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November 23,2004 NOA Project Number: E040140A 2.3 Current and Future On-Site Ground Water Uses A description of the existing wells on the Site is included in Section 4.2 of the SSS. Ground water is used for domestic purposes. Surface water irrigation is available for the vineyards. 3.0 SOURCES AND IMPACT OF NITRATE TO GROUND WATER 3.1 Current Off-Site Sources of Nitrate We recognize that any septic systems, agriculture,and dairies in the area may be the most significant sources of nitrate contamination to ground water. Septic tank use in the vicinity is discussed in Section 3.4 of the SSS and is estimated to 62 systems per square mile. The ground water sample, discussed in Sections 4.4 through 4.7 of the SSS,was found to have a nitrate concentration of 3.0 mg/L-NO3. This concentration of this sample suggests that the ground water aquifer may not be experiencing a buildup of nitrate leaching from surface sources in the area. ` 3.2 Contribution of Rainfall An estimate of the quantity and quality of rainfall was required for the nitrate loading analysis. The ` estimate of deep percolation of rain is based on the average monthly precipitation of rain fall and evapotranspiration for Lodi, California. The estimate first determines whether the average monthly precipitation exceeds average monthly potential evapotranspiration. If so, then the difference is potential deep percolation. This method does not consider runoff. See Plate 10 for the data and calculation. Average potential evapotranspiration was obtained from the California Department of Water Resources, California Irrigation Management Information System (CIMIS). Lodi is located within evapotranspiration zone number 12. The average rainfall for the Lodi, CA was obtained from the ` San Joaquin Soil Survey and was 17.16 inches. Based on this method, the average deep percolation of rain for the Lodi area is estimated to be 6.84 inches. The nitrate concentration of rain fall was estimated to be 1 mg/L-N (Hantzsche and Finnemore, 1992). 3.3 Current On-Site Sources of Nitrate The potential on-site sources of nitrate consist of three sources: 1) The use of septic systems, 2) the application of fertilizers for the vineyards and, 3) the waste water generated from the winery. Our office understands from Mr. Sikeotis that the winery waste water is applied to land under a permit through the California Regional Water Quality Control Board, Central Valley District. The waste water is pumped from a tank located near the winery on the subject parcel and is applied through a sprinkler over grasses on an adjacent parcel (APN 013-050-05)which is a 35.22 acre 3