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Mr. Kyle Christie 3 27 March 1989 r f defined, a complete and comprehensive PAR is to be completed and submitted to us and the SJLHD within three weeks of receiving the laboratory results but no later than 10 July 1989. As agreed in our 10 March 1989 meeting, monitoring wells are to be resamp led to determine if there is truly contamination at 80 feet below grade, as reported in monitoring well W-2b in June 1988, or was it an artifact of the drilling process. We request that monitoring wells W-2, W-2a and W-2b be sampled monthly in an .attempt to clarify this uncertainty. Quarterly monitoring of all wells for BTX&E, TPH, and ground water level elevations is to be continued with . quarterly reports submitted to us and the SJLHD by mid-April , July, October, and January for the previous calendar quarter GROUND>NATER EXTRAC-T•ION�.k'ELLT�: We do not recommend the installation of the proposed extraction well at this time. We agreed at the 10 March 1989 meeting that a deep extraction well was premature without the removal of free product. When we met on 1 April 1988 with you, the SJLHD and the City of Lodi , we stated that the free product should be removed before extracting and treating ground water. Pumping a deep extraction well will pull free product lower into the aquifer. This is unacceptable. In addition, it may be determined from the monthly sampling of monitoring well W- 2b that the hydrocarbon plume does not extend to 80 feet below the surface and a shallower extraction well (s) would better serve the purpose. If it is determined that the plume is limited to the upper portion of the aquifer, we do not want deep pumping to occur at this site. You mentioned in your 21 March 1989 conversation with Ed James of this office, that the extraction well pump would be placed at the base of Ithe plume, but if the well does not yield enough water to sustain the continuous flow rate needed to induce a cone of depression large enough to capture the entire plume, the pump would be lowered to increase the wells yield. We would rather have a number of shallow extraction wells pumping at low rates than one deep well pumping at a high rate which could pull hydrocarbons downward or pump unconta inated water from beneath the plume. - —Wo recommend- that tiie extraction yells; be designed to.include the -highest, anticipated ground water level within the screened interval . In April 1987 the reported depth to ground water was within 50 feet of the surface. The screened interval of the proposed extraction well starts at 55 feet below the surface and would not allow for the ground water fluctuations that occur at this site. It is stated in the proposed work plan that in addition to conducting an aquifer test, the immediate purpose of the extraction well is "to induce a cone of depression. . .to prevent further off-site migration of the hydrocarbon constituents." Until the long-term water disposal issue has been resolved, an induced cone of depression could not be maintained following the conclusion of a pumping test. It is also stated that, due to the City of Lodi 's refusal to allow long-term discharge of treated water oto the sewer system, ARCO will request a National Pollutant Discharge Elimination System (NPDES) permit. It must be noted it can take six months to get a NPDES permit approved and issued because both the Regional Board and EPA must concur and environmental documents must be prepared.