ARCHIVED REPORTS_COMBINED ANNUAL AND FOURTH QUARTER 2016 GROUNDWATER MONITORING REPORT

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Diamond Pet Food&AltaGas Ripon Energy January 31,2017 Combined Annual and Fourth-Quarter 2016 Groundwater-Monitoring Report Page S of 6 recent (October 2012) TDS value for Ripon Energy flow was 828 mg/L; previously(2010), TDS in the Ripon Energy discharge ranged between 500 and 1,200 mg/L. Historically, the Ripon Energy flow was blended with lower TDS paper-mill effluent before being discharged, in sequence, into the two aeration basins (ASB-1 and ASB-2)before being pumped to irrigation and percolation fields around the site for disposal. After the paper mill closed(May 2009), the Ripon Energy discharge was blended with water pumped from production well PW-6 before being dispersed to the irrigation fields. CITY OF RIPON The City of Ripon operates a municipal WWTF adjacent to the southwest quadrant of the DP/Ripon Energy site. The WWTF treats an average of 1.0 million gallons per day(MGD). The system consists of a series of clay-lined ponds with a surface mechanical aeration system to oxygenate the waste water. Treated effluent water is disposed by percolation from 45 acres of disposal ponds. The City is currently under directive from the CVRWQCB to evaluate the impacts of effluent disposal on groundwater quality. NESTLES Nestl6s USA formerly operated an instant coffee and tea processing plant, located approximately 2,000 feet north of the DP/Ripon Energy site, from 1948 through 1986. Solvents used in the decaffeination process, and their daughter products (trichloroethene, dichloroethene, and vinyl chloride) have impacted soils at the site and groundwater throughout the Ripon area. Nestl6s' consultant, Environmental Cost Management, currently operates two groundwater- treatment systems in the area to remediate the contaminant plumes. The plumes have impacted the upper and intermediate aquifers along the northern and western portions of the DP/Ripon Energy site, and have impacted wells south of the Stanislaus River. Based on the distance of the remediation system's extraction wells from the DP/Ripon Energy site and the volume of water treated by the system (<500 gpm), and the relatively high permeability of the aquifer, it is unlikely that the extraction system influences the hydraulic gradient in DP/Ripon Energy wells. The capture zone of the extraction wells, however, may extend beneath the DP/Ripon Energy site. An increase in TDS levels in the treatment system influent might indicate that higher TDS water originating at the DP/Ripon Energy site is being captured by the Nestl6s' system. HYDROGEOLOGIC SETTING Geology and hydrogeology of the site and vicinity have been described in detail in previous reports.2 Briefly, the DP/Ripon Energy site is located in the East San Joaquin Groundwater Basin and is underlain by a sequence of Tertiary- and Quaternary-aged continental deposits of the Tulare Formation. These deposits consist of interbedded sands/gravels and silts/clays or mixtures thereof. Four distinct aquifers or zones have been identified beneath the site and have been designated by L&A as the semiperched,upper, intermediate, and lower zones. The semiperched zone is unconfined and occurs from approximately 35 to 60 feet below ground surface (bgs). All other zones are semiconfined to confined. The upper zone occurs from approximately 85 to 110 feet bgs, the intermediate zone from 140 to 225 feet bgs, and the lower zone from 240 to greater 2 L&A,May 5, 1992,Impacts on Receiving Waters from Discharge at the Simpson Paper Company Facility, Ripon, California. 010107.08 Task 4 Lawrence&Associates W.9CLIENTSIDiamond Pet Foods1010107.01-Groundwater MonitoringlGroundwater Monitoring12016WQAnnua1201614TH QUARTER Annual 2016.doc