Laserfiche WebLink
Mr. Mike Desso - 2 - . 3 September 2010 <br /> Nestle USA Inc. <br /> 2. In the event that contaminant concentrations increase significantly after shutdown, <br /> Nestle may be required to restart the system and operate it until concentrations <br /> decrease. <br /> 3. Nestle must prey®at a long-term monitoring plan that will track the continued decline <br /> of contaminant concentrations associated with the Stockton Avenue sewer line leak <br /> until they have reached cleanup standards to be established in the Remedial Action <br /> Plan (RAP) stipulated by Required Action No. 15 and No. 16 of Cleanup and <br /> Abatement Order:No. R5-2006-720. <br /> Initially, the groundwater extraction system removed water from the Upper Aquifer <br /> contaminated with TCE from the sewer line leak. In 2004, Nestle expanded the system to <br /> extract groundwater from the Intermediate Aquifer, believing that the contaminants in the <br /> Intermediate Aquifer also originated from the sewer line leak. As documented in the <br /> 30 January 2009 Site Conceptual Model— January 2009 Update (SCM), it is now apparent <br /> that contaminants entered the Intermediate Aquifer from the City of Ripon sewer ponds and <br /> migrated in a radial pattern away from the ponds. In this manner, TCE, cis-1,2-DCE, and <br /> vinyl chloride appear to have reached the Intermediate Aquifer beneath the Stockton Avenue <br /> site. <br /> Central Valley Water Board staff agree with Nestle's SCM conclusion that concentrations of <br /> contaminants in the Intermediate Aquifer beneath the Stockton Avenue release site are likely <br /> a result of migration from the City of Ripon sewer ponds. Therefore, at this time it is <br /> appropriate for Nestle to shut off groundwater extraction well E-6. However, Nestle must <br /> include this area of the Intermediate Aquifer in the remedy for cleanup of the release from the <br /> City of Ripon sewer ponds, to be included in the RAP. Nestle has not submitted the RAP <br /> because it is preparing an addendum to the 16 October 2009 Revised Feasibility Study. <br /> Nestle's 24 June 2010 schedule indicates that the addendum will be submitted on <br /> 21 January 2011, after completion of focused feasibility studies in progress on the Industrial <br /> Avenue and City of Ripon sewer pond release sites. <br /> If you have any questions, please contact me at (916) 464-4675, or by email at <br /> jbrownell@waterboards.ca.gov. <br /> James R. Brownell, P.G. <br /> Associate Engineering Geologist <br /> Attachment: Distribution List <br />