Tungabhadra Dam Flood
Why in News- A flood warning has been issued in the downstream area of Tungabhadra Dam in Koppal district of Karnataka after one of the 33 crest gates of the massive stone dam across the Tungabhadra River was washed away.
UPSC Syllabus:
Prelims: Current Affairs of National & International Importance
Mains: GS-I, III: Geography, Disaster Management
Tungabhadra Dam
• Tungabhadra Dam is located on the Tungabhadra River in the Koppal district of Karnataka.
• The river is formed by the confluence of two rivers, Tunga and Bhadra, near Shimoga in Karnataka.
• The dam plays a vital role in managing water resources for the region and is located at a crucial point where the river joins the Krishna River at Sangamaleshwaram in Andhra Pradesh.
• This location makes the dam a vital infrastructure for both Karnataka and Andhra Pradesh, affecting the supply of water for irrigation, drinking, and industrial purposes.
Purpose of Dams:
Irrigation:
• Dams store large amounts of water, which can be used to irrigate agricultural fields, especially during the dry season.
• For example, the Tungabhadra Dam helps irrigate large parts of agricultural land in Karnataka and Andhra Pradesh
Flood Control:
• Dams help control the flow of water, especially during monsoons or heavy rainfall, thereby preventing flooding in downstream areas.
• However, incidents such as the recent gate failure at the Tungabhadra Dam can disrupt this function and cause flooding.
Hydroelectricity Generation:
• Many dams, including the Tungabhadra Dam, are equipped with hydroelectric power stations that generate electricity using the potential energy of stored water.
Drinking Water Supply:
• Dams are a major source of drinking water for urban and rural areas.
• For example, water stored in the Tungabhadra Dam is vital for supplying drinking water to many towns and villages in the region.
Industrial Use:
• Dams provide water for industrial processes, thereby supporting the functioning of industries and contributing to economic development.
Current Data and Facts
• As of August 2024, the Tungabhadra reservoir was at its maximum level of 1,633 feet, with a total capacity of about 105.8 thousand million cubic (TMC) feet.
• The inflow at the time of the incident was 40,925 cusecs, while the outflow was 28,133 cusecs.
• The failure of the dam’s spillway gates has caused a significant increase in outflow, raising concerns about potential flooding.
• Moreover, it is reported that about 30% of the dam’s original capacity is now filled with accumulated silt, reducing its efficiency and storage capacity
• The state government has proposed the construction of a balancing reservoir to address this problem and improve water management in the region.
Major Dams in India
Bhakra Nangal Dam (Punjab/Himachal Pradesh)
• The Bhakra Nangal Dam, one of the world’s tallest gravity dams, is located on the Sutlej River.
• It plays a vital role in irrigation, flood control, and hydroelectricity generation.
• The dam has a storage capacity of 9.34 billion cubic meters and provides water to several states in North India, including Punjab, Haryana, and Rajasthan.
Tehri Dam (Uttarakhand)
• The Tehri Dam, located on the Bhagirathi River in Uttarakhand, is the highest dam in India and one of the highest dams in the world.
• It serves multiple purposes including hydroelectricity generation, irrigation, and drinking water supply.
• The dam has a total storage capacity of 3.54 billion cubic meters and generates over 1,000 MW of electricity.
• Sardar Sarovar Dam (Gujarat) Sardar Sarovar Dam, part of the Narmada Valley Project, is located on the Narmada River in Gujarat.
• It is one of the largest dams in India and provides water for irrigation, drinking, and industrial use to several states, including Gujarat, Madhya Pradesh, Maharashtra, and Rajasthan.
• The dam has a storage capacity of 5.80 billion cubic meters and a power generation capacity of 1,450 MW.
Hirakud Dam (Odisha)
• The Hirakud Dam, located on the Mahanadi River in Odisha, is one of the longest dams in the world
• It was built primarily for flood control and irrigation, but it also generates hydroelectricity
• The dam has a storage capacity of 8.14 billion cubic meters and is the lifeline for Gujarat.
• The dam is vital for the agricultural economy of the region.
Nagarjuna Sagar Dam (Telangana/Andhra Pradesh)
• The Nagarjuna Sagar Dam on the Krishna River is one of the largest masonry dams in the world.
• It plays a vital role in irrigation by supplying water to over 1 million acres of agricultural land in Telangana and Andhra Pradesh.
• The dam has a total storage capacity of 11.56 billion cubic meters and also generates hydroelectric power.
Challenges Associated with Dams in India
Aging Infrastructure
• Many dams in India were built several decades ago and are now outdated.
• As these structures age, the risk of structural failures increases, such as the recent incident at the Tungabhadra Dam.
• Lack of regular maintenance and timely upgradation further aggravates the problem.
• According to the Central Water Commission (CWC), India has over 5,700 large dams, of which more than 1,000 are over 50 years old.
• Old infrastructure is one of the major factors that make dams more durable and costly.
siltation
• Siltation is the gradual deposition of silt and sediment in reservoirs, which reduces the water storage capacity of dams.
• This problem is particularly severe in India due to the high sediment loads carried by many rivers.
• For example, the Tungabhadra Dam has reportedly lost about 30% of its original capacity due to siltation.
• Low storage capacity not only limits the water supply capacity of the dam but also increases the risk of flooding during heavy water flows.
Seismic vulnerability
• India is located in a seismically active zone, and many dams are located in areas prone to earthquakes.
• The structural integrity of dams in these areas can be compromised by seismic activity, leading to potential disasters.
• The need for seismic retrofitting and strengthening of dams is critical to prevent catastrophic failures.
Climate change
• Climate change is leading to unpredictable weather patterns, including intense rainfall and prolonged droughts.
• This variability affects the inflow and outflow patterns of dams, making water management more challenging.
• Dams designed for historical rainfall patterns may not be able to cope with the changing climate, leading to either inadequate water supply or the risk of overflow during extreme weather events.
What is the way forward?
Dam Safety Act
• The Dam Safety Act, of 2021, was enacted by the Government of India to ensure the safe operation of dams across the country.
• The Act provides a comprehensive framework for the monitoring, inspection, operation, and maintenance of dams, intending to reduce risk and ensure dam safety.
National Committee on Dam Safety:
• The Act establishes a National Committee on Dam Safety, which is responsible for formulating policies and guidelines for dam safety in India.
• The Committee also coordinates with state-level authorities to ensure compliance with safety standards.
State Dam Safety Organisations:
• Each state is required to establish its dam safety organization, which will be responsible for regular inspection and maintenance of dams within the state.
• These organizations are also tasked with preparing emergency action plans for dams.
Routine Inspections:
• The Act mandates regular inspections to assess the structural integrity of all dams and identify potential risks.
• These inspections are to be carried out by qualified engineers and experts.
Emergency Action Plans:
• Dams are required to have well-defined emergency action plans to address potential failures or incidents
• These plans include procedures for warning and evacuating downstream communities in case of a dam breach.
Penalties for non-compliance:
• The Act imposes penalties for non-compliance with dam safety regulations, ensuring that dam operators adhere to the required safety standards.