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3. Annual Report for 2011 <br /> This section presents the 2011 annual report and includes a summary of groundwater <br /> monitoring results, an evaluation of the effectiveness of the current remediation system, and <br /> an evaluation of potential data gaps and deficiencies/redundancies in the MRP. <br /> 3.1 Groundwater Monitoring Results <br /> L. Two semiannual groundwater monitoring events were performed for the 2011 monitoring <br /> period (October 2010 through September 2011)in accordance with MRP No. R5-2007-0831. <br /> The results from the first semiannua12011 event were documented in a semiannual <br /> monitoring report submitted to the RWQCB on April 29,2011 (CH2M HILL,2011).The <br /> imp tables and figures that provide the tabular and graphical summaries of these data are <br /> provided in Appendix F. Results from the second semiannua12011 event are documented in <br /> !! <br /> Section 2 of this report.Section 3.4 of this report includes a comparison between standard <br /> purge and HydraSleeve split-sample data from the second semiannual groundwater <br /> monitoring event.The tabular and graphical summaries for these two events are organized <br /> into the following tables and figures: <br /> • Table 2-Groundwater Depths and Elevations <br /> 1 <br /> b. • Table 3-Hydrocarbon Concentrations and Field Parameter Results <br /> i • Table 4-Standard Purge versus HydraSleeve Hydrocarbon Concentrations and Field <br /> Parameter Results <br /> • Figure 3-Groundwater Elevation Contour Map <br /> i <br /> `, • Figure 4-Dissolved-Phase TPHg Concentration Map <br /> • Figure 5 -Dissolved-Phase Benzene Concentration Map <br /> L <br /> `. These current data are also presented in Appendix C as part of the tabulation of the eight <br /> most recent quarters of collected data: <br /> 1 <br /> L . Table C.1 -Historical Groundwater Elevation Data <br /> • Table C.2-Historical Groundwater Concentration Data <br /> Appendix D provides a graphical summary (time-series charts) of the water level data and <br /> select chemical monitoring data since quarterly monitoring was implemented in 1992. A <br /> hydrograph is provided for all monitoring wells.Time-series concentration charts are <br /> L provided for wells that have consistently detectable BTEX and TPH concentrations (wells <br /> 0-1, M-10,N-7,N-8, N-15,N-16,N-17, RW-1).Appendix E provides time-series <br /> concentration charts for these wells with the time scale expanded to 2050 to help assess <br /> ` potential long-term concentration trends. <br /> 4 <br /> L <br /> { E51024111633065C0/LW3521.DOCV112970003 3.1 <br /> •r1 <br />