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L & M OPERABLE UNIT-THIRD QUARTER 2014 SITE STATUS, REMEDIAL SUMMARY, <br /> AND GROUNDWATER MONITORING REPORT <br /> Groundwater Monitoring and Sampling <br /> October 31, 2014 <br /> included as Appendix D. Certified laboratory analytical reports, Stantec Lab Validation <br /> forms, COC documentation, and monitoring and sampling field data sheets are <br /> included as Appendix E. Gauging data for the City of Stockton in UOU and MOU wells <br /> (provided by Wallace-Kuhl) is included as Appendix F. Electronic Deliverable Format <br /> (EDF) upload confirmations for the 3Q14 L&M OU monitoring and sampling event are <br /> presented in Appendix G. <br /> 2.3 THIRD QUARTER 2014 A-ZONE GROUNDWATER RESULTS <br /> 2.3.1 Shallow Zone Groundwater Gradient <br /> Groundwater elevations for A-Zone wells at the L&M OU, MOU, and UOU, ranged from <br /> 2.64 ft below mean sea level (MSL; 2AMW-14) to 3.19 ft above MSL (MW-21; Table 3, <br /> Table 4, and Figure 2). Groundwater flow direction ranged from the east to the south- <br /> southwest at an average calculated gradient ranging from 0.007 to 0.033 foot per foot <br /> (ft/ft). In general, the shallow groundwater flow direction is to the east-southeast. <br /> Historic groundwater gradient data is included in Table 6; vertical gradients are <br /> summarized in Table 7. A groundwater elevation contour map of the July 7, 2014 <br /> monitoring event is included as Figure 2. <br /> 2.3.2 Shallow Zone Groundwater Analytical Data <br /> During 3Q14, groundwater samples were collected from 12 A-Zone wells. Groundwater <br /> analytical results are summarized below and presented on Table 3. TPHg, TPHd, TPHo, <br /> benzene, MTBE, and TBA isoconcentration contour maps are attached as Figure 3 <br /> through Figure 8, respectively. Certified laboratory analytical reports and laboratory <br /> validation forms for the L&M OU samples are included in Appendix E. <br /> 2.3.2.1 Separate Phase Hydrocarbons <br /> During 3Q14, sheen (SPH thickness of less than 0.1 inch) was observed in three A-Zone <br /> wells (2AMW-13, 2AMW-14, and MW-19). A figure depicting historical depth to SPH <br /> versus time in comparison to depth to groundwater levels measured in well 2AMW-14 is <br /> included as Figure 9. Well 2AMW-14 is singled out for trending purposes because it is <br /> centrally located on the Site and has contained measurable SPH or observed SPH <br /> sheen since its installation in second quarter 2002. <br /> 2.3.2.2 Petroleum Hydrocarbons and Fuel Oxygenates <br /> TPHg, TPHd, TPHo, and Fuel Oxygenates with concentrations at or above the laboratory <br /> method reporting limits (MRLs) are summarized on the following table. <br /> 5ta ntec 2.4 <br />