Damming Statistics

Date: 
Monday, October 22, 2007
  • Global number of dams: c. 800,000
  • Global number of large dams: >40,000
  • Global number of major dams: >300
  • Global area flooded by dams: >400,000 km²
  • Global number of people evicted by dams: 30m–60m
  • Percent of people evicted in India belonging to indigenous adivasi communities: 40
  • Percent of adivasis in Indian population: <6
  • Global number of people infected with schistosomiasis: 200m
  • Urinary schistosomiasis rates near Volta River, Ghana: 10%
  • Urinary schistosomiasis rates near Volta Reservoir: 90%
  • Intestinal schistosomiasis rates on lower Senegal River pre–Diama dam: 0%
  • Intestinal schistosomiasis rates on lower Senegal River post–Diama dam: 25–82%
  • Global % of freshwater fish endangered/extinct: 20
  • N. American freshwater fish endangered/extinct: 40
  • Percent of river discharge in N. America, Europe and ex–USSR affected by dams: 77
  • Typical % of river sediment trapped by large reservoir: 98
  • % of global reservoir storage capacity lost to sediment annually: 1
  • Cost of dredging this sediment: $100bn–$150bn
  • Percent of Chinese reservoir storage cap. lost to sediment annually: 2.3
  • Percent of global reservoir storage cap. lost to sediment by 1986: 20
  • Number of people killed by dam breaks in 20th century (ex–China): 13,500
  • Number of people killed by 1975 break of Banqiao and Shimantan Dams in central China: 80,000–230,000
  • Number of lives threatened by dangerously high level of Kakhovskaya Reservoir, Ukraine, February 1996: 500,000
  • Percent of dams built since 1950 which have failed (ex–China): 0.5
  • Percent of dams built since 1950 which have failed in China: 4
  • Average risk of any dam breaking in given year: 1 in 10,000
  • Number of dams more than 50 years old: 5,000
  • Average age in years of dams in US: 40
  • Estimated cost of decommissioning 2 dams in Washington state: $148m–203m
  • Number of articles on dam decommissioning seen by President of International Commission on Large Dams by 1992: 1
  • Number of reservoirs to induce earthquakes > magnitude 4.0: 32
  • Salmon run in Colombia River (US) mid–19th century: 10m–16m
  • Salmon run in Colombia River late 20th century: 1.5m
  • Wild salmon run in Colombia River late 20th century: 375,000
  • Annual cost of hatcheries in Colombia basin: $350m
  • Cost of losses to Colombia River salmon fishery 1960–1980: $6.5bn
  • Decline in sturgeon catches in Caspian Sea since damming of Volga: 98–99%
  • Cost of decline in Black, Azov and Caspian fisheries 1977–1987: $35bn
  • Times fish yields are higher in tropical rivers with annual floods than in rivers without floodplains: 100
  • Times per hectare fish yields are higher in tropical rivers with annual floods than in reservoirs: 4
  • Times more species in Mekong than in Mississippi: 3
  • Times more scientific articles on Mississippi fauna than Mekong fauna: 10,000
  • Number of 31 national dam agencies in industry survey which monitor environmental impacts of dams: 12