Influence of climate extremes on discharge inflow and reservoir management at the Kossou dam

In the context of climate change, the increasing frequency and intensity of extreme events are disrupting dam management in West Africa. Few studies have examined their impacts on water inflows and the operational management of dams. The Kossou Dam, located at the outlet of the White Bandama watershed in central Côte d'Ivoire offer a relevant case for such analysis. This study assesses the effect of extreme weather events on the river flows and dam operations using meteorological data (rainfall and temperatures) from nine (9) weather stations, combined with hydrological (Inflows) and operational record (outflows, storage, water levels, and energy). The methodology combines probability analysis, extreme climate indices and statistical tests, including the Mann – Kendall trend test (and Sneyers' modification) and correlation analyses. Results show spatial variability in extremes rainfall and temperature in the White Bandama watershed. Trends in extreme rainfall are generally not significant at the 95% confidence level, while extreme temperature indices vary by stations. Correlations above 0.30 between rainfall extremes and flows confirm rainfall's influence on flow rates whereas extreme temperature indices show no significant link with flows. For operational parameters, only water level and storage correlate (below 0.40) with Tmax, CSDI and WSDI.