Vadose zone

The vadose zone does not include the area that is still saturated above the water table, often referred to as the capillary fringe.

[1] Movement of water within the vadose zone is studied within soil physics and hydrology, particularly hydrogeology, and is of importance to agriculture, contaminant transport, and flood control.

Groundwater recharge, which is an important process that refills aquifers, generally occurs through the vadose zone from precipitation.

[2] The vadose zone is often the main factor controlling water movement from the land surface to the aquifer.

Flow rates and chemical reactions in the vadose zone also control whether, where, and how fast contaminants enter groundwater supplies.

Cross-section of a hillslope depicting the vadose zone, capillary fringe , water table , and phreatic or saturated zone. (Source: United States Geological Survey .)
Cross section showing the water table varying with surface topography as well as a perched water table
The sharp contact between the vadose zone (brown oxidized mudstone ) and the underlying phreatic zone (grey unoxidized mudstone) exposed at a construction site.
An example of a vadose cave passage in Mammoth Cave , Kentucky