The Land Transport Authority has just released a report on the second phase of the Environmental Impact Assessment (EIA) for the stretch of the underground Cross Island Line (CRL) in the vicinity of the Central Catchment Nature Reserve (CCNR).
Back in 2013, the Cross Island Line (CRL) was announced, a new 50km long train line that to “improve the connectivity, accessibility and coverage fo the rail network” in Singapore. It is targeted to be completed by 2030.
When the EIA for the first phase of the project was released, the assessment projected a “mainly moderate” impact if mitigation measures were taken. However, nature groups rallied to ask for more information on the EIA, as they worried about the impact this project would have on Singapore’s last remaining primary forest.
Even as debates flurried, LTA commenced soil investigation works to help inform Phase 2 of the EIA, this time looking specifically at the two different alignment options that were of most concern to nature groups – a direct route building a 4km tunnel underground, with 2km of it going under the CCNR or a route that skirts around the CCNR requiring about 7km of tunnels under roads and residential and commercial buildings.
In a statement, the LTA said that the report found that environmental impact of both proposed routes for the Cross Island Line (CRL) near the Central Catchment Nature Reserve (CCNR) “feasible” and that with the “comprehensive” mitigation and monitoring plants, the residual impacts can be “adequately managed”.
It added that an International Panel of Advisors (IPA) comprising industry experts in tunnelling and underground construction which reviewed the engineering schemes for both underground alignment options concluded that tunnelling along either underground alignment option is safe so long as control measures are in place.
The EIA on Alignment 1 – tunnelling under the CCNR
According to the report, impact during the construction phase on the loss of vegetation and habitat was assessed to be “major” as the construction would involve the clearance of 1.5 ha of forested land, though 1.2 ha of which will later be replanted. With additional mitigation measures such as transplantation of flora and shepherding of wildlife, the residual impact will be reduced to “moderate”.
As for habitat fragmentation, the pre-mitigation impact was assessed to be “major” at the first worksite and “moderate” at the second. However, additional mitigation will bring down the impact at the first worksite to “moderate”.
It was also assessed that construction would have a “major” impact in terms of disturbance to wildlife. Again, implementation of mitigation measures is expected to reduce the residual impact significance to “moderate”.
In terms of aquatic habitat, it was found that the impact would be “critical” and mitigation measures such as prohibiting discharges into drains and having regular inspections as well as removing the pathway between the worksite and streams would bring that down to “negligible”.
As for the impact of the CRL during the operation phase, it was found that pre-mitigation impact to the ecology and diversity would be “major” unless additional mitigation measures are employed. Those would bring the impact down to “moderate”.
The EIA on Alignment 2 – tunnels skirting around the CCNR
For the assessment of the second route option, the EIA found that impact on loss of vegetation and habitat resources during the construction phase would be “major” for species at two worksites and “moderate” for habitat at one of them.
Similar to the first option, about 1.5 ha of forested land would be cleared, 1.2 ha of which would be replanted after construction is completed. Additional mitigation measures expected to reduce those levels to “moderate”, or “as low as reasonably practicable”.
The report also noted that the disturbance to wildlife from construction activities was assessed to be “major”, though this could be brought down to “moderate” if additional mitigation measures are implemented.
As for impact during the operation phase, the report found that there would be “major” impact in terms of ecology and diversity. But again, this can be reduced to “moderate” with the right measures.
The report concluded that the no residual impacts associated with the first option were identified as “major” during the construction phase, adding that the impact during the operation phase was considered to be “moderate”.
Meanwhile, for the second route alignment, the residual impact on visual amenities for high-rise residents with additional mitigation measures was assed to be “major” while the residual impacts on the environment were considered to be “moderate” during both construction and operation phase.
The report stated that further baseline surveys will be undertaken at the worksites for both alignments during the AES stage of the project though it is not anticipated to significantly change the finding within this Phase 2 EIA report apart from additional refinements to the mitigation measures and monitoring plans.
In LTA’s statement, President of Nature Society Singapore Dr Shawn Lum was quoted as saying, “The conversation between the LTA and nature groups has been a careful, considered, and cordial one. Over several “deep dive” sessions, we looked through potential impacts and proposed mitigation measures for construction along either of the two proposed CRL alignments.”
“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 added.
“I am happy that the LTA is committed to implementing the proposed mitigation measures proposed. We have had our questions and concerns heard, and look forward to the continuing conversation.”
LTA asserted in their statement that the decision on the alignment option for the CRL in the vicinity of the CCNR has not been made. The decision will be made after considering other factors as well.
The authority added that it “will mitigate the environmental impact of the chosen alignment, and put in place a robust EMMP as laid out in the EIA report”, adding that no surface works within the CCNR will be carried out should either underground alignment is chosen.