Plan drafted for $36b undersea tunnel

China plans to build the world's longest underwater tunnel beneath the Bohai Sea by 2026, with a blueprint expected to be submitted to the State Council in April.

"Once approved, work could begin as early as 2015 or 2016," Wang Mengshu, a tunnel and railway expert at the Chinese Academy of Engineering who has worked on the plan since 2012, told China Daily.

The project will cost an estimated 220 billion yuan ($36 billion), he said.

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Work on a feasibility report could take two or three years, he said.

The 123-km underwater tunnel will house a rail line connecting the port cities of Dalian in Liaoning province and Yantai in Shandong province, according to the plan. Its planned life span will be about 100 years.

By length, it will surpass the combined length of the world's two longest underwater tunnels — Japan's Seikan Tunnel and the Channel Tunnel between Britain and France.

"Using the tunnel, it will take only 40 minutes to travel from Dalian to Yantai," Wang said.At the moment it is a 1,400-km drive or about eight hours by ferry.

Passenger vehicles can be loaded onto rail carriages and transported at about 220 km an hour, massively shortening the travel time between the two cities, according to the plan.

Wang said the project will consist of two underwater tunnels, both about 10 meters in diameter, and a service tunnel about 7 meters in diameter.

Authorities in Shandong and Liaoning are hoping the project will stimulate economic growth by connecting the northern area with the wealthy eastern coast.

The project has been proposed at the National People's Congress and the Chinese People's Political Consultative Conference every year since 2009.

Wang Liang, mayor of Yantai, said during the annual sessions of the top legislature and advisory body in 2013 that the project will boost the city's economic growth.

The project was mentioned in Shandong's regional plan approved by the State Council in 2011.

Research by Ludong University in Yantai showed daily traffic flow between Dalian and Yantai is expected to increase to more than 100,000 vehicles by 2015, which will pose a challenge for transport capacity.