If the problem contains one or more piezometric surfaces which would intersect a potential failure surface, they can be approximated by a series of coordinate points connected by straight line segments. If used, the piezometric surfaces must be defined continuously across the horizontal extent of the region to be investigated for possible failure surfaces. It is wise to extend the piezometric surfaces as far in each lateral direction as the ground surface is defined, to insure meeting this last requirement. Data for the coordinate points must be from left to right. Each point on a piezometric surface is defined by an X and Y coordinate specified in that order.

The connecting line segments defining a piezometric surface may lie above the ground surface and also may lie coincident with the ground surface or any profile boundary. This enables expression of not only the ground water table but also surfaces of seepage and still water surfaces of bodies of water such as lakes and streams. The option of defining several piezometric surfaces makes it possible to model conditions of artesian or perched water tables.

Also see:

Drawing Piezometric Surfaces

Water Table in an MSE Wall Analysis