New Delhi: In what could prove to be an engineering marvel, the Narendra Modi government has proposed a 15.6-km twin-tunnel under the mighty Brahmaputra river, which will not only protect the Kaziranga National Park by bypassing it but also benefit India strategically by cutting travel time between Assam and Arunachal Pradesh.
Each of the two tunnels will have two lanes for smooth flow of traffic and will be built 22 metres below the river bed. The total length of the project will be approximately 33 km, including the 15.6-km tunnel and 18-km approach roads to connect to the highway.
Owing to its strategic importance, the project has already been endorsed by the Directorate of Military Operations. India has been beefing up its road infrastructure along the borders, including in the Northeast to counter any challenge from neighbouring countries like China.
The proposed project will cost Rs 12,807 crore and is a greenfield alignment to provide a direct link between Gohpur on NH-52 and Numaligarh on NH-37 in Assam.
The link, which is part of the 315 km long NH-37 that connects Nagaon to Dibrugarh, will help bypass the Kaziranga belt that falls on this highway stretch.
The project will be funded entirely by the Ministry of Road Transport and Highways.
Way back in 2008, when the Cabinet Committee on Economic Affairs approved the four-laning of NH-37, a decision was taken to have an alternate alignment to bypass Kaziranga National Park. The ministry took time to come up with a new alignment that didn’t fall on the way of the park.
Senior officials in the road ministry told ThePrint that the National Highways and Infrastructure Development Corp. Ltd (NHIDCL), a fully owned company under the ministry, is preparing the Detailed Project Report (DPR) of the twin-tunnel.
“NHIDCL has submitted the draft geophysical study to the road ministry and the DPR is in advanced stage of preparation,” said a senior ministry official, who didn’t want to be named.
At a meeting chaired by Road Secretary Giridhar Armane on 1 September, NHIDCL was directed to prepare a draft note for the Cabinet Committee on Security after getting the project endorsed by the Ministry of Defence.
Senior road ministry officials told ThePrint that earlier, the Border Roads Organisation had planned another tunnel under the Brahmaputra but since the agency was yet to prepare the DPR, it was decided that NHIDCL should go ahead with its proposed project as its DPR was in advanced stage of preparation.
If the project gets cleared, it will be the second twin-tunnel that will be constructed under a river in India. Another twin-tunnel project, though not a road tunnel, is currently underway in Kolkata — a 10.8-km stretch of the East-West metro corridor under the Howrah.
An engineering marvel
The proposed four-lane tunnel under the Brahmaputra river will be constructed using tunnel boring machines. It is expected to be completed in two years after work starts.
The tunnels will have an electrical substation, sensors and CCTVs to monitor vehicular movement. “Both the tunnels will be inter-connected to help in evacuation in case of an accident or any other emergency,” an NHIDCL official said on condition of anonymity.
Originally, NHIDCL had proposed to build a four-lane bridge across the Brahmaputra to link Gohpur and Numaligarh. “But in 2019, it was decided to construct a twin tube tunnel because it was considered to be strategically more useful in case of war or any other external exigencies,” said a second road ministry official who didn’t wish to be named.
Currently, there are five bridges across the Brahmaputra while one more is under construction and another is being planned.
How will it help
As of now, it takes approximately six hours to cover the nearly 223-km distance from Numaligarh to Gohpur. There is a two-lane road adjacent to the Kaziranga wildlife sanctuary, which is prone to massive traffic congestion. It is also a circuitous route leading to longer travel time.
However, NHIDCL officials said that once the greenfield alignment under the river is completed, the distance between Numaligarh and Gohpur will reduce to 35 km and it will take under an hour to cover the stretch.
“The road project will improve connectivity between the north and south side of Brahmaputra and will result in greater economic development in the region,” added the NHIDCL official quoted above.