Laserfiche WebLink
T <br /> ' v <br /> A S S Q C I A T E S I N C <br /> GROUNDWATER FLOW DIRECTION <br /> Water level measurements were collected from wells MW-1 through MW-6 on November 19, <br /> 1999 Water levels ranged from 24 48 to 25 32 feet below the tops of the well casings, <br /> representing an average decrease in the water table elevation of approximately 0 58 feet since <br /> August 1999 The water level data were used to develop the groundwater elevation contour map <br /> (Figure 3) Assuming that horizontal isotropic conditions prevail, groundwater in the uppermost <br /> aquifer beneath the site flowed generally towards the east The average hydraulic gradient on <br /> November 19, 1999 was calculated to be 0 0009 ft/ft or approximately 5 ft/mile A summary of <br /> groundwater monitoring data is presented in Table 1 <br /> CONCLUSIONS <br /> Concentrations of petroleum hydrocarbon constituents remained approximately the same in well <br /> MW-3 and remained at nondetectable concentrations in wells MW-4, MW-5, and MW-6 MTBE <br /> was detected in well MW-1 at a concentration of 6 9 parts per billion (ppb) TPHg was detected <br /> at 170 ppb in well MW-2 for the first time since July 1998 <br /> The direction of groundwater flow and the magnitude of hydraulic gradient are generally <br /> consistent with previous quarters <br /> RECOMMENDATIONS <br /> Based on the results of the fourth quarter 1999 monitoring episode, we recommend evaluating the <br /> site for closure <br /> Please contact our office at (209) 579-2221 if you have any questions or comments <br /> Respectfully submitted, <br /> ATC Associates Inc <br /> -0 �c.--- <br /> a, <br /> Drew Van Allen - l <br /> Project Manager f•��� i .Sl�/� �` <br /> HOW, E <br /> Z'7"J <br /> LAJ r" <br /> V � <br /> Je a Homse N0' G0 -1410 <br /> CA Registered Civil Engineer No 47410 <br /> GIME <br /> cc Gerald Thiemann �P�` cw <br /> Marty Hartzell, RWQCB = <br /> w W26051quarllyl4gr-1999 doc 3 <br />