ENVIRONMENTAL concretisation and overdevelopment were the main factors for repeated flash floods in the Klang Valley, experts warned, adding that more frequent floods are imminent.

They said coupled with climate change acceleration the capital city and surrounding areas would be inundated more frequently.

They added that the development of water retention ponds in the Klang Valley have also contributed to the recent flooding.

Former National Hydraulic Research Institute of Malaysia director-general Salmah Zakaria said the Sungai Klang basin development was so dense that a large portion of the area was paved either by concrete or tar.

This increases the overland flow when it rains, she said.

Salmah was commenting on the recent floods which hit the capital city and surrounding areas. After Malaysia’s worst flooding in years that took place in December in the greater Klang Valley, Kuala Lumpur experienced three other floods on March 7, April 25 and May 25.

The floods caused widespread damage to businesses, property and vehicles.

“Before urbanisation, rainwater was intercepted by vegetation. The water would infiltrate into the ground and take time to travel to rivers,” she told The Malaysian Insight.

“After urbanisation, rainwater swiftly collects from roofs and other paved areas, flowing into drains, which efficiently carries it to the nearest rivers.

“If you look at satellite images of the Sungai Klang basin, the area is totally paved. You can have flash floods within one hour of a heavy downpour.”

There were 48 flash floods in the Klang Valley between 2015 and 2020. There were five in 2017, and 13 in 2020, an almost triple increase.

The Sungai Klang basin consists of seven rivers, Sungai Ampang, Sungai Batu, Sungai Damansara, Sungai Gombak, Sungai Kayu Ara, Sungai Kerayong and Sungai Klang.

Following regular floodings, the status of six of 15 water retention ponds in the capital came into question, as an auditor-general report found that the ponds were approved for development.

The six water retention ponds are Batu, Batu 4 ½, Delima, Nanyang, Taman Desa and Taman Wahyu.

Pertubuhan Pelindung Khazanah Alam Malaysia president Shariffa Sabrina Syed Akil said Malaysia should learn how to mitigate floods from neighbour Singapore.

“It rains year-round in Malaysia. We must remember this whenever and whatever we build, but we never upgrade drainage systems. There are also not enough trees in the cities,” Shariffa said.

“Look at Singapore, it builds, but it also plants lots of trees. The government does not cover its lakes.”

“It has reclaimed land, but what did it build? A forest, so it will absorb water when it rains.”

“We build malls, condos and industrial areas. There is nowhere for the water to go, all the lakes and water retention ponds are closed.”

“So where do you expect the water to go?”

Tunnel operator SMART Highway said Kuala Lumpur needs a holistic flood mitigation solution for the northwestern side of the capital, as the existing SMART tunnel serves to divert floodwater from a limited area.

SMART, which stands for Stormwater Management and Road Tunnel, mitigates floods along Sungai Klang that passes through the Kuala Lumpur city centre. These areas include Dataran Merdeka.

The company called for a holistic flood mitigation solution to cover the parts of Kuala Lumpur that lie within the catchments which are not served by the SMART Tunnel.

“Given the advent of climate change, an increased frequency of extreme weather events is forthcoming.

“Therefore a holistic flood mitigation solution targeting the northwestern side of Kuala Lumpur within the catchments of Sungai Gombak and Sungai Bunus will need to be expedited.

“A robust maintenance regime is needed for our local drainage networks to minimise the future impact of these extreme weather events in Kuala Lumpur.”

Effective measures

Kuala Lumpur Mayor Mahadi Che Ngah had said City Hall would be implementing 14 interim measures at a cost of about RM10 million under the Flash Flood Mitigation Action Plan 2022 from this month to tackle the issue of flash floods in the capital.

Mahadi said the interim measures would be carried out before long-term solutions, which are currently being reviewed by the Public Works Institute of Malaysia (Ikram) and expected to be completed next April, could be implemented.

Mahadi said they would focus on monitoring and cleaning works to ensure that outlets by the roadside for water to flow out are not clogged or obstructed, adding that this would be implemented by the Public Service Delivery Team supervised by City Hall.

Other measures, he said, included upgrading the scupper drains to ensure proper sloping for water to flow naturally and placing machinery and City Hall workers at strategic flood locations to facilitate the mobilisation of machinery, such as tow trucks, mobile water pump lorries and high-powered water pumps during floods.

Federal Territories Minister Shahidan Kassim said efforts to prevent and mitigate flash floods in the capital, based on the 14 interim measures that began early this month, have shown results.

He said this was observed during the recent flash floods where floodwaters on roads dispersed in just 30 minutes, and no stranded vehicles were reported.

He added that the recent incident did not involve evacuation of residents from their homes, as well as there being no reports of landslides.

Shahidan, who is also the member of Parliament for Arau, said the achievement was the result of the use of 120 portable water pumps for pumping out stagnant water.

The use of 5,000 sandbags on river banks managed to prevent the overflow of water from Sungai Klang and Sungai Gombak to affected areas, especially in Jalan Segambut and Jalan Ampang (in front of Bukit Nanas waterfall), he said. – May 29, 2022.