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Cleologccal rechAks Inc Page 3 Groundwater Monitonng Report Project No 425 2 November 12,2001 Table 2 of Appendix A summarizes the intermediate depth groundwater gradients and levels to date, and Figure 2B illustrates the September 7, 2001 groundwater direction and gradient --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 & 3B- Shallow and Intermediate Rose Diagrams 1.1.2 Vertical Groundwater Gradients 1 Vertical groundwater gradients were calculated using MW-2/MW-102 (shallow/intermediate well pair) and MW-102/MW-202 (intermediate/deep well pair) During the September 2001 event the vertical groundwater gradient in the shallow/intermediate well pair was in a downward direction with a magnitude of about five times that of the horizontal gradient The vertical gradient in the intermediate/deep well ' pair was upward at a magnitude of approximately twenty two times that of the horizontal gradient 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 order of magnitude greater than horizontal The relationship of upward and downward vertical gradients in the shallow/intermediate well pair is plotted in Figure 8 It should be ' noted from Figure 8 that the depth to groundwater is on a steady decline since project start, with annual late summer temporary rises in 1998, 1999, and 2000 ' Refer to Table 3 of Appendix A for a summary of the vertical gradient calculations 1.2 Groundwater Sampling Procedure ' On September 7, 2001, Del-Tech Geotechnical Support personnel arrived on-site, opened the wells, and measured the depth to water with an electrically actuated sounding tape The ' water level reading was recorded to an accuracy of 0 01 foot In wells where free-floating product was suspected, a clear disposable bailer was used to gauge the interface Free product was not evident in any well for the event, but a sheen was noted on the sample from well MW-2 ' Stagnant water in the well casing was purged using a Centrifugal pump as recorded in the field logs (Appendix C) The rate of well purging was monitored The wells were purged . of at least three casing volumes or until the groundwater parameters (temperature, conductivity, and pH) had stabilized (Appendix C) indicating that water, representative of