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Chevron U.S.A. <br /> Page 30 <br /> At the request of Chevron Oil Company, Dames &Moore prepared a remedial design <br /> for a vapor extraction system to remediate contaminated soils in the vicinity of the <br /> underground tanks. Prior to obtaining permits for the system's installation, <br /> quarterly monitoring of groundwater test results were reviewed and found that <br /> monitoring well MW-2 had shown significant increases since mid- 988. <br /> Chevron Oil Company requested that Dames& Moore prepare a workplan to replace <br /> AVO <br /> groundwater monitoring wells that had gone dry and to pace additional down gradient <br /> and lateral wells to help delineate any potential movement of petroleum contaminated <br /> groundwaters. <br /> -� Soil borings were drilled to observe and develop logs of subsoils, observe <br /> subsurface conditions, and obtain soil samples for chemical analysis. The soil <br /> borings were developed as groundwater monitoring wells,with subsequent chemical <br /> t analysts of groundwater samples. Seven exploratory borings were advanced at the <br /> subject property at various locations, including on down gradient off-site <br /> installation. These seven parings were all completed as groundwater monitoring wells. <br /> -s <br /> Groundwater monitoring wells were utilized to obtain data regarding groundwater <br /> conditions,including groundwater quality,depth to groundwater,direction of <br /> • groundwater flow,and groundwater gradient. <br /> The soils profile observed beneath the subject property is comprised <br /> predominantly of interbedded sands, silty sands, sandy silts,silts, and silty clays <br /> to the maximum depth explored of approximately 50 feet below the existing grade. <br /> 16000-206-044 <br /> ti �Scic�itt <br />