Achieving water security in poorly gauged regions is hindered by a lack of in situ hydrometeorological data. In this study, we validated nine existing gridded water resource reanalyses and eight evapotranspiration products in eight representative gauged basins in Central–West Africa. Our results show the strengths and and weaknesses of the existing products and that these products can be used to assess water security in ungauged basins. However, it is imperative to validate these products.

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.

Knowing the concentration of the pollutant field distribution in time and space contributes significantly to the prediction of exceptional phenomena. To this we simulate the transport and dispersion of salt at Nokoue Lagoon. Results showed that in flood period the freshwater inflows produce a net seaward transport, while in low water period the tides lead to periodic seaward and landward transport. Freshwater inflow plays a major role in flood period and tide in low water period on the lagoon.

The objective of this study is to assess the impact of climate change on water availability in Oueme catchment at Savè. Precipitation provided by 3 regional climate models was analyzed. Bias in these data was corrected using the Empirical Quantile Mapping method before being used as input to hydrological models: AWBM, ModHyPMA, HBV, GR4J, SimHyd, Hymod. The simulation with the HIRHAM5 data as inputs of models showed flows that vary at the horizons 2025, 2055, 2085 under scenarios RCP(4.5_8.5).