HOW TUNGABHADRA DAM GATE WAS SWEPT AWAY, WHY FARMERS ARE FEARFUL

Relevance:

  • GS 1 – Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc. and the effects of such changes.
  • GS 3 – Disaster and disaster management.

Why in the news?

  • A flood alert was issued downstream of the Tungabhadra dam in Karnataka’s Koppal district after one of the 33 crest gates was washed away on Saturday (i.e. 10th August 2024) evening.
  • The Tungabhadra Board stated that repairs can only be initiated once two-thirds of the dam’s water is emptied.

About the Tungabhadra River:

  • The Tungabhadra River is formed by the confluence of two streams, Tunga and Bhadra, near Shimoga, both of which originate in the Western Ghats.
  • The two rivers merge at Koodli in the Shimoga district of Karnataka, giving birth to the Tungabhadra River.
  • The river flows into the Krishna River at Sangamaleshwaram in Andhra Pradesh and serves as part of the boundary between Karnataka and Andhra Pradesh
  • The river has a total length of 531 km with a total catchment area of nearly 70,000 sq km.
  • Major Tributaries: Varada River and Hagari (Vedathy) River.
  • The river has several dams and reservoirs built on it, including the Tunga Anicut Dam, the Bhadra Dam, the Hemavathy Dam, and the Tungabhadra Dam.
  • The Hindus consider this river sacred, and there is a mention of the river in Ramayana, where it is referred to as Pampa.
  • The river was an important source of water for the Vijayanagara Empire, which ruled over the region from the 14th to the 17th century.
  • The city of Hampi, which was the capital of the Vijayanagara Empire, was located on the banks of the river.

HOW TUNGABHADRA DAM GATE WAS SWEPT AWAY, WHY FARMERS ARE FEARFUL - UPSC

The Tungabhadra Dam

  • The Tungabhadra reservoir covers an area of 378 sq km, primarily located in Karnataka’s Vijayanagar district.
  • It is a major reservoir in South India, supplying water for irrigation, industrial use, and drinking purposes to Karnataka and Andhra Pradesh.
  • The dam was initially conceived in 1860 to address the impact of recurrent famines in Rayalaseema. Construction began in 1945 under the governments of Hyderabad and Madras, and the project was completed in 1953.
  • The Tungabhadra Board was established by a presidential order in 1953. The Board consists of a chairman appointed by the Union government and four members representing the Union government and the states of Karnataka, Andhra Pradesh, and Telangana.

How the Gate Broke:

  • The dam has 33 ‘vertical lift’ gates that move on rollers embedded in the masonry, operated from an overhead bridge.
  • On August 10, 2024, 10 spillway gates (No. 12 to 21) were operated to a height of 5 feet, releasing 22,890 cusecs of water through the spillway.
  • At 10:50 pm, spillway gate No. 19 was washed away from its groove during the operation.
  • The crest gate failed due to a broken link in the chain used to operate it, causing the 60-foot-by-20-foot, 20-tonne gate to be swept 500 feet away by the force of the water.
  • Local sources reported that welding on the chain links of the spillway gates was done 3-4 years ago to strengthen them.

Water in Reservoir:

  • On August 10, the reservoir level reached its maximum of 1,633 feet, filling the dam to its full capacity of approximately 8 thousand million cubic (TMC) feet.
  • The inflow on that day was 40,925 cusecs, while the outflow was 28,133 cusecs, according to data from the Tungabhadra Board.
  • The Tungabhadra Board Secretary stated that due to early inflows, water was released through three gates on July 22. As inflows increased, around 1.65 lakh cusecs were released on August 1.
  • By Monday (12th August 2024) , the water level had slightly decreased to nearly 1,631 feet, with the reservoir holding 97.75 TMC feet of water.
  • Accumulated silt over the years now occupies about 30% of the dam’s original capacity. The state government has proposed constructing a balancing reservoir to address this issue.

