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Cyeolog"I7effma Inc. Page 3 Groundwater Momtonng Report ' Project No 724 2 November 21,2005 have had a consistent easterly (northeast to southeast) direction The rose diagram included an Figure 5C shows that the deep aquifer gradient has been to the east to southeast for the ' sounding events following the installation of four additional deep wells in December 2003 Vertical Groundwater Gradients , 1 ' Under vertical groundwater flow conditions, the water level in a monitoring well is a function of the length of the well screen and its depth or vertical position in the aquifer As with horizontal flow conditions, the diameter of the well or piezometer is immaterial ' The following procedure is used to calculate the vertical groundwater gradient • Determine vertical distance between the two measuring devices by the distance from the mid-point between the top and bottom seal of the deep well (MW-104, MW-106, MW- 107) and the mid-point between the groundwater elevation and the bottom seal in the e shallow well (MW-4, MW-6,MW-7) • Measure the head in both wells used in the calculations • If the lateral distance between the well pair is greater than a few feet, then calculations must be made to correct the down-gradient piezometric head to account for the sloping ' water table between the wells The calculation considers the slope of the water table and the distance in a down-gradient direction between the two wells used in the calculations Figures 2 through 4 show the location of the well pairs used for calculating vertical ~ groundwater gradient in this report MW-4/MW-104, MW-6/MW-106, and MW-7/MW-107 Tables 1, 2 & 3 show a Summary of Water Level and Gradients Slope and Bearing for the three aquifer horizons and Table 4 shows the calculated vertical gradients The information used in the calculations is shown below ' Vertical gradient calculation formulas are as follows • vertical correction for gradient [(gw gradient slope) x (distance) =vertical correction] ' • vertical head [(head of deep well) - (head of shallow + correction) = vertical head] O vertical gradient [(vertical head)/(vertical distance) = vertical gradient] ' For the August 2005 event, the vertical gradient for the MW-4/MW-104 well pair was negative (downward) In well pairs MW-6/MW-106 and MW-7/MW-107 the vertical gradient was positive (upward) The trend of negative and positive gradients in these well ' pairs is consistent with the historical data It is noted that the vertical distance to the deep well screen in the MW-4/MW-104 well pair is double that observed in the other two well pairs, which may have an influence over the vertical gradient direction 1.2 Groundwater Sampling Procedure ' 4n August 22, 2005, 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 1 �_