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F conversation with SJCEHD personnel, Caltrans proposed the destruction of wells MW-7, MW-8 and p p P MW-9 and installation of replacement wells MW-13, MW-14 and MW-15 with shallower screened intervals. In correspondence dated April 24, 2008, the SJCEHD requested preparation of a Site Conceptual Model (SCM). Once data has been obtained from the replacement wells, we will prepare the requested SCM. The purpose of the well installation and well destruction activities is to further evaluate impacted groundwater in shallow zones beneath the Site. The services requested by Caltrans consist of the installation of three groundwater monitoring wells and destruction of three groundwater monitoring wells. SCOPE OF SERVICES The following scope of services will be provided under Task Order No. 45: Pre-field Activities • Utilize the existing project-specific health and safety plan (HSP) to provide guidelines on the use of personal protective equipment and the health and safety procedures to be implemented during the proposed field activities. • Mark the proposed soil boring locations with white paint as required by law and provide a minimum of 48-hours notice to the local public utilities via Underground Service Alert(USA).We will also subcontract with a private utility locating service to further attempt to delineate subsurface public utilities and conduits in proximity to the proposed boring locations. • Obtain permits and pay requisite fees to the SJCEHD for the hollow-stem auger (HSA) well installation and well destruction activities. • Retain the services of Gregg Drilling, a Caltrans-approved, C57-licensed drilling company to perform the well installation and well destruction activities. • Retain the services of Advanced Technologies Laboratories (ATL), a California-certified analytical laboratory(ELAP No.,1838)to perform the analyses of soil samples if warranted. • Retain the services of Morrow Surveying, a California-licensed land surveyor, to provide latitude and longitude coordinates and top of casing elevations for each of the new monitoring well locations. Field Activities Well Installation Activities The well installation activities will consist of the advancement of three hollow-stem auger drilled soil borings for the purpose of installing groundwater monitoring wells. The proposed boring locations are depicted on Figure 2. Each boring will be advanced to approximately 15 feet below first encountered groundwater (approximately 60 feet below the ground surface) utilizing a HSA drill rig. Soil samples will be obtained in 6-inch-diameter stainless steel sample tubes at selected depth intervals for logging and screening purposes, and analytical testing where warranted. Stockton Yard Maintenance Station,Task Order No.45 Caltrans Contract 06A1141,EA lO-ON8300 Project No.S9200-06-45 -2 - June 26,2008