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' Fourth Quarter/Annual <br /> 2008 Groundwater <br /> ' ARCADIS Monitoring Report <br /> Chevron Bulk Fuel Terminal <br /> 100-1621 <br /> 22888 Kasson Road <br /> Banta, California <br /> System Performance Results <br /> Based on hour meter readings collected on October 14,2008(24,679 hours)and <br /> December 24, 2008(26,274 hours), the groundwater oxygenation system was <br /> ' approximately 81 percent operable during the fourth quarter of 2008. System downtime <br /> is attributed to the malfunction of the rotary vane compressor on October 3,2008. <br /> Once discovered by the field staffed and relayed to Mr. David Evans,the RWQCB was <br /> notified verbally and by email of the unscheduled shutdown on the day of the <br /> discovery. <br /> ' Operation of the system was verified every two weeks during site visits. Pressure <br /> readings at the manifold ranged between 9.5 and 12 psi,and pressure readings at the <br /> wellheads ranged between 1 and 8 psi. Flow readings at the well heads ranged from <br /> ' 0.0 to 1.7 actual cfm. Field data sheets are included in Appendix H. <br /> The biotransformation of MTBE to TBA in monitoring well MW-50A is a strong indicator <br /> ' of the positive effects of the groundwater oxygenation system(Appendix G, Figure 3). <br /> Since the groundwater system became operational on April 19,2004 a declining trend <br /> for MTBE has been observed. During the fourth quarter of 2008 a TBA/MTBE ratio of <br /> ' 30 was observed in monitoring well MW-50A. <br /> Summary <br /> ' As part of the Fourth Quarter 2008 Monitoring and Sampling Event,depth to <br /> groundwater measurements were collected on November 5,2008 and <br /> groundwater samples were collected between November 5 and November 6,2008 <br /> • Following development,groundwater sample were collected from the newly <br /> installed wells between November 3 and November 13,2008 <br /> ' • Groundwater flow data collected during the fourth quarter of 2008 is generally <br /> ' consistent with historical data <br /> o Groundwater flow direction in the Upper A Zone was towards the east- <br /> northeast at an approximate horizontal hydraulic gradient of 0.002 ft/ft <br /> o Groundwater flow direction in the A Zone was towards the northeast at <br /> an approximate horizontal hydraulic gradient ranging from 0.001 to <br /> ' 0.004 fVft <br /> 1 <br /> 12 of 17 <br />