Laserfiche WebLink
Sources of Nitrate <br /> Septic systems and dairies in the area have been found to be the most significant <br /> sources of nitrate in ground water. Orchards that require fertilization in sandy soils are�� 2�3 <br /> also a significant source of nitrate contamination in shallow or sandy aquifers in San <br /> Joaquin County. <br /> Contribution of Rainfall <br /> An estimate of the quantity and quality of rainfall was required for the nitrate loading <br /> analysis. An estimate of the deep percolation of rain was based on a calculation using <br /> average monthly precipitation of rainfall and evapotranspiration rates for the area. The <br /> calculation first determines whether the average monthly precipitation exceeds average <br /> monthly potential evapotranspiration. If so, then the difference is potential deep <br /> percolation. This method does not consider runoff. Based on the calculation shown in <br /> the following table, the estimated deeC4.17 <br /> of rain (recharge) for the South <br /> Stockton, California area is estimated toinche . 6. <br /> Table 3. Estimate of Deep PercolRainfall for South Stockton, CA. <br /> Average Rain- Average Potential Potential Deep <br /> Month Fall (inches) Evapotranspiration (incites) Percolation of Rain <br /> (inches) <br /> January 2.85 0.90 1.95 <br /> February 2.27 1.73 0.54 <br /> March 2.06 3.38 None <br /> April 1.12 5.04 None <br /> May 0.41 6.45 None <br /> June 0.08 7.54 None <br /> July 0.03 8.02 None <br /> August 0.04 7.11 None <br /> September 0.27 5.19 None <br /> October 0.72 3.33 None <br /> November 1.78 1.60 0.18 <br /> December 2.36 0.86 �15g <br /> Totals 14.00 51.15 4,17 <br /> Notes: CIMIS evapotranspiration information at wwwcimis.water.Ga.gov/cimis/for station 70 (Marr infall <br /> average from station 048558(Stockton WSO)at www.w=.dri.edu.Closest available stations to Site were selected. <br /> LOGE1025 Page 8 <br />