A STUDY to investigate the environmental impact of the Cross Island Line (CRL) on Singapore's largest nature reserve will begin next year.
The Land Transport Authority (LTA) yesterday said it will call a tender in the first quarter of next year for the assessment, which will help it decide if this MRT line should pass through the Central Catchment Nature Reserve or skirt around it.
Apart from investigating the impact of possible alignments, the consultant will also have to suggest how to reduce any possible negative impact and come up with guidelines on suitable ways to carry out works such as soil investigation in the reserve.
LTA chief executive Chew Hock Yong stressed that no decision on the CRL's route will be made until this assessment and other studies are completed.
Announced in January, the 50km, fully underground CRL, which will connect Jurong to Changi, is targeted to be ready in 2030.
Nature and environment groups soon raised concerns that works for the MRT line could cause irreparable damage to the nature reserve, which they say has a unique, complex and highly sensitive ecosystem. The area that could be affected is near the MacRitchie Reservoir.
In July, the Nature Society (Singapore) released a 40-page paper that suggested running the line around the reserve to reduce damage to its ecosystem.
After several meetings with the LTA, the nature groups have agreed to help define the questions that the consultant needs to answer as part of the environmental impact assessment.
Nature Society spokesman Tony O'Dempsey said the groups will help ensure that there is a "realistic assessment" of the impact of physical works on the reserve.
Mr Subaraj Rajathurai, director of Strix Wildlife Consultancy, said the groups are now collating available literature and research on the reserve's ecology for the study, to ensure that the assessment is "very comprehensive".
"We have to be careful to cover all bases. The nature groups involve many people who have spent many years in the reserve. We know the sensitivities that need to be looked at and the flora and fauna that are at risk."
While the nature groups favour a route which goes around the south of the reserve, some residents in the Thomson area are worried about how the CRL may affect their homes.
Thomson-Toa Payoh Citizens Consultative Committee chairman Ronald Lim noted the area will soon see the start of three other major projects - a deep cable tunnel project, the Thomson Line and the North-South Expressway.
"If the CRL is also built in the area, residents have to put up with the inconvenience for up to 15 years. And who knows if acquisitions may be required?" he said.
He hopes the LTA study will also take into account the urban impact of the CRL.
The assessment, which will take up to two years, is expected to be completed in 2016. That will be followed by an 18-month engineering feasibility study on the possible routes.
After that, LTA will consider all the relevant factors, from the environment to travel time and cost, before deciding on the route. Said Mr Chew: "The findings will guide us in making a considered decision on which option best serves the interests of the public."