NEO CHAI CHIN Today Online 5 Feb 16;
SINGAPORE — Sixteen holes as deep as 70m will be drilled in the Central Catchment Nature Reserve from the third quarter of this year to determine ground conditions for one of two possible alignments for the Cross Island MRT line.
The holes will be drilled only on public trails and areas without vegetation, as part of measures to manage their impact on the nature reserve, said the Land Transport Authority(LTA) today (Feb 5) as it gazetted the first phase of the Environmental Impact Assessment (EIA) of the Cross Island Line on the nature reserve.
Phase One of the EIA report concluded that with mitigating measures and controlled access, the proposed site investigation works would have moderate impact on areas of the nature reserve where the works will take place.
The site investigation is to gain knowledge of soil and rock conditions, as the Government decides how to align the future 50km MRT line that will link Jurong and Changi.
Two alignment options are on the table and site investigations will be done for both. One alignment cuts through the biodiverse Central Catchment Nature Reserve for about 2km, while the other skirts around it near Adam Road for about 9km. The latter alignment entails less ecological impact and the LTA said about 250 boreholes will be drilled to study its ground conditions.
For the alignment that affects the nature reserve, the number of holes, 16, was determined with input from nature groups and the environmental consultancy conducting the EIA. The number of holes was reduced from 72; the LTA will do non-intrusive geo-physical surveys to complement findings from the 16 boreholes.
Besides drilling along public trails and vegetation-free areas, there will be 30m buffer zones around streams, wetlands and marshes, as well as fluid containment tanks, to ensure no spillage of drilling fluid and to minimise erosion and siltation.
To reduce intermittent noise from the drilling, machines will have enclosures added. This will cut noise levels of around 80 to 85 decibels by 5 to 10 decibels.
The boreholes in the nature reserve will be up to 400m apart and two holes will be drilled at any one time, in general. The diameter of each hole is about 10cm and each workspace will measure about 2m by 11m. Drilling of each hole takes about two weeks and the work will take six to nine months, said LTA.
Personnel doing the non-intrusive geophysical surveys, using gadgets such as gravity meters, will work with the National Parks Board to ensure minimal disruption to the environment, said LTA.
The boreholes do not mean the Cross Island Line’s alignment has been decided; site investigations are to gain understanding of soil and rock profiles and structural geology, so that risks can be managed for any tunnel construction in future.
The consultancy conducting the EIA, Environmental Resources Management, will also assess the impact of the proposed MRT line cutting through the nature reserve during the construction and operation phase – this will make up the second part of the EIA report and will completed by the end of the year.
The EIA will be one of the factors determining the Cross Island Line’s alignment, said LTA. Other factors include travel times, cost and impact on home and land owners. When the MRT line, scheduled to complete around 2030, was first announced in 2013, nature groups had expressed serious concerns that it would cut directly under primary and regrowth forests that were over a century old, and over the potential impact of surface works.
Their input was incorporated when LTA called the EIA tender, and a report setting out about 400 tree species, 200 bird species, 400 insect species and 150 species of mammals and amphibians has also aided the EIA consultants.
Senior Minister of State for Transport Josephine Teo thanked the nature groups for their efforts, and LTA chief executive Chew Men Leong said: “The findings from the engineering feasibility study and the site investigation will provide critical information to help the Government make a considered decision on the CRL alignment that best serves the public interest.”
The EIA (Phase One) report will be available for public viewing, by appointment, for four weeks.
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.
Melissa Zhu and Liyana Othman Channel NewsAsia 5 Feb 16;
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.
NON-INTRUSIVE METHODS PLANNED FOR SITE INVESTIGATION WORKS
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".
CLOSE CONSULTATION WITH NATURE GROUPS, OTHER STAKEHOLDERS
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 WELCOME EIA REPORT
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.
AN ALTERNATIVE TO THE EAST-WEST LINE
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.
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.
