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ASSOCIATES(. 4kTC <br /> I NC . <br /> In December 2000, one cone penetrometer soil boring and five hollow-stem soil borings were <br /> advanced at the site. The hollow-stem auger borings were subsequently completed as <br /> groundwater monitoring wells. The new monitoring wells were developed and groundwater <br /> samples were collected from the new monitoring wells, the existing monitoring wells, and the <br /> on-site groundwater supply well Results of this investigation are pending. <br /> GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from wells MW1 through MW8 on January 18, 2001.. <br /> A sheen of.free product was encountered in well MW2. The sheen was not thick enough,to be <br /> measured. Water levels in wells MWl through MW7.ranged from 60.46 to 61.75 feet below the <br /> tops of the well casing elevations, representing an average increase in the water table elevation of <br /> approximately 0.57 feet since December 14, 2000. The water level data were used to develop the <br /> groundwater elevation contour map (Figure 2). Assuming that horizontal isotropic conditions <br /> prevail, groundwater in the uppermost aquifer beneath the site flowed towards the-west. The <br /> average hydraulic gradient on January 18, 2001 was calculated to be 0.0008 ft/ft or <br /> approximately 4 ft/mile. A summary of groundwater monitoring data is presented in Table 1. <br /> CONCLUSIONS <br /> The direction of groundwater flow is to the east. This is not consistent with the previous <br /> monitoring event. Groundwater elevations have increased since December 2000. ATC is <br /> currently negotiating with nearby property owners for permission to sample their drinking water <br /> wells. Results of the subsurface investigation conducted in December 2000 are pending. <br /> Please contact our office at(209) 579-2221 if you have any questions or comments. <br /> Respectfully submitted, <br /> ATC AssociatesIn�cc.' <br /> Drew Van Allen ,,•> 4N e <br /> � ;. <br /> Project Manager <br /> 2ene Homsey, P.E. Fup. <br /> CA Registered Civil Engineer No. 47410 r <br /> cc: Mr. Phil Cohn, Cohn Enterprises <br /> �— Mr. Warren Treisman, Attorney at Law <br /> Marty Hartzell, RWQCB <br /> w:1163931quartty\1-2601.doc 2 <br />