At 8.00 p.m. on Wednesday something very significant happened at Tehri in Uttaranchal. For the first time in history, River Bhagirathi — the name given to the Ganga before it joins River Alaknanda at Devprayag, stopped flowing.
There was relief and satisfaction among the engineers and workforce of the Tehri Hydro Development Corporation (THDC) as they lowered the eighth panel of the T-3 tunnel, thus putting a brake on the river's flow. For them it was an important culmination in
the effort to build one of the biggest dams.
But for millions across the nation, it was the moment when Hinduism's most sacred river had to stop to let development take precedent. There were tears among residents of Tehri town as they watched the river actually moving in a reverse direction when the
tunnel was finally closed.
The process to close the T-4 and T-3 tunnels started on Sunday following a green signal given by the Centre and it took more than 72 hours before all the sixteen panels of the two tunnels could be closed. The tunnels were closed to construct the stilling
basin for the main dam.
"Before constructing the actual dam, we have to divert the flow of the river. For this purpose, the two tunnels had to be closed. There are four tunnels, two on the left bank of the river and two on the right measuring nearly 11 metres in diameter," said
a THDC official.
Following the closure of the tunnels, water is slowly accumulating in the dam's reservoir. It would take another 20 months for the construction of the spilling basin to be over. Meanwhile, the flow of the river would be diverted through the T-1 and T-2
tunnels. The other two tunnels are likely to be closed by March 2003 and it will take another two years to fill the reservoir of the highest dam in India and the fourth highest in the world.
"We are determined to give the first unit power of 250 MW by March 2003 and the fourth and last unit by August the same year. The maximum output of 2,400 MW would be reached in another five years," said M L Gupta, Chairman-cum-Managing Director-THDC.
Within 36 hours after the last panel is closed, the water level of the Bhagirathi will reach a height of 636 m, thus threatening the safety of the bridge connecting Tehri to the rest of the world. Situated at 640 m above sea level, the closure of the
tunnels would also mark the beginning of the end for this nearly two-centuries old town and its 12,000 residents. (To be concluded)
