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Geological redm cs ltm Page 3 ' Groundwater Monitonng Report Project No 723 2 June 21,2006 ' of this twist in the tubing is that depth to water measurements could not be made because the instrument probe becomes lodged in the small chambers of the tubing But Del-Tech ' Geotechnical Support procured a new micro-water level meter that can be used in the CMTrm wells The first quarter of 2005 was the first time that the well chambers were sounded The ability to sound the wells resulted in changes in quarterly monitoring reports The wells have been grouped according to the aquifer interval that the screened section intercepted (see Figure 14 for well screen intervals) Shallow Wellss) MW-4, 5, 6, 7 screened 35—55 feet bgs)g , 8 & 9 Intermediate Wells (screened 43—70 feet bgs) MW-1, 2, 3, 107, 108 & 109 ' Deep Wells (screened 76—80 feet bgs) MW-207, 208 & 209 Deepest,Wells (screened 94—97 feet bgs) MW-101, 307, 308 & 309 ' The aquifer was divided in four horizons based on the screened intervals and groundwater gradient contour maps constructed for each horizon shallow, intermediate, deep and deepest 1.1 Hydrogeology of Site Horizontal Groundwater Gradients The calculated gradients for the April 2006 monitoring event are as follows ' Aquifer Zone Screen Interval Gradient Bearing MW No Water table 35 to 55 ft bgs 0 007 ft/ft N43°E 4, 5, 6, 7, 8 & 9 Intermediate 43 to 70 ft bgs 0 007 ft/ft N450E 1, 2, 3, 107, 108 & 109 ' Deep 76 to 80 ft bgs 0 003 ft/ft N53°E 207, 208 & 209 Deepest 94 to 97 ft bgs variable variable 101, 307, 308 & 309 ' Figures 2A through 2D illustrate four aquifer groundwater gradient maps for the April 2006 event Figure 3, Groundwater Gradient Rose Diagram, includes the historical shallow groundwater directions and gradients It is noted that groundwater elevation exceeded the ' screened interval of all of the site's wells for the second consecutive event Tables 1 —4 in Appendix A contain the groundwater elevations and gradients for the site Vertical Groundwater Gradients ' Under vertical groundwater flow conditions, the water level in a monitoring well 1s a function of the length of the well screen and its depth or vertical positron to the aquifer. As with horizontal flow conditions, the diameter of the well or piezometer :s immaterial A vertical ' gradient was calculated for the well pairs MW-3/MW-201, MW-8/MW-108 and MW- 108/MW-208 1