KENNETH CHENG Today Online 2 Sep 19;
SINGAPORE — The authorities are inviting public feedback on two proposed construction choices for the future Cross Island Line.
This is after the second stage of a report assessing the environmental impact of building Singapore’s eighth MRT line was gazetted on Monday (Sept 2). Gazetting allows public inspection of the report and feedback on its findings.
The Cross Island Line — which is set to run from Changi to Jurong and is expected to be opened in 2029 with 12 stations first — can either run directly under the Central Catchment Nature Reserve or go around it. It would take a longer route and be more costly to build if it skirts around the reserve.
However, both are feasible options when done with comprehensive mitigating measures and monitoring plans, the latest environmental-impact assessment found.
How will it affect the nature reserve or residents living around the train line? Here is a rundown of the key points to note.
OPTION 1: CUTTING BENEATH THE NATURE RESERVE
This option of direct tunnelling will mean that 4km of the route will run beneath the Singapore Island Country Club’s Island Golf Course, Central Catchment Nature Reserve and Pan Island Expressway. Of this, 2km will be under the reserve.
The tunnel will be built about 70m below average ground level, or around the height of a 25-storey public housing block. This will be the deepest MRT tunnel in Singapore.
On average, underground MRT tunnels are built at less than half that depth, at about 30m.
With this option, trips from Bright Hill Station in Sin Ming to the next yet-unnamed stop in the second operational phase of the Cross Island Line will take about five minutes.
Two above-ground work sites will have to be built away from the nature reserve, along Island Club Road and to the west of the reserve.
What are some of the ecological effects from this option?
Loss of habitat: The report found that, before mitigating measures are taken, the impact on species at both worksites would be major owing to the loss of vegetation and habitat resources. This is because 1.5ha of forested land would have to be cleared, with 1.2ha to be replanted after construction.
Mitigating measures will include surveys to identify flora species that can be conserved or salvaged for relocation, and wildlife shepherding.
These will reduce the residual impact to “moderate”, meaning the effects are “around the existing conditions” or accepted standards, or both.
Breaking up habitats: Clearance and construction activities were also assessed to have a potentially major impact in breaking up habitats at the Island Club Road worksite and a moderate impact at the site to the west of the reserve.
Mitigating measures will include setting up artificial crossing aids such as poles and rope bridges designed for creatures that live among trees such as the Malayan colugo, a gliding mammal, and the Raffles’ banded langur, a monkey, to help lower the impact to moderate levels.
Threats from vehicular traffic: Wildlife facing the risk of increased injury or death from being struck by vehicles was also assessed to be major.
Enforcing speed limits along Island Club Road and designing hoardings that take into account the context of the site will reduce these effects to moderate.
In summary: Aside from the ecological impact, other effects include those that relate to the environment such as ambient noise and air quality. In all, with mitigating measures, the impact across all factors will be lowered to moderate or minor, from moderate to critical levels.
OPTION 2: SKIRTING AROUND THE NATURE RESERVE
This option to build tunnels skirting the reserve would create a 9km route. These would be built at around 45m below average ground level.
A government estimate in 2016 showed that it would cost about S$2 billion more to go with this choice.
With this option, commuters will take a longer travelling time of 11 minutes from Bright Hill to the next station in the second operational phase of the Cross Island Line.
Three above-ground worksites will have to be built. The first worksite will be near Lakeview estate and the other two are along Lornie Road as well as between Adam Drive and the Pan Island Expressway.
An international panel of advisers on tunnelling and underground construction cautioned that the risk of incidents — tunnelling works could cause damage and cracks to buildings, for example — is higher for this option than for the first option, because of the “concentration of facilities including infrastructure and occupied buildings”.
With measures in place though, the panel said that the tunnels can be built to an “acceptable level of risk” — meaning there will be no adverse impact on buildings. These include using tunnel-boring machines suitable for specific ground conditions, and closely monitoring the machines' sensors and adjusting operational parameters.
What are some of the environmental effects of this option?
Ambient noise: Before mitigating measures, the noise impact on nearby residences was assessed to be moderate at the site along Lornie Road during night-time construction activities.
However, the impact is major for activities done at night at the worksites near Lakeview estate and between Adam Drive and the Pan Island Expressway. After rolling out measures, such as building noise barriers, minimising vehicular movement and the number of equipment running at night, the impact drops to moderate.
