Insight |
Teesta Dam failure: lessons in gate operation and dam safety
The Teesta Dam failure of 2023 serves as a crucial case study in dam safety, highlighting the role of hydro-mechanical equipment in preventing disasters. Mukulesh Debnath and Vinod Kumar Gupta delve into the technical failures, particularly delayed gate operations, that led to catastrophic consequences. They also outline the lessons learned in real-time decision-making, communication failures, and structural vulnerabilities
“DAMS ARE VITAL INFRASTRUCTURE designed to retain large bodies of water, crucial for irrigation, flood control, and hydroelectric power generation. Ensuring dam safety goes beyond the structural integrity of their massive concrete forms. It encompasses preventing cracks and scouring both upstream and downstream. While the public often focuses on the solidity of these imposing structures, the critical role of hydro-mechanical equipment cannot be overlooked. These components, such as gates and valves, are essential for managing water flow and maintaining the dam’s stability. If these mechanisms fail or operate inadequately, these can jeopardize the entire structure. The safe and efficient operation of gates is particularly pivotal, since malfunctioning of gates can lead to unpredictable stress and strain patterns within the dam, potentially compromising its integrity and safety.” This statement encapsulates the multidimensional aspects of dam safety, emphasizing both structural robustness and the pivotal role of operational equipment.
Analysis of various dam failures reveals that the majority of these incidents are primarily due to inefficiencies in the operation of hydro-mechanical equipment. Key components such as gates, valves, and turbines are crucial for controlling water flow and ensuring the structural integrity of dams. Malfunctions, such as faulty gates or slow response times, have frequently led to catastrophic outcomes. Additionally, poor maintenance, aging infrastructure, and human error exacerbate these risks. Hence, while structural stability is crucial, the reliable and responsive operation of hydro-mechanical equipment is equally, if not more, vital for preventing disasters and ensuring public safety. The total loss to the government due to this failure is estimated to be around Rs1,000 crore (approximately $120 million).
Background Teesta Dam is part of the Teesta-V power station
(510MW), located on the Teesta River in the Indian state of Sikkim. The dam serves multiple purposes, including hydroelectric power generation, irrigation, and flood control.
The Incident The failure occurred at 01:42 Hrs on 4th October
2023. The region experienced an unprecedented 10 | October 2024 |
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Short Duration High-Intensity Rainfall (SDHR) followed by an outburst of Lhonak Lake, leading to a sudden and massive inflow of water into the Teesta basin, which overtopped the entire dam body. The dam gates could not be operated in time to release the excess water, leading to overtopping and structural damage to the dam.
Causes Delayed gate operation was a significant factor, as
the gates could not be opened promptly when the water levels began to rise rapidly. There were potential malfunctions or delays in the automated gate control systems, or a lack of real-time decision-making support. Additionally, there were communication failures, including inadequate or delayed weather forecasting and inflow prediction, which did not provide sufficient warning to the dam operators. Poor coordination between meteorological agencies, dam operators, and disaster management authorities further exacerbated the situation.
Consequences The incident led to massive downstream flooding,
causing extensive damage to infrastructure, homes, and agriculture. There were reports of loss of life and injuries to residents in the affected areas The disaster also affected over 25,000 people, leading to the loss of lives, damage to homes, and the washing away of several bridges and roads. Furthermore, military equipment, including firearms and explosives, were swept away by the floodwaters, leading to additional losses. The economic impact was significant, with substantial losses due to damage to property, disruption of power supply, and agricultural losses.
Impact on hydro-mechanical
equipment The spillway gates, designed to control the release of excess water, were severely damaged. The sudden and massive influx of water rendered the gates inoperable. Structural deformation and mechanical failure of the gates occurred due to the high forces exerted by the floodwaters and debris, likely exacerbated by the impact of boulders and stoplog units that fell on the radial gate arms and cylinders during the dam’s overtopping. It is notable that ten
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