River Arnon

Wadi Mujib
Wadi Mujib near Dhiban, looking southwest
Nearest city	Dead Sea
Coordinates	31°27′57″N 35°34′24″E / 31.46583°N 35.57333°E / 31.46583; 35.57333Coordinates: 31°27′57″N 35°34′24″E / 31.46583°N 35.57333°E / 31.46583; 35.57333
Area	212 square kilometres (81.9 sq mi)
Established	1987
Governing body	Royal Society for the Conservation of Nature

Wadi Mujib, known from the Hebrew Bible as River Arnon, is a river in Jordan which enters the Dead Sea c 420 metres (1,380 ft) below sea level.

During the last Ice Age the water level of the Dead Sea reached 180 metres (590 ft) below sea level, about 240 metres (790 ft) higher than it is today. It flooded the lower areas of the canyons along its banks, which became bays and begun to accumulate sediments. As the climatic conditions changed, about 20,000 years ago, the water level of the lake dropped, leaving the re-emergent canyons blocked with lake marl. Most canyons managed to cut through their plugged outlets and to resume their lower courses. However, Wadi Mujib, abandoned its former outlet by breaking through a cleft in the sandstone. This narrow cleft became the bottleneck of an enormous drainage basin with a huge discharge. During the years the cleft was scoured deeper and the gorge of Wadi Mujib was formed.

The Mujib Reserve of Wadi Mujib is located in the mountainous landscape to the east of the Dead Sea, in the southern part of Jordan valley, approximately 90 kilometres (56 mi) south of Amman. A 212-square-kilometre (82 sq mi) reserve was created in 1987 by the Royal Society for the Conservation of Nature and is regionally and internationally important, particularly for the bird life that the reserve supports. In 2011, UNESCO declared Mujib biosphere reserve. It extends to the Kerak and Madaba mountains to the north and south, reaching 900 metres (3,000 ft) above sea level in some places. This 1,300-metre (4,300 ft) variation in elevation, combined with the valley's year round water flow from seven tributaries, means that Wadi Mujib enjoys a magnificent biodiversity that is still being explored and documented today. The reserve consists of mountainous, rocky, and sparsely vegetated desert (up to 800 metres (2,600 ft)), with cliffs and gorges cutting through plateaus. Perennial, spring-fed streams flow to the shores of the Dead Sea.