Harnessing the flow:The Zangmu Hydropower Station in Gyaca county in Lhoka, Tibet.AFPSTR  

A new study highlighting the impact of China’s dams on the Mekong river has raised fresh questions on whether dams being built on other rivers that originate in China, such as the Brahmaputra, may similarly impact countries downstream.

While China’s southwestern Yunnan province had above-average rainfall from May to October 2019, there was “severe lack of water in the lower Mekong”, the study found based on satellite data from 1992 to 2019.

The Mekong flows from China to Myanmar, Laos, Thailand, Cambodia and Vietnam. The Mekong River Commission, which comprises Cambodia, Laos, Thailand, and Vietnam, has said more scientific evidence was needed to establish whether dams caused a 2019 drought.

The study released this month said six dams built since the commissioning of the Nuozhadu dam in 2012 had altered natural flow of the river. It was published by the Sustainable Infrastructure Partnership in Bangkok and the Lower Mekong Initiative, which is a U.S. partnership with all the downstream countries besides Myanmar. The study was funded by the U.S. government.

‘Groundless study’

China has maintained that the dams it is building on the river, known as the Lancang there, are “run of the river” dams that only store water for power generation. The Foreign Ministry said the study was “groundless”. Yunnan had also suffered from drought, while the Lancang only accounted for 13.5% of the Mekong’s flows.

India has long expressed concerns over dam-building on the Brahmaptura. In 2015, China operationalised its first hydropower project at Zangmu, while three other dams at Dagu, Jiexu and Jiacha are being developed.

Indian officials have said the dams are not likely to impact the quantity of the Brahmaputra’s flows because they are only storing water for power generation. Moreover, the Brahmaputra is not entirely dependent on upstream flows and an estimated 35% of its basin is in India.

India does not have a water-sharing agreement with China, but both sides share hydrological data. “We have got China to cooperate with us for warnings on how floods are moving down the Yarlung Tsangpo and into the Brahmaputra, so that we can warn our population living in low-lying areas and move them safely to higher ground,” said Gautam Bambawale, who was India’s Ambassador to China until December 2018.

“India will continue to raise the issue of river waters in the Brahmaputra with China, as that appears to be the only methodology to ensure what happened on Mekong does not happen on Brahmaputra,” he said.

Management problem

“India, for the most part, doesn’t have a quantity problem but a management one,” added Ambika Vishwanath, who researches water security and is director of the Kubernein Initiative. “We really need to worry more about activity in China affecting quality, ecological balance, and flood management.”

The Mekong study, she added, was not conclusive on the question of how China’s dams had affected quantity of flows. “To state that the basin had less water because of activities in China alone is misleading, mainly because that only considers the water flowing into the lower basin at one station in Thailand,” she said, adding that the study did not consider other dams and water-use along the course of the river. The lower basin isn’t entirely dependent on flows from China, but also receives water from tributaries in all four countries, which the study did not account for.

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