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IRM Prove-Out Reports -2- 29 August 1991 DDRW, Tracy not only is extracting water, but is also injecting water into the aquifer, and because there is an inadequate hydraulic data base at this site, Tracy should monitor the SWL in the injection and extraction wells for a 24 hour period prior to the implementation of the full-phase operations. This information may be used as a baseline and to determine whether or not there are any fluctuations in the water levels due to pumping influences from on- or off-site supply wells. This hydraulic information may be useful for the final design of the ground water remedial system. 2. Page 4. It is unclear what is meant by the term "surface level " . The surface level was used as the reference point for ground water level measurements. It is assumed that the surface level is the top of the casing. 3. Page 5. One of the conclusions drawn from the Prove-Out Phase is that the performance (injection flow rate) of IW-2 is much lower than that of the other two injection wells. The report states that IW-2 fills up if the flow rate exceed 15 gallons per minute (gpm) . The limited performance of this injection well was not discussed in the report. Tracy needs to evaluate why the performance of this well is less than the design, particularly when the construction was similar to that of the other injection wells. The reasons for the poor performance of IW-2 should be considered for the final ground water remedial design to optimize the performance of that system. Tracy should also consider the use of pilot holes for the final remedial design to confirm the lithologies in the areas where the injection wells are to be installed. 4. Pages 5 and 10. The data collected during the Potable Water Start-Up and Prove-Out Phases are listed in different groups of tables and figures. However, the text of the report does not provide any discussion on the tables and figures. Of particular concern is that the differences in the patterns of measured ground water levels between the different wells was not discussed. Some type of data evaluation should have been presented in the text of the report. This discussion could be helpful for future design considerations of the final ground water remedial measure. 5. Page 6. It appears that the Contaminated Water Start-Up Phase was not performed. This phase was required under Discharge Specification C. 2. of the WORs. If the Contaminated Water Start-Up Phase was performed, the report did not provide any discussion on this phase. However, because the IRM proceeded to the Prove-Out Phase and ended up with positive results, this deficiency should not prevent the Full-Scale Operation of the IRM. 6. Page 8. It is unclear whether each extraction well pump was operated for one hour and observed through three pumping cycles to confirm the proper operation of the pumps. This requirement is listed under Discharge Specification C. 2. iii . of the WDRs. Because this was a requirement of the Contaminated Water Start-Up Phase, which appears not to have been performed, this may have been performed under the Prove-Out Phase. The report should have more clearly specified whether and when the proper operation of the pumps was determined. 7. Page 8. One of the extraction wells (EW-5) was not pumped for the full 96 hours as required under Discharge Specification C. 3. i . of the WDRs due to a malfunction of the discharge valve. However, the well was pumped for 78 hours with no other