It’s a little strange to write a fact sheet about a term that actually has no meaning.
That’s right – there’s no real definition of a “run-of-river” hydro project. As our former director, Patrick McCully, once said of run-of-river hydro, “It’s a sort of Alice in Wonderland, ‘it means exactly what I want it to mean’ term.”
Simply put, run-of-river (ROR) hydro projects have limited storage capacity as compared to conventional storage dams. But there, the clarity ends. The term has been applied to everything from micro-hydro projects providing electricity in remote villages to the Belo Monte mega-dam in Brazil, which will devastate an extensive area of the Brazilian rainforest, displace over 20,000 people, and threaten the survival of indigenous tribes that depend on the river.
One World Bank insider told me that Bank officials often misuse the term as short-hand for “low-impact.” That kind of imprecision lulls officials and the public into thinking ROR projects are the silver (or green) bullet: hydro projects that produce power but without the negative impacts. Because the term sounds so innocuous, ROR projects usually don’t get the level of scrutiny they require. And the truth is, run-of-river dams are anything but low-impact.
Preparing our new fact sheet, “Swindling Rivers,” I’ve learned a lot about run-of-river hydro, the different forms it takes, and the significant impact ROR projects can have:
The Himalayas are perforated by run-of-river tunnels where river flows are diverted to powerhouses, bypassing river channels for often dozens of kilometers. India’s Teesta River is undergoing a ROR boom that, once complete, will see more of the river flow though tunnels than the river channel itself. These ROR schemes divert some, or even all, of a river’s flow, often causing changes to a river’s temperature, velocity and depth that can completely kill off the natural life in a river.
At the same time, so-called “peaking” ROR projects are wreaking havoc on communities and aquatic life. Unlike the diversion tunnels, these projects often store a river’s flows behind a dam during the day, only to be released all at once in the evening to generate power during peak energy demand. These daily fluctuations between drought and flood are incredibly disruptive to river ecology. More tragically, these unexpected releases have made drownings a common occurrence for downstream communities in India.
And just like traditional dams, all run-of-river projects stymie the life cycle of migratory fish.
A new feature in The Economist highlights the perils of dam construction on one of the world’s greatest waterways, the Mekong River, where Laos is currently building the Xayaburi and Don Sahong Dams. These would be the first two of eleven dams planned on the lower mainstream of the river, all of which are classified as “run-of-river” projects, despite sizeable reservoirs. Laos’ downstream neighbors fear the dams’ impacts on fish populations and agriculture that sustain the livelihoods and food security of millions and have voiced strong concerns over the projects. The Government of Laos, in return, has pointed to the fact these projects are run-of-river in an attempt to downplay concern over their impacts. If the full suite of dams is constructed, they would transform more than half of the vibrant river into a series of stagnant reservoirs.
But the concerns are not going away. In fact, they were recently echoed in an article in the prestigious magazine Science, which raised the alarm about the threat of major biodiversity losses by run-of-river projects on the world’s great rivers – the Mekong, the Amazon and the Congo.
In short, there’s nothing innately better about run-of-river projects. If anything, the term is a greenwash for some deeply destructive projects. The upshot? Don’t be fooled by the name: All ROR projects deserve the same exacting scrutiny as any other dam.