ARCHIVED REPORTS_COMBINED ANNUAL AND SECOND-HALF 2012 GROUNDWATER MONITORING REPORT 01-31-2013

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WASTE DISCHARGE REQUIREMENTS ORDER R5-2012-0105 9 DIAMOND PET FOOD PROCESSORS OF RIPON, LLC AND RIPON COGENERATION, LLC DIAMOND PET FOOD RIPON FACILITY SAN JOAQUIN COUNTY located along the western property boundary near the City of Ripon's WWTF. The area of lowest TDS (background well OB-17)was in the southeastern comer of the site along the Stanislaus River. The average EC and TDS concentrations in all shallow zone wells except Well OB-17 are greater than the recommended Secondary Maximum Contaminant Levels (MCLS) of 900 pmhoslcm for EC and 500 mglL for TDS, respectively. The elevated TDS levels in the northeastern quadrant of the site are likely caused by the eucalyptus trees' concentrating effect on TDS. The elevated TDS levels observed along the western portion of the site, particularly in the southwest corner, probably reflect the infiltration of higher TDS water originating at the City of Ripon's WWTF encroaching onto the Diamond site. 39. After the paper mill was closed in May 2009, Ripon Cogeneration, LLC continued to discharge and dilute the discharge with lower salinity fresh water. Since then, the groundwater TDS concentrations in wells OB-2, OB-08, OB-10, OB-18, OB-19 and OB-20 have slightly decreased. However, the TDS concentrations in other shallow zone wells have not changed significantly. 40. The predicted wastewater TDS concentration of 684 mglL is less than the TDS concentrations in the shallow zone groundwater monitoring wells at the site, except for the wells near the river(Wells OB-17 and OB-22). Based on the projected effluent quality, the method of disposal and existing groundwater quality, it is unlikely that the proposed discharge will significantly degrade the groundwater quality for TDS. 41. The groundwater monitoring network should be designed to yield samples representative of the upper most portion of the first aquifer underlying the site. Therefore, this Order requires the Dischargers to monitor certain monitoring wells in the first aquifer zone. Those unused monitoring wells, which are not required to be monitored in this Order and are not monitored by Nestle for remediation, can be destroyed with the approval of the Central Valley Water Board. This Order requires the Dischargers to submit a Groundwater Monitoring Well Destruction Plan. Basin Plan, Beneficial Uses, and Regulatory Considerations 42. The Water Quality Control Plan for the Sacramento River and San Joaquin River Basins, Fourth Edition (hereafter"Basin Plan") designates beneficial uses, establishes water quality objectives, contains implementation plans and policies for protecting waters of the basin, and incorporates by reference plans and policies adopted by the State Board. Pursuant to Water Code section 13263(a), waste discharge requirements must implement the Basin Plan. 43. The site is immediately adjacent to the Stanislaus River, which is the southern property boundary of the facility. Local drainage is to the Stanislaus River. The designated beneficial uses of the Stanislaus River, as specified in the Basin Plan, are municipal and domestic supply; agricultural supply; industrial process and service supply; hydropower generation; water contact recreation; non-contact water recreation; warm and cold fresh water habitat; cold water migration of aquatic organisms; spawning, reproduction, and for early development; and wildlife habitat.