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' 3.0 CONCLUSIONS, RECOMMENDATIONS AND PROJECT STATUS <br /> Between September 12, and December 29, 2005, the groundwater surface rose an average of <br /> 3 13 feet, the groundwater gradient decreased from 0 0064 to 0 0052 foot/foot, and the <br /> groundwater flow direction remained toward the north-northeast These groundwater now and <br /> gradient characteristics are relatively consistent with seasonal and historical trends <br /> Between September 12, and December 29, 2005, the concentrations of gasoline compounds in <br /> groundwater remained relatively consistent In MW-2, the concentration of MTBE increased from <br /> 1 2 to 1 9 µg/I Gasoline compounds in the subsurface appear to be defined to the vicinity of well <br /> MW-2 and the former UST system Previous investigations have shown that the former on-site <br /> water supply well and nearby domestic wells have not been impacted by gasoline compounds <br /> ' released from the former UST system <br /> In general, the concentrations of gasoline compounds in groundwater beneath the site have <br /> declined, most likely in response to prior source removal efforts and natural attenuation <br /> processes Given the low and rapidly declining concentrations of gasoline compounds in <br /> groundwater, active soil and groundwater remediation has not been necessary to reduce <br /> concentrations to below water quality goals MTBE has not been detected above 5 µgA (the <br /> secondary Califomia Maximum Contaminant Level [MCL)) since March, 2003 (in well MW-2), and <br /> no other gasoline compound has exceeded its respective MCL, in any well, over the last four <br /> quarters <br /> ' Based on these conclusions Ramage Environmental mental recommends that EHD consider this case <br /> ' for regulatory closure Until the case is closed, the monitoring wells will continue to be monitored <br /> and sampled on a quarterly basis <br /> r <br /> i <br /> f <br /> ' 10 <br /> 1 <br /> 1 <br />