Cross Island Line site investigation works to be modified to reduce environmental impact

Cross Island Line site investigation works to be modified to reduce environmental impact

The Land Transport Authority will reduce the number of boreholes it plans to dig from the original 72 to 16, following the first phase of an Environmental Impact Assessment and feedback from nature groups.

SINGAPORE: Following feedback from nature groups, the Land Transport Authority (LTA) has customised site investigation plans for the upcoming Cross Island Line (CRL) to minimise disruption to the environment near the Central Catchment Nature Reserve, it said on Friday (Feb 5).

LTA said Phase 1 of a two-phase Environmental Impact Assessment (EIA) on the construction of the 50-kilometre line has concluded and that with mitigating factors, the impact on the environment is expected to be "moderate".

The MRT line will run from Jurong Industrial Estate pass Bukit Timah to Sin Ming and Pasir Ris before ending in Changi and is expected to be completed by 2030.


Part of the trails at MacRitchie Nature Reserve could be closed to the public from the third quarter of this year to facilitate soil investigation work for the new MRT line. This is for planners to better understand ground conditions so mitigation measures can be put in place to reduce safety or environmental risks while constructing the underground tunnel.

LTA explained that having the tunnel primarily situated in hard rock, rather than a mix of rock and soil, could help to minimise safety and engineering risks.

The level of rock could be assessed using boreholes, which are vertical shafts drilled into the ground. Some nature groups had expressed concern that these would affect the surrounding ecosystem.

LTA said on Friday that in light of the EIA report, it will reduce the number of boreholes placed along the route through the reserve from an initial estimate of 72 to 16, at the maximum spacing of 400 metres apart. The 10-cm wide holes, which will could be as much as 50 to 70 metres deep, will also be placed along existing trails and clearings to avoid having to remove vegetation at the site, it said. The boreholes will be dug along the Sime Track and Terentang Trail at MacRitchie, meaning parts of these trails may be closed to the public.

Given the fewer number of boreholes used in the investigations, LTA said non-intrusive methods such as seismic reflection, electrical resistivity surveys and gravity surveys would be used to generate more data. These are manually-administered methods carried out with small devices above ground level, and would have a less disruptive impact on the environment, LTA stated.

Nanyang Technological University’s School of Civil and Environmental Engineering Professor Chu Jian said: “16 boreholes for larger scale project is too little in my opinion, but I understand this is a special project and the project is going to be carried out in the nature reserve. And I understand that there will be other ways to cover the reduction in the borehole, for example to increase the usage of the physical survey, as well as doing horizontal drillings."

LTA said it would collaborate with the National Parks Board (NParks) to ensure careful execution of such site investigation works, as well as on the timings of the works to reduce disruption to human traffic.

LTA chief executive Chew Men Leong said the findings from the site investigation and a separate engineering feasibility study will provide critical information to help the Government make "a considered decision on the CRL alignment that best serves the public interest".


Since LTA announced the CRL in 2013, some nature groups have expressed concern about the environmental impact of the line possibly being built through the Central Catchment Nature Reserve.

The reserve, which encompasses the MacRitchie, Upper and Lower Pierce and Upper Seletar reservoirs has about 400 species of trees, 200 species of birds, 400 species of insects and 150 species of mammals and amphibians, according to a 2014 report released by some of the nature groups.

LTA said that pending more baseline information on ground conditions near the reserve, it was open to both of two possible alignments for the part of the MRT line around the area of the reserve - one cutting straight through the reserve and the other skirting around it as recommended by nature groups.

The EIA, conducted by consultant Environmental Resources Management (ERM), will be considered along with factors such as connectivity, travel time, cost and impact on home- or land-owners in the area when deciding on the final alignment of the MRT line, LTA said.

The first phase of the study was conducted between August 2014 and December 2015. To understand the possible impact of the works, LTA consulted NParks, ERM and the nature groups, held focus group discussions and spoke to other stakeholders such as advisors and grassroots leaders to address their concerns, it said.

Senior Minister of State for Transport Josephine Teo said the nature groups, in particular, had contributed many hours and days over the past two and a half years to the EIA study.

"Their input, suggestions and advice have been most valuable," she said.


Nature groups that Channel NewsAsia spoke with warned that the site investigation works could have long-lasting repercussions.

President of Nature Society (Singapore) Shawn Lum, said: "This is the original flora and fauna of Singapore that used to cover the whole island, and now there are only a few small, scattered patches.

“So, any impact would be disproportionate. People might say: ‘Why do you get so bothered by all of this?’ It's because it's so precious, and it's the heritage of all Singaporeans. If we lose this, we stand to lose something very precious to all of us."

Meanwhile, council member Tony O’dempsey said: "We have a zero-impact policy as a starting point. The reason why we have this policy is that every time we do something in a nature reserve, you create an impact that is long-lasting.

“We can't always measure what those impacts are accurately, and we don't like to take the risks. So every impact that occurs, no matter where in the nature reserve, different projects, different times, will accumulate.

“We call that death by a thousand cuts. It's like eating an apple. You take a bite out of an apple, that's one small bite. You take another bite, it's another small bite. But eventually, your apple will be finished.”

However, the representatives lauded LTA's efforts to seriously deliberate the environmental impacts on the nature reserve as a step in the right direction.

Singapore Environment Council Head of Eco-Certification Kavickumar Muruganathan, said: “It's very encouraging that an EIA has been conducted on such a project. We believe it's the very first time we've undertaken an EIA. So we believe in the future for more of such projects that involve construction and development, that EIAs are undertaken."

"It's the best we can do, I'll walk away from the table thinking, we've got the best solution we have, given the scenario,” Mr O’dempsey added.

The Nature Society (Singapore) said it plans to accompany the authorities during parts of their site investigation works.


ERM will next conduct Phase 2 of the study to assess the potential environmental impact arising from the construction and operation of the CRL. This is expected to be completed by end-2016.

The CRL is expected to serve as an alternative to the current East-West Line. It will also serve as a key transfer line by connecting to major radial lines, complementing the role currently played by the Circle Line, LTA said.

It added that the CRL is a critical component of LTA's plans to enable eight in 10 households to be within a 10-minute walk of a train station by 2030.

transport lines

Current and planned train lines in the Singapore public transportation system. (Image: Land Transport Authority)

The EIA (Phase 1) report was gazetted on Friday evening and will be available for public viewing by appointment at LTA for the next four weeks.

Source: CNA/mz