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1 16 4.0 Conclusions and Recommendations The groundwater at the site was calculated to flow in a south-westerly direction, as compared with a north-westerly flow direction calculated in November 1995 Two distinct potentiometric surfaces were identifiable at the site, based on the groundwater elevations measured in the six monitoring wells installed within the shallow and deep zones of the unconfined aquifer (Figure 2) A very shallow groundwater gradient was calculated from both the shallow wells (0 001 ft/ft) and the deep wells (0 002 ftift) This gradient is typical for groundwater at the site The water level at the site has risen by as much as 7 65 feet since November 1995 This variation is reportedly typical for the entire region, and is believed to be a result of recharge of the unconfined aquifer following the winter rainfall The entire region has experienced an "above-average" winter for the second consecutive year, thereby reflecting an increasing trend in the groundwater elevation The February 1996 average groundwater elevation was 10 24 feet above the average elevation measured in January 1995 Two groundwater pumping wells were identified on the facility, however neither wells indicate any impact on the groundwater flow or gradient at the site This quarterly sampling event continues to show minor, TPH as diesel concentrations in the groundwater at the site The measured concentrations are believed to be caused by dissolution of diesel that may be adsorbed to fine sediments located at an approximate depth of 60 feet The adsorbed diesel was probably dissolved when groundwater levels rose during the winter season It is recommended that quarterly sampling of the groundwater for TPH as diesel continue In addition, monitoring of the groundwater elevation and flow direction should be continued in order to evaluate any changes in groundwater flow direction, gradient or elevation MZ105-07-96/VDBF/96-0007 If 4-1