HONG KONG'S KowloonCanton Railway Corporation (KCRC) has won government backing for an £870M rail project, replacing an earlier scheme thrown out on environmental grounds.
The new scheme includes a 4.3km tunnel under the Long Valley, home to about 210 migratory bird species.
The original viaduct, part of the KCRC's 7.3km East Rail spur to a new Hong Kong-Guangdong boundary crossing at Lok Ma Chau, was strongly criticised on environmental grounds as destroying valuable wetland areas.
As a result, Hong Kong's environmental protection department refused to approve the project's environmental impact assessment.
KCRC East Rail extensions director Lee Kang-Kuen said the tunnel would add £174M to the £696M estimated cost of the line and lengthen the construction period by two years to 2007.
The remaining 3km of the link will stay on viaduct along an already approved alignment to the Lok Ma Chau terminal. In San Tin, 9ha of fish ponds would disappear but 28ha of replacement ponds would be upgraded.
Director of the HK environmental protection department Rob Law supported the tunnel.
'There's no reason to believe the tunnel would have any environmental drawback, ' he said.
A new environmental impact study would be required, but a permit could be issued as early as the second quarter next year, when HK's Executive Council could give final approval.
Construction could start by the end of next year.
'We are committed to building the spur line as soon as possible to meet the growing crossboundary passenger traffic demand and to ease the congestion at Lo Wu, ' said transport secretary Nicholas Ng.