ARCHIVED REPORTS_2010 ANNUAL REPORT

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Nestle USA, Inc., Ripon, California March 31, 2011 2010 Annual Report corrective actions taken to fix any problem detected during the inspection. Corrective actions included: • Installation of a gauging port in the EU-3 vault lid. The gauging port eliminates the need for the sampler to lift the lid to measure depth to water. The lid was too heavy for one person to lift; • Lowering the street boxes for wells M-1 8A, M-1 8B, and M-1 8C1 to mitigate trip hazard; • Replacing the vault lids to wells M-39A and M-39C which had been covered with asphalt; • Replacing damaged vaults at wells M-45A and M-45C. 3.2 WATER LEVEL MONITORING Table 2 provides the list of wells and a summary of the quarterly depth-to-water measurements gauged on January 11, April 5, July 19, and October 11 of 2010. This list includes all of the wells listed in the MRP as well as the recently installed wells that do not appear in the 2010 MRP. The sections below summarize observations regarding changes in water level elevations in each aquifer throughout 2010. ECM prepared potentiometric surface maps for the Upper, Intermediate and Lower Aquifers using first quarter (Figures 3-1, 4-1, and 5-1), second quarter (Figures 3-2, 4-2, and 5-2), third quarter (Figures 3-3, 4-3, and 5-3), and fourth quarter (Figures 3-4, 4-4, and 5-4) data. The results are discussed in Section 3.2.3. 3.2.1 WELLS NOT USED FOR POTENTIOMETRIC SURFACE MAPS Since water level elevation anomalies occur at well clusters where multiple wells are completed at different depth intervals within the same aquifer (e.g. M-1A and M-1 B, Table 2), some data were not used to develop the contour maps. This differential water elevation has been observed historically in well clusters, such as M-1, M-3, M-9, M-11, and M-15 in the Upper Aquifer and M-6 and M-25 in the Intermediate Aquifer. If the water level elevations between two co-located wells screened in different units of the same aquifer differed by more than 0.5 feet, one of the wells was excluded from the contouring process based on a comparison with the data for surrounding wells. The well data not used in 2010 are noted below: Upper Aquifer (A and B units) • Elevation data from well M-1A was not used to contour in January, July, and October 2010 because the elevation was greater than 0.5 feet higher than well M-113 and surrounding wells. • Elevation data from well M-9A was not used in the contouring process for January, April, July, and October because the elevation was greater than 0.5 feet lower than well M-913 and surrounding wells. • Elevation data from well W-7, a City of Ripon piezometer, was not used in the contouring process in January 2010 because the water level elevation was 0.95 feet lower than well TH-7, located immediately adjacent. The MRP does not require monitoring of piezometer W-7, but ECM uses the data supplied by the City of Ripon to supplement water level data in the vicinity of the WWTP for contouring. • Elevation data from well W-4, a City of Ripon piezometer, was not used in the contouring process in July 2010 because the water level elevation was inconsistent with historical values. The MRP does not require monitoring of piezometer W-4. 10