Physical Characteristics and Water Resources of the Litani River Basin

Abstract

Litani River, with a 2110-km² catchment area (about 20% of Lebanon ) and a 174-km length, releases an average annual discharge of about 385 mm³/year. The river in its northern part flattens between the Mount-Lebanon and Anti-Lebanon mountain chains , thereby spanning between several mountain ridges in the southern part. Consequent streams are connected to its primary watercourse . The Litani River Basin (LRB ) comprises an elongated catchment where it gently slopes from the north Bekaa Plain extending southward where it meanders westward to outlets into the Mediterranean Sea . Therefore, the river transits into the inner and coastal zones of Lebanon comprising two major drainage systems (described as the Upper and Lower Basins) occupied into one watershed . The Qaraaoun Reservoir , the largest of its type in Lebanon (about 12 km²), is located in the southern part of the Upper Basin . Before 1959, the site of the reservoir comprised a natural depression. However, when large volumes of water started to accumulate there, a dam was built. Snow has a significant contribution to feeding the river. The extension of the Litani River among the carbonate rocks and alluvial deposits makes it an open hydrogeological system that is fed from and feeds on the permeable and porous lithologies. This chapter introduces the major physical characteristics of the Litani River including the catchment and drainage properties as well as the water resources and land cover.