Plaquette : Making the Senegal river navigable - IAGF 6ème session

-, MAURITANie building of the dam of Diama building of the dam of Manantali lE 26 The approaching desert and a discharge with very marked seasonal variat ions quickly led the aut horit ies to reflect on optimising t he river's hydraulic potential and drawing up an ambitious overall development plan to combat c1imatic events. Its integrated development programme , based on controlling the river's water resources, was formulated on the basis of building two main structu res: the multipurpose regulation dam of Manantali (1988) and t he anti-salt dam of Diama (1986) in the delta. The combined functions of these two structu res should permit the joint production of hydroelectricity, the irrigation of farm land and navigat ion . Over ti me, the OMVS has become a wo rld reference. In 2016 , it was named the best basin organisation in the world fo r the quality of its prog rammes and its model of shared wate r management in the f ramework of community cooperation . In addition, it ensures the permanent secretariat of the African Network of Basin Organisations. Presentation of the Senegal River The Senegal River flows east-west along 1,790 km. Its source is the confluence of t he Bafing, the "black" river, wh ich flows from Fouta Djalon at an altitude of 800 m (Guinea), and the Bakoye, the "white " river whose source lies on the Man– dingue plateau. Its main tributary is the Falémé, which drains the entire eastern part of Senegal. The river basin covers 337,500 km 2 and more than 800,000 ha of arable land. It is divided into three main parts: the Up– per Basin, the Val– ley and the Delta. The average rainfall on the basin is 550 mm/year with consi– derable differences between t he Upper Basin (the Malian and Guinean parts of the basin) with a rainfall of about 1,500mm/ year and only 200– 250 mm/year in the Lower Valley (t he Senegalese and Mauri– tan ian parts of the basin). In addition to the c1imat ic contrast between the Upper Basin and the Lower Valley, another cha– racteristic of the rainfall in the Senegal Basin is its conside– rable intr a-seasonal and inter-annual variability.