Dry weather turns Kelantan rivers green

Climate warning: Mohamad Faiz says the phenomenon in Kelantan is an early warning of a water security crisis driven by climate change, as rainfall patterns become increasingly erratic and drought periods longer. — Picture courtesy of UPKN Kelantan Facebook page

KOTA BARU: The phenomena of river water turning green and reduced levels at several rivers in Kelantan are due to the prolonged dry weather and ecosystem stress, it was revealed.

Assoc Prof Dr Mohamad Faiz Mohd Amin, who is head of the Climate, Water and Environmental Resilience Research Group at the Faculty of Earth Sciences, Universiti Malaysia Kelantan (UMK), said both occurrences were interrelated due to the lack of rain.

He said that during the rainy season, Sungai Kelantan usually carried a high load of suspended sediment due to erosion, causing the water to be murky and brown.

However, he said the reduction in rainfall slowed down the flow of water and reduced the rate of erosion, causing the quantity of suspended sediment entering the river to decrease significantly.

“This change is often misinterpreted as an improvement in water quality. In fact, it is just a physical change.

“When the water becomes clearer, sunlight penetrates deeper and highlights the natural colours of the aquatic system, inclu­ding the presence of phytoplankton or algae to a certain extent,” he said, Bernama reported.

Mohamad Faiz said flowing ri­vers like Sungai Kelantan were not prone to large-scale algal blooms.

“As such, the green colour is more likely to be linked to a reduction in sediment than the presence of algae as the main cause,” he said.

On the decline in the level of Sungai Golok to 3.26m, well below the normal level of 5m, he said this would reduce the river’s abili­ty to dilute pollutants.

When water volume decreases, he said, substances like nutrients from agricultural waste or waste discharges would become more concentrated, while the water temperature increases.

“This situation can affect water quality and put pressure on aquatic life. The impact can extend to threats to raw water supplies and daily drinking water for residents,” he said.

Mohamad Faiz said the current phenomenon in Kelantan is an early indicator of a water security crisis driven by climate change, given increasingly erratic rainfall patterns and longer drought periods.

“Rivers that look more ‘beautiful’ today may actually be losing their natural ability to support life.

“So, the approach to water resource management needs to change to a more adaptive, data-based and responsive system to climate change,” he said.