Hello guys, hope you had a great week! If you remember, one of the crucial ecosystem services that mangroves provide is the protection of shorelines against coastal erosion. I think that this is an extremely interesting perspective to consider, especially in our Singapore context, given the practical nature of our government.
What do I mean by that? Singapore’s government is largely reputed to be one that is level-headed and takes action only with concrete justifications. As such, any course of action proposed to the authorities would have a much higher chance of being accepted if it has an intended tangible outcome, grounded in scientific evidence. Take for instance the successful appeal for conservation of Chek Jawa Wetlands way back in 2001. Originally slated for redevelopment for military training purposes, Chek Jawa saw a flurry of intense activism and scientifically-backed advocacy that year, including the very first transact study of the wetlands to highlight its unbelievably rich biodiversity, which eventually led to the government reversing its decision (Climate Conversations, 2019).
Source: http://habitatnews.nus.edu.sg/articles/cjtransect2004/
While the case for restoration of our mangroves is different in nature, it would be far more palatable to the authorities if we could argue our cause from a perspective that is tangibly in line with the government’s larger plan for Singapore’s development. This perspective has to go beyond the intrinsic value of biodiversity or the ecological ramifications, because these factors do not have a first-hand impact on the lives of Singaporeans or our national development.
This is where the idea of mangroves as a viable coastal protection measure comes into the picture. Given Singapore’s small land area and high population density, all available land is precious and must be protected. Coastal protection is undoubtedly a core issue in national development, with PM Lee Hsien Loong announcing a S$100 billion plan to protect our island-nation from coastal floodwaters and rising sea levels during the 2019 National Day Rally (Mokhtar, 2020).
Thus, wouldn’t our mangroves’ natural capabilities in coastal protection be a fantastic reason to conserve them? A recent study showed that Singapore’s mangroves, comprising mainly disturbed mangroves, have significant potential in reducing wave energy under both storm and average conditions, (Lee et al., 2020). Lee et al. also recommended that our mangroves be employed as a soft engineering approach in tandem with other hard engineering measures to safeguard the nation against coastal hazards (Lee et al., 2020). At the moment, it is estimated that 70% of Singapore’s coastlines is protected by hard engineering measures such as concrete seawalls, breakwaters and stone revetments, with the remainder comprising natural defenses, namely beaches and mangroves (PUB, 2020).
So where does the possibility of mangrove restoration lie in? In my reply to Dr Coleman’s comment in my previous post, I raised the example of the PUB’s ABC Waters Programme in which concrete waterways in Singapore are being converted into beautiful, natural-looking rivers that heavily incorporate elements of nature into their designs. Upon deeper thought, I see the resemblance between this programme and the issue of hard-engineering coastal defenses here. The ABC Waters programme tears down concrete channels and replaces them with the soft-engineering approach of pseudo-natural rivers. Similarly, might it be possible for our seawalls and other hard coastal protection infrastructure to be progressively replaced with replanted mangroves? While there is a current gap of feasibility studies on this idea, I’m confident that, considering the wonderful job that the authorities have done with the ABC Waters Programme as well as the mangrove restoration of Pasir Ris Park Mangroves, this idea is certainly a viable possibility.
Source: Ramboll Studio Dreiseitl
In my next post, I’ll be elaborating more on why mangroves would be a more favourable alternative than the current hard-engineering defenses, as well as how our mangroves can tie in with Singapore’s coastal protection plans for the future. Do stay tuned and see you then! Cheers!
References:
Climate Conversations. (2019, September 10). How passionate activism protected Chek Jawa’s wildlife. https://climateconversations.sg/climate-conversations-2019/posts/how-passionate-activism-protected-chek-jawas-wildlife
Mokhtar, F. (2020, February 26). Singapore has a S$100 billion plan to survive in a far hotter world than experts predicted. Bloomberg.com. https://www.bloomberg.com/news/features/2020-02-25/singapore-has-a-100-billion-plan-for-adapting-to-climate-change
Lee, W. K., Tay, S. H. X., Ooi, S. K., & Friess, D. A. (2020). Potential short wave attenuation function of disturbed mangroves [Article]. Estuarine, Coastal and Shelf Science, Article 106747. https://doi.org/10.1016/j.ecss.2020.106747
Public Utilities Board. (2020, March 4). PUB to lead Singapore’s coastal protection efforts. https://www.pub.gov.sg/news/pressreleases/PUBtoleadSingaporescoastalprotectionefforts
Hey Marcus,
Would you think the current investment in polders might be better spent on planting mangroves ? Also, since mangroves are normally interfaces between more natural inland habitats and the sea, do you think replacing seawalls with mangroves would require some renaturalisation of the land behind the seawall ?
Thanks !
jc
Hi Dr Coleman,
Thank you for dropping by! Yes, most of these questions are addressed in part 2 of this series. However, regarding your first question, I think I have more to add. The government’s plan to build polders along the East Coast stretch is an extremely audacious one, requiring investments of up to $100 billion. As such, I believe that they would have also considered planting mangroves as a much cheaper option instead, but they must have already done extensive cost-benefit analyses to find good reasons that polders are a better option than mangroves for this plan. I’m not sure what these reasons may be, but I can think of 2 possibilities. Firstly, the mangroves might not be able to keep up with the rate of rise in sea level, or perhaps their natural landward retreat would encroach into precious space, thereby displacing existing developments along the coast. Secondly, the authorities might be turning the problem of rising sea levels into an opportunity to reclaim more land for national development, as the polders would increase Singapore’s land area substantially.
Personally though, I would be sad if the polders plan goes through. We would lose the East Coast Park beach and coastline, which is a current hawksbill sea turtle nesting site and a hugely iconic recreational space for Singaporeans from all walks of life.