This research aims to evaluate the feasibility of using multiple rainfall-runoff hydrologic models Génie Rural à 4, 5, 6 paramètres Journalier (GR4J, GR5J, and GR6J) in the Upper Benue River (UBR) in Northern Cameroon. By using the Michel's calibration algorithm, we found that the composite criterion is the most sustainable objective function for model optimization. An honest evaluation empirically proves that the GR6J model performs better than the other two models follow by GR5J.

Runoff simulation is complex in poorly gauged and data-scarce hydrosystems of the West African Sahel. The results of this study showed that multi-sites calibration without nested sub-catchments is the best modelling scheme for capturing the hydrological response of the Sahelian catchments. This approach could therefore be applied to obtain regionalized parameter values for the West African Sahel region from small catchments distributed across all climatic zones.

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).

Hydropower (HP) is the 2nd source of energy in Côte d'Ivoire. However water resource for HP is threatened by climate change (CC). Therefore the hydro potential and production are impacted. This study investigates the impacts of future CC in the White Bandama watershed using hydrological modelling coupled with GIS analysis. It emerges that in the future an upward trend in flows will be recorded. This could contribute to the siltation of dams and an increase in the risk of flooding in the basin.

This study assessed ERA5 reanalysis on runoff, evapotranspiration, water table depth, and soil water content over the Benin basins at spatial scale and monthly time scale. The results showed that the reanalysis simulates well the peaks of mean runoff. It showed the best performance in terms of correlation (>0.50) for runoff, SWC, and ETR. But, the correlations were below 0.5 on the reanalysis for WTD with slight overestimation.

This study aims to assess the potential impacts of climate change on hydropower potential of the Lagdo dam. The results reveal that under global warming, the hydropower potential of the dam will decrease which is the result of the reduced precipitation and increase of PET, thus decrease in streamflow in the basin. This result will be take into account for future development planning in the basin.

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).

Le comblement et l’eutrophisation des retenues d’eau constituent des contraintes majeures pour les usages qu’en font les populations riveraines. L’étude bathymétrique a révélé une diminution moyenne de 0,116 m/an. Ce comblement s’explique par l’érosion, la dégradation du couvert végétal et le surpâturage. Les mesures directes de la qualité physique : le pH, la température et l’oxygène dissous ont permis d’évaluer le risque d’eutrophisation. Les eaux sont dans un état eutrophe.

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.

This study aims to assess simulated surface runoff before and after dam construction in the Mono catchment (West Africa) using two lumped models: GR4J (Rural Engineering with 4 Daily Parameters) and IHACRES (Identification of unit Hydrographs and Component flows from Rainfall, Evapotranspiration and Stream data) over two different periods (1964–1986 and 1988–2010). Daily rainfall, mean temperature, evapotranspiration and discharge in situ data were collected for the period 1964–2010.

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.

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

The impact of climate change on precipitation and water availability is of major concern for policy makers in the Mono Basin of West Africa, whose economy mainly depends on rainfed agriculture and hydropower generation. The objective of this study is to project rainfall, flows and evapotranspiration (ET) in the future period and understand their changes across Mono River Basin.

La sécheresse observée en Afrique tropicale vers la fin des années 1960, a également affecté le bassin de la Bénoué en Afrique centrale, avec une persistance remarquable qui s’est répercutée sur les écoulements. Les ruptures à la baisse ont été mises en évidence dans les séries hydropluviométriques de ce bassin au pas de temps annuel en 1970–71 (pluies) et 1971–72 (débits). Les déficits associés à cette rupture sont de −2,9 % pour les pluies et −14,2 % pour les débits.

The objective of this article is to assess recent trends of hydroclimatic quantities in Ogooue basin in the context of climate change. For this, the rainfall and discharges data of this basin were analyzed using the Pettitt test. The results of this study reveal a statistically significant decrease in runoff that the Pettitt test situates in 1972–73, but nothing like that for rainfall at this same time scale.

The FRIEND-Water program (FWP) is the oldest and the most transverse program within the UNESCO IHP. It allows large communities of hydrologists to collaborate across borders on common shared data and scientific topics, addressed through 8 large world regions. Research priorities evolve according to the projections given by the member States during the IHP councils. FWP further activities follow the IHP IX program with the support of the Montpellier UNESCO Category II Center ICIREWAD.

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.

This study evaluates the impact of future climate change on the hydropower generation potential of the Bamboi catchment (Black Volta). The results indicate a projected mean annual precipitation increase while a decrease of hydropower generation is expected.