SINGAPORE - Site investigation works needed to determine how a train tunnel can be built under Singapore's largest nature reserve will have a "small" impact on the area , even though the reserve is deemed highly sensitive.
This is because stringent mitigating measures will be adopted, said Senior Minister of State for National Development Desmond Lee in Parliament on Monday.
This was the assessment of the environmental consultants hired to assess the environmental impact of preliminary works for the upcoming Cross Island Line MRT project on the Central Catchment Nature Reserve.
Mr Lee was responding to Non-Constituency MP Leon Perera, who asked how the Government intends to mitigate the impact of site investigation works preceding the construction of the MRT line.
Overall, the independent environment impact assessment (EIA) done by consultancy Environmental Resources Management has determined that investigation works in the area would have a "moderate" impact on plants and animals there, but only if measures to reduce impact are strictly implemented.
Otherwise, the soil investigation works could have a large impact on the highly sensitive parts of the reserve, which comprises primary rainforest with ecologically sensitive habitats.
Mr Lee said stringent mitigating measures, developed in close consultation with several representatives of nature groups and the National Parks Board (NParks), have been proposed.
They include the use of enclosures to reduce engine noise and tanks to collect any discharge.
Site investigation works to determine the geological properties of the area will be done through two methods - borehole drilling and geophysical surveys - Mr Lee told the House.
For the former, boreholes about 10cm in diameter will be drilled into existing trails to extract vertical columns of soil samples. Confining this to existing trails will prevent surrounding vegetation from being affected, he said.
Drilling machines will also be modified to reduce noise and prevent spillage of slurry and fuel.
To minimise damage and disturbance to the forest, 16 boreholes will be drilled, instead of the earlier estimate of 72, he added.
To make up for having fewer soil samples, less intrusive geophysical surveys will also be carried out to supplement data collected from the boreholes.
This would involve surveyors going off-trail into the forest to collect data using hand-held equipment, Mr Lee said.
Although such geophysical surveys are of "significantly lower impact" than borehole drilling, he added, there are still concerns that surveyors may inadvertently trample on plants on the forest floor as they move through dense vegetation.
To guard against this, said Mr Lee, the geophysical survey will be limited to a 100m-wide corridor and will not be carried out in sensitive locations such as streams, swamps and dense vegetation.
NParks officers will supervise the surveyors full-time to ensure they adhere to the strict rules for moving around in off-trail forested areas.
All site investigation activities will also be restricted to daylight hours, so as not to affect nocturnal animals, Mr Lee said.
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 construction and operation of an underground MRT line right across the heart of the reserve, suggested that the line be built around the reserve, along Lornie Road, to minimise environmental harm.
The environmental report has assessed that the impact of soil investigation works along Lornie Road would be "negligible", and "minor" for areas near Venus Drive and a golf course.
Further studies on the total impact of the MRT project are planned and will take four to five years to complete. A decision on the route of the Cross Island Line will only be made after the studies are done.
Biologist David Tan from the Love Our MacRitchie Forest volunteer group said Parliament has not adequately addressed the possibility of the mitigating measures failing, which would be a serious threat to the nature reserve.
"Also ignored is the principle of planning an infrastructural project through the nature reserve," he said
Tests with 'low impact' at nature reserve
Audrey Tan Straits Times 1 Mar 16;
The impact of tests needed to see how a train tunnel can be built under Singapore's largest nature reserve will be reduced to a level that is "as low as reasonably practicable", Senior Minister of State for National Development Desmond Lee told Parliament yesterday.
This will be done through adopting mitigating measures to reduce damage and disturbance, he said.
An environmental impact assessment had determined that site investigation works for the Cross Island Line will have a "moderate" overall impact on the Central Catchment Nature Reserve. Non-Constituency MP Leon Perera had asked how the consultants arrived at the conclusion.
Mr Lee said consultancy Environmental Resources Management had considered the sensitivity of the nature reserve and magnitude of the impact the work will have.
Referring to a table he distributed to MPs, he told the House that the reserve comprising primary rainforests with ecologically sensitive habitats is considered highly sensitive.
But the magnitude of impact of the investigation works will be "small", he said, as the Government will put in place mitigating measures.
