Operations of hydropower projects in China have caused major river flow changes to the Mekong River since 2011, according to research recently published by scientists with Aalto University in Finland.
An analysis of river flows in Northern Thailand indicates that the hydropower operations increased dry season flows, decreased wet season flows, and made dry season flows increasingly variable.
Impacts were largest in 2014 after completion of Nuozhadu Dam, the largest hydropower project in the Mekong Basin, Aalto University says in a press release. This dam, in the Yunnan Province, impounds water for the 5,850-MW Huaneng Nuozhadu hydropower plant, which was reported to be the fourth largest hydro project in China in 2014. These impacts were observable more than 2,000 km downstream in Cambodia, researchers say.
The Mekong River is one of the world’s largest rivers. Energy demand is growing rapidly in the region.
Hydropower operations dampened the Mekong River’s annual flood, a key driver of ecological productivity. “The river flows are feared to affect the ecological productivity of the river and thus the livelihoods, economy and food security of the downstream people,” said research Timo Rasanen. “However, the ecological and social consequences of the hydropower operations are not yet well understood and more research is needed.”
Rasanen indicates downstream countries are building hydropower facilities and the cumulative impacts “need further attention.” “Therefore the research highlights the importance of strong transboundary cooperation between upstream and downstream countries for understanding and mitigating the negative consequences,” he says.
The research was published in the December 2016 Journal of Hydrology.
HydroWorld has reported on several hydro projects under construction on the Mekong River, including 1,285-MW Xayaburi in Laos.