A vocabulary of landscape — a landscape of words
1143 entries
vadose
Vadose describes the unsaturated ground above the water table, where the pores hold both air and water and gravity pulls water downward through them. It is the zone rain passes through on its way to the aquifer. In caves, the word names a passage cut by a stream running in air, which is typically a narrow canyon with a keyhole cross-section, as against a phreatic passage dissolved out below the water table, which is round.
Etymology
The word is Latin for shallow, from a verb meaning to wade, so the vadose zone is the shallow ground you could wade through if it were water. The same Latin verb gives English evade and invade, which both began as words about going somewhere on foot.
Notes
The shape of a cave passage records where the water table was. A round phreatic tube with a slot cut down from its floor means the water table dropped, so the passage was first dissolved underwater and then had a stream running through it in air, and reading a system for those transitions reconstructs the history of the whole landscape’s drainage. Phreatic covers the other half.