- CNA/mz
Cross Island Line: Site tests will be green
Audrey Tan and Adrian Lim, Straits Times AsiaOne 5 Feb 16;
Tests to see how a train tunnel through Singapore's largest and most important nature reserve can be built have been slated for the third quarter.
The impact on the animals and plants around the test sites can be kept to "moderate" levels, said the Land Transport Authority (LTA) yesterday without going into detail, citing the findings of an independent environmental study.
The study suggested several strategies to mitigate the impact to flora and fauna, including the use of enclosures to reduce engine noise, and tanks to collect discharge.
Still, nature groups told The Straits Times that "mitigation does not equal no impact".
The 50km Cross Island Line to link Changi and Jurong by 2030 was first announced in early 2013, and preliminary plans showed it cutting through primary and secondary forests in the Central Catchment Nature Reserve near MacRitchie Reservoir.
But nature groups, alarmed by the environmental harm which the construction and operation of an underground MRT line right across the heart of the reserve could cause, suggested that the line be built along Lornie Road. This alternate route goes around the reserve.
The decision on whether to build through or around the reserve is still being mulled over. But the LTA in 2013 did say that an environmental impact assessment (EIA) of the line on the reserve would be done.
The assessment's first phase, which includes looking at the potential impact of site investigation works, was carried out between August 2014 and last December by consultancy Environmental Resources Management.
Yesterday, the LTA gazetted the first phase of the EIA. "The report concluded that the proposed site investigation works, with the implementation of mitigating measures and controlled access, could be carried out with moderate impact on the few parts of the nature reserve where these works are to take place," it said.
The assessment also suggested alternative methods to collect data, so as to minimise the number of boreholes that need to be drilled within the nature area. Instead of drilling 72 boreholes, each of which is 10cm in diameter and stretches between 50m and 70m underground, only 16 will be needed to assess the soil and rock profile. The authorities will also use non-intrusive methods to find out about the soil and rock at the reserve.
In addition, the plan is to drill the boreholes only on public trails and clearings - which means that existing vegetation would not have to be cleared. In comparison, 250 boreholes will be drilled along the alternative route along Lornie Road.
Nature groups here welcomed the Government's efforts to check on the environmental impact of an MRT line in the reserve, which comprises pristine freshwater streams and the country's largest patch of primary lowland rainforest. It is also home to at least 413 species of plants, 218 species of birds, 30 mammals, 24 freshwater fish species and 17 species of amphibians.
Said Mr Tony O'Dempsey of the Nature Society (Singapore): "Our policy is that nature reserves should not be touched at all, as the impacts are cumulative, but the Nature Society is very happy to be involved in consultations with the authorities. We have some concerns on vibrations, noise and cave-ins, which we will discuss with the authorities during the next phase."
Wildlife consultant Subaraj Rajuthurai, who was also involved in the consultations with the authorities, said: "Acceptable impact is zero impact. All the other East-West systems, such as the current East-West MRT line or the Pan Island Expressway, have avoided tunnelling through the nature reserve.
"Although most of the work for the MRT line is underground, it could have a massive impact on the nature reserve, which is one of the most important nature areas for Singapore."
Phase Two of the EIA, which will be completed by the end of the year, will study and assess the potential environmental impact on the reserve arising from the construction and operation of the Cross Island Line for both routes.
The EIA findings will be one of the factors used by the authorities to decide on the final alignment of the Cross Island Line. Other factors include connectivity, travel times, costs and impact on home and other land owners.
When queried, Mr Sim Cheng Hai, director of policy and planning at the National Parks Board (NParks), said site investigation works are potentially impactful.
He said: "This is why NParks has worked with LTA to mitigate the potential impact of the site investigation on the Central Catchment Nature Reserve, such as reducing the number of boreholes for the Cross Island Line site investigation, defining areas which are off-limits and providing staff to monitor the works in the geophysical survey."
Related links
Love our MacRitchie Forest: walks, talks and petition. Also on facebook.