Vadose zone
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The vadose zone, also termed the unsaturated zone, is the portion of Earth between the land surface and the phreatic zone or zone of saturation ("vadose" is Latin for "shallow"). Water in the vadose zone has a pressure head less than atmospheric pressure, and is retained by a combination of adhesion (funiculary groundwater), and capillary action (capillary groundwater). If the vadose zone envelops soil, the water contained therein is termed soil moisture.
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. The Richards equation is often used to mathematically described the flow of water, which is based partially on Darcy's law.
In speleology, cave passages formed in the vadose zone tend to be canyon-like in shape, as the water dissolves bedrock on the floor of the passage. Passages created in completely water-filled conditions are called phreatic passages and tend to be circular in cross-section.
[edit] See also
[edit] References
- Unsaturated Zone Definitions Page. USGS. Retrieved on 2006-07-01.
- Unsaturated Zone Flow: Definitions and Details. USGS. Retrieved on 2006-07-01.
[edit] Further reading
- Vadose Zone Journal. Retrieved on 2006-07-01.
