The great biodiversity and precious resources of the Mekong are increasingly endangered by the rush to dam one of the world’s great rivers. A total of 11 mainstream dams and 120 dams on tributaries are planned, which scientists warn will imperil the already fragile river system. Recent studies call for a suspension and review of future projects.

The Mekong ranks as one of the world’s most productive inland fisheries. Its basin banks support a population of 60 million Thai, Laotians, Cambodians, and Vietnamese. But the amount of nutrient-rich sediment flowing downriver has already declined dramatically, so much that a UNESCO report has warned that Chinese dams built on the upper sections, known as Lancang, have caused a 70% reduction in sediment, which will adversely impact fisheries and rice production in Cambodia and Vietnam.

UNESCO, in the report written in partnership with the Stockholm Environment Institute, concludes:

If all the dams proposed for the Lower Mekong Basin are developed, including the planned or ongoing 11 mainstream dams, it could prevent up to 94% of the river’s sediment load from being transported further downstream.

Sediment is critical to the health of the river and essential for replenishing fish life. For Vietnam, the Mekong is crucial – a source from which the country draws approximately 50% of its foodstuffs, and which contributes more than 23% of its GDP. Vietnamese ecologist Nguyen Huu Thien is deeply worried about the next 15 to 20 years. “I am not sure how Vietnam can survive as a nation without the delta,” he said.

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