Wiktionary
groundwater level
n. (context construction English) (at a particular site) the level, below which the subsoil and rock masses of the earth are fully saturated with water.
WordNet
groundwater level
n. underground surface below which the ground is wholly saturated with water; "spring rains had raised the water table" [syn: water table, water level]
Usage examples of "groundwater level".
In this area the groundwater level has been fluctuating for millions of years.