A wadi looks like a river but works differently. Instead of flowing all year, it only fills during heavy rainstorms. The water can rush through in hours and then disappear back underground, leaving the sandy channel dry again. Even so, the soil along a wadi holds moisture long after the surface dries, so plants and animals gather here.
The name 'Red Channel' comes from the reddish iron-rich soil that colours the riverbanks. After a rare rainstorm, the water picks up this red soil and carries it downstream, making the whole flow look orange or brick-red - quite spectacular to see from a hillside.
People have lived along the Saguia el-Hamra for a very long time because the wadi offers something rare in the desert: underground water close to the surface. Wells dug near the wadi banks reach water more easily than wells dug in open desert, making the wadi corridor a natural corridor for travel and settlement.