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

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INFORMATION SHEET 4 WASTE DISCHARGE REQUIREMENTS ORDER R5-2012-0105 DIAMOND PET FOOD PROCESSORS OF RIPON, LLC AND RIPON COGENERATION, LLC DIAMOND PET FOOD RIPON FACILITY SAN JOAQUIN COUNTY are located at the Diamond site but owned by Nestle USA, Inc. Therefore, Diamond is monitoring a total 47 monitoring and supply wells. . Shallow groundwater is typically encountered approximately 35 feet below ground surface and the shallow groundwater flow direction is variable. The July 2010 groundwater elevation data show that mounding occurred in the vicinity of the Discharger's west percolation field and offsite north of the City of Ripon's WWTF ponds, which are immediately west of the Diamond site; however, the July 2011 groundwater elevation data show that the groundwater flow was away from the Stanislaus River and towards the northwest. In general, mounding occurs onsite and offsite in the vicinity of the City of Ripon's WWTF ponds. The City's WWTF treats up to 2.0 mgd and disposes of wastewater via percolation/evaporation ponds and land application area. Shallow groundwater quality has been characterized by monitoring wells in the first aquifer zone since January 1992. Based on recent shallow zone groundwater monitoring data from February 2007 through October 2011, the groundwater average TDS concentrations ranged between 630 mg/L and 1,449 mg/L in the compliance wells. 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. The predicted wastewater TDS concentration of 684 mg/L is less than the TDS concentrations in the 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. This Order requires the Dischargers to monitor certain monitoring wells in the first aquifer zone. Unused monitoring wells that 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. Discharge Prohibitions, Specifications and Provisions Influent flows to the clarifier shall not exceed the following limits: