Nearly 100 hydropower dams are planned for construction along tributaries off the Mekong River’s 2,700-mile stretch. The river, one of the world’s largest, flows through Burma, China, Vietnam, Laos, Thailand and Cambodia. It is an economic engine for fishermen and a food source for millions of people worldwide. And while the dams are expected to provide clean energy to the region, if not managed properly, they also have the potential to offset natural river patterns, which would damage food production, supply and business.
Arizona State University professor John Sabo; Albert Ruhi, Postdoctoral Fellow at the National Socio-Environmental Synthesis Center (SESYNC) at the University of Maryland; and collaborators have proposed a solution to this problem in the Dec. 8 issue of Science Magazine that allows dam operators to generate power in ways that also protect – and possibly improve – food supplies and businesses throughout the Mekong river basin. The proposed solution, the first of its kind for this problem, can be applied to other large river systems around the world facing similar tradeoffs.
“We have figured out the relationship between river flows and fish catch, and we have developed an algorithm for dam operators to use that will increase fish harvests and still generate power,” Sabo said. “Dams are going to be built no matter how much fuss we make, our research shows how we can be more strategic about the buildout and operations of these dams in the Mekong.”
The Mekong river floods annually, and it is known that those floods are important for fisheries, Sabo said. New in this research is the recognition that seasonal droughts are equally important. Long droughts combined with short floods may create the ideal conditions for terrestrial nutrients to be entrained into the freshwater system. With that in mind, the algorithm presented by Sabo et al. in Science recommends long low-flow periods punctuated by pulses of flooding, which will allow dam operators to co-manage their power generation priorities, while protecting livelihoods for fisheries downstream.
During Ruhi’s postdoctoral fellowship at SESYNC, he is further developing this line of research by asking which dams in the U.S. have the highest scope to be re-operated, and how we may be able to identify optimal trade-offs between maximizing water conservation in reservoirs (to increase human resilience to water scarcity) and securing as much biodiversity insurance as possible. He is using novel advances in time-series methods on long-term physical, ecological, and socio-economic data.