Hydrologic Monitoring and Forecasting in Africa: Developing Tools, Integrating Capacities

Through a continuing collaboration between The University of Arizona and diverse African partner institutions, ICIWaRM is developing monitoring tools and near real-time streamflow forecasting applications using satellite precipitation measurements and numerical weather model results. Adopting an integrative regional approach, we are working with three partners: International Senegal Basin Authority (Organisation pour la Mise en Valeur du Fleuve Senegal , OMVS Dakar), the AGRHYMET Regional Center (Niger), and the Climate Services Center of the Southern African Development Community (CSC-SADC, Botswana)

This initiative started with work in the Senegal Basin, where a detailed and applied research agenda was developed with the OMVS to help improve management tools to face complex challenges in the 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 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. As in other large African basins, the challenges 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 km squared, making satellite products the only near real-time estimates of precipitation to support water management and reservoir operations.

At present, several regional institutions spanning the African continent are being included in an effort to create a network that pools each other’s knowledge and expertise, and to quickly share and disseminate solutions that work, benefiting from both African and international expertise. A grant from the National Science Foundation is helping to facilitate our collaboration with the AGRHYMET Regional Center, representing nine member countries in the Sahel. As a specialized institute of the Permanent Interstate Committee for Drought Control in the Sahel (CILSS), the mandate of AGRHYMET is to contribute to achieving sustainable food security and rational natural resource management. This is done through collecting, processing and analyzing relevant data to produce and disseminate information to various decision makers, NGO’s and farmer associations; including training and transfer of tools and methods. AGRHYMET has an extensive historical database of climate and streamflows covering the nine member states. In addition to ground-based observation data, this effort will also benefit from the remote sensing expertise of the center, namely on satellite precipitation products over the Sahel. More information regarding this grant can be found here .

A very similar collaboration is ongoing with the Climate Services Centre of the Southern African Development Community, representing 15 member states in Southern Africa. Formerly the Drought Monitoring Centre, the Climate Services Centre principal purpose is to ensure that a mechanism for monitoring and predicting extremes in climate events is operational, thus reducing negative impacts on sustainable socio-economic development. Since its establishment in 1990, the SADC-CSC has continued to provide services and outreach products in weather and climate monitoring and prediction for the benefit of the SADC member states, as well as for regional and international institutions dealing with food security early warnings, disaster preparedness, and health and water management programs.

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.

This initiative has the support of the World Bank and is pending two research grants from NASA to fund activities in West, Sub-Saharan and Southern Africa. These also involve two additional institutions: (1) NASA’s SERVIR program in Africa, which integrates satellite observations and predictive models with other geographic information to monitor and forecast ecological changes and respond to natural disasters; and (2) its host institution, the Regional Center for Mapping of Resources for Development (RCMRD) in Nairobi (Kenya).

For more information, contact Aleix Serrat-Capdevila.