Opportunities to curb hydrological alterations via dam re-operation in the Mekong

In rivers around the world, hydropower development has altered the seasonal hydrological regime, which drives key ecosystem services. Dam re-operation efforts that minimize hydrological alterations are, therefore, critical to biological conservation, particularly in the tropics, where dam development is still booming. Here, we identify the limits and opportunities of alternative dam-management strategies in the Mekong, a biodiverse but rapidly developing river. We show that basin-wide efforts are needed to completely restore seasonal hydrological variability, probably an unfeasible solution in the Mekong’s institutional landscape. Instead, re-operation efforts focused on the Lower Mekong could yield tangible opportunities for partially restoring key elements of hydrological variability without affecting hydropower production. In fact, changing production plans across a few critical dams could raise Laos’ hydropower revenues by almost US$150 million per year (a third of the country’s hydropower revenues). Nexus solutions such as this one are a potential basis for safeguarding crucial economic interests and catalysing sustainable river management in international rivers.