The objective is to assess the causes of exceptional floods in the Ouémé basin using the HEC-RAS model. The results of the calculation made it possible to characterize: the losses and damage due to human settlement on the banks and agricultural production in the flood zone, the flooded extent and the height of submersion depend on the return period, most of the Flood waters converge towards the west of the basin (low risk) and towards the east around the Damè-Wogon depression (high risk).

Knowledge of rainfall statistical behaviour is a prerequisite to designing rainwater drainage facilities. In West Africa, most practitioners use the Gumbel distribution regardless of rainfall statistical behaviour. This study quantifies biases induced by the use of the Gumbel distribution. It was found that the use of the Gumbel distribution instead of appropriate distributions leads to an underestimation (−45.9 %) of annual daily rainfall maxima and thus to an uncertain design of facilities.

Floods are natural disasters that widely affect people, goods, and ecosystems. Some efforts have been made in predicting floods at a short-term range. However, the usefulness of flood prediction increases as the time lead increases. This work investigated covariates useful for flood prediction several months ahead. Very good relationships were found between flood discharge and some climate indexes which could serve as a basis for seasonal flood forecasting in West Africa.

This study addresses the importance of integrating the effect of land use on soil infiltration rate into land use change impact modeling. Based on field measurements; soil parameterization is computed in a hydrological model using a refined soil map integrating land use change impact of soil infiltration rate and a classic soil map not considering this interaction. The results show that integrating land use related effects on soil properties renders LULC change scenarios more plausible.

Climate change and population growth pose severe challenges to 21st century rural Africa. Within the framework of the West African Science Service Center on Climate Change and Adapted Land Use (WASCAL), an ensemble of high-resolution regional climate change simulations is provided to support adaptation and mitigation measures. This contribution presents the concept and design of the simulations and provides information on the format and dissemination of the available data.