Soil works are slated to start later this year to investigate the area's geological properties. Phase one of the environmental impact assessment had focused on the potential impact of this. Phase two will study the impact arising from the construction and operation of the MRT line that will link Changi to Jurong by 2030.
Mr Lee said the site investigation works will involve drilling boreholes about 10cm wide to extract soil samples, and geophysical surveys. Surveyors will go off-trail into the forest to collect data using hand-held equipment. Though it is less intrusive than the drilling, said Mr Lee, there are still concerns that surveyors may trample on plants.
He said stringent mitigating measures have been developed in consultation with nature groups and the National Parks Board. Among them:
• Geophysical surveys will be limited to a 100m-wide corridor and not be conducted in streams, swamps and dense vegetation
• NParks officers will be deployed to supervise surveyors
• 16 boreholes will be drilled instead of an earlier estimated 72
• Drilling will be confined to existing trails
• Drilling machines to be modified to reduce the noise level and prevent spillage of slurry and fuel
• Works will be done in the day to not disturb nocturnal animals
Studies on the total impact of the project may take more than two years to complete, and a decision on the route will only be made after.
Mr Louis Ng (Nee Soon GRC), who also raised questions on the issue, said he was glad options are being kept open. Nature groups have raised concerns that an MRT line running under the reserve would cause environmental harm.
Keep an open mind on Cross Island Line: Khaw
Adrian Lim, Straits Times AsiaOne 1 Mar 16;
The 50km Cross Island Line (CRL) will be an important part of Singapore's rail network, with about 30 stations - nearly all of them interchanges to other MRT lines - that will offer commuters many travel options, Transport Minister Khaw Boon Wan said.
Serving residential areas such as Loyang, Pasir Ris, Hougang, Ang Mo Kio, Sin Ming, Bukit Timah, Clementi and West Coast, commuters will make at least 600,000 trips on the CRL every day, he told Parliament yesterday.
But as to whether the underground CRL will be built through the Central Catchment Nature Reserve (CCNR) or route around it - an issue of contention - Mr Khaw said more environmental and engineering studies, along with public consultations, must be done.
These may take more than two years, before a decision on the alignment can be made, he added, in reply to questions from MP Louis Ng (Nee Soon GRC) about the CRL.
An Environmental Impact Assessment (EIA) report to study the effects of site investigation works, released last month, took two years.
Noting the CRL's importance, Mr Khaw said the line - to be completed by 2030 - will "significantly enhance" the MRT network's resilience, and its capacity and usage will far exceed that of the existing North-East Line.
Yesterday, he also revealed that the longer 9km skirt around the CCNR will incur an extra travel time of six minutes, compared with the more direct 4km route cutting through the reserve.
Suggesting that the public has high expectations of train efficiency, he quipped that in a minute of delay, a commuter could post 100 times on Twitter to "flame" the Land Transport Authority and the rail operator.
This extra six minutes could not just be "brush(ed) aside", he said.
While Mr Ng said the skirt-around alignment would serve more commuters, Mr Khaw replied that residents in the area are already served by the Circle Line and future Thomson-East Coast Line.
Additionally, he said this alignment would require longer tunnels and ventilation facilities on the surface. This would cost $2 billion more and could result in land acquisitions.
For the direct alignment option, 2km will be deep below the CCNR at about 40m - or 12 storeys - below ground level, and there will be no structures built at the surface level, the minister noted.
In a separate query, Mr Ng also asked for the total cost of the CRL project, and which houses and buildings will be acquired.
Mr Khaw replied that it was still too early to know these details, and a second phase of EIA, to look into the impact of construction and running of trains through the nature reserve, will be done.
He urged Singaporeans not to take a biased approach to the issue, adding that some comments on the first EIA were "very toxic".
Referring to the movie Zootopia he saw with his granddaughter, he said the film's protagonist, a female rabbit, had to fight off stereotypes and prejudices in her mission to be a police officer.
"Keep an open mind. I think go with the facts. Keep an open mind and look for the evidence," he said.
Related links
Love our MacRitchie Forest: walks, talks and petition. Also on facebook.