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i <br /> confined aquifer analysis method overestimates the capture zone for an unconfined aquifer <br />' Therefore, the capture zones for the wells reported herein are overestunated, relative to the <br /> unconfined aquifer method of Grubb (1993) Both of these techniques assume the achievement of <br /> Isteady state conditions (long continuous pumping) and that the aquifer is homogeneous, isotropic, <br /> and infinite in horizontal extent, a situation that is never attained <br /> 1 <br /> As indicated above, the equations outlined in Javandel and Tsang (1986) are utilized These <br /> equations are discussed below and are used to deternune the distance between dividing stream <br /> lines at the extraction wells (i e , the cross-gradient edge of the capture zone) and far upstream <br /> from the extraction wells (the upgradient extension of the capture zone), and the distance from <br /> the extraction wells to the stagnation points (downgradient end of the capture zone) <br /> 1 <br /> According to Javandel and Tsang (1986), the distance between dividing stream lines at the <br /> extraction well is represented by the equation <br /> 2BU <br /> Where Q is equal to the pumping rate in cubic feet per day, B is equal to the aquifer thickness in <br /> feet, and U is equal to the groundwater flow velocity in feet per day Groundwater flow velocity <br /> is equal to the hydraulic conductivity multiplied by the potentiometric surface gradient and then <br /> divided by the porosity <br /> 1 <br /> The distance between dividing stream fines far upstream from the extraction well is represented by <br /> the equation <br /> IBU <br /> The equation for the distance from the extraction well to the zone of stagnation (downgradient <br /> extent of capture) is represented by the equation <br /> Q <br /> 2 nBU <br /> Where Tc is PI which is equal to approximately 3 14159 <br /> H20GEGL A GROUNDWATER CONSULTANCY <br />