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' Ge0&glca!rechal"Inc. Page 3 Groundwater Momtonng Report Project No 425 2 May 10,2005 ' Zone B The average groundwater elevation is 73 03 feet AMSL and indicates a decrease of 0 08 feet from the previous monitoring event The groundwater gradient for Zone B was 0 0112 ft/ft ' flowing N18°W The predominant groundwater flow is to the northwest with the slope ranging from 0 0112 to 0 0040 ft/ft Table 3 of Appendix A summarizes the historical intermediate and deep groundwater data, Table 4 summarizes Zone B groundwater data and ' Figures 4 shows the groundwater gradients for April 11, 2005 groundwater monitoring event Zone C The average groundwater elevation in Zone C for the January 2005 monitoring event was 73 18 feet AMSL This represents an increase of 0 12 feet since the January 2005 monitoring event Groundwater bearing and slope for this zone cannot be calculated due to the linear positions of MW-101, MW-102, and MW-201 Table 5 summarizes the groundwater data from the Zone C ' Zone D The groundwater elevation in Zone D is 73 75 feet AMSL This represents a decrease of 0 05 feet from the previous monitoring event Groundwater bearing and slope for this zone cannot be calculated because there is only one well associated with this zone Table 6 summarizes the groundwater data from the Zone D M The historical groundwater adient and bearing data for Zone A are included in Figure 3 & g gr 5 The groundwater gradients and bearing data for Zone B for the last three monitoring ' events are included in Figures 4 &6 1.1.3 Vertical Groundwater Gradients Vertical groundwater gradients were calculated using groundwater-monitoring wells MW- 2/MW-2X (Zone A/Zone B well pair) and groundwater monitoring wells MW-2X/MW-202 (Zone B/Zone D well pair) (Table 7) The site-specific vertical groundwater gradient for ' April 2005 monitoring event for the MW-2/MW-2X pair is 0 0536 ft/ft The site-specific vertical groundwater gradient for the MW-2X/MW-202 pair is 0 0062 ft/ft The historically positive vertical groundwater gradients do not suggest downward movement of contaminants between different zones Vertical groundwater gradient calculations have ' been performed at regular intervals since August 25, 1997 1.2 Groundwater Sampling Procedure ' On April 11, 2005, Del-Tech Geotechnical Support (Del-Tech) 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