The Mekong River Commission (MRC)China and its Southeast Asian member states to share more data on hydropower operations that are contributing to the increasingly wild fluctuation in water levels on the vital waterway.
In its latest, released yesterday, the MRC said that changes in river levels had been caused partly by water releases from hydropower storage dams on the upper Mekong. The MRC noted that dam storage reservoirs had held back water at the start of this year’s dry season – in February, the commission conditions on the river as “worrying” – but that subsequent water releases were to blame for higher-than-average water flows in more recent months.
The MRC report covered the period of the driest season, from November 2020 to May 2021. During this time, it said, water levels on the Mekong in Laos and Thailand fluctuated, while water levels in Cambodia’s Great Lake, which expands and contracts in rhythm with the flow of the Mekong, were lower than usual.
Overall, flows in the Mekong in the first five months of 2021 were higher than the long-term average, the report found, due to releases from storage dams. While increased flows during dry months had some benefits for farmers along the lower Mekong, and could help stave off seawater intrusion in the Mekong Delta, the MRC stated that the recent erratic flow has affected navigation, river ecosystems, and riverbank stability on the lower Mekong, where more than 60 million people depend on the river for their livelihoods.
As a result, the MRC urged China, as well as its four members – Cambodia, Laos, Thailand and Vietnam – to share data with each other in order to mitigate the potential impact of dam-driven surges.
“For the sake of better management of the basin and of good faith cooperation, both Member Countries and China should notify any planned major changes in the operation of hydropower projects and share that information with the MRC Secretariat,” An Pich Hatda, the Secretariat’s chief executive officer, said in aaccompanying the release of the report.
While the MRC report was characteristically technical and diplomatic in its phrasing, a major impact on the river’s flow has come from the string of 11 dams that the Chinese government has built on the upper reaches of the Mekong, known as the Lancang inside China.
China’s dams are not solely to blame for the Mekong’s problems: The region has experienced a string of droughts due to an El Nino weather system, and also faces the long-run effects of climate change. But there is increasing evidence that China’s dam-building spree has exacerbated these problems.
In April of last year, the U.S.-based research and consulting group Eyes on Earth published a studyChinese dam reservoirs had held back excess monsoon rains across six months in mid-2019, exacerbating drought conditions in the five downstream nations.
Last year, in part due to mounting pressure from the U.S. government, China agreed to share data on water levels and rainfall with the MRC, promising to alert the commission and its members of abnormalities.
China’s foreign ministry spokesman Wang Wenbin said yesterday that Beijing was “completely open and transparent” in providing data via the Lancang-Mekong Cooperation mechanism, which facilitates cooperation between China and the Lower Mekong countries. (China is not a member of the MRC.)
“Since November 2020, China has been providing hydrological information of the Lancang River to Mekong countries on a daily basis… and has been offering notification on major changes in discharge volume downstream,” Wang said.
But from some accounts, the Chinese government has yet to provide the degree of transparency necessary to allow residents in Thailand, Laos, Cambodia and southern Vietnam to brace for the inevitable impacts of its engineers’ operations on the Lancang cascade.
In early January, shortly after a suddenin water levels, Beijing did its downstream neighbors that its dams were filling reservoirs and flow would soon be restored to “normal operation status” – but only after the damage had been done.