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0 0 <br /> Section 3. Sampling Location and Rationale <br /> The boring locations have been determined based on the areas planned for excavation and have been <br /> placed in an arrangement designed to most effectively characterize the contaminated soil to be excavated <br /> (See Figure 2). Forty eight soil borings will be drilled to the top of the water table, which has a predicted <br /> average depth of 11 feet bgs. As shown on Figure 2, 32 of the 48 boring locations are in Area 2A, within <br /> eight gridded areas and will be used to collect 24 four-point horizontal composite samples. Soil samples <br /> will be collected from the following depth intervals at each boring location: <br /> ■ One sample at 2 feet bgs representing approximately 0-4 ft bgs <br /> ■ One sample at 6 feet bgs representing approximately 4-8 ft bgs <br /> ■ One sample at 10 feet bgs representing approximately 8-12 ft bgs <br /> Following sample collection, samples will be submitted to the analytical laboratory to be composited into <br /> four-point composites. Samples collected from the same grid at the same depth interval will be <br /> composited together. A total of three composite samples will be submitted from each grid, for a total of <br /> 24 samples submitted from the 8 grids shown on Figure 2. <br /> Additionally 13, four point vertical composite samples will be collected from both Areas 2A and 24 at the <br /> locations shown on Figure 2. These samples will be collected from four discrete depths within a single <br /> boring and composited by the analytical laboratory for a total of 13 composite samples from these <br /> locations. A total of 37 composite samples will be submitted to the analytical laboratory and analyzed for <br /> the COCl. <br /> Three temporary piezometers will be installed within Area 2A, and two temporary piezometers will be <br /> installed at 24, at the boring locations shown on Figure 2. These piezometers are being installed to <br /> determine depth to groundwater and to characterize groundwater for treatment and/or discharge to the <br /> sanitary sewer during future excavation remedial construction activities tentatively scheduled to begin in <br /> August 2008. Once the soil samples are collected from a boring to be used as a piezometer, the boring <br /> will be advanced to a total of 20 feet bgs and the temporary well casings will be installed. The three <br /> piezometers in area 2A will be positioned from south to north, throughout the excavation area. One <br /> temporary piezometer will be placed in the northern portion of Area 2 near west Weber Street. One <br /> temporary piezometer will be located in the midsection of the property and one temporary piezometer will <br /> \con4sOPprojeds\2008_PmjectsUM78 City W Stockton SNI ExpvationO.Onginals\Sawling and Analysis Plan\Stockton_SAP_Diah 0U408_bh.doc <br /> 3-1 <br /> ERRG <br />