SITE INFORMATION AND CORRESPONDENCE

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CLEANUP AND ABATEMENT OSR NO.R5-2004-0705 • 2 DELICATO VINEYARDS WASTEWATER DISPOSAL SITE SAN JOAQUIN COUNTY 8. The first encountered groundwater below the site ranges from approximately 30 to 40 feet below ground surface. Groundwater flow direction is generally to the north,with an average gradient of 0.002 ft/ft. 9. Three groundwater monitoring wells (MW-1, MW-2, and MW-3)were constructed during the spring of 2001. MW-1 is south of both disposal areas and is considered to be representative of background conditions. MW-2 is immediately north of the southwest check and MW-3 is immediately north of the northeast check. MW-2 and MW-3 are considered to be hydraulically downgradient of the process water disposal areas. 10. The groundwater monitoring data indicate that concentrations of salt-related constituents often associated with winery wastewater are elevated in the two downgradient monitoring wells, as compared to concentrations in the background monitoring well. Average total dissolved solids (TDS) concentrations in MW-2 and MW-3 for 2001 through 2003 were 2,178 mg/1 and 1,763 mg/1 respectively as opposed to 1,105 mg/1 in background well MW-1. Average electrical conductivity (EC) concentrations in MW-2 and MW-3 for the same time period were 3,167 umhos/cm and 2,593 umhos/cm respectively as opposed to 1,587 umhos/cm in MW-1. The average calcium, sodium, magnesium, alkalinity, chloride, and sulfide concentrations in the downgradient wells were also elevated, ranging from two to six times higher than in the background well. Enforcement History 11. On 15 September 2003, Regional Board staff issued a Notice of Violation(NOV) to the Discharger for violation of the Groundwater Limitations contained in WDRs Order No. 96-077. The NOV requested the preparation and submittal of a Groundwater Degradation Evaluation Report to confirm whether or not the discharge is degrading the underlying groundwater. 12. On 29 December 2003, the Discharger submitted a report titled Report: Groundwater Degradation Evaluation Delicato Vineyards. The report concluded that the wine processing combined with waste application practices are contributing to the degradation of groundwater quality in the vicinity of the waste application areas. The report also indicated that the Discharger was assessing its process chemical usage and attempting to reduce the use of chemicals that were impacting groundwater quality. 13. Regional Board staff has completed a review of this report and concur with the report conclusions. A C&A Order is appropriate to ensure that the Discharger takes appropriate actions in a timely manner to prevent further groundwater degradation. Regulatory Considerations 14. The Regional Board's Water Quality Control Plan for the Sacramento and San Joaquin River Basins (Basin Plan) designates beneficial uses, includes water quality objectives to protect the beneficial uses, and includes implementation plans to implement the water quality objectives. 15. As a result of the events and activities described in this Order, the Discharger has caused or permitted waste to be discharged in such a manner that it has created, and continues to threaten to create, a condition of pollution or nuisance and potential public health threat. Water quality objectives in the Basin Plan include state drinking water standards by reference to Title 22