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Two samples will be taken downgradient of each impacted area, one sample at the southern <br /> boundary of Impacted Area #2, GW-2 and one sample 20 feet south of Impacted Area #1. <br /> Figure 5 depicts the groundwater sampling locations. The samples will be collected at two feet <br /> below groundwater, which is expected to be 9 feet bgs based upon nearby groundwater <br /> measurements. <br /> To sample the groundwater,the four boreholes will be accomplished with a hydraulic push probe <br /> device which does not generate drill cuttings. The device is 1 and 3/4 inch diameter probe made <br /> of stainless steel with a screen assembly at the top behind the expendable drive point. The probe <br /> will be driven down approximately one foot below the target sampling depth, two feet below <br /> groundwater. Once that depth has been reached, the expendable drive point will be disengaged <br /> while the push rod is retracted exposing the inlet screen. Groundwater will flow hydrostatically <br /> from the formation into the inlet screen. A small diameter bailer (1/2-inch) will be lowered <br /> through the hollow push rods into the screen section for sample collection. <br /> The four samples and one quality control sample will be analyzed for TPH diesel and hydraulic <br /> oil by EPA Method 8015 modified. <br /> 3.5 Delineation Sampling <br /> Concurrent with the groundwater sampling activities, two borings will be hand augured to 2 feet <br /> bgs and sampled to define the extent of contamination in the north section of Impacted Area #1. <br /> HA-1 will be located approximately 1 foot south of the asphalt crossing and HA-2 will be placed <br /> 15 feet south the asphalt crossing. Both will be centered along the railroad track.. Figure 5 <br /> depicts the sampling locations. The samples will be analyzed for TPH diesel and hydraulic oil <br /> by EPA Method 8015. <br /> Rough&Ready Island 15 Tetra Tech,Inc. <br /> Revised Draft Work Plan November 18, 1998 <br />