Power Minister R K Singh on Thursday said the area of subsidence in Joshimath was 15 km upstream from the components of the Tapovan-Vishnugad hydropower project and there were no signs of sinking of ground around its tunnel alignment.
In a written reply to a question in the Lok Sabha, Singh said land subsidence in Joshimath was "a very old issue" observed way back in 1976 and the M C Mishra Committee set up by the then state government listed "hill wash, natural angle of repose, cultivation area because of seepage and soil erosion" as probable causes for cracks in the Himalayan town.
The minister said a multi-institutional committee set up by the state authorities in July last year had made no mention of NTPC Tapovan-Vishnugad hydropower project causing land subsidence in Joshimath.
Singh said the construction for the Tapovan-Vishnugad project was started in
2006 after a detailed examination for environmental impact, geological, hydrological and seismic studies by the Geological Survey of India (GSI), Central Water Commission (CWC) and the National Council of Seismic Design Parameters (NCSDP).
"The area of subsidence in Joshimath is 15 km upstream from the project components. The tunnel is at a horizontal distance of around 1.1 km away from the outer boundary of Joshimath town and vertically around 1.1 km below the ground level. There are no signs of sinking around the tunnel alignment at the over ground surface," the minister said.
Singh said the M C Mishra Committee had said that Joshimath was not situated on in-situ rocks, but on weathered, landslide mass of big unsettled boulders in the loose matrix of fine micaceous sandy and clayey material.
"Joshimath lies on an ancient landslide. This landslide zone extends up to big nala near Parsari in the east, in the west up to north-west ridge and nala near Gaukh, in north up to riverbed where some in-situ outcrops are noted on the southern bank, while northern bank consists of solid in-situ bedrock (Hathi Parbat) and in the south up to and beyond Auli which may extend up to the high mountain ridge forming the watershed," Singh said, quoting the M C Mishra Committee report.
The minister said after the reports of land subsidence in Joshimath town, the Chamoli district administration has issued an order on January 5 to stop all the construction activities at the NTPC's Tapovan project till further orders.
Singh said the NTPC has not given any compensation to the villagers earlier due to any natural calamities or any other reasons.