wadi

Wadi is a term used in North Africa and Western Asia to denote a valley, gully, or dry riverbed that remains dry except during seasonal rains. In Arabic, wadi literally means a valley or riverbed, and the word has been adopted into English and other languages to describe arid-region channels that may flood rapidly after rainfall. Depending on local geology, a wadi can be formed in bedrock or over alluvial fans with steep, ravine-like sides.

Typically, wadis are dry for long periods, but during the rainy season they can carry sudden, flash floods. The water flow may carve channels and widen or deepen the valley; some wadis host pools, springs, or narrow canyons. Wadi landscapes are often characterized by exposed rock, stony terraces, and sparse vegetation, with oases or cultivated pockets in or at the margins of the valley.

Wadis are common across the deserts and arid regions of the Arab world, including the Maghreb, the Arabian Peninsula, the Levant, and the Horn of Africa. Notable examples include Wadi Rum in Jordan, Wadi Shab in Oman, and Wadi Bani Khalid, also in Oman; other regions feature similarly named channels and canyons.

In human use, wadis provide routes, water sources, and, in some cases, agricultural land in seasonal valleys. They are popular for trekking, sightseeing, and ecotourism, given their dramatic scenery.

Hazards include sudden flash floods, which can occur with little warning even after distant rainfall. Travelers are advised to check weather conditions and avoid entering narrow sections during storms.