BENGALURU: The failure of the 19th crest gate of the 71-year-old dam across the Tungabhadra river on Sunday afternoon has put lakhs of people in Karnataka and Andhra Pradesh on high alert for potential flooding. The dam, situated about 350km from Bengaluru, experienced a sudden surge of water as the gate collapsed.
The Tungabhadra project, a multi-state venture, is administered by the Karnataka govt.Gate 19 was carried away by substantial inflows to the project during the late hours of Saturday. The breach in the gate has put hundreds of thousands of farmers and villagers in the states of Karnataka and Andhra Pradesh at risk. The affected districts in Karnataka include Ballari, Vijayanagara, Koppal, and Raichur, while in Andhra Pradesh, Kurnool and Nandyal are on alert. The two districts in Andhra Pradesh are situated downstream of the dam, and Kurnool city is located on the banks of the Tungabhadra river, making them vulnerable to potential flooding.
What is history of Tungabhadra dam?
- Sir Arthur Cotton, a British engineer from the Madras Presidency, conceived the Tungabhadra Dam project in 1860. His primary objectives were to provide
irrigation facilities, generate electricity, and control floods in the region. - The construction of the dam began in 1949 as a joint venture between the Kingdom of Hyderabad and the Madras Presidency. The project was completed in 1953.
- The dam, also known as
Pampa Sagar , is situated across the Tungabhadra River near the towns of Hosapete and Koppal. - The Tungabhadra reservoir, along with the Mullaperiyar dam in Kerala, holds the unique distinction of being the only two reservoirs in India that were built using a combination of mud and limestone materials.
Why is the Tungabhadra dam significant?
- Tungabhadra Project provides essential services to the residents of Karnataka, Telangana, and Andhra Pradesh.
- It significantly contributes to the irrigation of agricultural land, facilitating the cultivation of crops across two seasons on an impressive 6.5 lakh hectares.
- The project plays a vital role in generating hydroelectric power, contributing to the energy needs of the surrounding states.
- It assists in managing and controlling floods, mitigating potential damage caused by excessive water flow.
- Tungabhadra Project ensures a reliable supply of drinking water for the local population, improving their access to clean and safe water resources.
What has happened?
- A
flood alert was issued in Karnataka’s Koppal region on Sunday after one of the gates of a massive dam broke loose. - Officials said rising water pressure after heavy rain dislodged a gate of the Pampa Sagar Dam on Karnataka’s Tungabhadra river.
- As a result, an enormous quantity of water has been gushing out of the gate.
What is the outflow status?
- Dam officials said about 1,020 tonnes of water is shooting out of the damaged Gate 19 every second, as against roughly 1,130 tonnes through the other gates.
- Dam’s design allows for release of up to 6.5 lakh cusecs of water at a time.
- In May 2024, the dam authorities carried out essential maintenance and thorough check of all crest gates.
- As of Saturday, the dam, which has a maximum storage capacity of 133tmcft, was holding 100tmcft of water, with the remaining 33tmcft being silt.
What triggered the dam gate chain snap?
- On Saturday night, 40,000 cusecs of water was being released into the Tungabhadra river through 10 crest gates.
- The highest recorded release was 3.6 lakh cusecs back in December 1992.
- At 12.50am, the 19th gate malfunctioned, causing a substantial flow of water into the river.
- All 33 crest gates were opened to reduce the pressure on the broken gate. The discharge increased to one lakh cusecs on Sunday morning.
How this can be fixed?
- Installing a stop lock could resolve the issue, and the project authorities were attempting to minimise water release.
- It’s impossible to repair the gate while water is gushing out of it, so the authorities might have to empty about 60% of the reservoir.
- Karnataka minister Shivaraj Tangadagi said, “We may have to release at least 60 to 65 TMC water from the dam. The problem can be resolved only after 20 feet of water is released.”
- Dam officials say the discharge from the other gates will need to be increased to ease the pressure on the broken gate. All but five of the undamaged gates have already been opened.
- To replace the damaged gate, it is necessary to release at least 60tmcft of the 100tmcft of water currently stored in the dam. This process, along with the construction of a new crest gate, is estimated to take up to four days or possibly longer.
- In an effort to manage the situation, 22 out of the 33 gates at the dam were opened on Saturday evening, allowing for the discharge of nearly 1 lakh cusecs of water into the Tungabhadra river.