Wadi

A wadi is a dry riverbed that only contains water during times of heavy rain.

The term "Wadi" is very widely found in Arabic place names. Wadis tend to be associated with centers of human population because of the availability of sub-surface water.

In English the term "Wadi" is sometimes used interchangeably with Oasis, which is correct linguistically, although many geographers and cartographers consider it an inaccurate usage.

Crossing wide wadis at certain times of the year can be very dangerous, because of unexpected flash floods. Each year in Saudi Arabia there are numerous deaths from this cause.