Hydrological risk of dam failure under climate change

Risco hidrológico de falha da barragem sob mudanças climáticas

ABSTRACT

Most water infrastructure was designed for climate conditions and demands that have been rapidly changing. In this study, we investigate flood magnitude and dam safety under climate change, using an ensemble of CMIP6 climate models, coupled to a hydrological model. We compare historical and future climate conditions of a watershed in Ceará, Northeast Brazil. Climate models revealed a wide range of risk levels of flood and hydrological failure. Half of the climate scenarios indicated a reduction in the flood return period. A flood associated with a 1000-year storm had an occurrence probability about 12 times higher when comparing the SSP5 8.5 scenario with historical conditions. In one more critical scenario, the water depth exceeded the height of the dam's crest. When considering a flood associated with a decamillennial storm, dam collapse risk was increased. Climate change might increase the risk of water infrastructure failure, which needs to be adapted to ensure the safety of the water system stakeholders.

Keywords:
Climate change; Extreme events; Intensity-duration-frequency; Risk assessment; Dam safety