Laserfiche WebLink
COlogxAl Tedvw fir. Page 3 <br /> Groundwater Monitoring Report <br /> Project No 724 2 <br /> April 25,2006 <br /> w <br /> The rose diagram included in Figure 5A shows that the water table groundwater gradients at <br /> this site are consistently towards the east In Figure 5A, arrows labeled 22 and above were <br /> measurements made after November 2000 Since additional wells were installed in <br />' November 2000, the groundwater direction has had a more southerly component suggesting <br /> that the earlier measurements were biased due to the spatial orientation of fewer wells The <br />' rose diagram included in Figure 5B shows that the intermediate aquifer gradients at this site <br /> have had a consistent easterly (northeast to southeast) direction The rose diagram included <br /> in Figure 5C shows that the deep aquifer gradient has been to the east to southeast for the <br /> ' sounding events following the installation of four additional deep wells in December 2003 <br /> Vertical Groundwater Gradients <br /> ' Under vertical groundwater flow conditions, the water level in a monitoring well is a function <br /> of the length of the well screen and its depth or vertical position in the aquifer As with <br /> horizontal flow conditions, the diameter of the well or piezometer is immaterial <br /> The following procedure is used to calculate the vertical groundwater gradient <br /> • Determine vertical distance between the two measunng 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 /> o Measure the head in both wells used in the calculations <br /> o 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 /> ' Figures 2 through 4 show the Iocation of the well pairs used for calculating vertical <br /> groundwater gradient in this report MW-4/MW-104, MW-6/MW-106, and MW-7/MW-107 <br /> Tables 1, 2 & 3 include Summaries of Water Level and Gradients Slope and Bearing for the <br /> three aquifer horizons and Table 4 shows the calculated vertical gradients The information <br /> used in the calculations is shown below <br /> ' Vertical gradient calculation formulas are as follows <br /> • vertical correction for gradient f(gw gradient slope) x (distance) =vertical correction] <br /> 1 • vertical head [(head of deep well) - (head of shallow +correction) =vertical head] <br /> • vertical gradient [(vertical head) / (vertical distance) =vertical gradient] <br /> ' For the February 2006 event, the vertical gradient for the MW-4/MW-104 pair was a negative <br /> (or downward) direction In well pairs MW-6/MW-106 and MW-7/MW-107 the vertical <br /> gradient was a positive (or upward) direction The trend of a negative gradient in MW- <br /> 4/MW-104 and a positive or no gradient in the other pairs is consistent with the historical <br /> data It is noted that the vertical distance to the deep well screen in the MW-4/MW-104 well <br />