SITE INFORMATION AND CORRESPONDENCE_FILE 1

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J.R. Simplot - 2 - 21 March 2008 Lathrop, San Joaquin Count, POND DISCHARGE AND PIPING 5. Section 5.1 and Appendix D — Piping Assessment and Repairs. The Work Plan does not show as-built drawings of piping runs; the DVD included in Appendix D was not a conclusive assessment of the condition of the piping system. Please provide detailed as- builts of the piping runs, annotated to show where the camera surveys were performed relative to surface features, and where any defects or damage were observed. 6. The Regional Water Board requested, in addition to a Work Plan, information on construction details of the sump area within the pump station, a history of its operations, and how it was operated. This information is still missing from Section 4.2. No as-built drawings of the new sump construction are provided. It is not evident from any provided figures or maps where the pump area is located relative to the ponds. It is presumed that no soil sampling was conducted in the immediate area of the sump; additional sampling points are needed to delineate lateral and vertical extent of releases in this area. Please provide this information in an addendum to the Work Plan. 7. The Work Plan states, in Section 5.2, that three background borings for the ponds are proposed north and east of the stormwater pond. We concur with these locations for background sampling purposes, but we emphasize that these locations should be considered as background sampling points not only for the pond area, but for the entire site. All background soil and groundwater samples should be analyzed for all constituents of concern, and their locations and lithologic profiles documented. 8. Four shallow and five deep soil borings, as well as one detection monitoring well, are proposed for the pond area. We request that an additional monitoring well be placed near soil borings EB-J, EB-Z, or EB-P to capture any potential migration of contaminants from the ponds to the west. 9. J.R. Simplot did not provide an evaluation of the liner systems for the pond discharge pipe area. No information is provided on the status of the installation of dykes. Please provide an update on when this work will be completed. We request that your consultant provide an evaluation of whether the liners are preventing new releases based on available data. Containment systems must be integrated into the Spill Prevention Plan and Stormwater Pollution Prevention Plan for the site. 10. J.R. Simplot did not provide integrity testing or sufficient identification information on the pipes near the ponds. J.R. Simplot indicates in Appendix D of the Work Plan that integrity testing was tentatively scheduled as early as October 2007, but that underground pipe locating had not been completed. Please provide an update on when this work will be completed. In addition, the diagrams and narrative provided in Appendix D are not adequate for the purpose of describing the buried pond piping or pump area or for identifying the pipes in the event of a future release. Please provide engineering as- built drawings that compile all of this information.