Forecasting streamflows in the International Senegal River Basin

Through a continuing collaboration between The University of Arizona and the International Senegal Basin Authority (Organisation pour la Mise en Valeur du Fleuve Senegal), ICIWaRM is developing a near real-time streamflow forecasting system using satellite precipitation measurements in the International Senegal River Basin.

The Senegal Basin is shared by Mauritania, Senegal, Mali and Guinea and is the second largest perennial water course in the Sahel and in West Africa. Virtually all the water flow is due to a four-month rainy season that occurs in the upper basin some 1500 km away from the mouth of the River. The Manantali Dam in Mali, with 11,000 hm3 of storage and regulating 40 to 60% of the annual flow, is the main multi-purpose reservoir and has to satisfy multiple downstream demands. The Diama Dam, close to the mouth of the river, prevents saline intrusion and maintains high water levels in the mid-basin for navigation and irrigation diversions.

The problems in the basin result from the competing demands between irrigated agriculture (made possible by the dams), a thousand year old traditional flood recession agriculture system (disrupted by the dams), hydropower, urban supply and navigation. Flows in the Basin are characterized by high seasonal and interannual variability. In other words, it is known that the rainy season will come but it is uncertain how much water it will bring. The basin is also poorly-gauged, with a density of one rain gauge for almost every 6,000 km2.

Currently, there are no operational near real-time streamflow forecasts using satellite precipitation products in any large and poorly-gauged river basin. By using real-time spatially explicit precipitation measurements as input to rainfall-runoff hydrological models, we aim at providing a daily operational forecast for the management of the Senegal Basin and its reservoirs. Such an application will be highly valuable and easily exportable to many other poorly gauged basins in Africa and the world.

For further information, please contact Aleix Serrat Capdevila.

Senegal River Basin