The Wadis

A wadi is a river valley or channel that is usually dry but carries water after heavy rain. The word is Arabic, and wadis are found across the Arabian Peninsula and North Africa.

What a wadi is

In a dry climate, rain often falls rarely but hard. A wadi is the path that water takes when it does. Most of the time the bed is stony and dry. After rain it can fill quickly, then empty again within hours or days.

Some wadis, especially in the mountains, are fed by springs and keep running water or deep pools all year. These are the ones most visitors come to see.

How wadis form

Rain runs off bare rock and hard ground rather than soaking in. The flowing water carries gravel and boulders and, over a very long time, cuts a channel. In the Hajar Mountains this has carved narrow gorges with steep rock walls, smooth stones and rounded boulders. Lower down, the valley opens out and the bed is wide and covered in gravel.

Water and pools

Where a spring or underground flow reaches the surface, water collects in natural pools between rocks. Some are shallow and some are deep enough to swim in. The water can be cool even on a hot day, and rocks are often slippery.

Oases and aflaj

Where there is water, there are often date palms, small fields and villages. Oman is known for its falaj (plural aflaj): channels that carry water, by gravity, from a spring, well or wadi to fields and homes, sometimes over long distances. Water is shared out among users by an agreed system of turns. Five aflaj in Oman are on the UNESCO World Heritage List.

Wildlife

Wadi pools and palm groves draw birds, insects, frogs and small fish, and dragonflies are often seen near water. Mammals such as the Arabian tahr live in the Hajar Mountains, though they are shy and rarely seen by casual visitors. Please do not feed animals or leave food scraps behind.

History and use

Wadi beds have long served as natural routes through the mountains, and settlements grew up wherever water could be found. People used wadi water for drinking, farming and livestock, and the cooler, shaded valleys offered shelter. Today many wadis are also popular for walking and swimming.

Safety and flash floods

The same features that make wadis dramatic make them dangerous in bad weather.

• Rain upstream can send a flood down a wadi where it is not raining. The water can rise very quickly and carry rocks and vehicles.
• Check the weather forecast and local advice before you go. Do not enter or camp in a wadi bed if rain is expected in the mountains.
• Never try to drive or walk across running water.
• If you see the water level or colour change, or hear a rumble upstream, move to high ground immediately.
• Rocks near pools are slippery. Wear suitable footwear and take care when jumping or diving.

See also the planning guide and the guide to individual wadis.