A stochastic methodology to assess the impact of climate change on the Eugui hydrological dam safety (Spain)

The study provides a stochastic methodology that considers the impact of climate change on floods (inflow hydrographs in the reservoir) and on the probability of a given water level in the reservoir in the future. Moreover, an uncertainty chain analysis is done to consider all the sources of errors in the methodology. A fully distributed hydrological model, the Real-time Interactive Basin Simulator (RIBS) model, is used to assess the impact of climate on flood quantiles at a sub-daily scale. The continuous HBV hydrological model is combined with a reservoir operation model to assess the future initial reservoir water level frequency at a daily scale. An ensemble of 12 climate models provides the climate projections for two emission scenarios (RCP 4.5 and RCP 8.5) and three time windows (2011-2040, 2041-2070, 2071-2100). The results show an increase in the future of maxima reservoir water levels associated with the most extreme events, especially in the 2071-2100 time window and RCP 8.5. Overtopping probability also increases in this latter scenario, while no changes are expected for the RCP 4.5.