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...ese 11 Environmental Site Assessment Work Plan Buena Vista Storm Drain,Stockton,CA February 7,2005 Page-2- 3.0 DIRECT PUSH BORING FIELD PROCEDURES This section includes a description of the site preparation and direct push boring procedures. 3.1 SITE PREPARATION Condor will complete a boring permit application for submittal to the San Joaquin County Environmental Health Department (SJCEHD) and an encroachment permit application for submittal to the City of Stockton. Condor will obtain the required permits prior to initiating fieldwork. The proposed boring locations will be marked with white paint and Underground Service Alert (USA) will be notified at least 48 hours in advance of the fieldwork to locate and identify underground utilities in and near the work area. 3.2 DIRECT PUSH BORING PROCEDURES Prior to commencement of fieldwork, a tailgate safety meeting will be held and a site-specific Health and Safety Plan will be discussed with, and presented to, all field personnel for their signatures. Twelve direct push borings will be installed for the purpose of collecting groundwater samples. The proposed borings are located in the right-of-way areas adjacent to properties that have the greatest potential to have impacted groundwater rather than being evenly spaced along the new storm drain collection system alignment. The proposed direct push boring locations are shown in Figure 2, Appendix A. The direct push borings will be hydraulically advanced to a depth of 20 feet below ground surface (bgs) using a 1.5-inch diameter conical bit. The bit and associated push rods will be thoroughly cleaned before each boring is advanced using laboratory-grade, non-phosphate detergent and deionized water and double rinsed with deionized water. After the bit is advanced to 20 feet bgs, the bit and push rods will be withdrawn from the boring. Five feet of Y4-inch PVC screen and 15 feet of blank 3/-inch PVC casing will be temporarily installed in the boring. Groundwater will flow hydrostatically from the formation into the screen. The depth to water in the boring will be measured. The boring will be marked with traffic cones and the direct push rig will be moved to the next boring location. Approximately eight of the borings will be installed in this manner during the first day of fieldwork. After the eight borings are installed, one groundwater sample will be collected from each boring, starting with the first boring that was installed. The purpose of installing all of the borings that are to be installed in one day of fieldwork prior to collecting groundwater samples from the borings is to allow the groundwater level in the temporary screens to stabilize. The depth to water will be measured in each boring before the groundwater sample is collected. The depth to water data will be used in planning for dewatering during construction. A groundwater sample will be collected from within the PVC screen in each boring with a length of clean, 3/8-inch diameter polytygon tubing equipped with a check valve at the bottom. The tubing will be moved up and down by hand to draw groundwater up inside the tubing. The groundwater samples will be discharged directly from the tubing into laboratory supplied sample containers. The sample containers will be sealed, labeled, placed in a cooler chilled with ice, and delivered under chain-of-custody procedures to a California certified laboratory for analyses. Upon completion of the borings and sample collection each day, the borings will be grouted with neat cement. It is anticipated that eight borings will be completed during the first day of fieldwork, and the four remaining borings will be completed on the second day. 4" IL 41 CONDOR