Views from homes: Despite mitigating measures, such as noise barriers designed to be as visually compatible to the surroundings, residents at three high-rise blocks in Lakeview estate along Upper Thomson Road are expected to be beset by major “visual disamenity” resulting from the worksite there. This means residents would see the worksite during the estimated five-and-a-half years of construction.
Air quality: The impact of elevated dust from earthworks at the worksites on nearby residences would be major. But measures including promptly cleaning up earth spillage on haulage routes and continuous monitoring of dust levels will bring this down to moderate.
Impact in other areas, including disturbance to wildlife and loss of habitat, is expected to be moderate or minor.
WHAT’S NEXT?
The public has a month to provide its views on the report, which is on the LTA website. Members of the public may, for instance, suggest other measures to reduce the negative impact of the two options. These will be considered before a decision is made by the authorities.
Advanced engineering studies for both alignments will likely begin next year. That is also when construction starts on the first stage of the MRT line, comprising 12 stops from Aviation Park in Changi to Bright Hill in Sin Ming.
The Cross Island Line, which will have about 30 stops, will be built in stages. When fully completed by about 2030, it will be Singapore’s longest underground train line at 50km to 60km long.
It is expected to carry more than 600,000 commuters daily in its initial years, with the number eventually hitting more than one million.
Cross Island Line: Environmental impact can be ‘adequately managed’ for both alignment options being considered, study finds
KENNETH CHENG Today Online 2 Sep 19;
SINGAPORE — The environmental impact of the two underground alignment options for the Cross Island Line (CRL) can be “adequately managed” with comprehensive mitigating measures and monitoring plans.
This was the conclusion of the second phase of an environmental-impact assessment on the potential effects from building and running the MRT line for both alignment options.
The Government had earlier said it is deciding between two alignment options for the CRL — one that runs beneath the Central Catchment Nature Reserve, and another slightly longer route that skirts around the nature reserve, which would cost S$2 billion more (based on a government estimate in 2016) and increase travel time by six minutes.
On Monday (Sept 2), the Land Transport Authority (LTA) gazetted the report on the assessment and the public has a month to give its feedback.
LTA has said that it will decide on the alignment based on factors such as connectivity, travel times, costs, and the impact on homeowners and the environment.
While the latest environmental-impact assessment will support decision-making on the alignment, LTA stressed that it has not reached a decision yet.
Advanced engineering studies for both alignment options are likely to begin next year, even as construction starts on the first stage of the line from Aviation Park in Changi to Bright Hill. This first phase is expected to be completed by 2029.
The CRL, which will be Singapore’s eighth MRT line, is due to be completed by about 2030.
ABOUT THE STUDY
Environment consultancy Environmental Resource Management (ERM) carried out the second phase of the assessment. It concluded that mitigating measures were expected to reduce the potential impact of construction work.
It ranked the impact assessment based on a matrix comprising a range of indicators: Negligible, minor, moderate, major and critical.
Major impact, for example, means effects of a large magnitude will occur to highly valued or sensitive subjects, including people and flora and fauna. Moderate impact means the effects are “around the existing conditions” or accepted standards, or both. Minor refers to a “noticeable effect”.
OPTION 1: PASSING UNDER THE NATURE RESERVE
On the 4km alignment option that runs beneath the nature reserve, ERM assessed that with mitigating measures, the impact will generally be lowered to moderate or minor, from moderate to critical levels.
These measures, which apply to both alignments, include a 30m buffer for worksites in areas connected to natural streams, wildlife shepherding, and replanting native species after construction works are completed.
There will also be measures specific to the option that tunnels through the nature reserve at about 70m below average ground level, the deepest for an MRT tunnel.
These include monthly water sampling of the stream in Windsor Nature Park, which is linked to the nature reserve, and monitoring vibration at selected locations on the surface before tunnel boring.
The impact is expected to be confined largely to parts of the tunnel alignment and the construction worksites. The direct-alignment option has two worksites away from the nature reserve along Island Club Road and to the west of the reserve.
For example, the residual impact of the direct alignment is expected to be moderate in areas such as:
Loss of vegetation and habitat resources.
Fragmentation of habitats.
Disturbance to wildlife.
Injury or death of wildlife due to more vehicle movements at the worksites.
