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SCOPE OF SERVICES Outlined below is a summary of the scope of services to be performed by Geocon under TO No. 10- OA5100-BG. Pre-field Activities • A pre-work site visit and TO meeting were conducted on April 15, 2003 to observe the work area, review project drawings and mark the proposed boring locations with white paint. Caltrans representative Mr. Gary Gagliolo and Geocon representatives Mr. David Bieber and Mr. John Mattey attended the pre-work meeting. • A Health and Safety Plan (HSP) is being prepared concurrently with this Workplan. The HSP will provide guidelines on the use of personal protective equipment and the health and safety procedures to be implemented during the proposed field activities. • Geocon will obtain a drilling permit from the San Joaquin County Environmental Health Department prior to performing the subsurface investigation. • Geocon will provide 48-hour notification to Underground Service Alert prior to performing the subsurface investigation. • Geocon will retain the services of Spectrum Geophysics, a Caltrans-approved and California- licensed geophysical subcontractor, to perform the geophysical surveys to attempt to locate USTs and provide utility location services. • Geocon, a California C57-licensed contractor, will provide the drilling equipment and perform the subsurface investigation. • Geocon will retain Creek Environmental Laboratories, Inc., a California-certified and a Caltrans- approved subcontractor, to perform chemical analyses of the soil samples. Geophysical Survey The geophysical survey will involve attempting to locate buried objects such as USTs, piping, sumps and utilities with ground penetrating radar (GPR) and EM-61 electromagnetic equipment. Electromagnetic methods are the most frequently employed techniques to detect underground utilities made of or containing conductive materials e.g. steel, copper. Examples of these utilities include water, natural gas lines, fuel lines, electrical utilities and telephone utilities. The EM61 measures the induced radio frequency (RF) of the utility. Often, buried electrical and telephone utilities radiate their own electromagnetic field and can be readily detected using the radio frequency (RF) receiver without inducing a current. By detecting the maximum signal strength at several locations, the surface trace of an underground utility can be determined. The EM61 equipment is used to induce an RF signal in conductive objects buried to depths as great as 4.6 meters(m)(15 feet)below ground surface(bgs). The geophysical surveys will be conducted along traverses within the vicinity of the service station building, pump island, presumed septic tank location and AST. The locations of recorded anomalies will be field mapped. A Geocon representative will be onsite during the geophysical survey. Project No.S8475-06-70 -2- April 30,2003