Why in News?
- According to a new study by the United Nations (UN), around 3,700 dams in India will lose 26 percent of their total storage by 2050 due to accumulation of sediments which can threaten water security, irrigation and power generation in future.
- The study was completed by the United Nations University Institute on Water, Environment and Health (UNU-INWEH), also referred as the UN’s think tank on water.
Key Highlights of the Study-
- Trapped sediment has already robbed approximately 50,000 large dams globally of an estimated 13 to 19% of their combined original storage capacity.
- It represents that 6,316 billion cubic metre of initial global storage in 47,403 large dams in 150 countries will reduce to 4,665 billion cubic metre, causing 26% storage loss by 2050.
- The loss of 1,650 billion cubic metre storage capacity is roughly equal to the annual water use of India, China, Indonesia, France and Canada combined.
- In 2022, the Asia-Pacific region, the world’s most heavily dammed region, is assessed to have lost 13% of its initial dam storage capacity.
- It will have lost around a quarter (23%) of initial storage capacity by mid-century.
- The region is home to 60% of the world’s population and water storage is very important for sustaining water and food security.
- China, meanwhile, the world’s most heavily dammed nation, has lost around 10% of its storage and will lose an additional 10% by 2050.
State of Indian Dams-
- India is ranked third in the world in terms of constructing large dams.
- Of the over 5,200 large dams built so far, about 1,100 large dams have already touched 50 years of age and some are more than 120 years old.
- The number of such dams will rise to 4,400 by 2050 i.e., 80% of the nation’s large dams face the prospect of becoming obsolete as they will be 50 years to over 150 years old.
- The situation with hundreds of thousands of medium and minor dams is even more dangerous as their shelf life is even lower than that of large dams.
- Examples- Krishna Raja Sagar dam was built in 1931 and is currently 90 years old. Similarly, Mettur dam was built in 1934 and is now 87 years old. Both these reservoirs are located in the water scarce Cauvery river basin.
- Significance- Dams provide numerous benefits including fresh water supply, water storage for irrigation, hydroelectric power generation, flood control, and improved navigation for transportation.
Issues with Indian Dams-
- Ageing infrastructure- Many of India’s dams were constructed several decades ago and are in need of maintenance and repair. This can lead to structural issues and an increased risk of failure.
- Built based on Rainfall Pattern- State of Indian dams are very old and were constructed based on the historical patterns of rainfall. They have been exposed recently by irregular rains.
- Though, the government is outfitting the dams with informational systems such as rainfall notifications and flood alerts and creating emergency action plans in order to avert all manner of accidents.
- Storage Capacity Declining- As dams get older, the water in the reservoirs is replaced by dirt. Consequently, it is not possible to say that today’s storage capacity is equivalent to that of the 1950s and 1900s.
- In India Reservoirs are losing storage space at a rate that is more than expected.
- Environmental impacts- Dams can have a significant impact on the environment, involving the displacement of local communities, the destruction of ecosystems, and changes in water flow and quality.
- Climate change- Climate change has increased variability in the availability of water and uncertainty in the availability of water in the near future.
- Governance and management- The issue of dam governance and management is a complex one in India, as there are several stakeholders involved, including state and central government agencies, local communities, and private companies.
- Socio-economic impacts- Dams can have a considerable impact on local communities, including displacement, loss of livelihood, and changes in access to water and other resources.
- Inefficient use of water- The state of Indian dams is not used efficiently, which leads to the waste of water. This is a key concern in a country where water is a precious resource.
- Lack of transparency- There is a lack of transparency in the operation and maintenance of dams in India, which makes it tough for stakeholders to hold the relevant authorities accountable.
Various Related initiatives-
- Water and water storage is a state subject, under the 7th Schedule of the Constitution of India.
- Thus, legislating dam safety is the responsibility of state governments.
- Though, the Central Government can enact legislation governing dams in certain scenarios.
- At the national level, the Central Water Commission (CWC) imparts technical expertise and guidance on all matters related to dams.
- It is tasked with research into dam safety, developing standards for dam design and operations, and it is included in the process of granting environmental clearance to dam construction projects.
- Dam Safety Act 2021 aims at surveillance, inspection, operation and maintenance of all specified dams across the country.
- The Act applies to all specified dams in the country i.e., those dams having a height of more than 15m and between 10m and 15m with certain design and structural conditions.