ANISOTROPIC AQUIFER INFLUENCE ON PUMPING WELL

Faculty of Engineering, Ain Shams University

Water well is a tool that can be used in extracting the groundwater for many purposes.

When the water is pumped out through the well, a drawdown increases according to the

amount of discharge. It is important to know the expected drawdown to locate the

submersible pump into the well at a proper position. If the designer of well located the

pump at wrong position, the pump may not work efficiently.

The drawdown is defined as the summation of aquifer loss and screen loss due to

suction process. These losses depend upon the hydraulic conductivity of the aquifer,

amount of discharge and the length of the screen. In general, designer assumes that the

soil of the aquifer is homogeneous and isotropy. Therefore, the selection of pump

position inside the well depends upon the soil lithology and the expected drawdown. In

fact, the aquifer soil may be homogeneous but may not to be isotropy. This means that

the hydraulic conductivities may have different values in x-direction and y-direction at

the same location and then the aquifer is so called anistropic aquifer. In this paper,

anisotropic aquifer response to pumping well is studied. It is concluded that the

anisotropic aquifer has a significant effect on the flow behavior towards the well. So,

care must be taken in designing the water well in an anisotropic aquifer to avoid

locating the submersible pump in wrong position.