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`+ KLEINFELDER <br /> The equation is as follows: <br /> N,=AW x NW(1-D) + (Nh) <br /> AW+r <br /> Where: <br /> Nc = calculated nitrate concentration in groundwater resulting from domestic sources and <br /> precipitation—mg/l, as N <br /> A = number of dwelling units per acres on septic tanks (unit/acre) = .1 <br /> W annual wastewater loading per dwelling unit per acre (inches) = 2 inches (from <br /> Questa Report) <br /> NW = nitrate concentration of nitrified leachfield effluent (mg/1) = 60 mg/1 as N (per <br /> discussion on September 20, 2001 with EHD still within limit recommendations by <br /> Questa report but in the low range to reflect dilution effect of residential flow) <br /> D = percent dentrification of leachfield effluent = 0.25 (per discussion on September 20, <br /> 2001 with the Environmental Health Division(EHD) <br /> r = annual deep percolation of precipitation (inches) = 3.0 inches (based on 13.5 inches <br /> precipitation, 2 inches runoff and 8.5 inches ET) <br /> Nb = background nitrate concentration of the deep percolating precipitation — mg/l = 2.2 <br /> mg/1 as N <br /> Our calculation is as follows: <br /> Nc _ .1( 2)x (60) (1-.25) +2.2 (3) <br /> .1(2) +3 <br /> 9 + 6.6 =4.9 <br /> 3.2 <br /> As noted above, the measured value for Nitrate concentration in groundwater resulting from <br /> domestic sources and precipitation is 4.9 mg/L, well below the maximum allowed of 10 mg/L. <br /> LIMITATIONS <br /> The conclusions of this report are based on the information provided regarding the proposed <br /> development and on site conditions. Our work was performed in general accordance with the <br /> Standard of Care that exists in San Joaquin County. No other guarantee or warranty, expressed <br /> or implied is made. <br /> 20-4600-01/2011 L647 Page 4 of 5 <br /> Copyright 2001 Kleinfelder,Inc. October 2,2001 <br />