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ORDER NO. R5-2002-0225 -2- ALPINE PACKING COMPANY,INC. WASTEWATER TREATMENT FACILITY SAN JOAQUIN COUNTY to one of two sumps for settling, and then it is piped to the wastewater treatment ponds. There are four ponds in series. Wastewater is pumped from the last pond to a 14-acre land treatment unit. Because the ponds are maintained at relatively constant levels, there is little available storage provided in the ponds. The lack of storage combined with the lack of evapotranspiration in the winter months indicates wastewater is being applied to land at inappropriate times during the winter months. The Discharger is required to perforin an evaluation of the storage capacity and construct improvements if needed. The treated wastewater is applied to a 14.0-acre land treatment unit. Approximately 66-acres are available for land treatment but were not proposed for use in the Report of Waste Discharge. This Order allows the additional land treatment unit(s)to be designated for use upon submittal of technical reports and approval of the Executive Officer. The Discharger plans to flood irrigate the land treatment unit; use of sprinklers to apply the water is acceptable if the discharge is performed in accordance with the WDRs. Groundwater Quality Groundwater monitoring wells were installed at the site in 2001. Based on three groundwater monitoring events, groundwater downgradient of the land treatment unit contains elevated concentrations of dissolved solids. This Order requires installation of additional wells, an evaluation of groundwater quality, and if requested by.the Executive Officer, a Mitigation Plan to address groundwater degradation. The Discharger has objected to the use of monitoring wells located upgradient and downgradient of the land treatment unit as being unrepresentative of present conditions. Staff agree that the previous discharge of larger amounts of wastewater may have degraded the groundwater below the land treatment units. However, it is noted that the wastewater being discharged presently, with the exception of TKN, possesses higher concentrations of dissolved solids than wastewater discharged prior to February 1999. To better evaluate any impact on groundwater quality the wastewater application is having, characterization and monitoring of vadose zone quality is required. The Discharger is required to prepare a vadose zone workplan that recommends investigation and monitoring techniques. The purpose of the monitoring is to determine whether the land treatment units are sufficiently treating the wastewater such that the underlying groundwater will not be degraded. The Discharger has stated the groundwater gradient may have reversed direction as measured in the 8 July 2002 groundwater monitoring event. However, the 21 July 2002 groundwater monitoring report prepared by Fall Creek Engineering, Inc. states, "The water level recorded for MW4 proved to be suspect." In the July 2002 sample event, data from only two of the four wells is considered reliable enough to determine groundwater depth. Groundwater gradient cannot be determined without three accurate data points. This indicates the depth to groundwater measurement data is questionable for the July 2002 monitoring event when the gradient reversal was reported. CAMy Docurwntsl Wyels50'BrienVW0.doe