For decades, hydropower has been an important pillar of the Swiss electric power system, flexibly providing both generation of electric energy and its storage. Simultaneously to the deployment of new renewables including solar and wind in line with the Swiss Energy Strategy 2050, considerable efforts are necessary to maintain hydropower’s role as the backbone of an increasingly volatile electric power system. Among other factors, reservoir sedimentation has a negative impact on hydropower storage capacities, however. An estimated loss of 7% of the seasonal storage capacity in Swiss reservoirs is anticipated until 2050. This project aims at reducing the uncertainties related to the assessment of reservoir sedimentation with long-term numerical simulations to model the effects of different sediment management strategies. This will lead to better information of the future availability of hydropower’s storage capacities.