OPTION 2: SKIRTING AROUND THE NATURE RESERVE
The other alignment option will be 5km longer, given that it skirts around the nature reserve, with three worksites near Lakeview estate, along Lornie Road, and between Adam Drive and the Pan Island Expressway.
Tunnel works will be about 45m below average ground level along the 9km alignment.
Skirting around the nature reserve would also mean commutes between Bright Hill Station in Bishan and the next stop, which has not been disclosed, will take 11 minutes, instead of five if the line were to pass under the nature reserve.
An extra mitigating measure for this alignment option is to document historical and genealogical information of all graves within the worksites and tunnels’ footprint, and within a 15m buffer of its tunnel and one of three worksites.
ERM concluded that there would be “major” residual impact on “visual amenity” for high-rise residents at the worksite near Lakeview estate. This means residents of three high-rise blocks there can see the worksite during the estimated five-and-a-half years of construction.
Impact in other areas, however, is estimated to be moderate or minor.
Those of moderate impact include:
Disturbance due to noise at all above-ground worksites.
Disturbance or health effects from dust generated by earthworks or the movement of construction equipment at the worksites.
Fragmentation of habitats.
Injury or death of wildlife.
NATURE SOCIETY: BOTH OPTIONS ‘FEASIBLE’
The 50 to 60km CRL — which will run fully underground from Jurong to Changi — has been intensely debated since plans for the line were announced in 2013.
Nature enthusiasts, who were first approached by the LTA for discussions in June 2013, were against the rail line cutting under the nature reserve, owing to potential damage to its fragile ecosystems and extensive wildlife.
But Dr Shawn Lum, president of Nature Society (Singapore), a non-profit, told TODAY that based on the latest environmental-assessment report, both options appear feasible and would present minimal impact to biodiversity.
Yet he noted that both alignments would have some immediate impact on the surrounding habitats, where rare species including the Sunda pangolin have been spotted.
The question was how comparable the impact from the two alignments would be, and this was important for those who will eventually decide on the alignment.
“How do we make these environmental-impact-assessment findings as comprehensible to a non-specialist as possible?” asked Dr Lum, who is also a senior lecturer at the Nanyang Technological University’s Asian School of the Environment.
For instance, will the impact on a certain animal species be the same at two worksites, or be greater because of higher sensitivity at one or more of the worksites, he asked.
The key, Dr Lum said, was to present a fair representation of the potential impact, so that the decision-makers will have a “full, holistic” picture of both alignments, while balancing these with other considerations.
Cross Island Line environmental impact on nature reserve can be 'adequately managed': LTA study
Aqil Haziq Mahmud Channel NewsAsia 2 Sep 19;
SINGAPORE: The environmental impact of both proposed routes for the Cross Island Line (CRL) near the Central Catchment Nature Reserve (CCNR) can be “adequately managed” with “comprehensive” mitigation and monitoring plans, a study commissioned by the Land Transport Authority (LTA) has found.
The direct route involves building a 2km tunnel about 70m deep under the CCNR, worrying green groups who want Singapore’s wildlife and nature preserved.
The other route is a 9km stretch going around the reserve and under homes and businesses, increasing end-to-end travel time by about four minutes. This option adds an estimated S$2 billion in costs, and the Government said it may also need to acquire land.
Both routes will not involve surface works in the nature reserve. The direct route will have two worksites outside the CCNR, while the skirting route will have three worksites outside the CCNR, one of which will be located next to a residential estate on Upper Thomson Road. The worksites will be converted to permanent facility buildings for the CRL.
LTA said in a statement on Monday (Sep 2) that the expected environmental impact of both routes is “largely confined” to parts of the tunnel and construction worksites outside the CCNR, adding that this can be managed by “robust” mitigation measures, citing the study.
“This can be achieved through locating the worksites as far as possible from the CCNR and the implementation of a comprehensive Environmental Monitoring and Management Plan (EMMP) to protect flora and fauna,” it stated.
“This EMMP will also help to mitigate any disamenities to nearby residents.”
An independent panel of international advisers, comprising industry experts in tunnelling and underground construction, has also reviewed engineering schemes for both routes and concluded that tunnelling along both options is safe with control measures in place.
These findings are part of the second phase of the Environmental Impact Assessment (EIA) for the underground stretch of the CRL near the CCNR. The first phase, completed in February 2016, had evaluated the environmental impact of site investigation works in the CCNR.
