Thursday, August 20, 2026
News and Views from the Global South
ENVIRONMENT: New Dams Threatening Many Rivers
Sanjay Suri
- Hundreds of new large dams are posing new dangers to river systems all around the world, WWF says in a report published Tuesday.
The Yangtze in China, the La Plata in South America, and the Tigris and Euphrates in the Middle East are likely to suffer most from dams, says the report ‘Rivers at Risk’.
The WWF report identifies the top 21 rivers at risk from dams being planned or under construction. It shows that more than 60 percent of the world’s 227 largest rivers have been fragmented by dams, which has led to the destruction of wetlands, a decline in freshwater species – including river dolphins, fish, and birds – and the forced displacement of tens of millions of people.
“We are looking at a very large number of large dams being planned or under construction,” David Cowdrey from WWF told IPS. “When you look at 46 dams on the Yangtze river, that is way, way beyond what the river can take. It means relocation of millions of people and sudden changes to large stretches of the environment. That cannot be right.”
For many of the new dams being built the benefits do not outweigh the costs, Cowdrey said. “People have to be moved, ecosystems are destroyed and the people who need the water and electricity do not get them, and then the dams silt up.”
The WWF report says recommendations of the World Commission on Dams are being widely disregarded. The Commission did not dismiss the benefits of all large dams outright, but set out several considerations that it said must be taken into account when planning to build them.
“Each dam needs to be looked at in its own right,” Cowdrey said. “If it is in the right location and it brings benefits, only then can it be looked at favourably.”
The report says that failure to do so has meant that “the benefits that dams provide – such as hydropower, irrigation, and flood control services – are often overtaken by negative environmental and social impacts.”
Often much of the water provided by dams is lost, mainly due to inefficient agriculture irrigation systems – which globally waste up to 1,500 trillion litres of water annually, the report says. This is about 10 times the annual water consumption of the entire African continent.
The ‘Rivers at Risk’ analysis examines threats to rivers on a basin scale from dams currently under construction that are over 60m high, as well as on data on planned dams that are either higher than 60m or will have an installed hydropower capacity of more than 100 MW as of 2003.
The analysis includes dams of all types: hydropower, irrigation, water supply, flood prevention and multi-purpose dams.
The report says downstream communities suffer most from dams, with rivers running dry and fish stocks decimated. “Dams disrupt the ecological balance of rivers by depleting them of oxygen and nutrients, and affecting the migration and reproduction of fish and other freshwater species,” the report says.
WWF urges decision-makers and dam developers to make efficient water use a priority by applying internationally accepted standards – such as those of the World Commission on Dams – on dam projects to minimise the negative social, economic, and environmental impacts of dams.
The EU Water Framework Directive applies strict conditions for the development of dams in EU member states, the report says. New projects are allowed only if there are no better environmental options but such progressive legislation, however, is rare, the report says.
“Dam construction projects often proceed with little attention to cumulative impacts and alternatives,” Ute Collier, head of the WWF’s dams initiative said in a statement. “In meeting growing global water and energy needs, we must not destroy the ecosystems that provide clean and sustainable water supplies.”
Following is a list of the 21 rivers most at risk listed by the WWF. The list gives in each instance the name of the river basin, the basin size in ‘000 square kilometers, the name of the countries in the river basin, and the number of large dams in that river system.
1 Yangtze/ 1,722/ China/ 46
2 La Plata/ 2,880/ Argentina, Bolivia, Brazil, Paraguay, and Uruguay/ 27
3 Tigris & Euphrates/ 766/ Turkey, Iraq, Syria, Iran and Jordan/ 26
5 Kizilirmak/ 82/ Turkey/ 15
7 Tocantins/ 764/ Brazil/12
8 Amazon/ 6,145/ Brazil, Peru, Bolivia, Colombia, Ecuador, Venezuela, Guyana, Suriname, Paraguay and French Guyana/ 11
9 Mekong/ 806/ Thailand, Laos, China, Cambodia, Vietnam and Myanmar/ 11
10 Brahmaputra/ 651/ China, India, Bhutan, Bangladesh/ 11
11 Xun Jiang (Pearl River)/ 409/ China, Vietnam/10
12 Danube/ 796/ Germany, Austria, Slovakia, Hungary, Croatia, Serbia & Montenegro, Romania, Bulgaria, Moldova, Ukraine/ 8
13 Hwang He (Yellow River)/ 945/ China/ 8
14 Kura-Araks/ 205/ Azerbaijan, Iran, Georgia, Armenia, Turkey/ 8 15 Yesil-Kelkit/ 41/ Turkey/ 8
16 Büyük Menderes/ 28/ Turkey/ 7
17 Çoruh/ 22/ Turkey/ 7
18 Simav/ 27/ Turkey/ 7
19 Ebro/ 83/ Spain and Andorra/ 6
20 Indus/ 1082/ Afghanistan, Pakistan, India, and China/ 6
21 Qezel Owzan/ 60/ Iran/ 6
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