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k4 KLEINFELDER 3.1 MONITORING WELL INSTALLATION AND SAMPLING In order to assess the shallow groundwater at the site Kleinfelder proposes to install two groundwater monitoring wells at the site near the upgradient eastern edge and downgradient western edge of the site. By locating at least one monitoring well in the upgradient position an initial point of groundwater flow through the site can be assessed. By locating the second monitoring well in the downgradient position to the site it appears logical that any migration of contaminants through the shallow subsurface at the site would be intercepted. The monitoring wells would be installed into first encountered groundwater. The following sub-tasks-describe the process. 3.1.1 Permitting and Pre-Field Activities The San Joaquin County Environmental Health Department (EHD) requires completion of a well permit, and payment of fees prior to installation of monitoring wells. Once contracted to conduct the work, Kleinfelder will prepare drilling permit applications for submittal to EHD along with the required.fees. The permits must be approved prior to drilling activities and sampling. EHD usually requires approximately two weeks to issue the permits. Kleinfelder will also prepare a site specific health and safety plan prior to implementation of any work on the site. The drilling subcontractor will contact Underground Service Alert 48 hours prior to conducting fieldwork to notify local utilities of our proposed subsurface assessment. 3.1.2 Monitorim, Well Installation The proposed well locations will be selected to ascertain groundwater conditions upgradient and downgradient on the property. Please see Plate 2 for the proposed locations of the monitoring wells. The soil borings will be drilled with a truck mounted drill rig equipped with 6 to 8-inch hollow stem augers. During advancement of the soil borings, soil samples will be collected continuously in one boring and every 5-feet in the remaining soil borings for lithologic classification. Lithologic classification will be based on the Unified Soil Classification System (USCS). All equipment used in the drilling and installation procedures will be cleaned and/or decontaminated as described in Appendix A. Based upon available information, we anticipate groundwater in the vicinity of the project site to be present at a depth of approximately 10 to 20 feet below the ground surface, with a groundwater flow direction to the north-northwest. Kleinfelder proposes to analyze three (3) soil samples from each boring. The first soil sample will be collected at the surface. The second soil sample will be collected at 5 feet below the ground surface, and the third soil sample will be collected just above groundwater. After collection, the soil samples will be labeled, logged on a chain-of-custody, and immediately stored in an iced cooler. The samples will be analyzed as described in Chapter 4. 27125.E01 /ST03R657 Page 5 of 15 Copyright 2003,Kleinfelder,Inc. May 23,2003