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• MEMORANDUM • • CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD - CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 361-5600 Sacramento, CA 95827-3098 ATSS Phone: 8-495-5600 TO: Greg Vaughn FROM: Camilla Williams Senior WRC Engineer Engineering Geologist DATE: 13 September 1990 SIGNATURE: fRil1LGJi�O�tar//ny SUBJECT: REVIEW OF THE MODIFIED CLOSURE PLAN, KEARNEY-KPF, SAN JOAQUIN COUNTY I have reviewed the 9 August 1990 Modified Closure Plan, submitted by Hargis and Associates for Kearney-KPF. The portion of the Plan which involves the closure of the surface impoundments is generally acceptable. However, the portion of the Plan regarding the construction of a disposal basin in the western field causes concern and the intended use of that basin is unclear. I concur with the proposals for closure to remove the soils which contain contaminants above the soluble designated levels (SDLs) to a Class I facility and to perform confirmation sampling. As previously noted in our review of the Soil Assessment Report, because the contaminated soils to be closed in-place are below the SDLs, it is not necessary to construct a compacted clay cover for the ponds. It is necessary; however, that the pond areas are regraded to divert drainage away from the surface impoundments. If Kearney-KPF does install a cover over the pond areas, we should require that the landfarmed cuttings and drilling muds from the remedial investigation (RI) are not placed in the upper one foot of the cover. There are two major aspects of the Plan which involve the proposed construction of a basin which are unacceptable and will require modification and clarification before they can be approved. The unacceptable portions of the Plan are discussed below. 1) The infiltration basin has been located directly over the cuttings and drilling mud disposal areas in the southwestern portion of the western field. The use of this portion of the site for waste disposal has been changed from that which was previously agreed upon with the Regional Board. Wastes from the RI were landfarmed only after the facility proposed this disposal alternative and guidelines for disposal were established with our concurrence as a one-time disposal for the RI . More wastes from Phase II of the RI will need to be disposed of in the future. The Plan proposes to use the landfarmed wastes in the construction of a cover over the pond areas. The wastes from the RI were only analyzed for heavy metals and volatile organic constituents and the landfarmed wastes have not been tested to determine if their properties are suitable for a cover. 2) The proposed primary use of the basin is for the disposal of all site drainage. This would include storm water runoff. The quality of the site drainage is unknown and the Plan did not include water quality data or proposals for monitoring or treatment of the drainage to assure that disposal into the basin will not pose a threat to the quality of the groundwater. Previous discussions with Hargis did not stress that the primary use of this basin was for site drainage, but rather for the disposal of treated groundwater. The disposal of