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Cease and Desist Order R501 - 4 - San 4 -San Joaquin County Department of Public Works Corral Hollow Sanitary Landfill San Joaquin County 21. In December 2006, Central Valley Water Board staff senna Notice of Violation for the continued detection of VOCs in groundwater at monitoring well MW-5, and directed the County to conduct an evaluation monitoring program (EMP) to define the nature and extent of the release from the WMU. On 9 March 2007, Central Valley Water Board staff issued a second Notice of Violation letter for VOCs present in groundwater at monitoring well MW-5. 22. In March 2007, the County submitted an Evaluation Monitoring Program (EMP) work plan. In a letter dated 11 April 2007 Board staff approved the EMP. However, the County requested that it not be required to implement the EMP and instead install additional corrective action measures. The County stated that LFG was the cause of the continued groundwater impacts and that additional LFG extraction wells installed adjacent to the northeastern property boundary would remediate the impacts. 23. In November 2007, an EMP was conducted, consisting of exploring for the presence of shallow groundwater along the northern and southern boundaries of the landfill. The investigation encountered a shallow groundwater aquifer approximately 400 feet west of MW-5, and monitoring well MW-8 was installed at that location. No shallow groundwater was detected further west than MW-8. On the southern boundary of the landfill, the borings did not encounter shallow groundwater to the west of MW-4 and therefore, no monitoring wells were installed. 24. On 14 January 2008, VOCs were detected in monitoring well MW-8. The . compounds and concentrations detected indicate that the source of ground water contamination emanates from an area near MW-5, most likely from LFG not captured by the existing LFG system. 25. In December 2008, five new LFG extraction wells were installed for a total of 44 LFG extraction wells. The additional wells were placed to control LFG impacts to groundwater near MW-5. 26. Groundwater monitoring wells MW-5 and MW-8 continue to contain VOCs, including tetrachloroethene (PCE), at concentrations over the Public Health Goal of 0.06 pg/L and the Title 27 Water Quality Protection Standard of non-detect. VOCs have been detected in well MW-5 since 1991, and although the number of compounds reported has decreased since corrective action has been implemented, ten VOC compounds were reported in well MW-5 during the fourth quarter 2010 groundwater monitoring event. 27. The additional LFG extraction wells installed in 2008 to abate detected pollution in wells MW-5 and MW-8 have had little effect on groundwater impacts observed. In a letter dated June 2010, the County stated that the uncovered refuse identified outside the WMU is a likely contributor to groundwater degradation. 28. On 7 July 2011, the Executive Officer issued a Water Code Section 13267. Among other items, the Order required the County to submit an Evaluation