Page 45 - Envision 17

Policy
Pulau Semakau Landfill –
A Haven For Coastal And Marine Biodiversity
The pressure to manage its solid waste and the lack of land led to Singapore’s decision to develop the world's first offshore landfill. Development considerations included minimising impacts to biodiversity. Today,
it is not only a landfill, but also a coastal and marine biodiversity haven. With the way forward, it can be featured as an illustration of sustainable development which addresses many of the United Nations Sustainable Development Goals.
Lim Tian Kuay
National Environment Agency
L.M. Chou
National University of Singapore
The 350-hectare Semakau Landfill, the first offshore landfill in the world, received the 2019 Hassib
J. Sabbagh Award for Engineering Construction Excellence on 23 November 2019. It was quite coincidental that Semakau Landfill won the engineering award for its outstanding engineering feat twenty years after its completion in 1999. A seven-kilometre rock bund demarcated 350 hectares of the sea linked to two islands that were previously inhabited. The larger is Pulau Semakau endowed with rich coastal and marine habitats including mangroves, coral reefs and seagrass beds. Reclaimed from the sea, the landfill area is demarcated by a perimeter bund within which, cells were progressively emptied off seawater and filled with incinerated ash.
Saving The Mangroves and Coral Reefs on and Around Pulau Semakau
It is lesser-known that during the physical development of Pulau Semakau, measures were taken to minimise environmental impacts and to safeguard and enhance the natural ecosystems, like mangroves and coral reefs. Firstly, to make up for the loss of 13.6 hectares of mangroves that had to be destroyed during the development, Professor Leo Tan and the late Professor Lee Sing Kong advised on the replanting of mangroves at alternative sites. This was a major undertaking at a time when mangrove restoration was not that well understood. Secondly, Professor Chou Loke Ming proposed the use of fine mesh silt screens to prevent sediment generated by the perimeter bund construction from spilling over to the coral reef and seagrass bed on the island’s western coast.
These measures were implemented as part of the Environmental Impact Assessment to mitigate adverse effects on Pulau Semakau’s coastal and marine habitats. The coral reef was monitored over the three years it took for the construction of the perimeter bund. Permanent transect lines and quadrat plots were established and surveyed to assess reef condition [see Figure 1]. The results indicated minimal impact to the reef with live coral cover remaining intact throughout the development.
01 Line transect deployed to measure reef condition.
Biodiversity of Pulau Semakau
At least five different types of ecosystems are found at Pulau Semakau, a testimony of its rich and diverse biodiversity. The ecosystems represented on both the landfill site and the more natural areas are: 1. Grass- and scrubland on the filled cells
a. Many coastal pioneer plant species like casuarinas now thrive on the island.
b. Wildflowers are widespread.
c. Many bird species, both resident and migratory species like the Great-billed Heron, Grey Heron, Large-tailed Nightjar, Barn Swallow, Pacific Swallow, Kingfisher, Changeable Hawk Eagle, Malaysian Plover, Pacific Golden Plover, etc., have been sighted.
d. Many arthropod species like bees, butterflies, beetles, dragonflies, etc. are present.
e. Marine life including hard corals, algae, and fishes have been observed in the unfilled cells currently holding seawater.
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