Tehri: A GSI success story
THE STAGE is set to commission the much-controversial Tehri dam. But more than its technical coordinators, it is the Geological Survey of India (GSI) which is celebrating the success.
Reason: The GSI experts, who have been providing geo-technical assistance to the dam for over 56 years, are quite happy over completion of one of the longest ever assignment given to the GSI. The GSI has been associated with Tehri dam – the first major attempt in India to tap immense resources of hydel energy – from the pre-conception stage and till now.
They not only helped bring out Tehri of all the technical controversies but also made it the first dam where water does not fall on the front face. They also added many other technical features, which were not their job.
The unique tube-canal waterfall, underground powerhouse complex, design and quake-proof construction safe and maximum utilisation of natural resource that may not be found in other dams in India are made possible by the GSI workforce.
It was GSI that gave this rocked filled dam (another first of its kind experiment in the country) such an operative shape that uses hydel energy through the ‘horse shoe shaped’ tunnel and not like conventional waterfall technique used in other dams.
At the very first instance at the dam, one can not see the fall or even the power generators as both are hidden. The credit goes to once again to the GSI that made it safe against a Maximum Credible Earthquake (MCE) of 8.6 on the Ritcher scale.
The role of GSI became important when the Vishwa Hindu Parishad raised controversy and an 11-member review committee was set up to study the feasibility of dam. Perhaps no other national project has seen as many technical reviews as the 260.5 mt high Tehri on the Bhagirathi has.
“When at first the GSI’s resident geologists were posted at the dam site in 1947, their work was just to select a site to intercept a catchment of 7511 sq. km. But seismic and geological investigations and geo-technical assistance remained with the dam all through the planning and construction stages,” deputy director general of the GSI, Dr PN Razdan told HT.
Even the detailed project report (DPR) of the dam was prepared by the GSI in 1961-62 after which the actual plan could go ahead in construction.
At the time of the commissioning, the dam would only start generating 1000 MW (comprising four units of 250 MW each), the transmission lines for which have already been laid.
By end of this year, another 1000 MW electricity generation is expected while another 400 MW would come up from the Koteshwar site.