A wadi is a dried up riverbed found in the mountain valleys. Wadis come into their own after heavy rains, when the rivers start running again and the vegetation is restored. However, some wadis have year-round running water, with deep, cool pools in which it is quite safe to swim if the currents are slow as in Wadi Bani Khalid(A'Sharqiyah). On the whole, wadis are only accessible with a four-wheel drive vehicle, as the terrain can be extremely bumpy.

Wadis are green, lush oases of palm trees, grasses, and flowering shrubs. The villagers often take their cars down for washing and groups of people have great fun splashing around in the clean water. It is always safest to visit wadis in a group or with a tour guide. Although they are beautiful places, they are often remote and car breakdowns can happen to anyone.

Visitors must also be on the alert for rain clouds, as sudden downpours can lead to flash floods, which are highly dangerous when in the gorges. Some of the pupular wadis in Oman include:

 

Wadi Dayqah

Known as the Devil's Gap, Wadi Dayqah was described by explorer S. B. Miles in 1896 as "the most singular piece of earth sculpture in Arabia". The wadi runs through a narrow winding vertical-sided canyon that looks as though the mountain has been split in two. The walls soar to 1,700 meters and close in to 12 meters in some places.

When it rains, the waters of the surrounding wadis and tributaries drain and pour through the canyon that can sweep away everything in its path. Swimming, or at the very least, deep wading, is usually necessary, especially when crossing deep pools and channels that lie beyond the huge boulders. The alterantive would be to scramble around these boulders.

 

Wadi Shab

The Wadi is 76 Km from Qurayyat–Muscat. The road to the wadi dips as it crosses the bed of the ravine and rises steeply on the other side where the houses of Tiwi cling to the cliffs. At the mouth of the wadi is a single beach dotted with fishing boats.

Water flows all year round. The wadi runs through a narrow gorge with date plantations, restful pools and lush vegetation. Oleander bushes attract butterflies and the singing of the birds is delightful.