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LOGE 1928: American Crane Rental Page 5 <br /> June 19, 2019 <br /> under-estimates recharge to the aquifer and, consequently, over-estimates nitrate <br /> loading. <br /> For the project Site, the local precipitation and evapotranspiration rates are presented in <br /> the attached Plate 1. The Site is located closest to the CIMIS Manteca station (70). <br /> Data for the Manteca station were available for 2014 through 2018; based on the <br /> calculation shown, the estimated rate of recharge from percolating waters for the <br /> Manteca station is determined to be 3.64 inches. A statistical error of 48 percent is <br /> associated with this value. <br /> The nitrate loading calculation is presented on the attached Plate 2. Inputs to and <br /> results of the calculation are as follows: <br /> Table 3. Nitrate Loading Calculation Inputs and Result, Current Project <br /> Variable Value Units Description <br /> Q 221.4 gpd Effluent flow rate <br /> Nw 85 mg/L-N Effluent stream concentration <br /> A 11.8 acres Site area (current) <br /> Nb 0.3 mg/L-N Concentration of rain (per LOGE sampling) <br /> d 0.25 constant Denitrification factor (typical rate per Hantzsche <br /> and Finnemore) <br /> R 3.64 inches per Deep percolation of rain water (CIMIS Manteca <br /> year Station) <br /> W 0.25 inches per Uniform waste water loading (calculated) <br /> year <br /> Nc 4.4 mg/L-N Result — Long-term average concentration <br /> of percolating effluent <br /> For this Site, the long-term average concentration of percolating effluent is found to be <br /> 4.4 mg/L-N when calculated as shown (Plate 2). This value is well below the US EPA <br /> recommended MCL for nitrate in drinking water of 10 mg/L-N. <br />