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' - - - ---Geo(vgual2'echnresInc -- - - - - - - - - --- - - - -- Page 3 Groundwater Monitoring Report Project No 425 2 February 17,2000 A review of the groundwater gradients shows that the dominant groundwater flow is to the ' north with the slope ranging from 0 0012 up to 0 0289 fi.lft Table 1 of Appendix A summarizes the water table groundwater gradients and levels to date Intermediate & Deep Wells The average groundwater elevation in the intermediate depth wells (MW-102, MW-105 & MW-107) for September was 74 17 feet above mean sea level and the intermediate depth groundwater gradient was 0 0034 ft/ft flowing N84°E The average groundwater elevation in the intermediate depth wells for December was 72 49 feet above mean sea level and the intermediate depth groundwater gradient was 0 0016 ft/ft flowing N63°E Table 2 of Appendix A summarizes the intermediate depth groundwater gradients and levels to date Table 2 also summarizes the groundwater level data from the deep well, MW-202 Figure 2 is a map showing both the water table and intermediate groundwater gradients +, 1.12 Vertical Groundwater Gradients Vertical groundwater gradients were calculated using MW-2 / 102 and MW-102 / 202 This site has experienced both negative (downward) vertical gradients and positive (upward) vertical gradients Typically the negative vertical gradients are 175 to 2 times greater than gradients in a horizontal direction and the positive vertical gradients are an order of magnitude greater than horizontal Refer to Table 3 of Appendix A for a summary of the vertical gradients calculated 1.2' Groundwater Sampling Procedure On September 1 and December 22 1999 Del-Tech Geotechnical Support personnel arrived p 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 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 actual aquifer ' conditions, was entering the well Groundwater parameter stabilization was characterized by three successive readings within 10%