Repairs to the Swept dam Gates:

  • The crest gate that was swept away is located in the middle of the dam, and repairs can only begin after 60-65% of the reservoir’s water is discharged.
  • The Tungabhadra Board stated that the repair will be carried out as soon as possible in consultation with experts. A new stop lock gate is being fabricated, with the work expected to be completed within a week.
  • The President of the Tungabhadra Farmers’ Association, mentioned that Karnataka had suggested replacing the old chain links with steel cables, similar to the system used at the Alamatti dam in Bagalkot district.
  • Upstream cultivators are concerned that draining the reservoir for repairs will negatively impact irrigation, while downstream farmers fear both reduced water availability and the possibility of flooding due to increased outflows.
  • The Karnataka State Natural Disaster Monitoring Centre has issued a flood alert for downstream areas.
  • Heavy rainfall could worsen the situation, but no heavy rain is forecasted for the region in the coming days.

Challenges in Managing Aging Dam Infrastructure in India

  • Lack of Maintenance: Many dams in India are aging and in need of repair, but there is often a lack of funding and resources devoted to this purpose.
  • Decreasing Storage Capacity: As dams age, silt replaces the water in the reservoirs, reducing storage capacity at a faster rate than anticipated.
  • Flawed Design: Studies show that the design of many of India’s reservoirs is flawed, leading to structural issues.
  • Safety Concerns: There have been incidents of dam failures in India in the past, which have resulted in loss of life and property damage, raising concerns about dam safety.
  • Governance and Management Issues: Dam governance and management is complex in India, with many stakeholders involved, often leading to a lack of coordination and conflicting interests.
  • Lack of Monitoring and Surveillance: There is often a lack of monitoring and surveillance of dams, making it difficult to identify and address potential safety issues in a timely manner.
  • Limited Data Availability: There is limited availability of data on the condition of dams, making it difficult to assess the risk of failure and plan for maintenance and repair.
  • Climate Change Impacts: Climate change has increased variability in water availability and uncertainty in the future, which can overwhelm a dam’s design limits and accelerate the aging process.
  • Socio-economic Impacts: Dams can have significant socio-economic impacts on local communities, including displacement, loss of livelihood, and changes in access to water and other resources.
  • Lack of Public Participation: Local communities, who are most affected by dams, often have little input in the planning and operation of dams, leading to a lack of transparency, accountability, and mistrust.

Way Forward for Addressing the Tungabhadra Dam Incident

  • Immediate Assessment: Conduct a thorough inspection of the dam structure and remaining gates to assess any potential vulnerabilities and ensure overall safety.
  • Emergency Repairs: Prioritize the fabrication and installation of a new stop lock gate to replace the swept-away gate, aiming for completion within a week.
  • Water Level Management: Implement a controlled water release strategy to manage the reservoir levels while minimizing the risk of flooding downstream.
  • Irrigation Support: Develop contingency plans to provide alternative irrigation solutions for upstream farmers impacted by the reduced water availability during repairs.
  • Monitoring System: Enhance monitoring of inflow and outflow levels at the dam to ensure timely responses to changing weather conditions and water levels.
  • Community Communication: Maintain open lines of communication with local farmers and residents to keep them informed about repair progress, water management strategies, and safety measures.
  • Long-term Infrastructure Review: Initiate a comprehensive review of the dam’s infrastructure, including the condition of all gates and operational mechanisms, to prevent future failures.
  • Silt Management: Address the issue of accumulated silt in the reservoir by exploring options for dredging or constructing a balancing reservoir to restore capacity.
  • Disaster Preparedness: Strengthen disaster management protocols in collaboration with local authorities and the Karnataka State Natural Disaster Monitoring Centre to enhance community preparedness for potential flooding.
  • Expert Consultation: Engage with engineering and hydrology experts to evaluate and improve the dam’s design and operational procedures, ensuring they meet current safety standards.
  • Public Awareness Campaign: Launch an awareness campaign to educate the local population about flood risks, safety protocols, and the importance of reporting any unusual dam activity.

Alternative articles

https://universalinstitutions.com/bfd_download/disaster-management-csm-2023/

https://universalinstitutions.com/providing-clean-water-to-all/

Source: https://indianexpress.com/article/explained/tungabhadra-dam-gate-swept-away-karnataka-flood-alert-d-k-shivakumar-dam-repair-work-9510416/

Mains question

Discuss the challenges in managing aging dam infrastructure in India. How do these challenges impact irrigation, flood control, and agriculture? (250 words)