Ageing Dams in India
Disaster Management > Disaster mitigation > Dams and reservoirs
- Over a thousand large dams in India will be roughly 50 years old in 2025 and such aging embankments across the world pose a growing threat, according to a United Nations (UN) report “Ageing water infrastructure: An emerging global risk”.
DAMS IN INDIA:
- As on June 2019, India ranks third globally with 5,745 large dams (includes dams under construction).
- Of these, 5,675 large dams are operated by states, 40 by central public sector undertakings, and five by private agencies. Most of these large dams are in Maharashtra (2394), Madhya Pradesh (906), and Gujarat (632).
- Over 75% of these dams are more than 20 years old and about 220 dams are more than 100 years old.
- According to the UN report In India, over 1,115 large dams will be at roughly 50 years mark by 2025.
- The report also finds that India's current dam construction rate is among the world's highest.
WHY INDIA NEED DAMS:
- For water security: Due to the large physiographic diversity of the country, there is a significant variation in water availability, both spatially and temporally. Hence, dams are crucial for ensuring the water security of the Country.
- Irrigation: Large dams are vital in providing year-round irrigation to farm fields. For eg: Bhakra Nangal, Beas projects and Indira Gandhi canal played a major role in the success of green revolution in the Punjab plains.
- Hydropower: Dams provide cheap hydroelectric projects, which in turn sustain industrial growth and domestic power consumption. Eg: The Mettur dam in Tamil nadu is a major contributor to the development of Aluminum industries in Salem .
- Flood control: Large dams are a crucial component of all flood control projects in India. For eg: The Damodar valley project, completed in 1948, still plays a crucial in controlling the floods along Jharkhand and West Bengal.
- Ecological regulation: Dams and barrages are used to control the salinity and ecological balance of delta regions. For eg: One of the objectives of the Farakka barrage is the reduction in salinity of water and thus improvement in availability of potable water to Kolkata and surrounding areas.
- Inland navigation: Dams help maintain a steady flow in the rivers, which in turn promotes inland water transport. For Eg: The Farakka barrage forms a major part of the National Waterway 1.
- Recreation & income source: Dams and reservoirs are popular tourist attractions in India. They also provide income sources to local population via inland fisheries, boating and hospitality services.
THREATS POSED BY AGEING DAMS:
- Enhances vulnerability to disasters:
- The older a dam, the more vulnerable it becomes to collapse due to structural decay, earthquakes, hydrostatic pressure etc.
- The longer a reservoir lasts, the chances of reservoir-induced earthquakes in the region increase.
- The lower reaches of all major dams are densely populated. For eg: Three million people live downriver of the 125-year-old Mullaperiyar Dam.
- Enhances threat from climate change: Old dams were designed and built on the basis of hydrological records in a pre-climate change era. With climate change bringing more extreme floods, aging dams threaten to become lethal.
- Alters ecological stability: Prolonged damming of rivers affects the fauna and flora in the river basins. They can lead to increased land degradation and encroachment by new invasive species. Eg: Damming the river, coupled with water intensive agriculture, diversion of land and climate change has led the Kaveri delta to shrink by 20%.
- Creates recurring conflicts: Increasing concerns over dam safety has been the root cause of river water disputes in India. The most notable is the Mullaperiyar dispute between Kerala, the state under threat, and Tamil Nadu, the state upstream that operates the dam.
- Increases cost of maintenance: Ageing dams require expensive repairs. Also, siltation reduces the capacity of dams. Hence, the net return from large dams diminishes in the long run.
Dam Rehabilitation and Improvement Project (DRIP):
- The project aims to improve safety and operational performance of selected dams, along with institutional strengthening the institutional mechanisms.
- The six-year Project is implemented by Ministry of Water Resources, River Development & Ganga Rejuvenation through Central Water Commission, with World Bank assistance.
- Under the project, presently 198 dam projects are being rehabilitated.
The Dam Safety Bill, 2019
- The Bill provides for the surveillance, inspection, operation, and maintenance of all specified dams across the country.
- It constitutes two national bodies:
- National Committee on Dam Safety, whose functions include evolving policies and recommending regulations regarding dam safety standards
- National Dam Safety Authority, whose functions include implementing policies of the National Committee and providing technical assistance.
- It also constitutes two state bodies responsible for the surveillance, inspection, and monitoring the operation and maintenance of dams within their jurisdiction, namely:
- State Committee on Dam Safety
- State Dam Safety Organisation
- The bill is yet to be passed because of concerns from States. As per the Constitution, states can make laws on water including water storage and water power. However, Parliament may regulate and develop inter-state river valleys if it deems it necessary in public interest. The question is whether Parliament has the jurisdiction to regulate dams on rivers flowing entirely within a state.
- Reassess the feasibility of dams, both existing and planned ones, with special emphasis on the rising demand for water and the possible impacts of climate change.
- Replace hydropower with alternative sources of energy, such as decentralized renewable power.
- Increase water use efficiency, by promoting micro irrigation techniques, mandatory recycling of industrial wastewater and community-led management of water resources.
- Promote academic research and development: Some dams are so big it is difficult to even approach the problem of their decommission. Hence, there is a need to foster research and technological development to decommission them.
- Promote sub-surface dams: Unlike a surface dam, water loss by evaporation is minimal in underground dams. In a country like India, where evaporation rates are very high, this can be the game changer. Countries like Japan that have created multiple sub-surface dams.
Q. Ageing dams are posing a growing threat to India. In this context, critically analyse the need of large hydro projects in India? ???????