However, LTA has not made a decision on the final route of the CRL.
“In addition to the EIA findings, the Government will consider other factors, such as transport connectivity, travel times, costs and impact on home owners and commuters, when deciding on the final route of the CRL,” it added.
LTA has not set a timeline on when it will make a decision on the final route. The public can give feedback on the report for one month, before LTA starts advanced engineering studies on one or both routes next year, a process that can take two years.
“LTA will mitigate the environmental impact of the chosen alignment, and put in place a robust EMMP as laid out in the EIA report,” the agency said. “The EMMP will also be further assessed and strengthened as the project progresses.
The CRL, a roughly 50km fully underground MRT line with about 30 stations spanning Jurong to Changi, is expected to open in 2030. Commuters are expected to make at least 600,000 trips daily on the CRL, more than the existing North-East Line.
It will also connect existing radial MRT lines with almost half of its stations being interchange stations, and is part of a plan to almost double Singapore's rail network by 2030 and put eight out of 10 households within a 10-minute walk of a train station.
IMPACT OF DIRECT ALIGNMENT
For the direct route, the impact to people during the construction phase includes an impact on nearby water resources and noise pollution to Windsor Park residents due to construction activities, the study found.
The study noted that this impact can be reduced to “negligible to minor” significance with mitigation measures like the diversion of water discharge points from the worksites to drains that are not connected to nearby streams, and the installation of visually compatible noise barriers.
The impact on plants and animals during the construction phase include the clearing of forest habitats and impact on a stream system within Windsor Nature Park due to sedimentation during construction, the study found.
The study noted that this impact can be reduced to “moderate” significance with mitigation measures like shepherding wildlife and erecting barriers during worksite clearance, and artificial crossing aids to reduce the impact of habitat separation.
The study added that the residual impact of vibration at the surface of the CCNR during tunelling works can be reduced to negligible through the monitoring, assessing and reviewing of vibration in advance of the works. This will allow the implementation of further mitigation measures to reduce vibration levels to below background levels.
The impact during the operation phase include an impact on surface water bodies due to an increase in surface runoff from the permanent facility buildings, and the potential risk of wildlife changing their behaviour and getting trapped in the buildings, the study found.
The study noted that this impact can be reduced to “moderate” significance with mitigating measures like the “sensitive design and location” of the buildings and proper removal of roosts found within their premises.
According to the study, a “moderate” significance indicates “small effects” that are comparable to existing conditions and/or accepted standards.
IMPACT OF SKIRTING ROUTE
For the skirting route, the impact on people during the construction phase will include increased dust around the worksites and increased noise levels during night-time works, the study found. High-rise residents near Upper Thomson Road will also have a view of the construction work.
The study noted that this impact can be reduced to “moderate” significance with mitigation measures like the installation of visually compatible noise barriers and advanced notification of tunnelling operations to affected residents.
However, the study pointed out that the residual impact will remain of “major” significance for high-rise residents in three blocks overlooking one of the worksites.
The impact on plants and animals during the construction phase will include worksite clearance and construction works, the study found, adding that the ecological impact at one worksite is negligible due to its highly urbanised location.
It noted that this impact can be reduced to “moderate” significance with mitigation measures like shepherding wildlife and erecting barriers during worksite clearance and the enforcement of speed limits along access roads.
The impact during the operation phase would be similar to that in the direct route option, the study found, adding that the impact can be reduced to “moderate” significance with similar mitigation measures.
NATURE GROUP “HAPPY” LTA COMMITTED TO MITIGATION MEASURES
Nature Society Singapore president Shawn Lum said he is “happy” that LTA is committed to implementing the proposed mitigation measures, adding that the agency had met members of the nature community over several “deep dive” sessions since June 2013.
“We sought to highlight potential environmental impacts as accurately and objectively as possible, with everyone committed to ensuring that the diversity and ecological integrity of CCNR is not impaired,” he stated.
“Finding a way to carry out vital infrastructure work without diminishing our precious natural heritage remains important common ground to all of us.”
Source: CNA/hz
Feasible for Cross Island MRT Line to run under Central Catchment or skirt around it: LTA impact study
Toh Ting Wei Straits Times 2 Sep 19;
SINGAPORE - The future Cross Island MRT line that will run from Tuas to Changi can either run under the Central Catchment Nature Reserve or go around it.
