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' G¢010guc417'¢ckruucs lric Page 2 Groundwater Monrtormg Report Project No 724 2 February 3, 2004 ' shallow groundwater gradient were mixed for this quarter Well pair MW-41104 exhibited a downward that is consistent with past events ' Nine new monitoring wells were installed at the site in December 2003 and the inclusion of these wells into the quarterly monitoring scheduled will take place in the first quarter of ' 2004 The data from these new wells will further define the extent of the groundwater plume at the site ' 1.0 GROUNDWATER MONITORING ' 1.1 Hydrogeology of Site Site-specific groundwater gradients and bearings for water table and intermediate wells ' were calculated utilizing computer generated contours ' On November 28, 2003, the gradient in water table wells MW-4, MW-5, MW-6 and MW-7 was flowing S73°E at 0 018 ft/ft Figure 2 illustrates the water table groundwater gradient map fol the monitoring event The average elevation of groundwater under the site was — 23 12 feet MSL (below mean sea level) or approximately 38 feet below grade surface This elevation represents a decrease of 0 32 feet since the September 2003 monitoring event The water level has risen significantly at the site since October of 1992 when groundwater ' was—39 feet MSL Figure 3 is an intermediate well groundwater gradient map for the November 28, 2003 ' event In the intermediate wells (water above the screened interval of the well) MW-1 through MW-3, MW-106 and MW-107, groundwater flowed S80°E at a gradient of 0 002 ft/ft Deep well MW-104 is not screened across similar elevations so a deeper gradient was ' not calculated for the event (see Table 6 for well construction details) Table 1 in Appendix A contains the shallow groundwater elevations and gradients for all ' events since the start of this project in October 1992 Table 2 in Appendix A contains the historical intennediate/deep groundwater elevations ' The rose diagram included in Figure 4A shows that the water table groundwater gradients at this site are consistently towards the east In Figure 4A, arrows labeled 22 and above were ' measurements made after November 2000 Since additional wells were installed in November 2000, the groundwater direction has had a more southerly component suggesting that the earlier measurements were biased due to the spatial orientation of fewer wells The t rose diagram included in Figure 4B shows that the intennediate aquifer gradients at this site range from northeast to southeast The gradients were consistently to the east for the last seven events