ARCHIVED REPORTS_RPT OF WASTE DISCHARGE FOR WASTEWATER DISPERSAL 2011

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Diamond Pet Food Processors of Ripon,LLC June 30,2011 Report of Waste Discharge Page 7 of 17 Four distinct aquifers or zones have been identified beneath the site and have been designated by Lawrence &Associates 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 deep zone from 240 to greater than 300 feet bgs. Permeability in the aquifer zones has been estimated at approximately 525 gpd/square foot; permeability in the confining layers has been estimated at 3.5 gpd/square foot.3 The direction of the groundwater gradient in the semiperched and upper semiconfined zones in the vicinity of Ripon is generally to the west.4 North of Ripon, the direction of the groundwater gradient is to the north. Southwest of Ripon, on the southwest side of the San Joaquin River, the groundwater gradient is to the north, towards the river. LOCAL HYDROGEOLOGIC SETTING Figures 10, 11, and 12 show groundwater elevation contour maps for October 2010, for the semiperched,upper, and intermediate zones, respectively. The deep zone is not contoured, as there is only one monitoring well at the site for that zone. All groundwater elevation (and quality) data previously have been presented in quarterly monitoring reports, and will not be included here.5 Mounding within the semiperched aquifer occurred offsite in the vicinity of the City of Ripon's wastewater treatment plant(WWTP)ponds and their fresh water infiltration pond. The gradient was extremely flat across most of the Diamond site. The direction of the groundwater gradient was away from the mound, and then generally towards the north. The magnitude of the gradient ranged between 0.0031 and 0.0017 feet/foot(ft/ft; Figure 10). Mounding also was present in the upper aquifer in approximately the same general areas where mounding was observed in the semiperched aquifer. The direction of the groundwater gradient was away from the mound, then generally towards the northeast. The magnitude of the gradient ranged between 0.0028 and 0.00156 ft/ft (Figure 11). Mounding within the intermediate aquifer was present in approximately the same general areas where mounding was observed in both the semiperched and upper aquifers. The direction of the groundwater gradient was away from the mounds, then generally towards the north. The magnitude of the gradient ranged between 0.0018 and 0.0031 (Figure 12). 3 Ibid., p.27. 4 Ibid., Figure 3. 5 For example,Lawrence&Associates,February 2010,Combined 2010 Annual Summary Report, 4th-Quarter 2010 Groundwater-Monitoring Report,And Preliminary Corrective Action Evaluation,Diamond Pet Foods,Ripon, California. 010107.00, Task I Lawrence&Associates w:Iclientsl diamond pet foods1010107.00-ripon rowdldiamondpet_rowdjune2011_draft.docx