ARCHIVED REPORTS_2013 ANNUAL REPORT

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Nestl6 USA, Inc., Ripon, California March 26, 2014 2013 Annual Report 2.2.4 GROUNDWATER MOUND As shown in Figure 2, the City of Ripon operates the WWTP lagoons and recharge pond and Diamond Pet Food operates percolation fields in the southern portion of the Study Area just north of the Stanislaus River. Water level data collected in this area has indicated seasonal groundwater mounding typically resulting in an elongated radial flow pattern in the Upper and Intermediate aquifers. The distribution and location of the top of the groundwater mound vary with the timing and volume of discharges to the lagoons, pond, and fields. The following is a summary of observations regarding groundwater mounding in 2013. • In 2013, the total volume of treated water discharged to the Diamond Pet Food percolation fields was 212 acre-feet over a total area of approximately 70 acres. Total monthly discharge rates were relatively constant throughout the year. During all four quarters in 2013, groundwater mounding was observed in this area in the Upper and Intermediate aquifers (Figure 3-1 through Figure 3-4 and Figure 4-1 through Figure 4- 4) consistent with Diamond Pet Food discharge data. • In 2013, the City of Ripon purchased 500 acre-feet of water from the South San Joaquin Irrigation District for the recharge pond (3 acres in size). This volume per unit area is relatively high compared to discharges to the City lagoons or the Diamond Pet Food percolation fields. Daily or monthly flows into the pond are not monitored by the City. In the Second, Third and Fourth quarters of 2013, the top of the groundwater mound in the Upper and Intermediate aquifers was located beneath the pond or in close proximity (Figure 3-2 through Figure 3-4 and Figure 4-2 through Figure 4-4) consistent with the high volume of water discharged to the pond. • The locations of the centers of the mounds in both the Intermediate Aquifer and Upper Aquifer are generally coincident in each quarter of 2013, suggesting that the potentiometric surfaces of both the Upper and Intermediate aquifers are responding to recharge from the City of Ripon WWTP lagoons and pond and the Diamond Pet Food percolation fields. High-resolution water-level monitoring is currently being conducted using pressure transducers in this area to further evaluate the relationship between recharge (lagoons, pond, and percolation fields), groundwater mounding, and groundwater flow. 2.3 WATER QUALITY ECM samples wells using either the Passive Diffusion Bag (PDB) technique or grab sampling. As of July 1, 2011, ECM samples all Nestle monitoring wells using PDB samplers. ECM collected grab samples from production wells, domestic wells, and the groundwater treatment systems. Sampling methods and water quality data summaries for the first three quarters of 2013 are provided in the quarterly Site Status Reports. TestAmerica Laboratories, Inc. (TestAmerica), a California-certified laboratory in Pleasanton, California, analyzed all samples for halogenated VOCs using EPA Method 8260B. TestAmerica's Irvine laboratory analyzed samples from municipal drinking water supply wells and domestic water supply wells using EPA Method 524.2 for drinking water. Appendix B (table format) and 7