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V o A S S O C I A T E S I N C GROUNDWATER FLOW DIRECTION Water level measurements were collected from wells MW 1 through MW5 on March 6, 2000 Water levels ranged from 19 92 to 20 85 feet below the tops of the well casing elevations, representing an average increase in the water table elevation of approximately 0 97 feet since December 1999 The water level data were used to develop the groundwater elevation contour map (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost aquifer beneath the site flowed towards the southwest The average hydraulic gradient on March 6, 2000 was calculated to be 0 0004 ft/ft or approximately 2 ft/mile A summary of groundwater monitoring data is presented in Table 1 ANALYTICAL RESULTS The groundwater sample collected from well MW2 contained detectable concentrations of TPHg, TPHd, toluene, ethylbenzene, and xylenes The TPHg concentration was 2,600 parts per billion (ppb), the TPHd concentration was 1,600 ppb, and toluene, ethylbenzene, and xylenes concentrations ranged from 1 9 to 380 ppb The groundwater samples collected from wells MW 1, MW4, and MWS contained TPHd at concentrations of 140 ppb, 200 ppb, and 120 ppb, respectively The groundwater samples from wells MW1, MW4, and MW5 did not contain detectable concentrations of TPHg or BTEX The groundwater sample from well MW3 did not contain detectable concentrations of TPHg, TPHd, or BTEX Analytical results of groundwater samples are summarized in Table 2 and laboratory data sheets are contained In Attachment 2 ADDITIONAL SITE ACTIVITIES On March 23, 2000, ATC personnel transported and disposed of two 55-gallon drums of soil cuttings generated during the advancement of monitoring wells that were stored on site Prior to the soil disposal, analytical data was supplied to Allied Waste Landfill to profile the soil for the appropriate disposal method ATC transported the soil to the Allied Waste Landfill in Stockton, California where it was properly disposed Copies of the non-hazardous waste manifests are included in Attachment 3 CONCLUSIONS Concentrations from wells MW1 through MW5 generally remain consistent with the results from the previous sampling event The direction of groundwater flow is consistent with the previous event Groundwater elevations have increased since December 1999 w 1130991quart1y\1gr-2000 doc 3