Singapore Cross Island MRT Line To Undergo Environmental Impact Assessment

The Singapore government is holding off its plans to run a new MRT line through a biodiverse nature reserve until a comprehensive assessment of environmental impacts has been made. Tan Hui Zhen and Shermaine Wong describe the role played by civic society and NGOs to effect the mindset shift.

Singapore, 22 March 2014. In January 2013, several days after the release of the population white paper which projected a 6.9 million population by 2030, the Ministry of Transport announced plans to expand Singapore’s rail network by 2030 to meet the growing ridership demands. This would be achieved through extensions of existing networks and the bold new additions of Cross Island MRT Line (CRL) and Jurong Region Line (JRL). 

Nevertheless, the proposed 50-km CRL spanning Singapore cuts through the Central Catchment Nature Reserve (CCNR), raising critical concerns among environmentalists in Singapore. This is the first time a nature reserve - accorded the highest legal protection in Singapore - has its boundaries transgressed.

Furthermore, the core area through which the line tunnels through includes some of Singapore’s last natural stream systems, primary lowland dipterocarp forests and mature regrowth forests. Significantly, these habitats are home to the more than half of Singapore’s residual native biodiversity. The new line is slated for completion in 2030. 

Alternative routes proposed to circumvent severe impacts to the CCNR. Source: Tony O’Dempsey

Alternative routes proposed to circumvent severe impacts to the CCNR. Source: Tony O’Dempsey


In response, Nature Society Singapore has released a position paper on this issue in July 2013 and alternative routes for the line were proposed (see diagram). Drawing upon the diverse expertise and knowledge of its members, the following key messages were highlighted in the paper:          

  • MacRitchie forest of CCNR carries unique floristic characteristics and is home to many forest-dependent native fauna species; any disturbances will be detrimental to the health of the entire forest ecosystem.

  • Regrowth forests in CCNR have recovered to a point where they support a whole range of native forest dependent fauna, thus secondary forests must be given the same degree of protection as primary forests.

  • Mitigation does not equate to no impacts. Any form of disturbances is undesirable.

  • Soil investigation works involving the creation of access roads and core drilling of 70m deep bores along the CRL alignment is likely to cause siltation, soil erosion, toxic pollution and forest fragmentation.

  • Ground borne noise and vibration is likely to result from hard-rock tunnelling during excavation through the CCNR and will affect the flora and fauna residing in the forests.

  • Nature reserve is not a vacant state land. It is critical to recognize the value of CCNR in providing critical ecosystems services and respect its conservation status. These intangible values should be considered in the project analysis and necessarily calls for a serious consideration of alternative routes to the CRL.

  • Construction of CRL through CCNR essentially deviates from the intended purpose of the nature reserve and violates the “public trust” conferred on the Government

Based on strong opposition from nature activists and civic groups such as NSS, the Land Transport Authority on 24 February 2014 called for a tender to assess the environmental impacts of the proposed line. Hydrology and geology experts are expected to be part of the EIA team. The EIA report is targeted for completion in 2016.

The Blue-eared Kingfisher, native to the Central Catchment Nature Reserve, will be in dire straits if waterways get polluted due to construction. Photo courtesy of Chloe Tan.

The Blue-eared Kingfisher, native to the Central Catchment Nature Reserve, will be in dire straits if waterways get polluted due to construction. Photo courtesy of Chloe Tan.


The potential impacts of the transport corridor through CCNR are highlighted by birdlife expert Dr Ho Hua Chew, one of of the core authors of the NSS Position paper.

“...opening up of the rail transect will invariably involve the clearing of obstructive  trees and undergrowth along the transect for implementation and maintenance purposes... species that are ground-moving, and also those more dependent on the undergrowth for food and nesting will be especially impacted severely by the intrusion of works (machinery noises and influx of workers) as well as any  alien features, temporary or permanent, erected along the transect in the deeper recesses of the forest, which are refuges for the shyer species,” he said.

