Quantcast
Energy

10 Things You Should Know About Dams

1. 50,000 Large Dams Are Clogging the World's Rivers:

About 50,000 dams with a height of 15 meters or more and millions of smaller dams have been built on the world's rivers. Some of them date back centuries, but most were built after World War II. About 5,000 dams have a height of 60 meters or more—another 350 such giants are currently under construction.

The Grand Coulee dam on the Columbia River in Washington State was constructed between 1933-1942. Photo credit: Wikimedia Commons

2. Dams Are Changing the Face of the Earth:

Dams have fragmented two-thirds of the world's large rivers and flooded a land area the size of Spain. Their reservoirs contain three times as much water as all the world's rivers, and constantly lose close to four Niagara Falls to evaporation. Dams trap 40 cubic kilometers of sediments every year, and starve deltas of the silt that protects them against the intruding sea.

3. Dams Provide Important Services:

Dams generate 16 percent of the world's electricity and irrigate food crops for 12-15 percent of the world's population. To a lesser extent, dams have also been built for water supply, flood protection, navigation and tourism purposes. Most dams have been built for irrigation, but 80 percent of the water they store is used for hydropower.

4. Dams Kill Fish:

Dams block the migration of fish, deplete rivers of oxygen and interfere with the biological triggers that guide fish. They also reduce the ability of rivers to clean themselves. Due to dam building and other factors, the population of freshwater species declined by 37 percent between 1970-2008—more than the populations of any other ecosystems. Tropical freshwater populations declined by a stunning 70 percent.

5. Dams Are Changing the Climate:

Dams are not climate-neutral. Particularly in the tropics, organic matter rotting in their reservoirs emits methane, an aggressive greenhouse gas. Scientists have estimated that reservoirs account for four percent of all human-made climate change, equivalent to the climate impact of aviation. The floods and droughts caused by climate change in turn make dams less safe and less economic.

6. Dams Displace People:

Dams have displaced an estimated 80 million people, with 23 million alone in China. Displacement robs people who are already poor and marginalized of their resources, skills and cultural identity, and impoverishes them further. Dams have also negatively impacted about 500 million people living downstream. The benefits of dams often bypass the people who sacrifice their livelihoods for them.

7. Dams Can Put Human Rights at Risk:

Most dams that displace large populations are being built by authoritarian governments. In Burma, China, Colombia, Ethiopia, Guatemala, Sudan and other countries, dam builders have often responded to opposition with serious human rights violations. In the worst dam-related massacre, more than 440 indigenous people were killed to make way for Guatemala's Chixoy Dam in 1982.

The Chixoy Dam in Guatamala was completed in 1982. Photo credit: Wikimedia Commons

8. Dams Are Expensive:

Large dams belong to the most expensive investments many governments have ever made. An estimated 2,000 billion dollars has been spent on dams since 1950. Due to planning errors, technical problems and corruption, dams experience average delays of 44 percent and cost overruns of 96 percent. Such massive overruns make them uneconomic.

9. Dams Don't Last Forever:

Sooner or later reservoirs silt up, and the cost of maintaining dams becomes bigger than their benefits. In the U.S., more than 1,000 dams have been removed at great cost. When dams are not properly built or maintained, they can break. In the world's biggest dam disaster, the failure of China's Banqiao Dam killed an estimated 171,000 people in 1975.

10. Better Solutions Are Usually Available:

In 2012, governments and businesses installed 75 gigawatt of wind and solar power, compared with 30 gigawatt of hydropower. Such alternatives fare even better when social and environmental impacts and transmission costs are included. The International Energy Agency has proposed that 60 percent of the funds needed to achieve energy access for all should go to local renewable energy projects.

--------

YOU MIGHT ALSO LIKE

DamNation Explores History of Dams and Brilliance of Rivers Reborn, Premieres at SXSW

Women Without Borders, Patagonia Without Dams

Groups Appeal to UN to Stop Forced Evictions of Indigenous People for Mega-Dam Construction

--------

Show Comments ()
Sponsored
Popular
Robert Vessels

Fly Fishing in Yellowstone: How One Veteran Found a New Life in the Outdoors

By Lindsey Robinson

Evan Bogart never wanted to sleep in a tent again. Between 2004-2011, he'd served in the U.S. Army as an infantryman and spent three long combat deployments in Afghanistan and Iraq. He'd spent a good portion of his years in service living in a tent in hot and hazardous deserts. He'd had enough of the outdoors; he wanted to be in places with air conditioning, electricity and no reminders of the war-torn lands he had experienced.

