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C4ealogrcal7'ecluucsW Page 3 Groundwater Monitoring Report Protect No 425 2 January 25, 2002 ' The average groundwater elevation in the intennediate depth wells (MW-102, MW-105 & MW-107) for the December 3 monitoring was 71 68 feet above mean sea level and the ' intermediate depth groundwater gradient was 0 0033 ft/ft flowing N6°W - On December 21, 2001, Thompson-Hysell Engineers of Modesto, California surveyed the wells in accordance the SWRCB Geotracker requirements of AB2886 The wells were also sounded foi depth to water measurements on this date The average water table elevation ' for this second event was 73 95 feet above mean sea level This represents a decrease of 0 12 feet since the December 3 monitoring event (data normalized to 12/21/01 survey) The water table groundwater gradient was 0 0011 ft/ft flowing N22°E The average groundwater elevation in the intermediate depth wells (MW-102, MW-105 & MW-107) for the December 21 monitoring was 73 86 feet above mean sea level and the groundwater gradient was 0 0017 ft/ft flowing N72°W ' A review of the groundwater gradients shows that the predominant groundwater flow vanes from north to northeast with the slope ranging from 0 0015 up to 0 0044 ft/ft in the water table wells Table 1 of Appendix A summarizes the water table groundwater gradients and levels to date, and Figure 2A and 2C illustrate the December 3 and 21, 2001 groundwater direction and gradients, respectively The predominant groundwater flow is to the east- northeast with the slope ranging from 0 0016 up to 0 027 ft/ft in the interinediate wells Table 2 of Appendix A summarizes the intermediate groundwater gradients and levels to date, and Figure 2B and 2D illustrate the December 3 and 21, 2001 groundwater direction and gradients, respectively ' Table 2 also summarizes the groundwater level data from the deep well, MW-202 The historical water table and intermediate groundwater gradients are included in Figures 3A & 313- Shallow and Intermediate Rose Diagrams 1.1.2 Vertical Groundwater Gradients Vertical groundwater gradients were calculated using MW-2/MW-102 (shallow/intennediate well pair) and MW-102/MW-202 (intennediate/deep well pair) During both December 2001 events the vertical groundwater gradient in the shallow/intennediate well pair was in an upward direction with a magnitude of 7 - 25 times that of the horizontal gradients The vertical gradient in the intermediate/deep well pair was ' upward for both events at a magnitude of approximately 9 — 15 times that of the horizontal gradients This site has experienced both negative (downward) vertical gradients and positive (upward.) vertical gradients Typically, the negative vertical gradients are 1 75 to 2 times ' greater than gradients in a horizontal direction and the positive vertical gradients are an r