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ATC Associates Inc. CVVATC 1617 Lone Palm ali orni Suite 1 Modesto,California 209-579-2221 AS SO 0 1 ATE S i N c. Fax:209-579-2225 From February 17 to approximately April 20, 2004, an ATG geologist supervised the installation of groundwater monitoring wells MW6c, MW7c, MW8, MW9a, MW9b, MW9c, MWl0a, MW10b, and MW10c. i A C-SpargeTM system was installed on site and became operational on June 17,2004. SCOPE OF WORK r Planning and Permits Upon approval of this workplan, ATC will evaluate the presence of underground utilities at each of the drilling sites by notifing Underground Services Alert (USA) as required and using aprivate utility locator to locate underground utilities and obtain encroachment permits from the City of Stockton and/or access agreements from property owners as necessary. If any boring locations are moved a significant distance, the San Joaquin County Environmental Health Department (EHD) will be promptly notified. Upon receipt of encroachment permits or access agreements, ATC will submit permit application and associated fees to EHD, ATC will schedule field personnel and equipment and perform other necessary field preparation and job start-up and safety activities. Advancement of CPT Soil Borings To assist in the characterization of the stratigraphy across the site, soil borings employing direct j push technology outfitted with Cone Penetrometer Technology(CPT) equipment will be avanced in seven different locations. The sensors in the CPT tip will measure the response of the soil to the force of the penetrating cone enabling the subsurface stratigraphy to be characterized. The CPT borings will be advanced until a significant clay layer is encountered that appears to separate the shallow aquifer from the deeper water bearing zones. To be considered significant, the clay layer will need to be approximately five feet in thickness or greater. Once significant clay layers have been discovered and the boring is advanced into an identified deeper water bearing zone (the C zone or deeper if allowed), the CPT boring will be terminated. ATC estimates these borings will be advanced approximately 120 feet bgs. if subsurface conditions allow it. The CPT logs will then be evaluated to identify psuspecte overlying aquitards and/or significant clay layers that have the potential to create hydraulically independent water bearing zones. Proposed boring locations are shown on Figure 2. After the subsurface stratigraphy has been characterized and each boring evaluated, discrete groundwater samples will be collected using the same direct push equipment but this time outfitted with a HydropuncO groundwater sampling collection device. Each boring will be advanced adjacent to but a sufficient distance away from the initial CPT boring to prevent re-entry into the first boring. The Hydropunce system includes an expendable drive point attached to a tool Jamar Service Station 3 i i i I