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Geofogsca(Technus Inc Page 2 <br /> Groundwater Monitoring Report <br /> Project No 724 2 <br /> April 11,2001 <br />' 10 GROUNDWATER MONITORING <br />' 1.1 Hydrogeology of Site <br /> A site-specific groundwater gradient and bearing were calculated from the depth to water <br /> measurements in wells MW-I, MW-2 and MW-3, as with past events The gradient was <br /> flowing S$1°E at 0 0035 ft/ft, which is consistent with previous monitoring events The <br /> average elevation of groundwater under the site was —16 62 feet (below) mean sea level <br />' (insl) The water level has risen significantly at the site since October of 1992 when <br /> groundwater was —39 feet insl <br />' Figure 2 is a groundwater gradient map for the March 15, 2001 monitoring event <br /> Historical groundwater gradient data are illustrated in Figure 3, Groundwater Gradient Rose <br /> Diagram <br /> Table 1 in Appendix A contains the shallow groundwater elevations and gradients for all <br /> events since the start of this project in October 1992 Table 2, Appendix A contains the <br /> intermediate/deep groundwater elevations for the January 2001 event Groundwater has <br /> predominately flowed to the east at an average of 0 0033 ft/ft <br /> Vertical Groundwater Gradients <br /> Under vertical groundwater flow conditions, the water level in a monitoring well is a <br />' function of the length of the well screen and its depth or vertical position in the aquifer As <br /> with horizontal flow conditions, the diameter of the well or piezometer is immaterial <br />' The following procedure is used to calculate vertical groundwater gradient <br /> • Determine vertical distance between the two measuring devices by the distance from the <br />' mid-point between the top and bottom seal of the deep well (MW-104, MW-106, MW- <br /> 107) and the mid-point between the groundwater elevation and the bottom seal in the <br /> shallow well (MW-4, MW-6, MW-7) <br />' • Measure the head in both wells used in the calculations <br /> • If the lateral distance between the well pair is greater than a few feet, then calculations <br /> must be made to correct the down-gradient piezometric head to account for the sloping <br /> water table between the wells The calculation considers the slope of the water table and <br /> the distance in a down-gradient direction between the two wells used in the calculations <br /> IFigure 2 shows the location of the well pairs used foi calculating vertical groundwater <br /> gradient in this report MW-4/MW-104, MW-6/MW-106, and MW-7/MW-107 Tables 1 & <br /> 2 show a Summary of Water Level and Gradients Slope and Bearing and Table 3 shows the <br /> calculated vertical gradients The inforination used in the calculations is shown below <br />