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REVISED CLEANUP AND ABATEMENT ORDER NO. 5-01-703 -4- CITY 4- CITY OF RIVERBANK WASTEWATER TREATMENT PLANT STANISLAUS COUNTY the Discharger to submit a pond water balance to show that the facility's disposal capacity was in compliance with the WDRs. 18. On 29 August 2000, staff received a verbal report from the Discharger that the western berm of the Summer 2 percolation pond failed two days earlier. A small berm leak was observed during a routine inspection, and the Discharger mobilized emergency repair crews, but they were unable to control the leak and the berm suddenly collapsed. Approximately 20 million gallons of treated effluent were discharged into neighboring walnut orchards owned by private citizens. Some of the effluent entered an agricultural drain that discharges to the Stanislaus River, but due to the poor state of the channel, it was not possible to determine the volume of effluent discharged to the river. The Discharger was unable to return any of the ponded effluent to the ponds because no excess capacity was available. The remainder of the affected pond was drained to the Summer 3 pond (which had been drying out in preparation for routine maintenance) and repairs were made soon thereafter. However, as a result of the temporary loss of capacity, the Discharger had to divert effluent flows to the Summer 3 pond, which had been drying out in preparation for discing to enhance percolation rates. Consequently, the Discharger did not perform any pond maintenance in 2000 to alleviate the reduced percolation capacity. 19. On 5 October 2000, staff met with the Discharger to discuss the recent pattern of serious violations. The Discharger stated that the current freeboard problem was not an indication of a capacity problem based on a recently completed water balance. The Discharger planned to dry and disc the Summer 2 or 3 Pond in the spring of 2001 before the start of the canning season, and at least two of the Winter Ponds would be ripped in early 2001. The status of other ongoing improvements was also discussed. 20. On 18 October 2001,the Executive Officer issued an NOV and Water Code Section 13267 Request for Reports. The Discharger was required to submit the following reports: a. Monthly status reports for the storm drain segregation project;the plant upgrade and expansion project; percolation pond ripping; the lift station back-up power system project; the lift station telemetry system project; and implementation of the Pretreatment Program Assessment Report. b. A Pond Berm Evaluation Report that identified each problem or potential problem observed; the nature and extent of the problem; recommended repair measures; recommendations for preventative maintenance; a recommended schedule for repairs and preventive maintenance; and recommendations for frequency of future inspections. c. A Water and Wastewater Systems Evaluation and Planning Report including a description of existing conveyance, treatment and disposal systems; a hydraulic capacity evaluation; an evaluation of future capacity needs; a description of improvements needed to bring the facilities up to current standards; a preliminary scope and schedule for capacity improvements; and an evaluation of user rates. 21. On 6 November 2000, the Discharger submitted a technical report that included the following: a. A review of existing conditions and system capacity for the wastewater treatment plant. The report concluded that there was sufficient excess treatment capacity to serve 2,400 additional residences and sufficient excess disposal capacity to serve an additional 3,600 residences as