Chief Minister Y.S. Jagan Mohan Reddy will be dedicating the Owk tunnel project in Nandyal district to the people of Andhra Pradesh on November 30 (Thursday). It is an integral component of the Galeru Nagari Sujala Sravanthi (GNSS) project.
The project will have a discharge capacity of 2 tmc ft per day, and it will address the perennial drought situations in the Rayalaseema region.
“The project includes 10,000 cusecs of water through the right tube (T-II) and the existing 10,000 cusecs through the diversion tunnels of the left tube, totalling to 20,000 cusecs,” Shashibhushan Kumar, Principal Secretary to Government, Water Resources Department, told The Hindu on November 29.
The work on Owk Tunnel-II to discharge 20,000 cusecs was taken up under the Jalayagnam programme in 2007 at an estimated cost of ₹570.83 crore. The project was originally designed as a single tunnel, and later it was changed to two tunnels due to technical problems in the discharge of water to the Owk reservoir.
Mr. Shashibhushan Kumar said that earthwork excavation in the twin tunnels was almost completed by 2010, except for the Fault Zone of 350 m in the left tube and 180 m in the right tube, wherein soft soil in the tunnel roof collapsed.
Meanwhile, in order to supply water to the Gandikota reservoir on top priority, two diversion tunnels were proposed to carry a discharge of 5,000 cusecs each.
Accordingly, Diversion Tunnel-1 was executed during 2017 and water released to the Gandikota reservoir. Further, Diversion Tunnel-2 was excavated during 2018. Both tunnels were put to use to carry a total discharge of 10,000 cusecs.
On the other hand, execution of Fault Zone in the right tube (T-II) had become technically unfeasible, and hence the work was pre-closed in 2020.
Meanwhile, the Chief Minister decided to achieve originally contemplated carrying capacity of 20,000 cusecs to divert the required water in short periods of floods in Krishna river.
Accordingly, administrative approval was accorded for execution of Fault Zone in right tube (T-II) for ₹126 crore in 2020 and the works started again.
The remaining lining work in the left tube and right tube was in progress, but the critical Fault Zone lining was completed in all respects, Mr. Shashibhushan Kumar said.
