Water table

It is a fundamental concept in hydrogeology, it indicates the depth (measured from the surface) at which we encounter pores of soil saturated with water. In other words, the water table represents the "upper surface" of the terrains saturated with water in an aquifer system.

The depth at which is encountered the water table can be measured with a piezometer. Depending on the aquifer considered, the water table can either be below ground, at the ground level or even above it.

The average theoretical normal water table can be used as the reference level for an aquifer system. The changes relative to this level of reference help to characterize whether the aquifer system is in excess, normal or below normal. For instance in the case of a river system, it would correspond to a flood, a normal flow or a drought flow (or baseflow).

Water Table

References

• Applied Hydrogeology C.W Fetter (2001)
• http://geology.er.usgs.gov/eespteam/brass/ground/groundintro.htm