An undersea expressway to Taiwan is among the idea of digging five tunnels to link islands and major coastal cities in 20-30 years time.

Undersea railways would link Dalian, Northeast China's Liaoning Province with Yantai in East China's Shandong Province, and the Leizhou Peninsula south of Guangdong with the island province of Hainan.

Road tunnels would link Shanghai with Ningbo in East China's Zhejiang Province, and Zhuhai in South China's Guangdong Province with Hong Kong and Macao.

Another road tunnel would leave the mainland for Taiwan in East China's Fujian Province.

"It is unlikely that construction of any of the five can start before 2010. But around 2020, some of them could be launched," Qian Qihu, a member of the Chinese Academy of Engineering, told China Daily on Friday.

"Whether or not the tunnels can really be built will depend on various conditions, including the status of local economic development," added Qian.

Qian first revealed the news at a two-day Sino-Russian seminar on engineering technology held in Beijing May 11-12.

The Ministry of Railways was not reachable yesterday, while sources with the Ministry of Communications declined to comment on the visionary subterranean transport network.

But it is widely held among engineering and economic experts that building cross-sea tunnels are cheaper than bridges.

Tunnels are also free of the influence of bad weather such as typhoons and heavy fog.

However, bridges would also be needed in other areas, Qian said.

Aside from the economic costs, engineers would face a plethora of technical problems such as the best way to securely tunnel under a sea-bed built through rock and silt.

China has listed two undersea tunnel projects.

The first undersea tunnel was launched in Xiamen, Fujian province. It will be 9 kilometres long and expected to be completed by 2010. It will cost 3.2 billion yuan (US$386 million).

"In Qingdao, Shandong Province, the construction of a 5.5 kilometre tunnel is expected to start by the end of the year," Qian said.

Minister of Communications Zhang Chunxian announced on January 13 that the country's planned expressway network would include a link with Taipei.

He said the two coasts could be linked by a tunnel or by "other means."

Zhang said the significance of the expressway to Taipei lies in logistics, which is of great importance in helping Taiwan, Hong Kong and the Chinese mainland lower their transportation costs, sharpen their competitive edges and upgrade living conditions "for every resident."

Source: China Daily