Flood woes: A balancing act

Government decision to balance drainage with roads and other land uses makes sense
Lee Wei Ling Straits Times 27 Mar 11;

This is already the end of March. The north-east monsoon should have ended. Yet I was awakened by torrential rain at 6am on a recent morning.

After a few minutes, I decided to go back to sleep and chase my dream. This was a technique I had developed myself. I found that if I could get back into the dream that I had woken up from, I could fall asleep again.

So I mentally went over my dream and indeed fell asleep, and the dream continued.

In my dream - which consisted more of recollection of my actual past rather than dreams - my bro-ther Hsien Yang and I were still pupils at Nanyang Primary School. To get to school, we were driven along Bukit Timah Road, which of course was next to the Bukit Timah canal.

In those days, the canal was much narrower than it is now, so whenever there was heavy rain, Bukit Timah Road tended to get flooded. If the heavy rain occurred at the same time as a high tide, flooding was certain.

Near Nanyang Primary in the 1960s were attap houses. The boys from the kampung would wade through the dirty flood water and offer to push stalled cars for a fee.

Readers under 30 years old would probably have never seen these attap houses for they stood on what is now prime land. Property prices near Nanyang Primary have gone up stupendously since the 1960s. Many ambitious parents move to be within 1km of Nanyang Primary to ensure that their children have a good chance of getting into the school.

Yang and I were in a car along Bukit Timah Road trapped in the flood. Our older brother Hsien Loong was attending Catholic High School and so was not around to chastise us.

Our car stalled because water had got into its engine. The canal had overflowed and one could not tell where the canal ended and where the road began.

It is amazing how daring one was before fear robbed us of the fun of childhood. Yang and I got out of the car, ignoring our driver's protests and tried to push the car. But we were too small and did not have enough strength to move the car. So, bashfully, we got back into the car, wet and muddy. Then three big boys came along to push our car in exchange for a fee.

Then I woke up and peered out of my window. It was too dark to see the rain, but the sound of heavy rain confirmed I hadn't just dreamt about it.

Now awake, I recalled clearly those days when Singapore flooded often. After the car was pushed to where the road was dry, the driver would open the bonnet, and remove the five cables attached to the distributor cap and dry them all with emery paper. I can remember this technical detail because the five cables attached to the cap were nicknamed sotong, which means cuttlefish in Malay.

We would eventually get to school, but less than half the pupils would have made it. So we would be told to go home.

Going home promised more fun. We would fold paper boats and place them in the drain which flowed away from our house. Now much older and a little wiser, I wonder whether the paper boats would have added to the obstructions in the drain further on.

Last year, we had exceptionally heavy rainfall over a very short period of time. Many roads which had never flooded before flooded. Some houses and shops were damaged. There was much complaining among those who were concerned about the losses they incurred.

My father Minister Mentor Lee Kuan Yew explained recently the Government's thinking on flood control:

To guard against a super-heavy rainfall that would occur once every 20 to 30 years, we would have to build more and bigger drains. But no amount of engineering can prevent floods. Also more and bigger drains would mean less space for roads. As it is, even the high cost of cars has not dissuaded people from wanting cars.

I don't always agree with the Government, but in this case, I do: It is better to have drains capable of coping with the usual rainfall, rather than invest in a system that can cope with the giant floods that occur only once every 20 to 30 years.

According to the PUB, there are currently 32 rivers and more than 7,000km of drains and canals in Singapore. They are part of PUB's flood management approach, which also involves:

Providing adequate drainage ahead of new developments;

Raising road and building levels, and getting building owners to implement flood protection measures; and

Making continual drainage improvement in areas affected by floods.

As a result of investing some $2 billion over the past 30 years in an extensive drainage system, our flood-prone areas have been significantly reduced by 98 per cent - from over 3,000ha in the 1970s to 56ha today. Singapore has achieved this despite increased urbanisation, which would usually have resulted in more floods. The flash floods that still occur tend to be localised affairs that subside within an hour.

Every decision comes with an opportunity cost. The wisest decision is one that minimises this cost. The public needs to understand the Government's logic. Unfortunately, grumbling is our favourite pastime.

The writer is director of the National Neuroscience Institute.