Tech & Gadgets

Why Do Flash Floods Even With A SMART Tunnel? Read This And You Know Why

SMART tunnel or the Stormwater Management And Road Tunnel were built starting from November 2003 until the construction completed in 2007. The tunnel was built to help in improving the drainage system in Kuala Lumpur.

Kuala Lumpur, being the country’s capital is crowded with skyscrapers and buildings which proved its success in economy and modernization. However, Kuala Lumpur will have to face flash floods every time there were heavy rains. This situation creates problems for the city’s residents as it will disturb their activities.

Due to this, the authorities took a preventive step by coming up with the SMART tunnel idea. The SMART tunnel is the first tunnel of its kind in the world. The storm drainage and road structure are one of the main roads used by Kuala Lumpur residents.

Recently, on 10 September, a flash flood hits the city again. It also struck major parts of the city after a torrential downpour on that day. Many people started to question the effectiveness of the SMART tunnel as it seemed not to give any improvement in handling the flash flood. Here is a thread made by @SkyscrapersMY on how the tunnel operates when handling flash floods in Kuala Lumpur.

The SMART tunnel, FIRST tunnel traffic & flood management IN THE WORLD.

This 9.7km tunnel has also been recognized by CNN as one of the Top 10 Tunnels in the World!

This thread will explain how it plays a role in resolving the floods that hit Kuala Lumpur.


Along with its name, Stormwater Management And Road Tunnel or SMART, it has two functions

1. For traffic routes
2. To REDIRECT floods from entering the city

Apart from that, it provides an alternative route for road users who frequently commute from south KL to the city center


It operates in 4 modes:

Mode 1: When there is no flood, it is just a regular road tunnel.

Mode 2: When there is a flood, water flows to the bottom of the tunnel. The upper part is open as usual for traffic lanes.


Mode 3: Large flash floods occur, traffic routes are cleared & closed within an hour. Floodwaters flow below.

Mode 4: When flash floods continue, water also flows into the traffic lanes. It will only reopen after 48 hours.


When it rains heavily, the floodwater from the Klang River is diverted to the Berembang reservoir pond, Ampang.

Next, water was flowed through the SMART tunnel into the Taman Desa reservoir pond before being released into the Kerayong River.

This SMART is like a connecting pipe between 2 rivers


After the flooding is complete, the tunnel for the traffic route is only open after 48 hours to clean the dirt, mud, garbage & other things which were brought by the flood water before this.

Tunnels are cleaned through the “pressure washing” method.


So, is the flood in Kuala Lumpur the other day (10 Sept 2020) due to the failure of the SMART system?

The answer is no.

According to hydrologist Chong Sun Fatt, SMART has done its best to prevent the Klang River from overflowing.


However, SMART cannot divert the excessive flow from Sungai Gombak & Sungai Batu because it can only divert flow from Sungai Ampang & Sungai Klang.

This causes the water level to rise in downtown KL as in the area of Masjid Jamek.


In addition, floods are more difficult to alleviate in low-lying areas & old city centers such as Kuala Lumpur, as they require substantial capital expenditure and large-scale relocation operations.


Technically and economically, we will not be able to cope with flash floods. It is too expensive and impractical to implement.

Each drainage system will only provide a certain level of protection. We cannot provide a flood-free drainage system.


According to Prof Alias Abdullah from UIA, although the flash floods require the authorities to review their emergency drainage SOP, the public also plays an important role in preventing the floods from continuing.


Disposing of garbage into drains, as well as logging & development activities, also has a detrimental effect on the city’s water drainage system.


SMART tunnels can be built as much as possible, but they are only temporary steps. All parties must be tolerant and work together in resolving the flash flood crisis in our beloved city of Kuala Lumpur ♥ ️🇲🇾


Source: Twitter

Adib Mohd

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