Building Bridges Across Borders to co-develop flood early warning in the Sahel

In West Africa, flood risk has increased exponentially since the beginning of the 21st century, due to both the growing magnitude and frequency of flood hazards and the rising exposure of urban and peri-urban areas. In the Sahel, in particular, floods have a severe impact on livelihoods, infrastructure, and production systems, thereby threatening sustainable development. The recent Early Warnings for All (EW4ALL) initiative, promoted by the World Meteorological Organization and other development partners, has emphasized the critical role of early warning systems in reducing the impact of natural disasters—especially floods.

In West Africa, flood early warning systems remain largely at an embryonic stage. However, recent experiences have laid the groundwork for strengthening national capacities in certain countries. Among these, the Système Local d’Alerte Précoce contre les Inondations de la Sirba (SLAPIS), developed in Niger between 2018 and 2020, has shown that a co-development approach—integrating both top-down and bottom-up methods—can effectively empower local communities and technical services to mitigate flood impacts.

This study presents the evolution of SLAPIS into a transboundary system between Niger and Burkina Faso, maintaining its community- and impact-based orientation while incorporating new hydraulic, hydrological, and meteorological forecasting components. The approach promotes interoperability with existing hydrological forecasting systems such as GLOFAS, HYPE, and SATH, and facilitates their localization and optimization. Moreover, the use of flood scenarios enables the linkage of observations and forecasts with hydrological thresholds, flood-prone zones, and potential impacts. The integration of citizen science in local flood observation and downstream alerting further enhances community awareness and ownership.

The expanded system, known as SLAPIS Sahel, is currently under development across the entire Sirba River basin (39,000 km² shared between Burkina Faso and Niger) and along the segment of the Niger River between the Sirba confluence and the city of Niamey in Niger.

The study suggests that investments aimed at improving existing tools and knowledge, and at reinforcing transboundary cooperation, coordination, and collaboration to reduce the impacts of hydrometeorological hazards and support the sustainable development of rural and urban areas, can be highly effective—provided that co-development approaches are appropriately applied.