Thousands of Large, Old Dams in India Pose Threat to Downstream Populations: UN Report
India’s aging dams, many of which will be more than 50 years old by 2025, could put at risk millions of citizens living downstream, according to a report by the United Nations.
Dam failures can result in the loss of lives, livelihoods, and properties, as well as the loss of ecosystems and habitats, to flooding.
“By 2050, most people on Earth will live downstream of tens of thousands of large dams built in the 20th century, many of them already operating at or beyond their design life,” the report notes.
In India, more than 1,000 large dams will be roughly 50 years old in 2025; more than 4,000 will be over 50 years old by 2050; and 64 will be more than 150 years old in 2050.
Citing the example of the Mullaperiyar Dam in Kerala, the report notes that approximately 3.5 million people would be at risk if it “were to fail,” leading to “catastrophic” consequences.
Flooding, internal erosion, seepage, and structural instability and deterioration are among the reasons dams might fail. Aging makes dams more vulnerable to these problems, lessens dams’ functionality and effectiveness, and progressively increases the cost of dam repair and maintenance.
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The risk of damage to water infrastructure is amplified due to climate change, which research suggests will make extreme flooding more frequent and commonplace. “…the rising frequency and severity of flooding and other extreme environmental events can overwhelm a dam’s design limits and accelerate a dam’s aging process,” Vladimir Smakhtin, an expert on hydrology at the United Nations University (UNU) who co-authored the report, told the media. A recent study on India found that 75% of the country’s districts are vulnerable to extreme weather events such as cyclones and floods.
Compiled by the Institute for Water, Environment and Health at the UNU, the academic and research arm of the UN, the report notes that 58,700 large dams worldwide were constructed between 1930 and 1970 with a design life of just 50 to 100 years, which they are rapidly approaching. At present, the volume of water being stored behind large dams is estimated at 7,000 to 8,300 cubic kilometers — for comparison, that’s enough to cover about 80% of Canada’s landmass under a meter of water.
The report further notes that 55% of large dams across the world are concentrated in just four Asian countries — India, China, Japan, and South Korea. Most of the dams in these countries will be over 50 years old soon.
Titled Ageing Water Storage Infrastructure: An Emerging Global Risk, the report aims to draw global attention to the risks posed by aging dams and stimulate international efforts to deal with the crisis.