According to a UN research, 3,700 dams in India will lose 26% of their storage capacity owing to sedimentation by 2050.

According to a new United Nations assessment, around 3,700 dams in India may lose 26% of their entire storage by 2050 owing to sediment deposition, which might jeopardize future water security, irrigation, and power generation. The Central Water Commission revealed in 2015 that one-quarter of 141 big reservoirs over 50 years old had lost at least 30% of their initial storage capacity.

Sediment has already robbed around 50,000 major dams worldwide of 13 to 19% of their whole initial storage capacity. According to a study conducted by the United Nations University Institute on Water, Environment, and Health (UNU-INWEH), also known as the UN's water think tank, 6,316 billion cubic meters of initial global storage in 47,403 large dams in 150 countries will be reduced to 4,665 billion cubic meters by 2050, resulting in a 26% storage loss.

The loss of 1,650 billion cubic meters of storage capacity is about equivalent to India's, China's, Indonesia's, France's, and Canada's combined annual water demand. The Asia-Pacific region, the world's most intensively dammed region, is expected to lose 13% of its initial dam storage capacity by 2022. By mid-century, it will have lost roughly a quarter (23%) of its initial storage capacity. Water storage is critical for sustaining water and food security in the region, which is home to 60% of the world's population.

"UNU-INWEH projects that by 2050, India's 3,700 big dams will have lost on average 26% of their initial total storage," according to the paper. Meanwhile, China, the world's most heavily dammed nation, has lost approximately 10% of its storage and will lose another 10% by 2050, according to the report. Infrastructure for water storage is vital for development. Large dams and reservoirs supply hydroelectricity, flood control, irrigation, and drinking water, and they frequently serve numerous purposes at the same time. Sediment accumulation reduces reservoir capacity over time and impacts reservoir life expectancy. A dam is called "big" if it is higher than 15 meters or between 5 and 15 meters high but holds more than 3 million cubic meters of water.

(source : PTI)