President’s Message
Message 07/2018
Mr Lim Soon Heng, PE, FIMarEST.
Founder President
Tekong: Polder or lagoon?
Singapore has expanded its footprint from 567 sq.km when I was a schoolboy in the 1950’s to 720 sq. km now that I am a septuagenarian. For a projected peak population of 10 million (a figure that has been touted by people in high positions) we would need 830 sq.km based on a population density of 12,000 persons/sq. km. It would need the addition land in about 56 years based on a compound annual growth rate of 1%.
We expanded our shoreline with indigenous fill material: by cutting hills in Jurong and Bedok, and by dredging sand from our sea. When those options ran out we resort to importing sand from Malaysia, Indonesia, Vietnam, Cambodia and Myanmar. Mining and exporting sand is banned by these countries. At least officially. Singapore is today the world’s biggest importer of sand. It is one superlative we rather not have it mentioned.
What is left of our waters is generally too deep to reclaim economically. The reclamation thus far has snuffed out many species in the marine ecosystem. The importation of sand from abroad presents a threat of marine bio-invasion like the discharge of untreated ballast water by cargo vessels which will be prohibited by IMO (International Maritime Organisation.)
Rightly the Government is seeking ways to resolve the problem of land scarcity. The decision to empolder (build an embankment) north west Tekong Island seems sensible but is it? Have the risks been properly and extensively evaluated? Is the long-term life cycle cost fully understood? Should we be more sensitive to a worldwide concern that sand mining is destroying the livelihoods of many fishermen and riverside farmers? Given the political uncertainties around us how dependable is the supply of sand necessary to complete this five-year project?
It is not often for Singapore government agencies to let consultants be interviewed by the media but on the Tekong project the consultant was in the frontline fielding questions. “Building the polder at the moment is the most economical way to reclaiming land.” This harks back to the time when Singapore had to decide on a viable transport system for the future. The Harvard University professors recommended against the construction of a rail-based transport system because of its high cost. Then Minister for Trade and Industry, Dr Tony Tan called the MRT a “foolish” undertaking.
Cost is the basis for evaluating the viability of a project. But cost is an elusive butterfly. Many life cycle costings are flawed because they do not look beyond the immediacy of the capital, operating and maintenance expenditures. Other intangible cost to the society need to be consider, including environmental ones. Other benefits also.
Moving away from conventional land reclamation to poldering is an incremental learning experience. A quantum leap is possible with the expertise here at home to go even further; to floating structures.
In the past 40 years, the search for offshore oil has resulted in a slew of innovations in the design of stationary floating exploration, drilling and production platforms. The design and engineering of seakeeping systems have made great strides. Many of these solutions are finding applications in near shore development. We should consider these options just as Mr Ong Teng Cheong then Minister for Communications in 1980 was bold and visionary enough to press the cabinet to opt for a rail-based transport system and to look beyond the capital expenditure.
With regards to Tekong, we urge that we seriously take that visionary quantum leap to create a deep lagoon by enclosing the 810-ha area with floating berths or submerged caissons. They need not be contiguously linked. The enclosed area is four times the area of Marina Bay. The potential for development as a military base or even as a new city is immense.
The enclosed area would need no sand. In fact, it may yield sand for other projects as the area can be dredged. A deep lagoon is preferable to shallow one. Within the lagoon one could have an entire complex of offices, residential quarters, workshops, logistic stores, recreation grounds, water desalination plants and even berths for ferries and frigates. These structures would be erected on concrete platforms. There would be basement space beneath deck levels for storage of weaponry and ammunition, portable water and fuel.
The proposed sand dyke is not a robust structure and vulnerable to a number environmental, technical, geopolitical and human error risks which a caisson or a floating berth is better able to withstand. These structures can take physical impacts and can be designed with reserved buoyancy in the event its wall is badly damaged.
A good example of a floating berth is the one in Monaco which is more than 352 meters long. The structure houses four basement car parks and shops. In New York the refurbished Floating Pier 57 in the Hudson River is another example of how floating structures may be used. In this case the shopping mall and offices are above the main deck. In terms of military application, floating naval bases are being proposed in the US and China. In the UK, one has already been built as a floating jetty in a naval base in Scotland.
I am working on a dissertation on the subject which I shall share with our policy makers.
Lim Soon Heng
30 July 2018