KLANG: The flood situation in the country is expected to worsen, especially in the west coast due to climate change, experts say.
Universiti Sains Malaysia (USM) Centre for Marine and Coastal Studies director Prof Datuk Dr Aileen Tan Shau Hwai said a higher frequency of extreme weather, such as heatwaves and storms, is expected.
She said the impact of these changes will be more drastic in the west coast of Peninsular Malaysia compared with the east coast as well as Sabah and Sarawak.
This is because the South China Sea, where the east coast as well as Sabah and Sarawak are located, is a bigger basin compared with the west coast’s Strait of Malacca, she added.
“The Strait of Malacca is also exposed to more intense anthropogenic impacts (changes caused by humans) due to population density along the west coast stretch of the country,’’ Tan said.
She said to make matters worse, the west coast has extremely higher run-offs (drainage of water) from land into the Strait of Malacca compared with the South China Sea, which introduces land-based pollution to the ocean.
Marine environmental scientist Prof Datuk Dr Zulfigar Yasin said flooding will become more severe as climate change progresses. He said this is due to factors such as frequency and intensity of adverse weather, such as storms and extreme river flows.
He said 130,000 people are expected to be affected by floods, at a cost of RM1.8bil annually, with the numbers and cost increasing with time.
The experts: Tan (left) and Zulfigar.
Zulfigar, who is with USM and the Penang Institute, said communities living in lowland and low-lying areas near the Malaysian coastline will be adversely affected by the sea water rise.
“Much of our lowlands near the coast are susceptible. The degree of impact is dependent not only on the rate of increase in sea level but the ability of our coastlines to adapt to sea level changes,’’ he said.
The phenomenon will also affect agriculture activities such as padi cultivation in places like coastal Kuala Selangor in northern Selangor.
“Padi is very sensitive to saline water intrusion and the salt water will make the area unsuitable for padi cultivation; this will impact our food security,’’ Zulfigar said.
He said coastal storms, which could affect homes in the area, will become more severe as the current tidal gates and coastal measures that form barriers to the rising water may not be sufficient to stem the sea.
As such, he said it was crucial to have a sound flood mitigation system and strategy in place to reduce the impact of climate change.In the 2022 Auditor-General’s Report, which was released recently, it was revealed that five out of 10 flood mitigation projects in Klang had failed.
Meanwhile, USM River Engineering and Urban Drainage Research Centre director Assoc Prof Dr Mohd Remy Rozainy Mohd Arif Zainol said flood mitigation projects that have failed to function effectively need to be relooked from several angles.
He explained that the design of most of the current flood mitigation projects was based on a 100-year rainfall recurrence.
However, he said this has proven to be inadequate in containing or controlling high water volumes due to the rainfall patterns over the past few years.
Mohd Remy Rozainy said the design of flood mitigation structures must be upgraded to accommodate a 200-year rainfall recurrence.
He cited Japan as an example, adding that the country’s floodplains (land alongside rivers to accommodate water when rivers overflow) were vast and expansive though the country’s urban residential areas were densely populated.
He said the Japanese were willing to sacrifice large areas of land to function as floodplains to accommodate rainfall volumes up to a 1,000-year recurrence.
Mohd Remy Rozainy said the Malaysian floodplains were much lacking compared with Japan.
“The drains in Malaysian cities resemble trash bins. Everything is dumped into them, inevitably resulting in floods,’’ he said.
He added that regular maintenance to clear drains and rivers while ensuring the proper functioning of pumps and other mechanical equipment was needed.According to him, as Malaysia receives high levels of rainfall every year, the current infrastructure must be able to handle the high volume of water.
Mohd Remy Rozainy also said if only every home in urban areas could store one cubic m3 of rainwater in its premises, it would aid in reducing the volume of water flowing into rivers.
“It is time for local authorities and consultants to come together to implement the ‘sponge city’ concept for water volumes to be absorbed and slowed down to reduce the flow into rivers.
“Rainwater harvesting as well as water storage systems have to be expanded. We are well aware that floodplains in Malaysian cities are very limited and narrow.
“The ‘sponge city’ concept is a progressive step that we need to explore and develop.
“It is also undeniable that technology and funds must go hand in hand to ensure that what is planned can be implemented,” he added.
