SITE INFORMATION AND CORRESPONDENCE

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• CLEANUP AND ABATEMENT ORDER NO.R5-2006-0720 NESTLE USA,INC. RIPON,SAN JOAQUIN COUNTY 5. Local Hydrogeology: Local hydrostratigraphic units have been defined by the Discharger as the Upper, Intermediate, and Lower aquifer zones. Each zone is comprised of highly permeable sands and gravels interbedded with silts and clays. The Upper aquifer zone includes the water table aquifer and is generally encountered between 25 and 120 feet below ground surface(bgs). The Intermediate aquifer zone is encountered between 120 and 220 feet bgs. The Intermediate aquifer zone contains two distinct sand layers identified as the CI and C2. The CI and C2 sands are encountered at approximately 140 to 160 feet bgs and 180 to 190 feet bgs, respectively. The Lower aquifer zone is generally encountered below 220 feet and is separated from the Intermediate aquifer zone by a locally(and possibly regionally) continuous clay aquitard. The distribution of volatile organic compounds(VOCs)and groundwater potentiometric surface data suggest the Upper and Intermediate aquifer zones are hydraulically connected. VOCs have been detected in Lower aquifer monitoring wells, suggesting there may be areas within the TCE plume where the Intermediate and Lower aquifer zones are also hydraulically connected. 6. The depth to the local water table is approximately 20 to 25 bgs. The horizontal and vertical groundwater gradients vary seasonally in response to pumping of municipal and industrial supply wells located to the west, north, and east/southeast. Currently, pumping of City of Ripon wells 3,4, 7, 9, 10 and I I and Fox River Paper wells 6 and 7 is believed to influence groundwater flow in the vicinity of the Facility (Figure 3). Based on the current distribution of VOCs and historical groundwater elevation data, it appears that the predominant groundwater flow direction may have been southward before the City of Ripon began extracting large volumes of groundwater to supply drinking water to their residents. The period when this potential reversal of groundwater flow direction occurred is uncertain. Recent groundwater elevation data suggests groundwater in the Intermediate and Lower aquifer zones in south Ripon may still be flowing southward and/or parallel to the Stanislaus River. 7. In October 1985 and January 1986,the Discharger sampled on-site supply wells N1 and N2. TCE was detected in these supply wells that were screened in the lower portion of the Upper aquifer zone. The presence of volatile organic compounds in groundwater is attributed to accidental spills from the aboveground storage tanks near the former decaffeination building, accidental leaks/spills of chemicals near or in the water treatment chemical storage building, and unanticipated leaks in the industrial sewer system. 8. In July 1986, the Discharger installed a granular activated carbon (GAC) system for the treatment of their production water from supply well NI. Supply well N2 was not used at that time. This action was performed as an interim remedial measure. 9. In 1995, supply wells NI and N2 were abandoned and pumping continued from Upper aquifer zone extraction wells EI-1, installed in February 1989, and EW-1, installed in January 1992. From July 1986 through 2002, with the exception of an approved shutdown in 1999/2000 for pilot testing,the Discharger extracted and treated groundwater from Industrial Avenue extraction wells NI, EI-1, or EW-1 at a rate of approximately 40 to 140 gallons per minute (gpm). In 2003,the Discharger pumped and treated an average of approximately 34 gpm from Industrial Avenue extraction well EW-1, in 2004, approximately 21 gpm,and in 2005, approximately 10 gpm. 2