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i <br /> . I <br /> ameO <br /> 3.3.4 Abandonment of Soil Borings <br /> 9 <br /> Upon completion of drilling and grab groundwater sample collection, the borings will be <br /> abandoned in accordance with state and San Joaquin County standards. The boreholes will <br /> be filled with an approved grout mixture using a tremie pipe and the surface will be repaired to <br /> match existing grade. <br /> 3.4 WELL INSTALLATION <br /> The rationale and location of each proposed well, soil screening and sampling procedures, <br /> well installation procedures, and well development activities are described in the following <br /> sections. <br /> 3.4.1 Rationale and Location <br /> An AS well will be installed for use as the pilot test well. Atmospheric air will be pumped into <br /> this AS well and will diffuse into the saturated subsurface. Perimeter observation wells will be <br /> installed and used to monitor field parameters during the proposed AS pilot test. While the <br /> exact location of the AS test wells will be determined from the results of the CPT/ MIP <br /> investigation, the rationale and general locations for the AS test wells are described below: <br /> hydrocarbon <br /> AS well AS-1 will be installed in the area with the highest petroleum h <br /> • 9 P Y <br /> impacts identified during the source area characterization activities. <br /> • Groundwater observation wells OW-1 through OW-3 will be installed approximately <br /> 4, 7 and 10 feet from AS-1, in varying directions to measure the effects of AS <br /> influence during the proposed test. <br /> 3.4.2 Drilling and Well Installation Procedures <br /> AS-1, OW-1, OW-2, and OW-3 will be installed using hollow stem auger(HSA) drilling <br /> techniques. All drilling and well installation activities will be conducted under the supervision <br /> of a California Professional Geologist. Below are the proposed completion details for each <br /> well: <br /> • AS-1 will be constructed of 2-inch diameter Schedule 40 PVC with 2:-feet of well <br /> screen at the bottom of the well. The well will be screened entirely in the saturated <br /> zone (minimum of 2 feet below the water table)and at depths consistent with the <br /> highest petroleum hydrocarbon impacts measured by the MIP. <br /> • OW-1 through OW-3 will be constructed of 2-inch diameter Schedule 40 PVC <br /> installed at varying distances to AS-1. Each observation well will have Afeet of <br /> well screen installed across the water table. <br /> L.a AMEC Geomatrixnc. <br /> PAProject\14000s\14443_Caltrans\TO 10\11000_PLANS\AS WP March 2010WS WP.doc <br />