KUALA LUMPUR: Overconfidence in their own safety and the belief that tragedy will not befall them are among the reasons some people continue to risk camping and swimming in rivers during the rainy season.
Universiti Putra Malaysia environmental governance expert Associate Professor Dr Haliza Abdul Rahman said low risk perception, or optimism bias, could lead visitors to be lulled into a false sense of security by clear skies, clear water and seemingly calm river currents at recreational areas.
“They fail to realise that heavy rain upstream can cause water levels downstream to rise suddenly, even when the weather at the recreational area shows no signs of change.
“Many underestimate the risks because they believe misfortune happens only to others and that tragedy will not strike them or their families,” she said when contacted.
Haliza said a lack of understanding of how water surges occur also led visitors to ignore warning signs, restrictions on entering high-risk areas and advice from the authorities.
She said the absence of clear warning signs, sirens and physical monitoring at open recreational areas further compounded the problem by creating a false sense of security among visitors.
“Water surges are usually triggered by a combination of extreme weather and disturbances in catchment areas, particularly when prolonged heavy rain affects upstream areas.
“The risks are greater in areas with steep terrain, narrow valleys and rocky river channels, which accelerate the flow of water downstream,” she said.
She cited Kuala Kubu Baru, particularly Ulu Yam, Sungai Chiling and recreational areas near the Titiwangsa Range, as locations highly exposed to sudden increases in water flow because of their hilly terrain and network of tributaries.
Haliza said the threat of water surges was heightened when upstream soil became saturated, while land clearing and the loss of forest cover reduced the ground’s ability to absorb water.
“Accumulated wood debris and rubbish in tributaries can also form temporary dams. When these break under water pressure, high-velocity waves can surge downstream.
“Climate change and increasingly unpredictable rainfall patterns also worsen the situation, with extreme rain occurring within short periods,” she said.
To address the threat, Haliza said water surge risk management must be carried out through an integrated approach involving the government, technical agencies, recreational site operators, local communities and visitors.
Key measures include installing early warning systems such as automatic sirens, rain gauges, water-level sensors, current-speed detectors and surveillance cameras in high-risk upstream areas.
“The data from these systems should be linked directly to the Department of Irrigation and Drainage (DID), Malaysian Meteorological Department (MetMalaysia), National Disaster Management Agency (Nadma) and Fire and Rescue Department to enable early evacuations.
“At the same time, monitoring and enforcement should be strengthened through warning signs, physical barriers or control posts, as well as restrictions on activities throughout the monsoon season.
“Local authorities should also temporarily close high-risk recreational areas as soon as warnings of heavy rain or water surges are issued,” she said.