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07/13/2006 08:24 FAX - Background nitrate nitrogen concentration of rainfall recharge at the water Nt, = table = 0.5 mg/I (per . Technical Memorandum, Hydrologic and Soil ' Investigation for the Chico Urban Area, page 6, Dames and Moore, April 1996) ' Our calculation that includes both the proposed temple and the existing home is as follows: 2.76 45 10.2) + (9_2)(0.5) __ = 8.7 mg/l as N N` (2.76 + 9.2) ' Given the above factors, we estimate that the facility would require an average waste/sewage flow over 10,200 gal./week in order to exceed the state drinking water standard for nitrogen (N) of 10 mg1l 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 Sikh Temple. N a 1 Nw 1-D + R Nh + AWN„, (1-D�+ c (I+R) AW + R Where: ' Na = Average calculated nitrate-nitrogen in groundwater resulting from leach field ' source and precipitations-mg/!, as N. I = Volume rate of waste water from the proposed Sikh "Temple entering the soil ' averaged over the gross developed Sikh Temple area = 2.76 Inches per year(calculated as follows: (8,400 gal/week x 52 weeks/year x 0.1337 cubic ftlgaly(5.83 acres x 43,560 sq ft(acre)x 1 fi/12 inches)) ' N, = Nitrate concentration of nitrified leach-field effluent (mg/1) = 45 mg/I (The Hantzsche and Finnemore (1992) technical paper indicates that the average ' total nitrogen concentration in septic tank effluent ranges form 35 to 45 mg/I, This range was also reported in the 1996 Dames and Moore technical memorandum, Accordingly, our assumed value is considered conservative.) ' D - 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 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 to the groundwater 7132.1.G01/ST06R759 July 13,2006 tCopyrigrd 2006 Kleinteldor,Irc. 1