The past two years have seen an increase in the occurrence of floods, especially in the lower lying areas of Singapore.
These three episodes are part of a larger pattern of rainfall change in Singapore over the past decades. A recent analysis by the Meteorological Service Singapore indicates that rainfall over Singapore has become more intense over the past 30 years.
Whilst increased rainfall was expected and managed, the occurrence of flash floods are a recent phenomenon. The Ministry of Environment and Water Resources has been taking action to reduce this (see below), and studies are in place to determine if a costly, sledgehammer approach to the issue of floods will be required.
As part of PUB’s efforts to limit damage caused by floods, PUB has been working with building owners at all flood prone areas -to recommend additional preventive measures, to review SOPs, and to ensure that building and renovation plans conform to drainage regulations, stepped up the frequency of cleansing and inspecting of drains to ensure that existing drains are free flowing and perform according to specifications.
The Marina Barrage
There has been much speculation on the role Marina Barrage had played on the floods. PUB had set the operating level of Marina Reservoir to below mean sea level throughout the month of December 2011.
Even on 23 December 2011, despite the major inflow, PUB was able to keep the water level below mean sea level at all times. This is only possible because of the gates and pumps at Marina Reservoir. This removed tidal influence from the various drains feeding into the reservoir and helped keep low lying areas in the city such as Chinatown free from floods.
(the figure is an illustrative estimation)
The operations of Marina Barrage, however, do not have any effect in the upper reaches of Orchard Road which are higher, and beyond the ‘zone of influence’ on the reservoir.
Some of the preventive measures in place include:
– Changing the geography by increasing height of roads
– Proposed work to increase capacity of Stamford Canal
– Frequent drain clearing operations
– Alert system to public
– Working with building owners to install flood protection systems