According to Dr Ho, understorey dwellers like the Moustache Babbler, Orange-bellied Flowerpecker and Blue-winged Pitta will be particularly affected by investigation and construction works. Additionally, the survival of specialists of riverine and swampy habitats like the Blue-eared Kingfisher, or even species that uses the waterbodies in the catchment as foraging and bathing sites will be threatened if the forest streams are polluted. Many of these birds are not only forest-dependent species, but they are also critically endangered. Thus, Dr Ho asserts that the CRL must be diverted to the edge of the Nature Reserve along Lornie Road-Bt Brown Area or not be constructed at all.


Another instrumental figure in championing against the CRL cause was Chloe Tan, part of the Love MacRitchie campaign that was launched in response to the construction of the CRL. Love MacRitchie civic group hope that through their sharing of how special the MacRitchie Forest is to SIngapore, the public will find reasons to love it, and lend their voices to save it.

Part of the Love MacRitchie campaign includes guided walks at MacRitchie. According to Chloe, “the response has been pretty overwhelming”. Chloe also shared that the Toddycats (Nature and Environment Volunteers with the Raffles Museum of Biodiversity Research, NUS) conducted three walks last year, all of which were full with about 25 participants subscribing to each walk. This year, all five scheduled walks through 12 April were also fully subscribed. There are also other NGOs (e.g. Cicada Tree Eco-Place, NIE) and individuals (e.g. Subaraj Rajathurai, Tony O'Dempsey) who conduct walks, usually meant for enthusiastic nature lovers...

We asked Chloe what made her decide to take up the Love MacRitchie cause.“It is important to me that the boundaries of the Central Catchment Nature Reserve are not breached by developmental works because this would open the flood gates to further encroachment into our Nature Reserves in future … We know what we stand to lose if CRL runs its proposed course. I want to help prevent this tragedy from happening.”

Having done her university honours project on the diversity of small mammals in different types of forests in Singapore, Chloe found that native species such as the Singapore Rat (Rattus annandalei) and Common Treeshrew (Tupaia glis) are only doing well in and around the mature forests of the Central Water Catchment. She also observed that regenerating forest patches elsewhere are dominated by introduced urban pests like the Asian House Rat (Rattus tanezumi) and Asia House Shrew (Suncus murinus). Postulating that this could very well be the case for other groups of animals, she added that “any disruption to the already heavily impacted and delicate habitats of the Nature Reserves would be costly to native biodiversity”.

Finally, we asked Chloe about the future direction of this campaign.

How about a walk guided by Love MacRitchie group to discover Singapore's wildlife? Picture by Shermaine Wong.

How about a walk guided by Love MacRitchie group to discover Singapore's wildlife? Picture by Shermaine Wong.

“Love MacRitchie will continue to be active until a decision is made by the LTA about the alignment of CRL. This should be in about two to three years, after the Environmental Impact Assessment is complete. The emphasis on this campaign is on raising awareness and celebrating the rich biodiversity of our nature reserve. A lot of our advocacy efforts are focused on the younger generation as they will be the ones to bear the brunt of the government's decisions today,” she said.

“In the long run, regardless of the government's decision, I foresee that Love MacRitchie will continue to hold events to commemorate and advocate the protection of our forest reserves. And it is our hope that through this experience, biodiversity and environmental awareness is mainstreamed as a consideration for future urban development in Singapore.”

Keen to be part of the movement to keep this forest reserve intact? Find out more about Love MacRitchie at

Images courtesy of Tony O'Dempsey, Chloe Tan, Shermaine Wong and Nick Baker.

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About the authors:

Tan Hui Zhen hails from the island city-state Singapore. She majors in Environmental Geography at the National University of Singapore and is interested in environmental conservation, natural resource management and sustainability issues. She hopes to learn scuba-diving and explore the colourful underwater world of our blue planet.

Shermaine Wong is based in Singapore. She has a fascination with both the built and natural environment. She is an Environmental Studies undergraduate majoring in Environmental Geography and minoring in Aquatic Ecology. Her interests are in reading, writing, photography and travelling. One of her life goals is to produce an environmental documentary. 

Edited by Mallika Naguran