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1.0 INTRODUCTION, RPOSE AND SCOPE Tri/Valley Growers (TVG) Plant No. 4 is located at 3200 East Eight Mile Road in Stockton. The plant will discharge up to 4.0 million gallons per day (mgd ) by flood irrigation over an area of approximately 350 acres. The effluent is pumped from an open conveyance ditch to the reclamation/disposal areas . Wastewater is applied such that no tailwater is created. The plant and disposal areas are shown on Figure 1 . Surface disposal is regulated under waste discharge require- ments and Monitoring and Reporting program No. 88-147, which require the preparation of a technical report delineating hydrologic conditions at the site and assessing potential impacts on groundwater quality due to land disposal. 2.0 DATA COLLECTION/SAMPLING PLAN 2. 1 Monitor Well Installation and Development Five groundwater monitoring wells were installed to provide water quality data for evaluating the impact of process water disposal on the groundwater beneath the site, and to provide measurement points for the determination of ground- water flow direction and hydraulic gradient. Figure 1 shows the locations of the wells. Each well was constructed with 2-inch F480 polyvinyl chlo- ride (PVC) casing. The screened interval of each well was positioned from approximately five feet above to 15 feet below the encountered water table to allow for seasonal water level fluctuations . The screen slot size is 0. 01 inch. The boring for each well was advanced with 8-inch outside diameter hollow stem augers. When the augers were advanced to the desired depth, the well casing was lowered down the center of the augers and set to the appropriate depth. The annular space between the augers and the screened portion of the well was backfilled with Lonestar #2/12 sand. As the filter pack was placed, the augers were withdrawn from the borehole so the sand flowed from the augers and into the annular space of the borehole. The filter pack was extended to approximately two feet above the top of the screened portion of the casing. A two foot seal of bentonite clay was placed in the annular space above the filter pack . Since the bentonite seal was positioned above the water table, five gallons of potable water was added to allow the bentonite to swell . The remaining annular space was back- filled to the surface with a neat cement slurry. 1