Only a little more than one-third of the world’s 246 longest rivers remain free-flowing, drastically reducing the diverse benefits that healthy rivers provide to people and nature everywhere, according to a new study by WWF and partners.
A team of researchers from WWF, McGill University, and other institutions studied about 7.5 million miles of rivers worldwide to determine whether they’re well connected. They found that only 37% are free-flowing—meaning they’re largely unaffected by human-made changes to its flow and connectivity. Dams built in the wrong place and climate change are impacting river health worldwide, and the planet’s remaining free-flowing rivers are largely restricted to remote regions of the Arctic, the Amazon Basin, and the Congo Basin.
Vanishing free-flowing rivers
Long free-flowing rivers are vanishing. Around the world, rivers are becoming increasingly fragmented by dams and other development—such as roads or dikes—endangering freshwater ecosystems and the people and wildlife that rely on them. Free-flowing rivers transport water, nutrients, and species that sustain biodiversity and benefit millions of people. To help countries and communities better protect their freshwater resources, WWF and partners came up with a technical definition of a free-flowing river and then created a first-of-its-kind, scientifically backed map—a comprehensive inventory of the world’s last free-flowing rivers, rivers with good connectivity and impacted rivers.
Mapping dams
Dams provide safe drinking water and electricity to millions of people. But when built in the wrong place—for instance, a river’s main stem—they can impede a river’s flow, causing drastic declines in biodiversity and affecting fish migration, agriculture, and livelihoods. Today there are more than 60,000 major dams around the world—a number that’s increasing to meet demand for hydropower. WWF is helping national governments, industries, and developers consider both the long-term impacts on local people and habitats and other potential alternative options for meeting water and energy supply needs, as well as helping them identify the best opportunities for river restoration projects. Solar and wind prices are going down, making them attractive alternatives.
Response to McGill/WWF study by IHA
Richard Taylor, Chief Executive of the International Hydropower Association (IHA) said: “Hydropower is a major source of renewable power generation - enough for more than a billion people worldwide – supplying electricity in 160 countries."
"In managing the climate change that humanity has already caused, hydropower infrastructure can also assist in responsible freshwater management. Hydropower has an extremely low carbon footprint and causes no air pollution. Freshwater stored by hydropower infrastructure contributes to reliable supply for people, agriculture and industry, and reservoirs help countries halt or reduce the impacts of floods and drought."
"Thanks to hydropower’s unique operational flexibility and ability to soak up and store surplus electrical energy in the system, it plays a critical role in supporting the greater use of solar and wind power. Thus, it forms the backbone of our renewable energy future."
“All hydropower projects should be developed and operated responsibly and have a strategic fit in a river basin. This should be in consideration of local concerns and national priorities. There needs to be a balanced approach to water security, biodiversity and socio-economic development. The internationally recognised Hydropower Sustainability Guidelines on Good International Industry Practice and related assessment tools help to ensure projects follow good practice that is both clearly defined and measurable.”
