ARCHIVED REPORTS_RESPONSE TO COMMENTS ON DRAFT REMEDIAL ACTION PLAN 2015

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Page 4 wells located south of the Stanislaus River. After the monitoring wells along the River were installed in 2006 and monitored for a few years, the Nestle team recognized complicated groundwater flow patterns in this area influenced by dynamic hydraulic stresses on the aquifers (attributed to interaction of the River, the lagoons, the nearby recharge ponds, and the pumping wells in the area). Therefore,Nestle installed pressure transducers in 16 wells on both sides of the River to gain a better understanding of aquifer response to these hydraulic stresses. The results of this study are being used to update the groundwater flow model and will also be presented in the 2014 Annual Report due on March 31, 2015. The updated groundwater flow model will be used, along with new groundwater characterization data, to identify appropriate locations for additional monitoring wells. Nestle will submit a work plan for characterization and well installation on 30 April 2015. During past discussions between Water Board Staff and Nestl6, no party had identified a need for well installations south of the wastewater treatment ponds. For this reason, additional monitoring wells in this area were not included as part of the Draft RAP. 4. The Draft RAP does not select numerical groundwater cleanup levels. We understand that selecting cleanup levels can be a contentious and time-consuming process, but we cannot support a "Final" RAP that does not have well-defined enforceable cleanup objectives. Furthermore, monitored natural attenuation (MNA) is not a remedy component that we can support at this time (see General Comment 2). However,we want to implement the groundwater extraction and treatment actions proposed in the Draft RAP as soon as possible to prevent further migration of the TCE plume in the Upper Aquifer Zone, and we concur that institutional controls should be implemented to protect local groundwater resources and prevent human exposure to contaminated groundwater. As an interim solution,Nestle should do the following: remove MNA from the proposed groundwater remedy, select interim groundwater cleanup levels equal to State and/or Federal Maximum Contaminant Levels (if different, the lower standard should be selected), and retitle the Draft RAP to "Interim Remedial Action Plan". Although the Final RAP will have to consider complete restoration of local groundwater impacted by Nestle's groundwater contamination, this interim solution will allow Nestle to move forward quickly with most of the proposed components of their groundwater remedy. After completion of the on-going MNA study, and if concurrence is received from Central Valley Water Board staff that MNA can be selected as part of the final groundwater remedy,Nestle can then provide a Final RAP. The Final RAP should clearly describes the objectives of MNA and contain conservative triggers to implement more aggressive remedial actions should groundwater monitoring indicate remedial action objectives are not being met. Nestl6 Response: Comment noted. Nestle is moving forward with the groundwater extraction and treatment system to address TCE-impacted groundwater northwest of the former facility as an Interim Remedial Action.