Wadis can be found throughout the Middle East.
A wadi is a ravine, stream bed, or valley that is characterized by being extremely dry. Many wadis flood during the rainy season, posing a significant safety risk to unfamiliar travelers. In the New World, the word “stream” is often used to describe a comparable geographic feature. Geologists believe that features such as wadis formed during periods when water levels on Earth were markedly different, and that these valleys were likely carved out by streams and rivers that later dried up.
Many petrified and fossilized remains, including those of petrified trees, are often found near a wadi.
The bottom of a wadi is often covered with sand and coarse rock, and the sides may be steep and made of sandstone or similar materials. Depending on where the wadi is located, it may be covered with bushes and small trees, or it may be bare. Classically, the floor of a wadi is very hard, making wadis dangerous in the rainy season; the water cannot quickly drain through the ground and disperse, so it forms a flood that breaks out, sometimes very suddenly.
In some cases, an underground river or spring may be found in a wadi; These water sources are remnants of the body of water that once flowed through the wadi and can be a valuable resource for people who live and travel in the desert. As a result, a wadi can sometimes be used as an oasis, as a place to stop and renew the water supply, and in some cases small communities have been built around wadis. In parts of the Middle East and North Africa, the term “wadi” is used to mean “oasis”.
Wadis can be found throughout the Middle East and vary widely in size. The natives are often familiar with the wadis in their region and are aware of how dangerous they can be. Visitors are encouraged to inquire about local wadis, especially if traveling during the rainy season, to ensure they don’t end up in a potentially dangerous location. It is an especially bad idea to camp in a wadi during the rainy season, as floods can come very suddenly and will rip matted tents off the ground.
Archaeologists are often interested in wadis as they sometimes contain historical artifacts left over from the period when the wadi was a fruitful river. Many fossilized hominin remains, for example, have been found in or near wadis, protected by thousands of years of mud and emerging to tell a story about early human communities.