My concerns about the plans to build a direct underground MRT tunnel underneath MacRitchie rainforest in Singapore

Several days ago, I emailed Land Transport Authority (LTA) of Singapore to voice my concerns about the plans to build a direct underground MRT tunnel underneath MacRitchie rainforest in Singapore, as follows.

Dear sir/madam,
I am writing to provide my feedback on the cross island line construction.
I am concerned about the environmental impact on the central nature reserve that may be caused directly or indirectly by the direct alignment option.

Such impact can be detrimental to both wildlife and natural vegetation in profound ways that we may yet fully understand.
Below are my specific concerns:
1. NParks signboards state that we are only guests in the fragile nature reserves, and we should preserve it for ourselves and future generations. Therefore, no construction works should be carried out within the central nature reserve, even if they are deep underground or along the periphery of the rainforest.
2. NParks also states that any noise within the zone will affect sensitive wildlife in the central reserve. Please see attached screenshot. We cannot guarantee that the construction works won’t generate noise or vibrations, whether they are carried out along the forest fringes or underneath the forest floor, even if it mainly comprises hard rocks underground.
3. We cannot totally rule out the possibility of any tunnel accident or collapse, whether during or after construction. The Nicoll highway MRT tunnel construction accident is a cautionary tale for us. In the event of an accident or incident in an underground tunnel below the nature reserve, any rescue work will likely affect the nature reserve, especially if a shaft needs to be bored deep into the earth, like in the case of the dramatic rescue of the Chilean miners some years ago.
4. Last but not least, we cannot fully ascertain the vastness of the underground hot spring around Sembawang. I believe there is a reason why the existing MRT tracks are built above the ground along the North-South line between Kranji and Bishan MRT stations. It is possible that the northern and north-central parts of Singapore may have hot underground reservoirs, which may extend to the area between Lower Peirce reservoir and MacRitchie reservoir. If so, it would be dangerous for any kind of deep underground construction works to be carried out in this region. Please see attached diagram for reference.
The nature reserves are the only remaining primary rainforest and wildlife habitat we have left in Singapore. With the ongoing development works that have been destroying other green spaces including Bidadari, Lentor and Tengah forest, we cannot afford to risk losing or affecting the last vestiges of our original forests. They are our most important natural heritage, and they serve as our green lungs, refuge for our wildlife residents and sanctuary for our soul.
Thank you for your kind attention and I look forward to your positive response.

I then followed up with a second email to LTA.

Dear Sir/Madam,

In addition to my first email, I would like to add the following point.
While LTA may be concerned about time and cost factors, as stated in the EIA report, my stance is that no amount of time and money can recover or compensate for the potential loss and/or disturbance of the fragile biodiversity.
A case in point:
Years ago, Singapore built Bukit Timah expressway that divides between Bukit Timah nature reserve and Central nature reserve, which invariably affects the migratory routes and long-term survival of our native wildlife species.
As a result, we recently have had to spend enormous amounts of money and resources to build an Eco-link to hopefully restore some amount of ecological balance in the nature reserves.
Isn’t it better to leave the natural ecosystem untouched in the first place instead of creating disturbance and then spending even more time and money to rectify the situation?
Finally, there is no doubt that LTA wants to enhance the mobility and convenience for people in Singapore even further by building the cross island line.
But we have to bear in mind that many, if not all, of our native wildlife species, which we share our home with, are not as resilient or adaptable as us human beings in the face of rapid urbanisation, as shown in the innumerable cases of wildlife species being driven to extinction around the world by unsustainable development and environmental degradation over the years.
The following is the reply I received from LTA.

Dear Jimmy,

Thank you for your interest and feedback on the Phase 2 Environmental Impact Assessment (EIA) for the Cross Island Line (CRL).

During the EIA study process, measures to avoid or reduce impacts associated with the proposed alignment options were prioritized. This has led to the placement of worksites as far from the primary forest patches within the CCNR as possible. For both direct and skirting alignment, there will not be any surface construction works or above ground structures within the CCNR. Railway construction and operations, including and not limited to emergency procedures and escape provisions, will conform with current codes of practices and operational requirements in the existing MRT lines.

Measurements were undertaken to establish the vibration baseline levels within the CCNR, and vibration generated from tunneling activities were assessed to be below the baseline vibration levels that are currently experienced by wildlife. As a precautionary measure, LTA will carry out vibration monitoring during the tunnelling works to ensure the levels are kept below the baseline levels. The vibration levels generated during railway operation were assessed to be even lower than those generated during construction, it is therefore not expected to give rise to impacts to wildlife within the CCNR.

In view of the value and sensitivity of the forest habitat, LTA will be exploring further means to optimize the worksite footprint at the Advanced Engineering Study stage of the Project, so that site clearance can be minimized. In addition, LTA will be collaborating with NParks on reforestation plans to restore connectivity between forest fragments around the Project area. A comprehensive Environmental Management and Monitoring Plan (EMMP) to mitigate the impact has also been developed in consultation with various stakeholders. The EMMP will be a framework for monitoring and checking of mitigation measures, so that changes can be made to ensure these measures continue to remain effective throughout the Project construction.

Based on the EIA, both underground alignments for the CRL are feasible and the residual impacts are largely moderate or below. These impacts can be managed with mitigation measures. Thus far, the Government has not made a decision yet on the alignment option. In deciding on which alignment to adopt, the Government will have to consider the full range of factors such as travel time, commuter benefits, impacts on home owners and environment.

Once again, we thank you for sharing your views with us. Views and suggestions of different stakeholders will be taken into considerations for Government to make decision on the final alignment of the CRL.

There is no mention of my concern about the underground hot springs in their reply. I suppose they probably need to look into this matter first.