Evan separated in 2011 as an E6 Squad Leader, with an honorable discharge and two Purple Hearts. But his own heart was heavy and troubled. He'd become disillusioned with the U.S. military and its goals in the Middle East. The violence and destruction he'd witnessed left him feeling both angry and guilty. He distinctly remembers one moment in Iraq: "An old woman told me I was a bad man, and I realized I agreed with her."

Keep reading... Show less
Popular
Make A Change World

How Two Brothers Convinced the Indonesian Government to Clean Up the World's Most Polluted River

By Gary Bencheghib and Sam Bencheghib

On August 14, we set out to kayak down the world's most polluted river, the Citarum River located in Indonesia, to document and raise awareness about the highly toxic chemicals in its waters and the masses of plastics floating on its surface.

We paddled a total of 68km in two weeks on two plastic bottle kayaks from the village of Majalaya, located just south of Bandung to Pantai Bahagia, the river mouth at the Java Sea. Each kayak was made of 300 plastic bottles to demonstrate that trash can have a second life.

Keep reading... Show less
Popular

General Motors to Run Ohio, Indiana Factories With 100% Wind P​ower

By Greg Alvarez

Last week I predicted it wouldn't be long before we had more news on Fortune 500 wind power purchases. Well, a whole seven days passed before there were new deals to report.

Keep reading... Show less
Popular
South Carolina United Turtle Enthusiasts (S.C.U.T.E) unearthed three baby loggerheads after a nest inventory at Pawleys Island beach. Lorraine Chow

Sea Turtle Population Rebounding But Many Threats Remain

A new study published in Science Advances has found that most global sea turtles populations are recovering after historical declines.

The results from the analysis suggest that conservation programs actually work, and why we must defend the Endangered Species Act (ESA) that protects vulnerable plants and animals, and is currently under attack by political and business interests.

Keep reading... Show less
Sponsored
Popular
www.youtube.com

Baby Rhino Brings New Hope to India’s Manas National Park

A baby rhino spotted alongside its mother in Manas National Park, located in the northeastern Indian state of Assam, is an encouraging new sign that the rhino population in the protected area is on the upswing. The mother, named Jamuna, was rescued as a calf from Kaziranga National Park, located about 200 miles east of Manas and raised at the Center for Wildlife Rehabilitation and Conservation, a facility that cares for injured or orphaned wild animals run by Wildlife Trust of India/International Fund for Animal Welfare and the Assam Forest Department. She was moved to the Manas in 2008 as part of the country's rhino conservation efforts.

The calf is her second since 2013—a positive indication that despite concerns due to poaching of mature males, rhinos in Manas are reproducing.

Keep reading... Show less
Popular
Cedar Mesa Valley of the Gods in the Bears Ears National Monument in southeastern Utah. Bob Wick, BLM

Navajo Nation Readies Legal Action if Trump Shrinks Bears Ears National Monument

Interior Sec. Ryan Zinke's recommendation to reduce the size of the Bears Ears National Monument in Utah could spark a legal battle between the Navajo Nation and the Trump administration.

"We are prepared to challenge immediately whatever official action is taken to modify the monument or restructure any aspect of that, such as the Bears Ears Commission," Ethel Branch, Navajo Nation attorney general, told Reuters.

Keep reading... Show less
Sponsored
Popular
Jilson Tiu / Greenpeace

Nestlé, Unilever, P&G Among Worst Offenders for Plastic Pollution in Philippines Beach Audit

A week-long beach clean up and audit at Freedom Island in Manila Bay has exposed the companies most responsible for plastic pollution in the critical wetland habitat and Ramsar site—one of the worst locations for plastic pollution in the Philippines.

The Greenpeace Philippines and #breakfreefromplastic movement audit, the first of its kind in the country, revealed that Nestlé, Unilever and Indonesian company PT Torabika Mayora are the top three contributors of plastic waste discovered in the area, contributing to the 1.88 million metric tonnes of mismanaged plastic waste in the Philippines per year.

Keep reading... Show less
GMO
www.youtube.com

Arkansas Plant Board Backs Dicamba Ban Next Summer in Blow to Monsanto

The Arkansas Plant Board has approved new regulations that prohibit the use of dicamba from April 16 through Oct. 31, 2018 after receiving nearly 1,000 complaints of pesticide misuse in the state.

Arkansas, which temporarily banned the highly volatile weedkiller in July, could now face legal action from Monsanto, the developers of dicamba-resistant soybeans or cotton and the corresponding pesticide, aka the Xtend crop system.

Keep reading... Show less
Sponsored

mail-copy

Get EcoWatch in your inbox