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Stantec <br /> L & M OPERABLE UNIT- FOURTH QUARTER AND ANNUAL 2012 SITE STATUS, <br /> REMEDIAL SUMMARY, AND GROUNDWATER MONITORING REPORT <br /> February 1, 2013 <br /> 5.0 Summary of 2012 Annual Monitoring and Sampling <br /> 5.1 SHALLOW ZONE TRENDS IN GROUNDWATER GRADIENT <br /> During 2012, groundwater elevations in the shallow zone wells ranged between 2.89 feet below <br /> MSL (MW-3, 4Q12) and 4.52 feet above MSL (MW-30, 2Q12). The highest groundwater <br /> elevations were generally measured during 2Q12 and 31012. The lowest groundwater <br /> elevations were generally measured during the 1Q12 and 41012. Groundwater elevation <br /> contour maps for the 11012, 2Q12, and 3Q12 are included in Appendix K. <br /> Groundwater flow direction during 2012 was consistent across the shallow zone groundwater. <br /> Groundwater flow direction during 2012 was generally observed in two sections of the Site <br /> (north/northeast/east and central/south/southwest). Along the north/northeast/east portion of <br /> the Site, groundwater flow direction was generally to the southwest and south-southwest. In the <br /> central/south/southwestern part of the Site, groundwater flow direction was generally to the <br /> east-northeast, east-southeast, and east. The hydraulic gradients across the shallow zone <br /> wells ranged between 0.003 ft/ft (2Q12 and 3Q12) and 0.02 ft/ft (4Q12). <br /> 5.2 B-ZONE TRENDS IN GROUNDWATER GRADIENT <br /> During 2012, groundwater elevations in the B-Zone wells ranged between 6.34 feet below MSL <br /> (MW-35,4Q12) and 2.04 feet above MSL (MW-44, 3Q12). The highest groundwater elevations <br /> were generally measured during 2Q12 and 3Q12. The lowest groundwater elevations were <br /> measured during the 1Q12 and 4Q12. Groundwater elevation contour maps for 1Q12, 2Q12, <br /> and 3Q12 are included in Appendix K. <br /> Groundwater flow direction during 2012 was generally consistent across the B-Zone <br /> groundwater. Groundwater flow direction during the 1Q12 and 2Q12 was to the northeast. <br /> Groundwater flow direction during the 3Q12 and 4Q12 was observed in two sections of the Site <br /> (west and central). Along western portion of the Site, groundwater flow direction was to the <br /> north-northwest. In the central portion of the Site, groundwater flow direction was to the <br /> northeast and north-northeast. The hydraulic gradients across the B-Zone wells ranged <br /> between 0.006 ft/ft (1Q12 and 2Q12) and 0.009 ft/ft (4Q12). <br /> 5.3 C-ZONE TRENDS IN GROUNDWATER GRADIENT <br /> During 2012, groundwater elevations in the C-Zone wells ranged between 6.50 feet below MSL <br /> (MW-62 and MW-64, 4Q12) and 5.05 feet below MSL (MW-66, 2Q12). The highest <br /> groundwater elevations were generally measured during 2Q12. The lowest groundwater <br /> elevations were measured during the 4Q12. Groundwater elevation contour maps for 1Q12, <br /> 2Q12, and 3Q12 are included in Appendix K. <br /> Groundwater flow directions in C-Zone wells were consistent in 2012. Groundwater flow <br /> direction during 1Q12 was observed in three sections of the Site (north, central, and eastern). <br /> Along the northern portion of the Site, groundwater flow direction was to the south-southeast. In <br /> I:\Tidewater\TW Stockton(P2A)\QMRs\2012\4Q12-Ann ual\4Q12 and Annual QSSR QRSR QMR Stockton_FINAL.doc 5.1 <br />