Wadis form when rain falls heavily in the mountains and rushes downhill, carving channels through the rock over thousands of years. In the dry months, some wadis run low, but Wadi Shab always has clear, cool water fed by underground springs. The water gets its turquoise colour from the minerals dissolved in it.
The walk through Wadi Shab is an adventure. Visitors cross from one side of the river to the other on a small rowing boat, then follow a path that squeezes between giant boulders, past palm trees and wild fig trees. Birds called kingfishers — bright orange and blue — dart over the water hunting small fish.
Near the end of the trail, swimmers can dive under a low rock and come up inside a cave where a waterfall drops from the ceiling into a deep pool. It is completely dark except for the glow coming through the water and a crack of light in the cave roof. It feels like entering a secret world.
Wadis remind Omanis how precious water is. Communities have managed their wadi water carefully for centuries, sharing it fairly between villages using the traditional aflaj system of channels and timed turns.