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— KLEINFELDER <br /> Test Soil Test Hole Percolation SJCEHD <br /> Number Description Depth ft. Rate min./inch Approved <br /> P-1 Sandy Silt 4'/2 11.9 Yes <br /> P-2 Silty Sand 10 20.8 No <br /> P-3 Silty Sand 15 5.4 Yes <br /> P-4 Silty Sand 3'/4 20.8 Yes <br /> 9. NITRATE LOADING CALCULATIONS <br /> Per SJCEHD requirements, the following summarizes our nitrate loading calculations <br /> for the proposed leach field. The state drinking water standard for nitrate is 45 <br /> milligrams per liter (NO3) and 10 mg/I as Nitrogen (N) in groundwater. In our <br /> evaluation of nitrate loading, we have used the Hantzsche mass balance equation <br /> (source: Predicting Groundwater Nitrate-Nitrogen Impacts, Hantzsche and Finnemore <br /> (1992)), which is presented below. <br /> Nc = l(Nw)(1-D) + R(Nb) <br /> (I+R) <br /> The selection of parameters used in the equation was based on previous studies and <br /> investigations performed by our firm and others, San Joaquin County Sewage <br /> Standards, previous Communications with Mr. Mike Huggins and Mr. Rodney Estrata <br /> with SJCEHD, and information provided in a report dated March 19, 1997 prepared by <br /> the Questa Engineering Corporation and authored by Mr. Hantzsche for a <br /> development in the Stockton area. <br /> Nc = Average calculated nitrate-nitrogen in groundwater resulting from leach field <br /> source and precipitation — mg/I, as N. <br /> I = Volume rate of waste water entering the soil averaged over the gross <br /> developed area = 1.69 inches per year (calculated as follows: (7,580 <br /> gal/week x 52 weeks/year x 0.1337 gal/cubic ft)/(8.6 acres x 43,560 sq <br /> ft/acre) x 12 inches/ft)) <br /> Nw = Nitrate concentration of nitrified leach-field effluent (mg/1) = 70 mg/I ((Based <br /> on conservations with Mr. Mike Huggins with SJCEHD. The Hantzsche and <br /> Finnemore (1992) technical paper indicates that the average total nitrogen <br /> concentration in septic tank effluent ranges form 35 to 45 mg/I. This range <br /> was also reported in the 1996 Dames and Moore technical memorandum. <br /> Accordingly, our assumed value is considered conservative.) <br /> 59149.G01/ST05R1062 December 15,2005 <br /> Copyright 2005 Kainfelder, Inc. Page 5 of 7 <br />