SINGAPORE - When soil investigation works for the upcoming Cross Island MRT line start in the Central Catchment Nature Reserve in the third quarter of 2016, there will be measures in place to reduce their impact on the plants and animals in the Republic's largest nature reserve.
Among the mitigation strategies revealed by the Land Transport Authority (LTA) on Friday are plans to use enclosures to reduce engine noise and tanks to contain discharge.
Alternative methods have also been proposed to collect ground data, so as to minimise the number of boreholes that will have to be drilled within the sensitive nature areas.
Instead of 72 boreholes to assess the soil and rock profile and structural geology, the number has been reduced to 16. Roughly 10cm in diameter, they will go between 50m and 70m underground, and the plan is to drill the boreholes only on public trails and clearings - which means that existing vegetation would not have to be cleared.
Nature groups here welcomed the Government's efforts to evaluate impact and make informed decisions about the alignment of the MRT track. But although mitigation plans were included, they told The Straits Times that "mitigation does not equal to no impact" - especially when there is an alternative route.
The Cross Island Line was first announced by the Government in early 2013, and preliminary plans showed it cutting through primary and secondary forests in the Central Catchment Nature Reserve near MacRitchie Reservoir.
Nature groups here have suggested instead that the line be built along Lornie Road - a route that goes around the reserve - instead of through it.
The Central Catchment Nature Reserve is the country's largest patch of primary rainforest. It is home to at least 413 species of plants, 218 species of birds, 30 mammals, 24 freshwater fish species, and 17 species of amphibians.
The planned soil investigation works will help the LTA assess both routes and determine if the ground is suitable for tunnel construction.
The effort to reduce the impact of soil investigation works on the surrounding nature areas - including parts of Singapore's last remaining patches of primary rainforest - were part of the findings from the first phase of the Environmental Impact Assessment (EIA) commissioned by the LTA, with input from the nature groups in Singapore.
This phase, undertaken by Environmental Resources Management from August 2014 to December 2015, included a baseline study on the existing ecosystem and the physical conditions of the Central Catchment Nature Reserve in the vicinity of the two proposed Cross Island Line alignments.
The next phase of the EIA will study and assess the potential environmental impact on the Central Catchment Nature Reserve arising from the construction and operation of the Cross Island Line.
The findings from the EIA, the second phase of which will be completed by the end of 2016, will be one of the factors used by the authorities to decide on the route taken by the Cross Island Line.
Other factors include connectivity, travel times, costs and impact on homes and other land owners.
Said LTA chief executive Chew Men Leong: "Since the announcement of the Cross Island Line in January 2013, we have worked closely with nature groups, the National Parks Board, and engineering experts to study the best way to conduct site investigation works in the vicinity of Central Catchment Nature Reserve.
"We have incorporated the valuable views and suggestions of the nature groups in the report. 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 CL alignment that best serves public interest."
The EIA (Phase 1) report will be available for public viewing, by appointment only, at Land Transport Authority, 1 Hampshire Road (Blk 11 Level 4, Room 2), Singapore 219428, for four weeks from Feb 5. To view the report, please contact Ms Michelle Chan (email LTA_CRL_CCNR_EIA@lta.gov.sg or call 6295 7437) to make an appointment.