Both options are feasible with adequate mitigation measures, said the Land Transport Authority (LTA), which has completed a major study of the potential impact of construction works on the environment and residents. Skirting the reserve would make for a longer route and is also the more expensive option.
If the final decision - expected some time next year - is to build through the reserve, tunnelling will be done 70m underground.
The LTA's latest findings were announced in the Environment Impact Assessment (Phase 2) report.
The report was commissioned by the LTA, with the research conducted by consultancy Environmental Resource Management (ERM).
LTA said: "Based on the report, both underground alignments are feasible, and the residual impacts are largely (negligible to) moderate.
"LTA is committed to undertake all necessary mitigation measures to minimise the potential environmental impact."
It said that no decision has been made on the alignment.
But an independent panel of advisers engaged by the LTA said the skirting alignment would result in greater risk of safety-related incidents as compared to the direct alignment.
The Cross Island Line (CRL), Singapore's eighth MRT line, is projected to have an initial daily ridership of 600,000. The number is expected to eventually grow to one million.
The first phase of the line is expected to be completed by 2029 and will span 12 stations from Changi to Sin Ming.
Nature groups have said that any plan to build part of the second phase of the line through the Central Catchment would damage the nature reserve and affect the biodiversity there.
But residents, such as those in the Thomson area, say the alternative option to skirt around the nature reserve would affect their lives and their homes.
The Government has also said the skirting option could cost an additional $2 billion.
LTA's report on Monday stated that the option to build a direct alignment option would create a 4km route with 2km under the reserve. This would be built 70m below average ground level - roughly the height of a 25-storey Housing Board block.
It would also require the construction of two work sites and proposed facility buildings outside of the nature reserve.
This route would allow trips between the last station of the second phase of CRL and Bright Hill station, the first station from the first phase of the line, to be completed in five minutes.
The implementation of mitigation measures would reduce the impact of construction on the ecology and biodiversity in the Central Catchment Nature Reserve to negligible levels, said LTA.
At the work sites, which are located outside the nature reserve, the impact on the two factors would range from negligible to moderate.
Meanwhile, the option to build a skirting tunnel would create a 9km route. This would be built at 45m below average ground level, a safe level for existing buildings based on current construction standards.
It would require the construction of three work sites and facility buildings in open spaces away from residential areas.
The skirting route would result in a longer travelling time of 11 minutes from Bright Hill to the same next station. The LTA said based on the planned route for the skirting, it would not be feasible to build an additional station along this 11-minute stretch.
The construction in this case would cause residents issues such as groundborne vibration, poorer air quality and ambient noise. But the impact of these issues can also be mitigated from negligible to moderate levels, said LTA.
Some residents near Lakeview Estate and Upper Thomson Road, where a work site would be set up in case the option is chosen, might however have the view of their surroundings affected.
Nature Society Singapore president Shawn Lum said engagement with LTA on the issue is ongoing.
He added: "Finding a way to carry out vital infrastructure work without diminishing our precious natural heritage remains important common ground to all of us.
"I am happy that the LTA is committed to implement the proposed mitigation measures proposed."
The public will be able to read the report at LTA's website.
The report will be open to public feedback for a month, and all relevant feedback will be considered by the LTA before a decision is made on the issue.
Mitigation measures can cut wildlife impact of running Cross Island MRT line under nature reserve: LTA
Audrey Tan Straits Times 2 Sep 19;
SINGAPORE - Tunnelling under Singapore's largest nature reserve to build the Cross Island MRT line would call for 3ha of forests next to the reserve - the size of four football fields - to be cleared, which could mean loss of habitat for critically endangered wildlife.
But if mitigation measures are carried out - such as if trees are re-planted in the affected areas, or security fences made "wildlife-friendly" - the impact of the upcoming train line on the Central Catchment Nature Reserve could be reduced, the Land Transport Authority said.
This was a key finding of a lengthy environmental impact assessment report for the Cross Island Line which the LTA released on Monday (Sept 2).
The LTA-commissioned report had looked at how the construction and operation of the upcoming Cross Island Line could affect the reserve, and the plants and animals which call it home.
Even though the line may go 70m under the reserve, two structures at ground level are needed for ventilation, if the authorities opt for the MRT line to run under the reserve, rather than skirting it.
