SITE INFORMATION AND CORRESPONDENCE

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Kearney-KPF 3 13 September 1990 Modified Closure Plan Figure 1 (untitled) , it appears that none of the test pits were located in the landfarmed wastes within the disposal areas. The laboratory and field tests performed on these soils would therefore, not be representative of the landfarmed wastes and the performance of the landfarmed soils for use in a cover is unknown. Page 3. The site soil conditions were described and were compared to the well log of KSH-4. The use of this data for comparison and verification is commendable; however, the log of KSH-4 should have been provided in the report for review by the regulatory agencies. Monitor well KSH-4 was drilled as part of Phase II and the report of this phase of RI has not yet been submitted. Page 3. The primary use of the basin is to collect and dispose of all site drainage. This proposal is unacceptable because the quality of the site drainage, in particular the storm water runoff, is unknown. The Plan must be modified to assure that disposal of these waters do not threaten the quality of the ground water. Although the site drainage may be considered to be innocuous, the facility should determine whether or not the site drainage is a waste. This could be demonstrated through the collection of site drainage from one wet season prior to the construction of the basin. If the site drainage is not a waste then the drainage could be disposed of in an infiltration basin and the WDRs may not be revised. However, if it is determined that the site drainage is a waste then the disposal must meet the requirements under Subchapter 15 for a Class II surface impoundment. In addition, if the basin is constructed, the WDRs could be revised to include monitoring of the site drainage discharged into the basin. Page 3. Because the primary use of the basin is to dispose of all site drainage, a water balance should have been presented in the Plan. A water balance based on the design criteria would indicate how much of the site drainage disposed of in the basin is estimated to infiltrate and how much would evaporate. Based on these calculations the use of the basin would either be for infiltration or for evaporation. Although the site has an unsaturated zone of about 70 feet and is composed of clayey soils, the discharger should be required to do a water balance, especially because the water quality of the site drainage is unknown. Page 3. The secondary use of the basin is to provide a method of disposal for the treated ground water through infiltration and injection (dry wells) . The plan states that the extraction system is expected to produce approximately 250 gallons per minute of treated ground water. The plan however, does not provide adequate information such as which wells will be used for extraction, whether the estimated flow is a function of the aquifer or the treatment system or whether the design of the basin was based on the estimates for the interim or final ground water treatment system.