Why Flash Flood in KL?

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Recently everyone is concern about the flash flood happened in Kuala Lumpur. Over this 2 weeks the weather in Klang Valley was very unusual and flash flood occurred in several places in KL in this 2 weeks.

Many people don't know why it happened and started to blame or point fingers to each other. I'm not surprise to see it, because everytime when anything wrong happened, everyone will started blame on each other. To me, I'll find out what is the main causes to lead on flash flood happened, it's no point for me to blame on others.

Here I just want share with you all my research and study on this situation for the past few years. Let's look at the geographical of Klang Valley, the major rivers are Klang River, Gombak River and Batu River. The other tributaries are Ampang River, Keroh River, Kerayong River, Kuyoh River, Damansara River, Penchala River and others.

We have two dams (Batu Dam and Klang Gates Dam) and few flood retention ponds but it's still not adequate to hold the rain water.


History of Major Floods

There are many major floods happened in Klang Valley since in 1920s. If you observe the frequent of floods, you can see the numbers of flood increasing in recent years.

From my record, the 1971 major flood was the worst ever in the history which happened almost whole Peninsular of Malaysia. It was believe the rainfall was 100 years return period, which is possible happen at least once in 100 years.

Let's look at some major flood pictures...





Causes of Floods

1. Rapid and Uncontrolled Development
2. Heavy Siltation
3. Reduction of River Capacity
4. River Constrictions

From 4 major causes, let me give some simple explains how it happens:


Look at the figure above, the land after development will become like 'water proof', the rain water will have no where to go through into the soil, so this phenomena will increase the surface water run off. If the drainage system are not design properly, the water run off will cause the flash flood happen.


Improper land development also will caused heavy siltation in drainage system, not only that, it also can caused land slide happened.

This is what happened on improper planning of a township, the heavy siltation in rivers will reduce the river capacity. It also destroyed the river ecosystem/diversity, this is why we hardly to see any living things like fish in the city's river.


Constrictions of river also another problem to create river water over flow from river. For example the picture above, the bridge was constructed lower than the flood level. That's why the bridge will block the water flow in the river and the back flow of water will spille out from the river.

Constrictions of structures also will disturbed the water flow during rainy days.


This is the very common situation we can see, illegal squatters and rubbish. I'm really sad that the mentality of Malaysian still treat our rivers as a rubbish dumping ground. I've seen on my own eyes a mamak shop in KL throw their rubbish directly into the river. Imagine if everyone does the same thing, our living place will become very sick.

Our river or drainage system is like artery in our body, once got any blockages, we will in trouble such as heart attack. Now, we are living in a 'heart decease' environment, it will burst anytime without any notice.


So, my conclusion is we have to blame on ourself for without the awareness of keeping our living place healthy. You can still blame on government of never did their job to clean it, but have you ever think that who did it in the first place?

The business mentality here also never concern about the environmental impact, they just never let go any empty land or reserved forest to develop the properties for their big profit only. If they follow all the EIA (Environmental Impact Assessments) studies and some proper guidelines, this will reduce the flash flood happened.

Prevention is Better Than Cure.