ARCHIVED REPORTS_RESPONSE TO COMMENTS ON DRAFT REMEDIAL ACTION PLAN 2015

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Page 3 conditions near the City of Ripon wastewater treatment lagoons and Stanislaus River. Implementation of hydraulic containment in this area would involve pumping hundreds of millions of gallons of water per year and discharging to the River,with no guarantee of complete containment and protection of receptors. Pumping millions of gallons of groundwater out of the aquifers and into the Stanislaus River would deplete groundwater resources in a time of extreme drought, with little remediation progress in terms of mass removal. Residents and land owners on the south side of the Stanislaus River are protected under the sampling, notification, and water replacement requirements contained in the WRCP. 3. As stated at the 14 January 2015 monthly project conference call between Central Valley Water Board staff and Nestle,we request that Nestle proceed with submittal of the design plan for the groundwater extraction and treatment system proposed for the Upper Aquifer Zone plume. This system must be operational as soon as possible to prevent further westward migration of the trichloroethene (TCE) plume towards potential receptors,which includes several drinking water supply wells. We already concur that this proposed remedial action is necessary and Nestle cannot delay implementation until the RAP is completed. Please submit the draft design plan by 30 April 2015. As previously discussed at the project conference call,we also request that Nestle submit a work plan to install additional groundwater monitoring wells south of the City of Ripon's wastewater ponds. Additional wells are needed to monitor potential migration of TCE and its daughter products towards potential receptors on the south side of the river. The existing monitoring wells north of the river were installed to define the extent of the TCE plume and to protect receptors on the north side of the river. These wells are not optimally located/designed to act as guard wells to protect receptors on the south side of the river. Furthermore,the existing wells are spaced too far apart to detect subtle changes in the local groundwater gradient that may indicate plume migration beneath the river. As stated in General Comment 2,these additional monitoring wells will also be required if MNA is part of the final remedy. Please submit a draft work plan to install these wells by 30 April 2015. Nestl6 Response: Nestl6 agrees to move forward with the additional treatment system requested by the Water Board. Nestl6 prepared and submitted design drawings to the City of Ripon for approval on January 8, 2015. The City of Ripon owns the land where the remediation wells and equipment are to be installed. Nestl6 began the process of leasing this land from the City of Ripon on October 27, 2014 and is currently in negotiations with the City, as Nestl6 reported to the Water Board staff during monthly teleconferences throughout 2014. Nestl6 will submit an Interim Remedial Action Plan(IRAP) that will include draft design plans for additional groundwater extraction and treatment targeting the upper aquifer on or before 30 April 2015. Regarding monitoring well locations and past groundwater characterization in the area south of the wastewater lagoons,please take note that Nestle advanced nine exploratory borings and collected 67 depth-discrete groundwater samples on both sides of the Stanislaus River between 2003 and 2005. Based on this sampling,Nestl6 installed 18 monitoring wells, including ten monitoring wells south of the River, all with the review and approval of the Water Board. The groundwater monitoring program includes monthly sampling of CDCs at more than 10 private