What is a Potentiometric Map?
The potentiometric surface is the level to which water rises in a well. In a confined aquifer this surface is above the top of the aquifer unit; whereas, in an unconfined aquifer, it is the same as the water table. The following cartoon depicts an aquifer with an unconfined section on the left and a confined section on the right (Fetter, 1994).
(Fetter, 1994)
As you might expect, a potentiometric map is a contour map of the potentiometric surface. As on the surface of the earth, water flows from high elevation, or potential, to low elevation. Thus a potentiometric map indicates which direction water is moving in the subsurface.
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