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Kennedy/Jenks Consultants <br /> MW-7 are both located downgradient from the vineyards irrigated with treated process water, <br /> sanitary wastewater septic tank and leachfield systems, and the ponds. <br /> As can be seen in Figure 5, groundwater gradient contours are steeper near the Mokelumne <br /> River and flatten out as distance from the river increases indicating the river is discharging water <br /> into the surrounding groundwater. Section 4.6 discusses proposed additional investigation <br /> activities that will help assess the impact of the Mokelumne River on the groundwater <br /> monitoring network. <br /> Concentration versus time plots as presented in Figures 7 through 14 suggest a majority of the <br /> constituents sampled in the monitoring wells exhibit decreasing concentrations with <br /> groundwater gradient and distance from the river. Three possible explanations for the onsite <br /> water quality conditions are: <br /> 1. Constituent levels onsite are influenced by existing and past practices of surrounding <br /> offsite agricultural and wastewater discharge activities. <br /> 2. Elevated levels of TDS, nitrate and TKN are reflective of the process water management <br /> system. <br /> 3. Variable concentrations found in downgradient wells and upgradient wells are due to <br /> dilution effects of the Mokelumne River. Concentration levels inferred from the figures <br /> suggest that the Mokelumne River is likely discharging into shallow groundwater and <br /> resulting in lower levels of EC and TDS for wells closest to the river (MW-1,2, and 3, <br /> Figures 8 & 9) because of groundwater dilution. <br /> Because of the effects of the river, such interpretation of groundwater quality based only on the <br /> concentration plots and groundwater elevations from onsite monitoring wells is questionable. It <br /> is then crucial to characterize the quality of offsite groundwater to then be able to quantitatively <br /> assess and reasonably explain the likely relationship between offsite groundwater constituents <br /> and their migration paths beneath the site and possible co-occupancy with constituents found <br /> onsite. <br /> 4.4.1 Trend Analysis <br /> Kennedy/Jenks is proposing to perform a groundwater flow and constituent mass balance <br /> between offsite and onsite conditions, sometimes known as trend analysis and source <br /> identification. A detailed evaluation of surrounding land uses and practices and existing <br /> groundwater data needs to be performed in order to develop a complete understanding of the <br /> impacts to groundwater quality upgradient, beneath, and downgradient of the Facility. A trend <br /> analysis of the groundwater quality(i.e., time plots of constituents) using the offsite wells in <br /> addition to the existing onsite wells will be used to evaluate the spatial and temporal variation in <br /> constituent concentrations, and to assess whether the differences in concentrations can be <br /> attributed to activities onsite, offsite, or both. <br /> 4.5 Planned Site Investigation Activities <br /> This section discusses existing groundwater data to support additional groundwater monitoring <br /> efforts. The primary objectives for additional groundwater investigations are to: (1) delineate the <br /> Groundwater Protection Work Plan, Woodbridge Winery Page 45 <br /> Robert Mondavi, Acampo, California <br /> gvsnmvG'��nyobN3�L39113.L0_;n+:�dsv�A4repy�Wvv_piobaiutertt.yln4ay..dx <br />