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FGROUNDWATER INFORMATION 2.1, SSS§--4.1. . Groundwater depths and elevations throughout Sab-ioaquin County are ated on maps.pub]ished by the County Flood Control and Water Conservation District. The ecent Lines of Equal Depth map (1.999) indicates the groundwater depth to be approximately t. The 2003 Lines of Equal Elevation Map illustrates the groundwater-directional flow to be generally in a.westerly direction toward the Delta. This flow direction,corresponds with on-site groundwater studies. .The most accurate!groundwater studies have occurred on-site because of monitoring of the wastewater ponds and the existing mound disposal system.-Groundwater elevation under the entire facility is extremely flat;-thus creating very-slow groundwater flows.At has been estimated by the engineering firm conducting the on-site groundwater monitoring1hat it,will take 30,000 years for the groundwater flow direction to traverse from the east end of the.facility to the west end. A Weil Log of the on-.site domestic well was not available; therefore; underlying lithology could not be discerned.. Groundwater research-in the'scientific literature-suggests there may be significant denitrification potential'within aquifers or saturated zones composed of a fine (vs. a coarse) soil fraction. Nhalyticaltest results of the domestic well reveal a nitrate concentration of 0,45 ppm, so this denitrification potential appears to be occurring. . SSS§ 2.1. Since the.part of the property that is under investigation has been intensely farmed for a number of decades andthe probability.for nitrate contamination in the underlying groundwater is significant:. The location-Where-the disposal area is to:be iristalIed is currently planted in wine- grapes, which don't require`as much nitrogen as row crops. As referenced, the water table nitrate analysis between the two sample'locations reveals a 2..6x increase.in_nitrate:concentration from the east sample location in comparison to the west sample location.-Water table nitrate concentrations appear to be directly correlated with soil nitrate nitrogen concentrations,as noted below. w NLS§.2.2;3.1, SSS§4.2. ._Water table tested constituents are illustrated below in Table 4. Test results for the water table in the east test pit show a high nitrate.concentration of 234 ppm, with an average nitrate-nitr.ogen soil concentration within the soil profile:-of 31.4 ppm. -Nitrate test results for the water table sample from.the west backhoe test pitwas 90 ppm, with an average soil profile -.nitrate-nitrogen concentration of just 11.6 ppm. Total Kjeldahl Nitrogen(TKN) was also analyzed to determine if the organic- and ammonium fractions of nitrogen are reaching the.water_table. Total "Dissolved Solids (TDS) were also high in both the east and west samples at 689 mglL and 475 mg/L, respectively. TDS has a secondary.standard of 1,000 ppm. Total alkalinity was of lower concentrations than typically seen in water table samples, at 310ppm-and'335 for the east and west samples, respectively. NLS§.2.3, SSS§ 4.3, 4.4, 4.5. The large domestic well that serves the entire Winery facility is located southeast of the:proposed disposal area, near the Winery entrance(See aerial photo, Appendix C). This well is:sampled quarterly;.with the most recent test results found in Appendix F. Selected constituents of-concern for this study, are found below in Table.5. .-LL. Chesney Consulting