• A sediment model has been used to estimate the impact of constructed and planned dams and climate change on the Mekong River • Reservoir storage capacity is forecasted to increase in the next two decades, with consequences for the sediment flux • Planned dams will reduce suspended sediment fluxes to the delta by up to 50% in the next twenty years • Climate change play a secondary role compared to dams • Historical declines are mostly attributed to dams in China, but future declines will be triggered by dams in Lao and Cambodia