Low sediment turning the Mekong river blue
The year 2020 is shaping up to be crucial for the Mekong River, which is under threat from climate change and faces uncertain changes wrought by two new hydropower dams that have come online in Laos in the last three months.
Many fear the new Lao dams - the first on the Lower Mekong that generates most of the vast system’s sediment - will impede the nutrient flow.
Scientists say the Mekong’s new blue colour – first seen in November in northern Thailand and now evident down the river into Cambodia - is caused by shallow, slower moving waters.
Normally, sediment flows all through the 2,390-km Lower Mekong, nourishing fishing grounds and farmlands as it flows in from China then winds past Myanmar, Laos, Thailand, Cambodia and Vietnam.
It is the sediment that keeps the river a muddy brown, but when the water flow slows, the sediment can settle.
Unpredictable and extreme
The fishers and farmers of the Thai village of Bungkhla say they have seen the Mekong gradually changing before their eyes in the past decade, with less predictable rainy and dry seasons and fewer, smaller fish.
But in the past year, the change has been more dramatic as a drought during the last rainy season, from May to October, extended into this dry season.
“I’ve never seen the river this dry,” said Tongchai, 52, who has plied the river since he was a teenager.
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