During the
last ice age the water level of the
Dead Sea reached below sea level, about 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; but 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 of with a huge
discharge and annual
sediment yield of 143,780 tonnes. During the years the cleft was scoured deeper and the gorge of Wadi Mujib was formed. The
Mujib Dam was completed in 2004 at the bottom of the wadi, where the modern road crosses the river. As a result, a large lake has formed.
Mujib Reserve 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 south of
Amman. A 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. The reserve consists of mountainous, rocky, and sparsely vegetated desert (up to ), with cliffs and
gorges cutting through plateaus. Perennial, spring-fed streams flow to the shores of the
Dead Sea. Over 300 species of plants, 10 species of carnivores and numerous species of permanent and migratory birds have been recorded. Some of the remote mountain and valley areas are difficult to reach, and thus offer safe haven for rare species of cats, goats and other mountain animals. The slopes of the mountainous land are very sparsely vegetated, with a
steppe-type vegetation on plateaus. Groundwater seepage does occur in places along the Dead Sea shore, for example at the
hot springs of Zara, which support a luxuriant thicket of
Acacia,
Tamarix,
Phoenix and
Nerium, and a small marsh. The less severe slopes of the reserve are used by pastoralists for the grazing of sheep and goats. The hot springs of
Hammamat Ma'in lie close to the borders of the reserve and popular for tourism and recreation. The
Jordanian military have a temporary camp in the south of the reserve. == Biology and ecology ==