All 33 crest gates of the Tungabhadra Dam need to be replaced as they have outlived their lifespan, said Kannaiah Naidu, a retired dam expert, who had saved the day for Karnataka and two other riparian states of Andhra and Telangana after one of the 33 crest gates of Tungabhadra dam in Koppal was washed away last month, causing a flood alarm.
Naidu (77), a national expert on hydraulic gate and handling equipment, rushed from Hyderabad to the dam site and worked tirelessly for five days with a team of experts to design, fabricate and install the new gate, in record time.
On Sunday, Chief Minister Siddaramaiah and Deputy Chief Minister DK Shivakumar, who offered ‘bagina’ to the dam on reaching its full capacity (103 tmc ft), felicitated Naidu and his team.
Naidu, who spoke to THE WEEK, said he cautioned the government to replace all the crest gates as they are already 70 years old and have outlived their lifespan.
According to the Government of India gazette, the total life of a concrete dam is 100 years and the equipment (including the gates) is 45 years. Since Tungabhadra was commissioned in 1954, almost 70 years, it is time all its gates are replaced, said Naidu.
“Once the dam gates complete 2.5 million cycles, they fail. All 33 gates need to be replaced and it may cost around Rs 250 crore. The new design will have vertical gates with higher density and will be stronger than the existing gates,” said Naidu, adding that the country had many ageing dams and the state governments should give priority to dam safety.
Recalling the Morbi (Machchu dam) disaster in Gujarat (in 1979) when 2,000 lives were lost, Naidu said the Dam Safety Act was enacted only in 2021 in response to the disasters related to dam failure due to inadequate maintenance and surveillance.
In India which has around 6,000 large dams, states are required to classify dams based on the level of hazard they pose, and are to regularly inspect dams, create emergency action plans and flood warning systems.
“Now, regular inspections are being carried out in India though not all states have foolproof systems of surveillance. The Centre has realised the importance of dam management and if dams are not managed well, by 2030, there could be a scarcity of drinking water. So, the centre has roped in experienced dam experts to assess the risk and take corrective measures. But the state governments have to take it seriously and provide funds to carry out the replacement of the gates and overall maintenance,” said Naidu, who has commissioned 170 dams across the country and extended technical know-how to 500 dams, since his retirement in 2002.
With dam safety concerning all three state governments, they must take a call on TB dam unanimously. “We have replaced the gates in some of the dams already. In 2002, I replaced the Prakasam barrage gates. The Gujarat government has made a rule that all the dam gates will be replaced on competition of 45 years. The dam gates at the Krishna Raja Sagara dam in Mysuru were also replaced as they had completed 75 years. We stopped the storage of water and carried out the replacement work. I am conversant with all the dams – from Trivandrum to Kargil. Even after retirement, I am controlling the dams in Gujarat and many southern states. I do this as a service to the farmers,” added Naidu.
Earlier, Naidu shared his experience of replacing the broken gate at the TB dam, which was crucial to avoid a drought-like situation. On August 10, the gate had crashed and the excessive outflow of water threatened to empty out the dam causing another drought year in the river basin.
“I got a call from the chief minister asking me to help save the farmers who had already completed sowing. The CM also told me we might not have enough rice to eat if we don’t act fast,” recalled Naidu.
Karnataka Chief Minister Siddaramaiah with Deputy CM DK Shivakumar at Tungabhadra Dam after it was filled for the second time | PTI
The TB had stored 105 tmc of water as all the dams on the Tungabhadra river – from TB Dam in Koppal in Karnataka to Prakasam barrage in Vijayawada (Andhra) – had received good rains. When the 19th crest gate (chain link) snapped and was washed away, the initial plan was to empty out 65 tmc ft of water from the dam and retain only 40 tmc ft to install the new gate. But, the deputy commissioners of Koppal (Karnataka) and Anantapur (Andhra) districts were apprehensive as they felt it could not meet the drinking water needs of the two districts. Farmers had sown across 26 lakh acres of land.
“The TB dam is managed by three governments – Karnataka, Andhra and Telangana and is administered by the Centre. So, the Karnataka chief minister, finance and irrigation minister of Andhra visited the site and a joint action plan was prepared. As we wanted to store at least 75 tmc ft of water in the dam, we decided to drop the stoplog elements in the flowing water of 12 ft depth. At the emergency (virtual) meeting chaired by the chairman of the Central Water Commission (CWC) and chairman of Tungabhadra Board, it was decided to issue the work order under my guidance. Around 150 workmen worked for three days continuously to fabricate three elements of the stoplog gate at the Jindal plant and two more elements were fabricated at Hindusthan company and Narayana engineering companies,” explained Naidu.
The challenge was the design. “We designed the gate based on the main gate groove and by matching the stop log. If we hadn’t acted swiftly no water would have been left in the dam. It would have taken three months to install the gates. Now, the broken gate has been replaced with a new gate. But this gate cannot be operated as it is a temporary one used only to stop water from flowing out. The flood control should be done using the other 32 gates,” said Naidu, adding that there were several other hurdles too.
The installation posed a major challenge. The vent width was 60 ft, gate length was 60.5 ft, groove width was 64 ft. The team could not afford to let the elements collide with the stone walls of the old dam and invite another disaster. “Initially the Centre did not give permission to remove the horse bridge. We had to convince them that such efforts had been made at the Narayanapura dam in Karnataka, Singur dam in Andhra and Tehri dam in Uttarakhand. And they agreed,” recalled Naidu.
On August 15 morning, the horse bridges were removed and the following day, they lowered the three elements of the stop log gate and plugged the flow of water. People rejoiced at the sight as precious water was finally saved from going to waste. On August 17, they handed over the project to the authorities. Farmers came in with sweets and there was jubilation as we could save water hopefully to harvest two crops this year.
At 77, Naidu worked tirelessly for five days without a break. He says the operation was one of its kind as it was a major challenge but accomplished in record time. The police had imposed Section 144 around the dam site as farmers and people were anxious and agitated over losing water stored in the dam through the broken gate.
“I was standing throughout the operation and it took a toll on my health, which was already delicate. Everyone wanted to felicitate me. But I quietly came back to the Jindal plant taking the outer ring road, trying to avoid the villages, which were in a celebratory mood. I took a flight to Hyderabad,” said Naidu, a native of Andhra Pradesh.
Born into a farming family in Dasarapalli village in Chittoor district, Andhra, Naidu did his mechanical engineering from Venkateshwara college in Tirupati. He joined Madras State Company and trained in dam design for five years under Srirangachari Thiruvalla Iyengar. His mentor told him to apply for a job at Tungabhadra Steels. Having joined Tungabhadra Steels on January 16, 1976, and in March 2002 he took voluntary retirement but continued to stay at Hospet till 2005. During his career, he designed and built crest gates, sluice gates, power generation gates and canal water regulator gates, which helped him get close to the farmers in the Tungabhadra basin.
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