G&P Water and Maritime principal adviser Chong Sun Fatt and Prof Alias Abdullah of International Islamic University Malaysia said extremely heavy rain was unpredictable and was the primary cause of the flash floods.
Chong, a hydrology expert, noted that Thursday’s rainfall in the Klang Valley was especially heavy in the northern and eastern part of Kuala Lumpur, where the Gombak and Batu rivers are.
The southern part of the city received lower rainfall and was spared from flooding, he told FMT.
“The SMART Tunnel could only divert river runoff from the Sungai Ampang and Sungai Klang tributaries.
“The enormous volume of river runoff from Sungai Gombak and Sungai Batu could not be diverted by SMART. This caused high river water levels in the city centre, like the Masjid Jamek area.”
Chong also said the tunnel had “effectively reduced” a certain amount of flood water and that it had prevented the Klang river from overflowing.
He said flood mitigation was harder for low lying areas and older city centres such as Kuala Lumpur, as it would require huge capital expenditure and massive relocation operations.
“Technically and economically, we will not be able to do away with flash floods. It is too expensive and impractical for implementation.
“Every drainage system will only provide a certain level of protection in terms of return periods. We cannot provide a totally flood-free drainage system.”
Alias, who specialises in urban and regional planning, said while the flash floods showed a need for the authorities to review their emergency drainage SOPs, the public also played a part in preventing further floods.
“We cannot just blame one entity, like Kuala Lumpur City Hall (DBKL, for not managing it well. At the same time, the public at large have to be careful as they also contribute (to floods) by throwing rubbish in drains.”
Alias also said other activities such as logging and property developments added to the city’s poor water drainage systems.
“You could build lots of SMART tunnels, but it will only be a temporary measure. All parties have to tolerate and work together as a team (to overcome the problem),” he said.