When Crest Gate No. 19 of the Tungabhadra Dam near Hosapete was washed away late on August 10, 2024, it triggered panic among lakhs of farmers dependent on the reservoir for irrigation.
The massive reservoir, considered the lifeline of north Karnataka and parts of Andhra Pradesh and Telangana, was then brimful with 105.788 tmcft of water at the Full Reservoir Level (FRL) of 1,633 feet. Within minutes of the chain link snapping, nearly 35,000 cusecs of water began gushing uncontrollably through the damaged bay. Engineers scrambled to open the remaining gates to reduce pressure on the structure even as fears mounted downstream.
What began as a terrifying engineering emergency soon evolved into one of the biggest dam rehabilitation exercises undertaken in recent years. The crisis triggered intense technical efforts, political attention, farmers’ anxiety and inter-State coordination. Nearly two years later, it has culminated in the replacement of all the 33 crest gates. The old ones operated through an overhead bridge mechanism involving chains, gearboxes, motors and counterweights. For nearly seven decades, the gates functioned without major overhauling.
When the gates gave way in 2024, experts from Hyderabad, Chennai and Bengaluru, along with engineers from JSW Steel and local fabrication companies, began working. Hydro-mechanical expert N. Kannaiah Naidu emerged as a key figure in the operation, preparing designs and technical drawings for the temporary stop-log arrangement. The operation itself was extremely risky as the engineers had to work amid powerful currents and fluctuating discharge conditions.
Against all odds, the engineers succeeded. On August 17, 2024, just seven days after the disaster, the team successfully installed the temporary stop-log gate made up of five massive steel elements. It prevented further catastrophic water loss.
Experts, who inspected the dam after the incident, advised comprehensive replacement of all the 33 crest gates, considering their age and long years of operation without major overhaul. Following technical committee recommendations, the Tungabhadra Board decided to replace all 33 spillway gates. The Tungabhadra Board later entrusted the replacement work to Ahmedabad-based Hardware Tools & Machinery Projects Pvt. Ltd.
The large-scale replacement work gathered momentum in late 2025, involving dismantling old gates and erecting new ones within a narrow working window.
The dismantling and erection of all 33 gates was completed in 123 days, between December 24, 2025, and April 25, 2026. Trial runs had also been successfully conducted for the newly installed gates, while the remaining finishing works are in the final stages of completion.
The project also involved the replacement of 68 lifting chains and 100 bevel gear units. Though a detailed examination had found the existing chains to be structurally strong, the then Deputy Chief Minister D.K. Shivakumar (now Chief Minister-designate), during his visit to the dam on May 3, 2026, said that the government had decided to replace all the chains as a precautionary measure. Third-party quality inspection agencies from Hyderabad were engaged for testing and monitoring the works. The total cost of replacing all 33 spillway gates, along with chain links and quality inspections, stood at around ₹51 crore.
The successful replacement of all 33 crest gates has now become a story of recovery after crisis, with relentless effort by engineers and workers, who raced against time to save one of South India’s most important irrigation projects.
As the renovated gates prepare to be formally dedicated, the Tungabhadra Dam stands not just restored, but renewed. Engineers associated with the project believe the comprehensive replacement of all the 33 crest gates has enhanced the structural safety of the dam and extended its operational life by another 50 years.
Soon, the government is planning to hold a huge public meeting inviting the farmers from the command area, especially from Koppal, Raichur and Ballari, to dedicate the renewed dam to the nation.
Published - May 16, 2026 06:58 pm IST
Source: The Hindu - India News
