SINGAPORE — Investigations to examine ground conditions in the Central Catchment Nature Reserve for the future Cross Island MRT Line (CRL) will start in the fourth quarter of this year, with the Land Transport Authority (LTA) putting in place more measures than previously announced to reduce the impact of borehole drilling and other surveys.

The safeguards will protect the less mobile and more sensitive animals in particular, such as leaf-litter insects and the slow loris.

Among the extra mitigation measures: Giving officers from the National Parks Board (NParks) the right to issue immediate stop-work orders if any pollution is detected, or if there is deviation from agreed practices. Trained representatives from various nature groups will be invited as observers, and the LTA will do away with the use of the Mackintosh Probe tool to avoid any work in the streams of the nature reserve.

Drilling of boreholes and non-intrusive geophysical surveys will be synchronised and carried out within the same sector in phases, to allow animals to move away from activity zones. Arborists will be engaged to avoid damage to trees.

NParks gave the go-ahead on Wednesday (June 8) for site investigation works in the reserve, after reviewing the “stringent safeguards” and “comprehensive and substantive mitigation measures” that the LTA will put in place. 

The statutory board, which oversees parks and nature reserves here, said full compliance with the mitigation measures will ensure that potential residual impact of site investigations are “limited and short-term”.

The LTA issued a tender on Wednesday to appoint a specialist for site investigations in the nature reserve. This is for the CRL alignment option that will cut under the reserve for about 2km. 

The other alignment option skirts around the reserve near Lornie Road, and the LTA said site investigations for it began last month.

In a press release, LTA chief executive Chew Men Leong said the authority will work with nature groups and NParks to “rigorously” implement all mitigating measures. “We will continue to study both possible alignments objectively, taking into consideration all factors and the concerns of all stakeholders ...” he said.

The CRL, due to be completed around 2030, has been intensely debated since plans for the line were announced in 2013. Nature enthusiasts do not want the rail line to cut under the nature reserve, due to potential damage to its fragile ecosystems and extensive wildlife. 

The Government has said the CRL will link Jurong and Changi, and pass through Hougang, Ang Mo Kio, West Coast and other estates. About half of its 30-plus stations will be interchange stations and daily ridership will be at least 600,000.

The environmental impact assessment (EIA) of site investigations for both alignments was released in February. It found that with mitigation measures in place – such as drilling holes only on existing trails and areas without vegetation – the works would have “moderate” impact on the nature reserve. NParks said with the extra measures, residual impact would be “small” in most areas. 

Contacted on Wednesday, wildlife consultant Subaraj Rajathurai said giving NParks the right to issue stop-work orders is “very important”. 

“Because at some point, if we find that this process is going to be too damaging to the forest or if there’s a danger that that can happen, I’m trusting… NParks to say, enough is enough,” said Mr Subaraj, who is part of a working group with fellow nature experts in talks with the LTA on the future rail line.

Adding that he would be among the observers helping to monitor compliance with conditions, Mr Subaraj said: “While we disagree with the whole site investigation, we also have to work on what the decision is … Since that’s going ahead, we want to have the minimum impact possible.” According to the EIA addendum report dated May 27 that the LTA posted online, the site investigations could start late-December and take about 10 months.

Meanwhile, LTA’s Mr Chew has responded to volunteers from the Love Our MacRitchie Forest movement, who submitted an appeal this week for the authorities to reconsider CRL-related works in the nature reserve. The petition contained signatures of over 10,000 people.

Mr Chew said the alignment of the CRL has not been decided. Site investigations are an important phase, as the outcome of the study will help in fully determining the engineering challenges, and benefits and trade-offs, for both alignment options, he added.