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WASTE DISCHARGE REQUIREMENTS ORDER R5-2012-0103 - 16 - CONSTELLATION BRANDS U.S. OPERATIONS, INC. dba WOODBRIDGE WINERY WOODBRIDGE WINERY SAN JOAQUIN COUNTY 1 µmhos/cm UP = Upgradient of facility CG = Cross gradient of facility and Land Application Areas DGP = Downgradient of wastewater ponds DGLA = Downgradient of land application area CGLA = Crossgradient of land application area DQWLA = Downgradient of winery and land application area 47. Monitoring wells MW -1, MW -2, and MW -3 consistently have lower TDS concentrations, as compared to the other monitoring wells associated with the facility. Average TDS concentrations in MW-1, MW -2, and MW -3 are 61 mg/L, 288 mg/L, and 138 mg/L, respectively. According to the April 2006 Groundwater Characterization Report, TDS concentrations in the Mokelumne River generally range from 20 mg/L to 50 mg/L, with only a few concentrations reported over 60 mg/L in the data collected since 1960. Because groundwater consistently flows away from the Mokelumne River to the north/northwest, the infiltrating river water strongly affects groundwater quality at the facility, providing a continuous supply of high quality (low TDS) groundwater. 48. Determining background groundwater quality is complicated due to the close proximity of the Mokelumne River and agricultural nature of the local area. Monitoring wells MW -12 and MW-14 are considered representative of background conditions unaffected by winery activities. Well MW-12 is upgradient of the discharge areas and is approximately 1,400 feet north of the Mokelumne River; Well MW -14 is crossgradient of winery activities and is approximately 4,000 feet north of the Mokelumne River. These two monitoring wells are considered representative of ambient groundwater at varying distances from the river. The following table summarizes statistical analysis of key salinity constituents for the two background groundwater monitoring wells. Analyte Units MW-12 MW-14 Mean 95% UCL 95% UTL Mean 95% UCL 95% UTL EC µmhos/cm 157.4 165 201 541 560 614 TDS mg/L 170.5 182 240 394 404 450 TKN mg/L <0.2 -- -- <0.2 -- -- NO3-N mg/L 1.2 1.3 2.0 7.9 8.5 10 Sulfate mg/L 4.3 -- -- 48 -- -- Chloride mg/L 7.4 -- -- 21 -- -- Sodium mg/L 9.6 -- -- 33 -- -- UCL = Upper Confidence Limit for the mean. UTL = Upper Threshold Limit for the data set. -- Insufficient data set Review of the statistical analysis presented above indicates that the downgradient water quality recharged from the Mokelumne River increases in salinity as it migrates through the aquifer, independent of the winery activities but not necessarily independent of local agricultural activities. It is expected that with longer residence times in the shallow aquifer, groundwater will become more saline.