SITE INFORMATION AND CORRESPONDENCE_FILE 1

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Monitoring and Reporting__ogram No. 5 J.R. Simplot Company Lathrop, San Joaquin County 3. Groundwater Monitoring The following Groundwater Monitoring Program shall be implemented at the facility. The Discharger shall analyze samples from the water table groundwater monitoring wells LP-4, LP-5, LP-6 and LP-7 for the parameters and constituents at the indicated frequencies as shown in Table 2 below and report the analytical results to the Regional Board. The Discharger shall sample and analyze annually monitoring wells LP-1, LP-2, LP-3 and LP-1- 48 for the parameters and constituents on Table 2. All annual sampling shall be conducted alternately during the first and third quarters and reported in the associated quarterly monitoring report. Monitoring wells LP-1 and LP-2 monitor the deeper portion of the aquifer near the locations monitored by water table wells LP-4 and LP-5, respectively. PW- 1-48 and LP-3 are completed below the water table and are cross-gradient and/or downgradient of the surface impoundments, depending on the groundwater gradient at the time of monitoring. Monitoring data from these wells will be used to determine if pollutants in groundwater are migrating downward or cross-gradient. Groundwater sampling shall include an accurate determination of the groundwater elevation and field parameters for each compliance monitoring point and background monitoring point. Groundwater elevations taken prior to purging the well and sampling for monitoring parameters shall be used to fulfillthe groundwater gradient/flow direction analyses required. For each monitored groundwater body, the Discharger shall measure the water level in each well and determine groundwater gradient and direction at least quarterly, thereby including the times of expected highest and lowest elevations of the water level for the respective groundwater body. Groundwater elevations for all background and downgradient wells for a given groundwater body shall be measured within a period of time short enough to avoid temporal variations in groundwater flow which could preclude accurate determination of groundwater gradient and flow direction. This information shall be included in the quarterly monitoring reports. The groundwater elevation in all wells shall be used in conjunction with available hydrogeologic data to determine the velocity and directions of groundwater flow. The Discharger annually shall submit groundwater contour maps and/or groundwater flow nets prepared from the maximum wet weather and minimum dry weather water level measurements and hydrogeologic information pertaining to this site. All springs, seeps, and creeks within 1,000 feet from the site shall be identified and used in preparing the groundwater contour maps and/or flow nets. All parameters shall be graphed to show historical trends at each well.