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soils exist to the depth of the ground water aquifer, it is possible that any remaining surface contaminants may be transported to the first saturated zone of the aquifer. First ground water is predicted at 200 to 240 feet below ground surface for this Site; consequently, significant nitrate reduction would be anticipated as the septic effluent percolates downward. Sources of Nitrate Dairies, orchards that require fertilization in sandy soils, and septic systems have been found to be the most significant sources of nitrate in ground water. Percolating Recharge Waters One of the most determinant factors in the Hantzsche and Finnemore equation is the rate of recharge from percolating waters, which mix with the downward-percolating effluent generated by on-site septic systems. In the original Hantzsche and Finnemore paper, only "average recharge rate of rainfall" was considered. For the Chico area, Hantzsche and Finnemore present an average rainfall of 22.5 inches per year and an estimated recharge of 16.8 inches per year. Based on San Joaquin County Environmental Health Department policy (personal communication, March 18, 2019), the recharge input for the Hantzsche and Finnemore equation should be derived from average monthly precipitation of rainfall and evapotranspiration rates for the area; the data should be obtained from the California Irrigation Management Information System (CIMIS), preferably from stations located within San Joaquin County. Recharge is calculated by first determining whether the average monthly precipitation exceeds average monthly potential evapotranspiration. If so, then the difference is the percolating recharge water into the aquifer. Runoff and stream infiltration drainage are not factored into the calculation. This approach likely under-estimates recharge to the aquifer and, consequently, over-estimates nitrate loading. The project Site is located relatively far from any CIMIS stations (over 15 miles from the closest station within San Joaquin County) but relatively close (approximately six miles) to a station monitored by the Western Regional Climate Center (WRCC). As a result, two scenarios have been run for the Site, the first using strictly CIMIS data, and the second using a combination of CIMIS and WRCC data. Recharge Scenario 1 — CIMIS Ripon and Holt Stations For the CIMIS-only scenario, the local percolation and evapotranspiration rates obtained through CIMIS are presented in Plate 12. The closest CIMIS station to the Site is Ripon (Station 249; just over 15 miles away), followed by Holt (Station 248, approximately 16.7 LOGE 1849 Page 9