These plots are outside reserve boundaries, but levelling them would result in the loss of habitat for critically endangered wildlife such as the Sunda pangolin and Raffles' banded langur, and increase the likelihood of these animals being disturbed or injured by traffic during construction, said the report.
Despite the "major" impacts that the construction and operation of the Cross Island Line could have on the ecology and biodiversity of the reserve, these could be reduced to "moderate" or even "negligible" depending on the worksite, provided that mitigation measures to reduce impact are carried out.
The report, which is almost 1,000 pages long and done by consultancy Environmental Resources Management, detailed a few such strategies.
It suggested that to reduce the impact of construction works on wildlife, re-planting could reduce habitat loss, while installing rope bridges and poles could help canopy-dwelling species get from one forest patch to another.
Diverting discharge outlets away from rare freshwater streams could also help to reduce pollution of the aquatic habitats.
In terms of reducing the impact of the tunnel operations, the report said that other than wildlife-friendly fences, roosts and nests identified during inspections could be removed with the aid of the National Parks Board.
DETERMINING IMPACT
Whether a development could have "major", "moderate", "minor" or "negligible" impacts on the surrounding environments depends on two key factors.
The first is the sensitivity of the habitat.
To determine this, consultants look at factors such as if the habitat falls within a designated nature area, or if it is important for endangered wildlife species.
In this case, both work sites were considered by consultants to comprise highly sensitive habitats, as the globally threatened Sunda pangolin has been found in them, even though the work sites fall outside the boundaries of the Central Catchment Nature Reserve.
The second factor looked at is the magnitude of the impact.
Again, whether this is large, medium, small or negligible depends on a few factors, including the proportion of the area affected, or the extent of impact on a species population.
For example, large impact magnitudes are classified as such if the works are deemed to affect the entire habitat or a significant proportion of it, or if the works could cause a substantial decline in abundance.
Both factors - sensitivity of area affected and impact magnitude - are considered in the evaluation of the final impact magnitude.
For both work sites, habitat loss was considered to have medium impact magnitude. Taking into account that the area is highly sensitive, the overall impact significance was deemed major.
However, the report said that mitigation measures can reduce the impact magnitude to small, bringing down the overall impact significance to moderate.
Examples of mitigation measures that could aid in this reduction include wildlife shepherding, re-planting of trees, and the translocation of plant species of conservation interest.
National University of Singapore biology lecturer N. Sivasothi said that even with the mitigation measures, it was a "big jump" to say that reduction in impact would be reduced from "major" to "moderate".
"The scale makes the impact sound benign. This is a big problem which the community and the Government needs to review," he said.
The Cross Island Line would link Changi and Jurong by 2030, and span at least 50km.
It was first announced in early 2013, and preliminary plans showed it running under 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 under or around the reserve is still being mulled over, and an environmental impact assessment of the line for both alignments was done.
The latest study had found that for the skirting alignment, there would be “major” residual impact for residents due to “visual” elements – such as activities at above-ground worksites and the presence of workers.
The alternate route would also involve above-ground works in wildlife-rich areas in the vicinity of Lornie Road and Bukit Brown, said the report.
However, it noted that the impact could be reduced to “moderate” with mitigation strategies similar to those on the direct alignment.
Wildlife consultant Subaraj Rajathurai, whom LTA had consulted for the project, noted that these areas on the skirting alignment were home to wildlife such as the Sunda pangolin and common palm civet.
However, these animals are more widespread compared to “forest specialists” – animals that live only in good forests, such as the Raffles’ banded langur and the lesser mousedeer – which can be found in the forested plot east of the nature reserve which would have to be cleared if the line is built there.
“The eastern node of the direct alignment is the area with threatened forest specialists, and impact there should be higher than moderate,” said Mr Subaraj, who has been studying Singapore’s forests for decades.
“The skirting node at Bukit Brown has animals such as the colugo and pangolin, but these animals, while threatened, are more widespread and should not be compared to the node in the direct alignment,” he said.
The LTA had earlier said that the alternative alignment could add about $2 billion to the rail project. This 9km-long skirting alignment will require longer tunnels and extra ventilation facilities, it said, compared with the 4km direct route, of which 2km will run under Singapore's largest nature reserve.
No figure was available for the total cost of adopting mitigation measures should the direct alignment be chosen.
Related links
Give feedback to LTA plus links to the EIA.
