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Regarding groundwater gradient and flow direction, Figure 3 presents a graphical interpretation of the data obtained by measurement of water levels in all monitoring wells and conversion of the depth-to-water measurements to Mean Sea Level (MSI_.) elevations The groundwater gradient is approximately 0 0048 feet per foot and the flow direction is generally toward the south and east While the flow direction has changed approximately 90' from the first quarter I993, the direction is back to that most commonly observed during previous sampling events With the flow direction generally south and east, monitor well MW-5 continues to provide groundwater quality data downgradient from the former tank site While low concentrations of benzene were seen in this well during the first three quarters of monitoring, no concentration were observed this quarter, which indicates there is no discernable migration from the site Because groundwater depth has vaned at the site significantly over the history of the project and the relationship of groundwater depth to hydrocarbon residues in the soils is an issue of interest ' to potential future remedial activities, Figure 4 presents a chronology of MSL water levels at monitor well MW-2 Well MW-2 has been selected to represent water levels at the site due to its central location ' As shown by Figure 4, the groundwater level at the site has steadily risen approximately 12 feet since October 92, presumably in response to the winter and spring rainy season It is encouraging to note that groundwater chemical concentrations have generally not increased along with the rising groundwater levels This lack of correlation may indicate that either there are no hydrocarbons bound up in the soils of the previously saturated zone or, if they do exist, the rising water level is not mobilizing them Further monitoring will determine if this lack of correlation continues ' 3.0 REMEDIAL PROGRAM STATUS As noted in the "Future Planned Activities" section of the 1st Quarter 1993 Report, continued future quarterly monitoring is anticipated to develop seasonal data on groundwater quality, depth and direction for the purposes of evaluating remedial needs The relationship between groundwater quality and depth is particularly important now that groundwater has risen at the site without producing higher chemical concentrations This data, if substantiated during future monitoring periods, would indicate that the concerns about hydrocarbons being bound up in the previous saturated zone and migrating when the water table returns to non-drought levels is not an issue This data would then suggest that remediation of the previous saturated zone is unnecessary and that the primary environmental issue at the site would become solely groundwater quality in the immediate vicinity of the site San Joaquin County EHD has recently asked that feasibility work leading toward development of a remedial plan by April 25, 1994 be conducted Planning is now under way to determine which issues need to be addressed and what data or studies are necessary to complete a remedial ' plan by the requested date SFK%Rp'mAREG2QTR wP 6 09/02/93