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Soil Suitability and Nitrate Loading Evaluation-DRAFT Page 7 of 18 <br /> Great Pacific Nut—Nut Processing Facility Expansion <br /> 3501 Lehman Road, Tracy, California <br /> May 15,2019 CTE Job#25-071 OG <br /> Two Lay. (2.5 Gal/use): 2 x 3 per day x 2.5 Gal= 15 Gal/day <br /> Two Toilets (2.0 Gal/use): 2 x 14 per day x 2 Gal =56 Gal/day <br /> Total Flow = 191 Gal/day <br /> Safety Factor(15%) =28.7 Gal/day <br /> Design Flow =219.7Gal/day <br /> I = Volume rate in Gal/day from above conderted to inches/year and averaged <br /> over the gross developed area(using 1/10 acre): <br /> 219.7 Gal/day x 365 days/year x ft3/7.48 gal x 1 acre/43,560 ft2 x 12 in/ft <br /> x 1/10 acres= 0.29 inches/year <br /> NW = Nitrate concentratio�f nitrified leach-field effluent is assumed to be on <br /> the orde o T m 1 (per previous Soil Suitability&Nitrate Loading <br /> Study repo �t&Kleinfelder, Inc., dated August 30, 2005). <br /> D = Fraction of nitrate-nitrogen to du dentrification of leach field effluent <br /> is assumed to be on the ord (of2er Hantzshe and Finnemore, 1992 <br /> 0.10 to 0.35 is typical). <br /> R = Average recharge rate due to rainfall (taken as 80%of annual 15.5 in with, <br /> ��20%assumed lost to offsite drainage &evapotranspiratign) = 12.4 in/year <br /> Nb = Background nitrate nitrogen concentration of rainfall recharge at the <br /> water table is assumed to be on the order of 0 5-mg/1'(per Technical <br /> Memorandum: "Hydrologic and Soil Investigation for the Chico Urban <br /> Area", by Dames and Moore, April 1996). <br /> Our nitrate calculation is as follows: <br /> NC _ [I(NW)(1-D)+R(Nb)] /(I+R) <br /> Nc _ [0.29(70) (1-0.20)+ 12.4 (0.5)] /(0.29+124)= 1.77 mg/1 as N <br /> The calculated nitrate (1.77 mg/L as N) for groundwater Nitrate-Nitrogen Impacts is <br /> below the State drinking water standard of 10 mg/L for nitrogen (N). <br /> 8.00ONCLUSIONS <br /> A suitable soil condition for septic percolation tests in San Joaquin County is defined as'a <br /> stratum capable of percolating water at a rate of 60 minutes per inch (min/inch) at a depth <br /> of up to 3.5 feet below existing site grade or 30 min/inch for deeper tests. CTE's <br /> percolation results for this project were 480 min/inch at a depth of up to 3.0 feet. Based <br /> SACRAMENTO • FREMONT • MODESTO <br /> INSPECTION&TESTING•GEOTECHNICAL•ENVIRONMENTAL•CONSTRUCTION ENGINEERING <br />