|Photo from Minister Khaw's blog post.|
In his post NEWater and New Earth? on 10 Aug, Minister Khaw shared that "Last year, 8.5mil m3 of materials were excavated to build basement carparks and shops, underground expressways, and MRT tunnels – this is equivalent to about 3,400 Olympic-sized swimming pools."
This humungous quantity of earth has led to complaints in June in the Straits Times that "Lorries [carrying excavated earth] now line up for as long as five hours to discharge their loads of earth when just six months ago, there was no wait." Indeed, I came across this very long queue of lorries in April, at the Changi stanging ground during my field trips in the area.
|Image from Minister Khaw's blog post.|
However, Minister Khaw did not mention how much of this excavated soil continues to be dumped at sea. A Straits Times article about Minister Khaw's blog post says that "A National Development Ministry spokesman said almost 50 per cent of the debris collected - or 3.9 million cu m - was sent to Pulau Tekong for land reclamation."
The June Straits Times article mentioned there were four 'staging grounds' or offloading points for lorries to transport excavated soil for disposal:
Currently, most lorries go to the one in Changi, which is managed by the Housing Board, and takes in earth from all construction projects. There are three others. Two, in Marina Coastal Drive and Fort Road, are run by the Land Transport Authority, and open only to lorries from transport-related developments, owing to the extensive excavation from projects like the new MRT lines.
The third, at Tuas, accepts only a certain high-quality grade of earth that can be used immediately for land reclamation. It is costly and difficult for sites to identify and sort the types of earth beforehand, so few lorries go to Tuas, said construction bosses.
Where does the excavated soil go after the staging grounds?
From the June Straits Times article I got the sense that most of the soil is dumped at sea!
The earth from all four points is then loaded onto barges and moved to various offshore dumping sites, like one near St John's Island.
Why is dumping at sea an issue for marine life?
When soil is dumped at sea, this buries whatever is directly under the dumping site. And our seabed is not dead! See the amazing marine life found in June on Singapore's sea bed during the Mega Marine Survey!
|Photo by Sam Yeo|
|Murky waters at Kusu Island.|
So how much is being dumped at sea and how is this controlled?
I raised this question of dumping at sea with the Maritime Port Authority (MPA), who replied recently by email that
MPA has controlled measures in place, with regard to the dumping of dredged and land-based excavated materials at offshore dumping grounds managed by MPA, land reclamation sites and Offshore Disposal Sites (ODS).
All applicants need to submit information such as the sampling size, method of dredging, characteristics of dredged or excavated material etc, to MPA’s Committee for Marine Projects. Please see attached document for reference [online here as a DOC for download www.mpa.gov.sg/sites/doc/chemical17oct07.doc]
MPA also monitors the actual dumping that takes place, in terms of the time, route and amount that is being dumped.
Unfortunately, I'm unable to find in the public domain, a list of these Offshore Disposal Sites and their exact locations. When large scale dumping does take place, though, there is usually an MPA circular about it.
- NEWater and New Earth? on Minister Khaw's blog - Housing Matters
- Khaw Boon Wan on recycling excavated materials Julia Ng Channel NewsAsia 10 Aug 12;
- Builders facing long wait to dump earth Too few sites to cope with spike in construction projects, they say, Rachel Chang Straits Times 16 Jun 12;
- What is sedimentation and why does it matter on the wild shores of singapore blog.