ARCHIVED REPORTS_XR0006720 CASE 1

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3.0 CONCLUSIONS, RECOMMENDATIONS AND PROJECT STATUS rBetween March 26, and June 6, 2003, the groundwater surface dropped an average of 1 70 feet, the groundwater gradient increased from 0 0044 to 0 0094 foottfoot, and the groundwater flow direction shifted approximately 10 degrees toward the northeast These groundwater flow and gradient characteristics are consistent with historical trends Based on cumulative soil and groundwater analytical results, gasoline compounds in the subsurface appear to be mostly defined to the dispenser area and to the northeast within the property boundaries As such, despite the close proximity and shallow construction of the on-site water supply well and nearby domestic wells, they do not appear to have been impacted by gasoline compounds released from the former UST system Concentrations of gasoline compounds in groundwater beneath the site have generally declined, probably in response to prior source removal efforts and natural attenuation processes Given the relatively low and rapidly declining concentrations of gasoline compounds in groundwater beneath the site, active soil and groundwater remediation does not appear to be necessary to reduce concentrations to below water quality goals The site has been adequately characterized, the source of gasoline has been removed, the plume of impacted groundwater is defined, and concentrations of gasoline compounds in groundwater appear to be degrading Based on these conditions, Ramage Environmental recommends that EHD and RWQCB consider the case for regulatory closure In the meantime, the six monitoring wells and on-site water supply well should continue to be monitored and sampled on a quarterly basis The next monitoring event is scheduled for September 2003 8 1