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recharge within the County (personal communication with Rodney Estrada, Lead <br /> REHS, January 6, 2017). <br /> As discussed above, the average of the four surrounding stations yields an <br /> annual rainfall value of 12.78 inches (Table 3). Assuming 75 percent of this <br /> precipitation percolates to the aquifer, the rate of recharge from percolating <br /> waters is calculated to be an average of 9.6 inches per year. <br /> • Regional Recharge from Percolating Waters: In 2018, the Eastern San <br /> Joaquin Groundwater Authority (ESJGA) commissioned a comprehensive <br /> ground-water model covering parts of San Joaquin County, northern Stanislaus <br /> County, and southern Sacramento County. In the model, percolating recharge <br /> waters throughout the Eastern San Joaquin subbasin (portion of the model area) <br /> were evaluated; a value of 650,000 acre-feet was used for ground-water <br /> recharge throughout the subbasin. This value was derived after numerous model <br /> calibration runs. By dividing 650,000 acre-feet by the total acreage of the <br /> subbasin (772,376 acres), and converting to inches, a regional rate of recharge <br /> from percolating waters throughout the subbasin was found to be 10.1 inches per <br /> year. This value should be viewed as an average for the subbasin area. <br /> Calculated Rates of Recharge from Percolating Waters for Project Site <br /> • The following table summarizes the values for rate of recharge from percolating waters <br /> obtained from the methods discussed above for the project Site: <br /> Table 5. Rates of Recharge from Percolating Waters for Site <br /> Method Result (in.lyr.) <br /> 100 Percent Rainfall 12.78 <br /> Evapotranspiration Reduction 2.65 <br /> Reduced Rainfall 9.6 <br /> Regional Recharge from Percolating Waters 10.1 <br /> For this Site, the average rate of 9.6 inches per year of recharge from percolating <br /> waters obtained through the reduced rainfall method has been selected. This value <br /> compares favorably with the predicted rate of recharge from percolating waters <br /> throughout the Eastern San Joaquin subbasin of 10.1 inches. The other two values are <br /> believed to over- and under-estimate recharge. <br /> • LOGE 1901 Page 12 <br />