ARCHIVED REPORTS_2013 ANNUAL REPORT

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Nestl6 USA, Inc., Ripon, California March 26, 2014 2013 Annual Report 4.2 VIDEO SURVEYS AND MW-3 DEPTH PROFILING Under the direction of ECM, BESST, Inc. (BESST) completed well video surveys and depth profiles of select wells in October and November 2013. The video surveys were performed to assess well construction details and conditions. Dynamic flow and chemical depth profiling were performed at well MW-3 to assess the location and concentrations at which CDCs were entering the well. BESST used a miniature camera (3/4-inch diameter) to video survey municipal well MW-3; private wells 5600 Hall Road, 5725 Hall Road, and 802 Vera Avenue; and Ripon School District well RPS-1. A video survey at RPS-2 could not be completed because a layer of oil floating on the water inside the well casing. Table A-1 (presented in Appendix A) was updated with well depth and well screen (or open hole) interval information based on the results of the video surveys. Flow profile data at MW-3 indicated 91 percent of water production occurs from the open-hole interval at well depths between 127 and 140 feet. Well MW-3 chemical profiling indicated the highest concentrations of nitrates, TCE, and 1,2-cis-DCE also occurs in groundwater produced from this depth interval. The highest concentration of disinfectant byproducts was reported in the shallowest sample (95 feet). Concentrations of all analytes detected in the groundwater samples were below the MCLs. BESST prepared a report that summarizes the depth profiling field procedures implemented at well MW-3, data analysis, and concluded that most of the COCs were entering MW-3 from the Intermediate Aquifer from the open hole interval at depths between 127 feet below ground surface (bgs) and 140 feet bgs. Appendix F includes the BESST report and the laboratory report for groundwater samples collected from well MW-3 during chemical profiling activities. 4.3 WATER REPLACEMENT CONTINGENCY PLAN ECM conducted O&M activities and collected water quality samples at three private wellhead treatment systems in 2013. The wellhead treatment systems at 7501 Kiernan Avenue and 5725 Hall Road consist of two 1,000-pound GAC vessels in series. The treatment system at 802 Vera Avenue consists of two 200-pound GAC vessels in series. ECM analyzed the influent samples for VOCs and nitrate monthly, the mid-point samples monthly for nitrate and bimonthly for VOCs, and the effluent samples twice per month for VOCs per the MRP (Table 8.2). As part of the Water Replacement Contingency Plan" (WCRP), ECM completes an initial review of analytical data (for all priority wells as defined in Section 4 of the WRCP) within one business day of receipt of the laboratory reports. As a result of the priority well data review, ECM replaced the carbon at 802 Vera Avenue on September 27, 2013 following the detection of cis-1,2-dichloroethene in the mid-sample. Analytical results for effluent samples were below laboratory detection limits for drinking water for all the CDCs tested in 2013 at the three wells. Nestl6 has provided a replacement well at one of the system locations, and, per the WRCP, is currently negotiating with the well owner to remove the treatment system at that location. 17