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' 3.0 RESULTS AND DISCUSSION <br /> This section presents a discussion of the fourth quarter 1999 monitoring event, and a <br /> summary of historical data <br /> 1 3 1 Groundwater Levels and Flow Direction <br /> Groundwater levels measured on December 20, 1999 ranged from 38 41 to 39 15 feet <br /> below ground surface Between September and December 1999, groundwater levels <br /> showed a slight increase ranging from 0 04 to 0 19 feet A decline of 0 16 feet was <br /> observed at well DMW-3 The direction of groundwater flow in December 1999 was <br /> generally towards the north-northeast, which is consistent with previous measurements <br /> (Figure 3) The groundwater gradient was measured to be approximately 0 001 <br /> Groundwater level data recorded since August 1990 is presented in Table 2 Groundwater <br /> levels appear to have reached a maximum elevation of approximately 35 feet bgs in June <br /> 1999 The deepest groundwater levels reported during this 12-year period were <br /> approximately 69 feet bgs in July 1991 This indicates a water elevation variation in the <br /> range of 34 feet <br /> 1 Rising water levels since July 1991 has resulted in the monitoring well screens being <br /> submerged in several wells (Table 2) The screened intervals in wells DMW-1, DMW-2, <br /> and DMW-4 have been submerged since at least May 1994 The screen interval in DMW-4 <br /> has been submerged since at least May 1995, and DMW-5 has been submerged since at <br /> least January 1997 Monitoring wells DMW-6 and DMW-7 both have screened intervals <br />' that currently intersect the water table <br /> Variations in the direction of groundwater flow during the 12-year period are presented in <br /> Figure 3 The general direction of flow appears to have shifted from west in 1987 to the <br /> east in 1995, and is currently in the general direction of north-northeast to northeast <br /> 1 32 TP H-D in Groundwater <br /> TPH-D groundwater results for samples collected on December 20, 1999 have been <br /> compiled with previous data in Table 3 Groundwater samples collected during this round <br /> from wells DMW-6 and DMW-7 contain what appears to be weathered diesel at <br /> concentrations of 420 ,ugll (DMW-6) and 390 ug/l (DMW-7) No petroleum hydrocarbons <br /> exactly matching the laboratory diesel standard were reported in any samples collected in <br /> DAMES&MOORE 411DM_SACIWOL_21JOB1AFPIREPORTIQ4-1999 DOC <br />