Flood Early Warning and Mitigation for The Zambezi River Basin

The Zambezi River Basin is home to approximately 32 million people that reside in eight countries in southern Africa. The Zambezi River is the fourth longest river in Africa draining over 132 million square kilometers which is about the half of the size of Nile River basin. Historically, seasonal flooding has continued to be a threat to lives and property of populations which reside in the floodplain. Floods have caused over 2300 deaths and affected over 16 million people in the eight Zambezi countries during the last three decades (EMDAT:OFDA/CRED).

Hydrometeorological observation networks and forecast capacity have deteriorated in the basin leading paucity of data that are critical for observations and forecasting to provide necessary lead time to decision makers such as disaster managers and communities. The trans-boundary nature of the river contributes to complexity of flood early warning and mitigation efforts due to limited exchange of data in real-time. In addition, the multi-purpose use of two large reservoirs in the watershed –the Kariba and Cahora Bassa dams presents additional challenges to flood management in the basin. Sudden water releases from these reservoirs can exasperate flooding in downstream countries, especially when heavy rainfalls or tropical cyclone events coincide with above-normal inflows to the reservoirs. Currently, there is no integrated flood warning system or protocol in the basin. Basin-wide cooperation would greatly improve the lead time and flood management capacities of the riparian countries while preserving the environmental benefits of flooding and strengthen water resource management for multi-purposes and increasing resilience to water-induced disasters while laying foundation for climate change adaptation.

The United States Agency for International Development (USAID) Office of Foreign Disaster Assistance (OFDA) in partnership with the World Meteorological Organization (WMO) and National Meteorological and Hydrological Services has recently developed a Flood Forecasting and Early Warning System (FFEWS) Strategy for the basin to address transboundary challenges and develop an integrated framework in the basin. The Strategy establishes an “End-to-end FFEWS” framework at the basin and national levels as a first step towards reducing vulnerability to flood in the Zambezi . USAID/OFDA is also supporting a three-year initiative implemented by IFRC to help vulnerable communities adapt to climate-related threats such as flooding through conservation-based farming techniques, soil conservation, water-harvesting techniques, and reforestation. The strategy and IFRC programming will help link technology to communities, encouraging the development of a framework for a sustainable, integrated flood early warning and management in the Zambezi basin. USAID OFDA is coordinating with the World Bank and other donors to join efforts for integrating into a basinwide framework and develop a system design and a project implementation plan for flood early warning in the basin.