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Social & Environmental Cost of Building dams

Social & Environmental Cost of Building dams


  • GS 3 || Economy || Infrastructure || Power

Why in News?

  • Constructions of large dams have some potential repercussions to the society.

Dams & The Repercussions

  • Most developed countries have reduced the construction of large dams for the production of electricity in recent decades, developing countries, including Brazil, have embarked on even more massive hydropower developments.
  • Countries don’t usually count the impacts of large dams in these scenarios:
    • Loss because of deforestation,
    • Loss of Biodiversity,
    • Social Consequences, e.g. displacement of thousands of people
    • Economic Damages, suffered by the denizens of the terrain
  • These effects should be computed in the total cost of such projects. Worse still, these projects ignore the context of climate change, which will lead to lower amounts of water available for storage and electricity generation.
  • Hydropower is the leading source of renewable energy worldwide, accounting for as much as 71 % of the total in 2016. Developed countries in North America and Europe built thousands of dams between 1920 and 1970, until the best sites had already been developed and environmental and social concerns made the costs unacceptable.
  • Many large hydropower developments in these countries are now at the end of their working lives, and more dams are being removed than built in North America and Europe. In the U.S. alone, 546 dams were dismantled between 2006 and 2014.
  • When a large dam is built, the result is a downstream loss of a great many fish species that are important to riverine populations.
  • “The cost of removing a dam once its useful life is over is extremely high, and should be taken into account when computing the total cost of a new hydro development,”
  • “If the cost of removal had to be included, many dams wouldn’t be built.”

Local Impacts

  • The first dams were also built in North America and Europe to supply power to rural areas and provide water for irrigation systems. “These projects had social purposes in the past. In contrast, the dams now under construction along the rivers of the Amazon basin in South America, on the Congo River in Africa and on the Mekong River in Southeast Asia are mostly designed to supply power to steel manufacturers, for example, without benefiting local communities.
  • These communities will have to continue somehow making a living despite dwindling fish stocks for 15 or 20 years, for example, and the costs of these projects don’t take such economic and social losses into account.”
  • The most exemplary case is the proposed Grand Inga Dam on the Congo River at Inga Falls, the world’s largest waterfall by volume. The dam could increase the total amount of power produced in Africa by over a third and will export electricity to South Africa for use by mining companies.

Impact of climate change

  • Climate change will strongly affect the dams that have been built in the Amazon basin in recent years, according to the article.
  • The Jirau & Santo Antonio dams on the Madeira, completed in the last five years, are now expected to produce only a fraction of the 3GW they were each designed to generate owing to climate change and the small storage capacity of their run-of-the-river reservoirs.
  • Most of the climate models predict higher temperatures and lower rainfall in Madeira basins.
  • Like the effects of climate change, the effects of changing land use on power generation potential are frequently ignored by dam builders.
  • Deforestation in the region–deforestation inhibits rainfall and reduces groundwater in tropical rainforest areas.


  • Social and environment  cost of  building dams surpass  their desired economic benefits. Elucidate.