Dams Initiative

Dams - blessing and curse?

Over 48,000 large dams are in operation worldwide. They provide drinking water, irrigate the land, produce hydro-electricity and prevent floods.

Yet, today over one billion people do not have access to safe drinking water. More than double that number lack basic sanitation. Two billion people have no access to electricity. And those numbers are set to rise.

With the world's population growing faster than ever, by 2050 at least 1 in 4 people will be living in a country affected by water shortages.

And in the most alarming scenario, by that time up to seven billion people in 60 countries are expected to face water scarcity. To meet the demand for water, more large dams are proposed as a key solution.

But will they really bring benefits to those whose needs are largest? Too often, the benefits they bring have come at a great environmental and social cost, as dams destroy ecosystems and cause people to lose their homes and livelihoods.

A WWF report warns that indiscriminate dam-building is threatening the world's largest and most important rivers, with the Yangtze in China, the La Plata in South America, and the Tigris and Euphrates in the Middle East likely to suffer most from dams.

The WWF report, Rivers at Risk, identifies the top 21 rivers at risk from dams being planned or under construction.

It shows that over 60% 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.

The report highlights the Yangtze as the river at most risk with 46 large dams planned or under construction. The Danube and Amazon rivers are also included in the list.

Getting the balance right is crucial.

The World Commission on Dams provided recommendations and guidelines that allow us to do just that. However, the report concludes that governments are not applying these recommendations to their dam projects. As a result, the benefits that dams provide - such as hydropower, irrigation, and flood control services - are often overtaken by negative environmental and social impacts.

For example, 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. This is equivalent to 10 times the annual water consumption of the entire African continent.

According to the report, 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.

For example, China - the country with the most number of dams planned or under construction in the world - may lose endangered species such as the Yangtze River Dolphin and many water birds if indiscriminate dam-building continues to destroy their habitats.

It is not just important that we get it right. It's critical that we get it Dam right.