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FAMarch 11^,2005. <br /> NOA Project Number: E040159A <br /> j/2.3 Current and Future On-Site Ground Water Uses <br /> Fill <br /> A description of the existing wells.on the Site is included in Section 4.3 of the SSS. Ground water is <br /> currently used for residential and agricultural purposes. <br /> W- - <br /> F 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER <br />'k 3.1 Current Off-Site Sources of Nitrate <br /> !. Septic systems, agriculture;and dairies in-the area may be.the most significant sources of.nitrate. <br /> Septic tank use'in.the"vicinity is discussed in Section 3.4 was found to be moderate. .The ground <br /> water sample, dtscuss­eTin ec 'ons 4.3 through 4.6 of the SSS,was found to have a nitrate <br /> Fi concentration of . m /L= 3. This water sample tends to suggest that the ground water aquifer <br /> which the well is drawing from may not.be not.experiencing any nitrate build up.from various <br /> sources in the area over the long term. <br /> 3.2 Contribution of Rainfall <br /> F1An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The <br /> estimate of deep percolation of rain is based-on the average monthly precipitation of rain fall and <br /> Fievapotranspiration for Lodi, California.. The-estimate first determines whether the average monthly <br /> precipitation exceeds average monthly potential evapotranspiration. If so, then the difference is <br /> potential deep percolation. This method does not consider runoff. See Plate 9 for the data and <br />` calculation. = — <br /> 4 <br /> Average potential evapotranspiration was obtained-from the California Irrigaation Management <br /> Information System (CIMIS). The average monthly rainfall for the Lodi area was obtained from <br />' the USDA Soil Conservation Service, San Joaquin County, CA.. <br /> Based on this method, the average deep percolation of ra' Lodi area 's timated to be 6.84 <br /> inches. The nitrate concentration of rain fall was estimated be 1 mg/L-N (Rant sche and <br /> Finnemore, 1992). <br /> [ : 3.3 Current On-Site Sources of Nitrate <br /> Current on-site Sources of Nitrate include the current septic system. The property also contains a <br /> J vineyard. Vineyards which are regarded as low'consumers of nitrogen fertilizers. For the purposes <br /> of the nitrate estimate,we will assume that any fertilizers and irrigation are applies at agronomic <br /> "j rates. So that any leaching to ground water is iriinimal and appropriate management practices are <br /> used.'The nitrate loading study will not considerany vineyard fertilizers for the nitrate balance <br /> equation. According to Mr. Dart,.personal communication Februa-ty.22, 2005, the winery generates <br /> at most 600 gal,of waste water per y ar. He en applies this wastewater to tlne eyards. <br />