The Atal Tunnel at Rohtang, near Manali, is almost complete in all respects with finishing touches being given to it before Prime Minister Narendra Modi inaugurates it late September. The 9-km-long tunnel under the Pir Panjal range, named after former Prime Minister Atal Bihari Vajpayee, will be the world’s longest highway tunnel above the altitude of 10,000 feet (3000 metres). It was scheduled to be completed by May 2020, in a revised estimate, but the Covid-19 pandemic pushed back the completion by a few months due to lockdown conditions.
Rohtang tunnel: What is the genesis of the project?
A feasibility study of the project Rohtang Tunnel was carried out in May 1990 following which the geological report was submitted in June 2004. This was followed by a design and specification report which was prepared and finalised in December 2006. Border Roads Organisation (BRO) officials say the project received final technical approval in 2003. Following approval by Cabinet Committee on Security in 2005, tenders were floated in 2007 and the foundation stone was laid in July 2010 by UPA chairperson Sonia Gandhi. The project was scheduled to be completed by February 2015 but it got delayed due to unexpected problems. It was originally designed to be 8.8 km long but GPS readings taken on completion show it to be 9 km long.
What were the problems faced by the Rohtang tunnel project?
The construction teams faced fast flowing water from Seri Nullah, which flowed on top of the tunnel route and impeded construction efforts. The sheer volume of water prevented construction for several months while project engineers grappled with a way to tackle the problem. The rock structures faced by the engineers too caused impediments.
A BRO official told The Indian Express on a site visit that the south portal of the tunnel had schist, migmatites and phyllite rocks while the north portal had incoherently folded gneiss and biotite schist which were brittle and ductile in nature.
What is the strategic advantage of the Rohtang tunnel?
Cutting through the Pir Panjal range, the tunnel will reduce the distance between Manali and Leh by 46 km. The Rohtang Pass, to which the tunnel provides an alternate, is located at a height of 13,050 feet, and a journey from Manali Valley to Lahaul and Spiti Valley, which normally takes around five hours to negotiate, would now be completed in little over ten minutes.
While the tunnel will be a boon to the residents of the Lahaul and Spiti Valley who remain cut off from the rest of the country in winters for nearly six months due to heavy snowfall, the tunnel will provide almost all-weather connectivity to the troops stationed in Ladakh.
However, for full all-weather connectivity, additional tunnels will have to be built on the Manali-Leh route so that the high passes on the axis do not impede movement due to snowfall. A 13.2 km long tunnel will have to be built to negotiate the 16,040 feet high Baralacha pass and another 14.78 km long tunnel will be required at the Lachung La pass at 16,800 feet. A third 7.32 km long tunnel will be required at Tanglang La pass at 17,480 feet.
What are the salient features of the Rohtang tunnel?
The unique features of this tunnel begin a fair distance away from it on the approach roads to the north and south portals. Bridges in rivers on the approach to the tunnel from both the portals have also been completed and are now being painted. Snow galleries have also been built at the approach road to the tunnel from Manali side, and this will ensure all-weather connectivity.
Other features include an emergency escape tunnel under the main tunnel. This would provide an emergency exit in case of any untoward incident which may render the main tunnel unuseable.
The tunnel also provides a telephone every 150 metres, fire hydrant every 60 metres, emergency exit every 500 metres, turning cavern every 2.2 km, air quality monitoring every one km, broadcasting system and automatic incident detection system with CCTV cameras every 250 metres.
BRO officials say vehicles will travel at a maximum speed of 80 km per hour. Up to 1,500 trucks and 3,000 cars are expected to use it per day when the situation gets to normal post Covid-19 restrictions.
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