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).

A scientific model to simulate river discharges in un-measured locations is made available via a service on the web for end-users. It is shown how this allows an increasing uptake by non-modelers, for the benefit of hydrological assessments and management.

Fair and safe allocation of natural resources for the Euro-Mediterranean area, especially for semi-arid regions, strongly relies on the adoption of WEFE (Water Energy Food Ecosystem) Nexus strategies. Transitioning to WEFE Nexus requires novel quantifiable assessment for interlinked analysis of the four WEFE sectors. Several indicator-based tools exist for agricultural sustainability at the farm scale. This contribution investigates on the application of IDEA method for WEFE Nexus approaches.

This short paper is the preface of the PIAHS volume of the IAHS/UNESCO FRIEND-Water conference of Cotonou in November 2021.

The 8th Global FRIEND conference highlighted the advance in hydrological science and innovation in water management. 52 accepted papers cover study areas in precipitation and climate impact; observation, analysis and simulations of hydrologic processes; floods in the changing environments; drought monitoring and analysis; water resources and environmental impacts. The outcome of the conference presented in the proceedings will be shared and discussed widely among UNESCO IHP networks.