ARCHIVED REPORTS XR0000039 - Laserfiche WebLink

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3 0 CONCLUSIONS, RECOMMENDATIONS AND PROJECT STATUS 1 Between March 7, and June 6, 2003, the groundwater potentiometnc surface dropped an average ' of 0 94 feet, the groundwater gradient decreased from 0 00231 to 0 00151 foot/foot, and the groundwater flow direction shifted approximately 60 degrees toward the northeast Between March 7, and June 6, 2003, the concentrations of petroleum hydrocarbons in groundwater at MW-1 decreased significantly, and at MW-2 and MW-3 increased slightly This is probably in response to seasonal shifts in the potentiometnc surface and/or continued natural attenuation processes iIn groundwater, petroleum hydrocarbons appear to continue to be concentrated on the west side of the former fuel farm To the north and south of the former fuel farm, lower concentrations of petroleum hydrocarbons in groundwater suggest that the impact attenuates by natural processes The lateral extent of impacted groundwater remains undefined i On March 21, 2003, EHD documented their review of Ramage Environmental's Monitoring Well Installation Report, dated January 9, 2003 Since the three monitoring wells did not completely define the extent of impacted groundwater, EHD directed that a work plan be submitted to continue the subsurface investigation ' On April 4, 2003, by telephone, Ramage Environmental and EHD agreed that, to further evaluate seasonal shifts in the potentiometric surface and the general decline in petroleum hydrocarbon concentrations in groundwater, at least four quarters of groundwater monitoring and sampling data should be evaluated before proposing additional site investigation tasks in a work plan As ' such, Ramage Environmental recommends that the three monitoring wells continue to be monitored and sampled on a quarterly basis The next (fourth) quarterly groundwater monitoring event is scheduled for September 2003 i 1 • 1 6