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VV <br /> . A S S O C I A T E S I N C C I A S S O C I A T E S I N C <br /> Groundwater samples from wells MW 1, MW3, and MW7 continue to contain elevated <br /> Please contact our office at (209) 579-2221 if you ha concentrations of TPHg and BTEX A summary of analytical results is presented in Table 1 <br /> Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 <br /> Respectfully submitted, <br /> ATC Associates Inc GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from wells MW1 through MW7, and CW on <br /> September 14, 2000 Water levels ranged from 20 81 to 23 73 feet below the tops of the well <br /> Jennifer Cox casing elevations, representing an average decrease in the water table elevation of approximately <br /> Staff Geologist 1 09 feet since June 2000 The water level data were used to develop the groundwater elevation <br /> contour map (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in <br /> VW, the uppermost aquifer beneath the site flowed towards the northeast The average hydraulic <br /> gradient on September 14, 2000 was calculated to be 0 006 ft/ft or approximately 32 ft/mile A <br /> Drew Van Allen summary of groundwater monitoring data is presented in Table 1 <br /> Project Manager <br /> CONCLUSIONS <br /> Concentrations of TPHg and BTEX in wells MWl through MW7 remain consistent with the <br /> Jeanne Hornsey, P E results from previous sampling events Concentrations of some BTEX constituents have <br /> CA Registered Civil Engineer No 47410 increased in wells CW and MW2 It appears as though there are petroleum hydrocarbons <br /> remaining in the soil The direction of groundwater flow and the magnitude of hydraulic <br /> cc Mr and Mrs Raymond Farmer gradient are generally consistent with the previous event Groundwater elevations have <br /> Marty Hartzell, RWQCB decreased since June 2000 <br /> RECOMMENDATIONS <br /> Based on the results of the Third Quarter 2000 monitoring episode, we recommend the <br /> following <br /> • Conduct the Fourth Quarter 2000 groundwater monitoring and sampling wells MW1 <br /> through MW7 and CW and analyze samples for TPHg and BTEX by EPA Method 8020 <br /> • C <br /> w 1625961quart1yl3gr-2000 doc 4 w 1625961quart1yl3gr-2000 doc 3 <br />