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I 5.0 CONCLUSIONS AND RECOMMENDATIONS On behalf of the San Joaquin Catholic Cemetery, Ramage Environmental has prepared this PAR ' and CAP for regulatory review and approval Upon regulatory approval of this document, final design drawings will be drafted and a bid solicitation package will be prepared in accordance with UST Cleanup Fund guidelines The preparation of the PAR included the installation of 2 additional groundwater monitoring wells (MW-6 and MW-7) at the site so that the downgradient extent of impacted groundwater could be defined and so that a groundwater table monitoring capability could be re-established On May 1, 1998, groundwater was monitored and sampled from the 2 newly-installed wells and the 2 deep vapor extraction wells (VW-1 D and VW-21)), and the elevations of all on-site wellheads were surveyed to an established benchmark Results of the groundwater monitoring indicate that the depth-to-groundwater beneath the site is between 38 and 40 feet bgs and that the groundwater table has risen an average of 6 18 feet ' since the wells were last monitored in February 1998 The groundwater flow direction remains northeast at a gradient of 0 0014 foottfoot Results of the groundwater sampling and analysis indicate that significant concentrations of gasoline still exist in proximity to the former USTs and that the downgradient extent of impacted ' groundwater is defined by MW-6 and MW-7 The previously-generated soil vapor extraction test data and the location and construction of the ' existing network of soil vapor extraction wells were evaluated to determine the feasibility of sod vapor extraction as a remediation alternative According to the existing data, the majority of hydrocarbon mass is contained in vadose zone sod between 10 and 30 feet bgs Extraction flow rates in this interval ranged from 7 to 17 acfm at vacuums ranging from 40 to 82 inches of H2O These relatively high wellhead vacuums at low test flow rates are reflective of the relatively low permeability associated with the silt- and clay-based sediments of the vadose zone ' Vacuum responses of 0 2 inches of H2O occurred within an average distance of 28 feet from the extraction well Using a conservatively-selected ROI of 20 feet, a minimum of 3 vapor extraction wells are required for remedial coverage Therefore, the 4 existing vapor extraction wells (VW-1, VW-2, VW-3 and VW-4) are constructed and positioned to effectively remediate the impacted soil �1 • 18