Argument: Hydroelectric dams can be used to provide flood control and irrigation

The large water reservoirs created by hydroelectric dams can provide facilities for water sports and can become tourist attractions themselves. The reservoirs can be used for irrigation to help farmers and can be a means for flood control. A prime example of this is the Tennessee Valley Authority, an organisation responsible for flood control, electricity generation, economic development and even fertilizer generation in the Tennessee Valley in the U.S., spanning parts of Alabama, Mississippi, Kentucky, Georgia, North Carolina and Virginia. [1]

[1] Tennessee Valley Authority, homepage.

Candidate 1: "As well as benefits hydroelectric dams have added dangers. Dams increase the risk of earthquakes, because the weight of the water-reservoir impacts the Earth’s crust underneath. [1] Moreover, big dams run the risk of bursting, causing massive damage in their wake. The bursting of the Chinese Banqiao dam in 1975 is estimated to have cost about 230,000 lives. [2]

[1] BBC News, ‘Earthquake risk from dams’, 2002

[2] The New Internationalist, ‘Big dams, big trouble’, 2003"
Candidate 2: "Hydroelectric dams destroy communities

What applies to the environment, also applies to the human communities. Building dams often involves relocating people and removing them from their ancestral homelands. For example, China’s Three Gorges Dam involved relocating 1.3 million people, [1] involved severe human rights abuses [2] and has had dire social consequences. [3]

[1] CBS News, ‘China Completes Three Gorges Dam’, 2009

[2] International Rivers, Human Rights dammed of at Three Gorges, 2003

[3] New York Times, ‘Chinese Dam Projects Criticized for Their Human Costs’, 2007"
Candidate 3: "Hydro electric dams destroy existing ecosystems

Large dams wreak havoc with the environment: they destroy habitats and ecosystems both further upstream and downstream. They prevent salmon from swimming upstream to spawn. The water going through them is often warmer and devoid of nutrients, depriving downstream riverine wildlife of their natural habitat. A shocking example is China’s Three Gorges Dam, which Scientific American called ‘an environmental disaster’. [1]

[1] Scientific American, ‘China’s Three Gorges Dam: An environmental disaster?’ 2008"
Candidate 4: "Hydroelectric dams require massive initial investments. True, dams generate cheap electricity, when the dams are eventually built. But building dams is incredibly costly. Actual costs for hydropower dams are almost always far higher than estimated; in a number of cases, the actual cost was more than double the estimated cost. The Itaipu Dam in South America cost $20 billion and took 18 years to build. This was 488% higher than originally estimated. [1] Given that there are cheaper alternatives than large-scale dams for renewable and accessible energy, dams aren’t worth it from an economic perspective.

[1] International Rivers, Frequently Asked Questions."
Candidate 5: "Hydroelectric dams increase methane emissions

Hydroelectric dams emit a lot of methane, which is an even more potent greenhouse gas then carbon dioxide. This happens when the plants and vegetation submerged in the reservoir start to rot under water: they then produce methane which bubbles up and is released into the atmosphere. On balance, some dams produce more greenhouse gasses than conventional power plants running on fossil fuel. [1]

[1] New Scientist, ‘Hydroelectric power's dirty secret revealed’, 2005"
Candidate 6: "Hydroelectric dams don’t reduce carbon dioxide emissions. Dams currently hold off about 15% of global freshwater runoff. If we want to sustain biodiversity and river-related goods and services, we can’t easily increase the number of dams. [1] Also: building dams requires cutting down forests, which themselves are important tools in combating greenhouse gases, since they consume and ‘lock up’ carbon dioxide. Plus, the construction of the dams themselves releases carbon dioxide. Finally: global energy demand is expected to continue increasing, [2] meaning that hydropower will probably just be added to the supply and not replace coal.

[1] International Rivers, Frequently Asked Questions.

[2] IEA, World Energy Outlook, 2010, Executive summary"

As well as benefits hydroelectric dams have added dangers. Dams increase the risk of earthquakes, because the weight of the water-reservoir impacts the Earth’s crust underneath. [1] Moreover, big dams run the risk of bursting, causing massive damage in their wake. The bursting of the Chinese Banqiao dam in 1975 is estimated to have cost about 230,000 lives. [2]

[1] BBC News, ‘Earthquake risk from dams’, 2002

[2] The New Internationalist, ‘Big dams, big trouble’, 2003
