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KLElNFELDER EXPECT MORE" 2 DRILLING DETAILS AND MONITORING WELL DESIGN The San Joaquin County Department of Environmental Health (EHD) requires completion of a well permit including establishment of a Master File Record (MFR) for the site, and payment of fees prior to installation of monitoring wells. Kleinfelder will prepare drilling permit applications and aid in preparing the MFR (if not previously done) for submittal to EHD along with the required fees. The permits must be approved prior to drilling activities and sampling. EHD usually requires up to two weeks to issue the permits. The drilling subcontractor will contact Underground Service Alert 48 hours prior to conducting fieldwork to notify local utilities of our proposed subsurface assessment. Kleinfelder will additionally prepare a health and safety plan prior to the actual field assessment. 2.1 DRILLING DETAILS An experienced staff or project geologist/engineer will be present during drilling operations under the direction of a California professional geologist. The well borings will be drilled with a truck mounted drill rig equipped with 8-inch hollow stem augers. During advancement of the soil borings, soil samples will be collected at five-foot intervals for lithologic classification. Samples will be collected from a California-modified split-spoon sampler lined with stainless steel tubes. Lithologic classification will be based on the Unified Soil Classification System (USCS). To reduce the potential for cross-contamination, augers and associated equipment will be steam cleaned prior to drilling each boring. In addition, down-hole sampling equipment that is not steam cleaned will be cleaned with a laboratory grade detergent (Liquinox) followed by a potable and distilled water rinse. 2.2 MONITORING WELL DESIGN Groundwater elevations as of the third quarter of 2006 have ranged from approximately 3 to 4 feet above mean sea level (msl). This is fairly consistent with projected groundwater elevations based on groundwater modeling summarized in the background summary (Attachment B). Surface elevations at the site are approximately 12 to 17 feet above msl. Groundwater elevations may continue to rise at this site, based on former pumping of Oakwood Lake. Kleinfelder anticipates groundwater in the vicinity of the project site to be present at a depth of approximately 10 feet bgs, with a groundwater flow direction towards the west/northwest. Based on this information the well borings will be advanced to approximately 20 feet bgs. 48093.E01/ST07R052/CJC/Iv Page 5 of 15 ©2007 Kleinfelder, Inc January 26,2007