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J. K. 5implot, Latnrop -1- 1 August 2UU-1 <br /> San Joaquin County <br /> The Regional Water Board staff generally concurs with the findings in the EMPA that conclude <br /> significant impacts around the lined surface impoundments; however, the report did not <br /> include a thorough evaluation of the data or conclusions as to whether assessment was <br /> complete in the area of the surface impoundments. In addition, the report did not include <br /> recommendations for any future work (i.e. additional assessment work, feasibility study, and/or <br /> corrective action). Based on the data presented, it appears that the lateral and vertical extent <br /> of the soil and groundwater impacts have not been fully characterized around and <br /> downgradient from the surface impoundments. As a result, we request that J.R. Simplot <br /> provide a detailed scope of work (Work Plan) that will determine the extent of soil and <br /> groundwater impacts around and downgradient of the surface impoundments and determine if <br /> the ponds are a continuing source. Please submit the requested Work Plan to this agency by <br /> 12 September 2007. <br /> Pond Discharge Pump Area and Piping Inspection Report <br /> J. R. Simplot's Pond Discharge Pump Area and Piping Inspection Report (PDPA-PIR,) dated <br /> 20 June 2007, presented information on the pellet plant pond discharge pump station and <br /> aboveground and underground piping system associated with the lined surface <br /> impoundments. The PDPA-PIR indicated that in the pond discharge pump station area there <br /> was a sand bottom between the sump and the concrete under the pumps. The report further <br /> indicated that the aboveground piping from the tunnel (unknown location) to the ponds was in <br /> good condition. J. R. Simplot stated these pipes consist of a 10-inch diameter high density <br /> polyethylene (HDPE) sump discharge pump line from the West Pond; two 3-inch diameter <br /> HDPE lines that are open ended and out of service lying in the same trench as the above 10- <br /> inch diameter line; a 14-inch diameter HDPE line that extends from the pond discharge pump <br /> station to the southwest corner of the West Pond; a 12-inch diameter line that is locked out of <br /> service that was used to carry flows from the main sump discharge to the rainwater retention <br /> pond; and a newly discovered section of 12 to14-inch diameter polyvinyl chloride (PVC) pipe <br /> that is not on any piping diagrams, which is being further investigated. Based on the above <br /> information presented in the PDPA-PIR, Regional Water Board staff has the following <br /> comments: <br /> 1) We appreciate the information on the pond discharge pump station area; however, the <br /> report fails to assess and/or conclude the potential for soil and/or groundwater impacts <br /> that may come from this area. In addition, the report lacks the detail of the former <br /> design of the sump area within the pump station and how it is or was operated. This <br /> information is crucial to determine whether or not the area poses or posed a significant <br /> threat to soils and groundwater. Please provide construction details for the previous <br /> discharge pump station area layout, information on its operations, how often this area <br /> received discharges/spills, and discuss any needs to assess the soils beneath this area <br /> including the underlying groundwater. Please include this information in the requested <br /> Work Plan mentioned above by 12 September 2007. <br /> 2) J. R. Simplot indicated that a borehole inspection of the outer pipe that surrounds the <br /> pond discharge pipe was conducted in March 2007. The report indicated that no <br /> evidence of a leak was found. Please provide this inspection report. We assume that <br /> this report will detail the type of inspection performed, visual or pressurized using a <br /> tracer substance. In addition, in the PDPA-PIR, J. R. Simplot indicated that the <br />