KOTA BHARU: The phenomenon of river water turning green and the fall in water levels in several rivers in Kelantan is currently due to prolonged dry weather and ecosystem stress and not an indication that the rivers are getting cleaner.
Head of the Climate, Water and Environmental Resilience Research Group, Faculty of Earth Sciences, Universiti Malaysia Kelantan (UMK), Associate Professor Dr Mohamad Faiz Mohd Amin said the two situations were interrelated due to the lack of rain.
He explained that during the rainy season, Sungai Kelantan usually carries a high load of suspended sediment due to erosion, causing the water to be murky and brown.
However, he explained that the reduction in the amount of rainfall slows down the flow of water and reduces 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 told Bernama recently.
Mohamad Faiz said flowing rivers like the Sungai Kelantan are not prone to large-scale algal blooms.
“Therefore, this green colour is more likely to be linked to a reduction in sediment than the presence of algae as the main cause,” he said.
Commenting on the decline in the water level of Sungai Golok to 3.26 metres, well below the normal level of five metres, Mohamad Faiz warned that the situation reduced the river’s ability to dilute pollutants.
According to him, when the volume of water decreases, substances such as nutrients from agricultural waste or waste discharges will become more concentrated, while the water temperature will increase.
“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.
He also stressed that the current phenomenon in Kelantan is an early indicator of a water security crisis driven by climate change, given the increasingly erratic rainfall patterns and longer drought periods.
“Rivers that look more ‘beautiful’ today may actually be losing their natural ability to support life.
“Therefore, the approach to water resource management needs to change to a more adaptive, data-based, and responsive system to climate change,” he said. – BERNAMA
