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- LIVE OAK GEO ENVIRONMENTAL, INC. <br /> 407 W. Oak St., Lodi, CA 95240 e• (209)369-0375 :• logelodi.com <br /> March 21, 2019 <br /> Project Number: 1903 <br /> Linda Turkatte, Director <br /> San Joaquin County Environmental Health Department <br /> 1868 E. Hazelton Ave. <br /> Stockton, CA 95205 <br /> Regarding: Addendum to Nitrate Loading Study <br /> Coldani Winery & Olive Mill <br /> 13950 N. Thornton Rd., Lodi, CA <br /> Original report dated February 1, 2019 <br /> Ms. Turkatte: <br /> Based on our meeting at your office on Monday, we have prepared this addendum to <br /> the above Nitrate Loading Study. You indicated that the nitrate loading calculation for <br /> the Site should be re-evaluated using precipitation and evapotranspiration data <br /> obtained from the California Irrigation Management Information System for the past <br /> five years. <br /> As in the previous report prepared by our office, the method utilized for the nitrate <br /> loading analysis is based on a mass balance formula discussed in a published paper by <br /> Hantzsche and Finnemore (1992). The Hantzsche and Finnemore equation is a <br /> conservative approximation of ground-water nitrate-nitrogen concentration resulting <br /> from the combined effect of on-site sewage disposal systems and percolating recharge <br /> waters. <br /> For this addendum, the recharge input for the Hantzsche and Finnemore equation is <br /> derived from average monthly precipitation of rainfall and evapotranspiration rates for <br /> the area. The calculation first determines whether the average monthly precipitation <br /> exceeds average monthly potential evapotranspiration. If so, then the difference is the <br /> percolating recharge water into the aquifer. Runoff and stream infiltration drainage are <br /> not factored into the calculation. <br /> For the project Site, the local percolation and evapotranspiration rates are presented in <br /> Plate 1. The closest CIMIS station to the Site is Staten Island (station 242). Data for <br /> the Staten Island station were available for the past three years; based on the <br /> calculation shown, the estimated rate of recharge from percolating waters for the Staten <br /> Island station is determined to be 12.60 inches (Plate 1). A statistical error of 49% is <br /> associated with this value. <br /> Environmental Engineering Geology Geophysics <br />