How a plan to repair the Tungabhadra crest gate was made in a matter of hours and how experts overcame the challenges and risks on their way.
Published Aug 31, 2024 | 9:00 AM ⚊ Updated Aug 31, 2024 | 9:00 AM
Tungabhadra dam
The expertise gained from several years of working with a public sector undertaking may come in handy in the most unexpected ways – engineer Khanaiya Naidu, who led the operation to repair the 19th crest gate at the Tungabhadra Water Reservoir, had worked 27 long years with Tungabhadra Steel Products Limited (TSPL).
He drew on associations formed with professional experts during his tenure in the government-owned firm to accomplish the task of preventing catastrophe as one of the 33 crest gates of the reservoir collapsed on 10 August 2024, after a sudden surge of water.
The 71-year-old dam across the Tungabhadra River, about 350 km from Bengaluru, is administered by the Central Water Commission (CWC), which falls under the jurisdiction of the Union government; flooding in the area would have affected farmers in Karnataka and Andhra Pradesh.
Following a midnight alert on 10 August, Naidu swiftly devised an innovative solution, presenting an alternative design in five hours. Besides the obvious difficulty of conducting repairs while water was gushing out at the rate of over 1000 tonnes per second, there were procedural hurdles to be overcome. Approval was needed from the regulatory authority, CWC.
There were logistical complexities and technical challenges to face before the five stop log elements were successfully installed, ensuring the stability of the reservoir and securing the water supply for seven districts.
When staff at the Tungabhadra Water Reservoir realised the gravity of the crisis, they turned to Hyderabad-based engineer Khanaiya Naidu for help. Naidu, who had been working as a private consultant after TSPL was shut down by the Union government officially in 2018, set to work straight away and was able to produce a viable plan of action to address the crest gate collapse in about five hours.
“Around midnight of 10 August, I received a call from the supervising staff at the Tungabhadra reservoir informing me that the 19th gate had slipped; a severed link between chain and gate had caused the collapse,” Naidu told South First.
“I promptly requested them to send details of the groove and vent, which were readily available. I also reminded them to refer to the relevant file for further information. I received the details of the incident via email and WhatsApp while I was in Hyderabad. I alerted my consultancy firm, which is run from my residence and comprises my elder daughter, son-in-law, other experts, and programmers,” he explained.
He said the team had an emergency meeting right away, well past midnight. Together, they studied the situation and prepared an alternative design. “By 5 am, I sent an email to the dam authorities outlining the necessary action to ensure safety of the reservoir. I also mailed a copy to the CWC Chairman Kushivnder Vohra,” Naidu said.
On 11 August, Andhra Pradesh Chief Minister Chandrababu Naidu spoke with engineer Naidu on the phone, requesting help. That same day, Kanhaiya Naidu had a three-hour discussion with the CWC chairman. “The challenge was that any decisions we took required Central approval, as well as the consensus of three state governments. I was left with no autonomy,” Naidu told South First.
Meanwhile, officials from Andhra Pradesh, Telangana and Karnataka had converged at the reservoir; Kanhaiya Naidu arrived there on 12 August.
“We outlined a programme detailing how to proceed with the stop log arrangements, utilising the existing groove of the main gate. I provided guidance on handling and other aspects,” engineer Naidu said.
“These gates are 60ft span(width) X21 ft height whereas other dams will have only 45 ft width gates. It is very difficult to insert single gate in groove. So, we made 5 elements of 60 ft width X 4 ft height (each stoplog gate size). Overall 5 elements weight is around 75 tonnes. The fabrication process involved approximately 75 tonnes of material for the five elements. Given the requirement for 100 percent accuracy in fabrication, we sought the expertise of Jindal, where a couple of engineers who had previously worked with me at TSPL were employed,” Naidu explained, showing how he relied on professional ties from his years in government service.
“Chief Engineer Mehaboob from Jindal, renowned for his exceptional skills in fabrication and quality control, was put in charge. Under his leadership, a team of 150 people worked tirelessly for three consecutive days and nights to deliver three elements,” Naidu said, explaining that given the material had to be readied swiftly, the other two elements were outsourced to Narayana Engineering and Hindusthan Engineering.
“Two of our retired engineers from TSPL, GT Chandrashekar and YS Chandrashekar, were entrusted with coordinating with each of the companies involved,” Naidu said, adding that experts were deployed to oversee the engineering works.
“A large crowd of 10,000 farmers gathered at the dam site. The previous day, a decision had been made to release 65 tmc of water, which would enable the installation of the gates. However, the Koppal Deputy Commissioner Nalini Atul expressed concern that he could not provide drinking water with only 40tmc in the reservoir,” Naidu said, explaining that water needed to be conserved, even though it was a crisis.
“This was particularly worrying for the Rabi season, which would affect seven districts, and the 26 other districts that relied on the water supply. Last year, the area had faced severe drought, leaving no food for these seven districts. In light of this, all three ministers collectively made a decision to take a risk and close the gates by at least 12 ft to retain around 75 tmc of water. They requested me to plan and assured me of their full support,” Naidu said.
Naidu further elaborated on how the team went about it. “I began outlining a programme with other officers. We sought permission from higher authorities, including the CWC chairman and the Tungabhadra Board. We held a virtual meeting at 3 pm, during which we were offered financial assistance. We submitted our applications and action plan, presenting it to the CWC chairman. However, the CWC said it could not grant permission to close the gates by more than 4 ft of water. I responded, explaining that 4ft was insufficient, and I intended to close the gates by 12 ft to ensure the necessary water flow.”
“I sought permission, highlighting the risks involved. After discussing my experience and other matters, they concluded that the committee would have to work under the guidelines of Kanhaiya Naidu – that effectively gave me the authority to close the gates,” Naidu said, explaining that much deliberation preceded the granting of autonomy.
“In a similar situation, we had previously dropped elements from the top, as we did in the Narayanapura Project, across the Krishna River. I requested that the hosit bridge be removed, but they refused, citing it might consume more time to fix the damaged gate.”
“We attempted to insert the fabrication, but the vent was 60ft, the element was 63.5ft, and the groove was 64 ft from end to end, making it impossible to insert. The element was stuck, and we could not proceed,” Naidu said.
He then contacted the Karnataka Chief Minister’s Office to explain on 14 August that if the element was stuck at the hoist bridge, inserting it would become impossible and the operation would fail.
He was assured of support from the Centre, and it was decided that the elements would be removed one by one on 15 August. “However, the bridge could not handle the load. We sent a crane to remove each element, and bring in fresh elements for installation, causing delay. We finally installed all the five stop log elements by Saturday evening (17 August), and all arrangements were made for emergencies. We achieved success on Friday (16 August) itself, and by Saturday evening, all the gates were closed. I witnessed farmers distributing sweets in celebration,” the engineer explained.
(Edited by Rosamma Thomas)
(South First is now on WhatsApp and Telegram)
