The Proposed Long Island Project in Singapore, is there a More Sustainable Way?

The Singapore Government recently announced plans for an 800-hectare reclamation on Long Island, south of East Coast Park. The announcement came under the scrutiny from city planners, and the academia as well environmental scientists, and NGOs. The government is seeking inputs from those who have interests. The multi-year in-depth feasibility study will commence in 2024. Several alternatives are possible. The government’s proposal is essentially an 800-hectare polder. Between the existing shoreline and the landward side of the reclaimed land a large strip serves as a catchment for freshwater fed by monsoon rain. This paper proffers a solution using a series of gravity-based caisson (GBC) modules to form a lagoon separating the freshwater from the seawater. They can be manufactured offsite, launched and towed to its final position where it is aligned and ballasted with seawater. Some of the GBCs are designed to accommodate floating gates which when partially raised by deballasting allows excess water in the lagoon to be discharged into the sea. The top deck of the GBC is designed as a roadway for light vehicles. Within the lagoon, floating platforms serve as foundations for residential and commercial buildings and for recreation parks or as dormitories for students in nearby institutions of higher learning. Transportation may be by ferries, flying taxis (such as the EH216-S) or buses similar to Vaporetto in Venice. Floating electric bicycles would be a personal mobility option. There will not be any roads or drains to build or maintain. Floating bridges link key points to the mainland or the caisson roadways. Small barges ply the lagoon to collect garbage and floating debris which are mechanically transferred to a larger barge outside the lagoon for transport to incinerators. There will not be any roads or drains to build or maintain. Why would a government consider this proposal when a major source of its income is leasing land? First, it is a greener option. Second, the capital outlay will be a fraction of the cost of land reclamation (estimated at SGD 6.4 billion). Third, the seaspace can also generate a source of revenue. At the end of the lease the plot can be freed up in a short time frame (by the owner), freeing up the plot for another investor to lease. Maintenance of reclaimed land is costly as experience at the Kansai Airport and Jumeirah Island has shown. Foundations for land-based buildings take more money and time to complete. Buoyancy is a principle of physics independent of the soil properties below.