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Catherine Quinn <br /> Page 4 <br /> June 27,2002 <br /> Approach <br /> The extent of petroleum hydrocarbon affected groundwater from the hydrocarbon soils that <br /> were excavated in November 2001 will be assessed by performing field investigations,with <br /> samples collected in a step-wise manner away from the release point to maximize the value <br /> of information gained during the course of the work. The field investigation will utilize four <br /> to five initial temporary piezometers to assess the groundwater flow direction followed by <br /> subsequent grab groundwater sampling from temporary borings to assess the presence and <br /> concentrations of petroleum hydrocarbon constituents at the water table. The temporary <br /> piezometers and borings will be advanced using direct-push drilling methods (Geoprobe)in <br /> a step-wise fashion,moving outwards from the release point to assess the extent of <br /> impacted groundwater. It is anticipated that the piezometers and temporary borings will be <br /> advanced to a depth of approximately 10 feet below ground surface,corresponding to <br /> approximately 5-feet below the water table identified during the November 2001 soil <br /> excavation activities. The grab groundwater samples will be analyzed for TPH (gas and <br /> diesel),BTEX,and MTBE. <br /> Scope of Work <br /> The scope of work will include preparing for the field investigation,performing the field <br /> investigation,and preparing a letter report providing the results of the field investigation. <br /> This work will be performed under the direction of a California Registered Geologist. The <br /> field investigation work will require temporary borings to be placed in an agricultural field, <br /> which will require an access agreement with the property owner. <br /> Task 1—Prepare for Field Investigation. CH2M HILL will prepare for the field j <br /> investigation work,which will include the following activities: <br /> • Obtaining access agreement with the property owner of the agricultural field <br /> • Preparing a health and safety plan <br /> • Obtaining temporary boring permits from San Joaquin County <br /> • Procuring a drilling contractor to perform the field work <br /> • Coordinating with the analytical laboratory <br /> • Locating underground utilities using Underground Service Alert for utilities located on <br /> public right-of-way and using a private utility locator for utilities located on site <br />