A tunnel under the mighty Brahmaputra River will finally become a reality, Assam chief minister Himanta Biswa Sarma announced on Friday. He said that the centre has approved the project, and tenders will be invited to prepare DPR for the project soon. He informed that a tunnel will be constructed under the Brahmaputra at an estimated cost of ₹6000 crore.
Addressing a public rally at Biswanath Chariali in Assam, Himanta Biswa Sarma said he thought that a tunnel under the river was just a dream, and it will not become a reality. But he was surprised during a recent visit to Delhi, where the union govt told him that the project has been greenlighted. He said that after much deliberation, it was decided that the tunnel will be constructed between Gohpur on the north bank and Numaligarh in the south bank. It will be a road cum rail tunnel.
Assam CM said that the first tenders for Detailed Project Report (DPR) will be opened on 4th July. ‘If everything goes as planned, we may be able to start the construction during the current tenure of my govt,’ he said. Sarma further said that PM Narendra Modi has already signed a file to connect the north and south banks of Brahmaputra through a tunnel. The tunnel will connect NH 15 on the north with NH 715 on the south.
Coming soon – Assam’s first underwater tunnel pic.twitter.com/4jmOTSBLhe
— Himanta Biswa Sarma (@himantabiswa) June 24, 2023
The centre has entrusted NHIDCL (National Highways and Infrastructure Development Corporation Ltd.) with the project. The NHIDCL has floated tenders to prepare DPR and will start pre-construction activities for the construction of the tunnel soon. 4-lane approach roads on both ends of the tunnel are part of the project.
Tunnel Boring Machine will be deployed for the main tunnel under the river, while the open cut and cover method will be used for the sections of the tunnels on both ends. The length of the main tunnel will be 11.4 km, with a total length of around 15 km.
Artificial islands are also proposed on the northern and southern sides of the river Brahmaputra, and the construction zone will be created within the islands to facilitate the construction of the tunnel and also during the operational phase. The islands will act as bunds to prevent flood water from entering the tunnels.
NHIDCL has already prepared a Pre-Feasibility Report for the tunnel project. However, the report is only for a two-lane road tunnel and does not mention a rail tunnel. Therefore, significant changes in the DPR is expected from this report.
At present, there are six bridges over the Brahmaputra, which include twin bridges at Guwahati and Tezpur. Three more bridges at Dhubri, Guwahati and Majuli are under construction. Construction of two more bridges in Guwahati, on its eastern and western ends, will start soon, and Railway will build two bridges at Guwahati and Tezpur. Several other bridges are under the pipeline connecting the north and south banks of the Brahmaputra river across the state.
However, the bridges are seen as vulnerable in case of a war or major terrorist activities in the region, and the security establishment was considering a tunnel as an alternate route. Connectivity across the Brahmaputra is vital for the defence of the frontline on the border with China, and a tunnel is considered much more secure compared to a bridge over the river.
According to previous reports, there will be three separate tunnels, one for road, the second one for rail, and the third one for emergency use including military transport. The tunnels, including the 11.4 km long main tunnels, will be around 15 km long and will be around 32 meters below the riverbed.
The proposal for a tunnel was originally floated by the Border Roads Organization (BRO), considering its strategic importance. BRO started surveys for the project in 2014 and selected two sites, Tezpur-Nagaon and Gohpur-Numaligarh. In 2020, the centre gave in-principle approval for the project, after which detailed studies were conducted, including an airborne electromagnetic survey.
Initially, the Tezpur site was favoured, as the river is narrower there, and Tezpur is home to the headquarters of the GOC 4 Corps of the Indian Army. However, later the Gohpur-Numaligarh location was selected.
There are already two road bridges over the Brahmaputra at Tezpur, and a Railway bridge has been planned. That could be the reason for not selecting the site as both banks of the river are already well connected there. With the tunnel coming, the plan for a bridge between Gohpur and Numaligarh will be scrapped. In fact, the project was delayed because the centre was deliberating between the tunnel and the bridge, which would have been a cheaper option. The tunnel was approved after several cabinet ministers supported the plan, considering its strategic importance.
The project will be undertaken under the Special Accelerated Road Development Programme (SARDP-NE) of the Union Ministry of Road Transport & Highways.
