nitrate nitrogen concentration Hydrologic andhSogl Investigatioe at the en for the 0.5 mgll (per Technical Memorandum, Y Nb e 6, Dames and Moore, April 1996) ' T Chico Urban Area, pag W r! ti March 5,2007 page 6 of 8 78311.G0115To7R193 O 2007 Kieinfelder,Inc.