PRC’s hydroelectric dams threaten Mekong River

FORUM Staff

The Mekong River stretches nearly 5,000 kilometers from the Tibetan plateau, winding through Myanmar, Laos, Thailand, Cambodia and, ultimately, Vietnam’s Mekong Delta. The river, the longest in Southeast Asia, carries nutrient-rich sediment essential to the livelihoods of those who rely on the waterway for agriculture and fisheries.

But the river is drying up. In recent years, its water levels have been among the lowest recorded, according to an analysis by the Stimson Center, a Washington, D.C.-based think tank, Radio Free Asia reported in 2022. On the lower Mekong, levels are sometimes so low that people can walk across. Much of the vital sediment, which 15 years ago was estimated at 143 million tons yearly, is being blocked. Such conditions contribute to food insecurity and environmental crises for nearly 60 million people downstream, according to an August 2023 report by Voice of America (VOA).

While acknowledging the role of climate change, experts say there is a direct culprit for the river’s woes: the People’s Republic of China’s (PRC) construction of hydroelectric dams on the upper Mekong, which is known as the Lancang in China.

“Dams act as physical barriers that block fish migration pathways and trap sediment and nutrients, with knock-on effects on … lower water levels and saline intrusion,” the World Wildlife Fund reported in October 2023.

The PRC has built at least 95 hydroelectric dams on the Mekong’s tributaries, Reuters reported in December 2022. Since 1995, it also has built 11 mainstream mega-dams, with more planned, and helped build two dams in Laos.

It is not only the dams, but how they are managed that contributes to the crises downstream, with analysts contending that Beijing acts with little regard for other Mekong nations.

The PRC “takes water out of the river during the wet season and then puts it back during the dry season for hydropower production,” Brian Eyler, director of the Stimson Center’s Southeast Asia Program, told VOA. “That exacerbates the kind of drought conditions that are setting in now.”

The PRC “needs to recognize that wet season flows need to be robust, and to date, China denies this,” he said.

The Mekong River Commission estimates that by 2040 less than 5 million tons of river-borne soils will reach the delta each year. The commission, which was formed in 1995 by countries bordering the river basin, works with member nations to manage water resources. The PRC, however, has not signed a water-sharing agreement with its neighbors.

“The river is not bringing sediment, the soil is salinized,” Tran Van Cung, who has grown rice at his family’s farm in Vietnam for more than 40 years, told Reuters.

Cung, 60, said his harvest brings in barely half of what he earned a few years ago, and that his two children and neighbors have left the region to seek work.

“Without sediment,” he said, “we are done.”