US researchers have collected satellite data for 28 years, showing that Chinese hydroelectric dams alter the natural flow of the Mekong.

"In 2019, the water level of the Mekong River measured at Chian Saen Station is much lower than the estimated natural flow," said Alan Basist, Director of Eyes on the Earth (EOE), co-author of the newspaper.

According to Basist, EOE, funded by the US Department of State, used satellite data to estimate the natural flow of the Mekong River, for 28 years, from 1992 to 2019. After 28 years, EOE calculated

"From the data above, we speculate that the natural flow of the Mekong has been completely blocked by hydroelectric dams in China," Basist said.

In fact, the MRC in July 2019 published a report showing that the Mekong water was then below its previous lowest level.

Basist lists 11 Chinese hydropower dams operating from 1993 to 2018: Man Loan, Dai Trieu Son, Canh Hong, Tieu Loan, No Trac Do, Mieu Vi, Hoang Dang, Dai Hoa Kieu, Cong Qua Kieu and Ly De.

According to Basist, China is also changing the natural flow of the Mekong by releasing water to operate hydroelectric dams.

EOE data shows that in 2002, an unusually large amount of water in the Mekong flow downstream.

"The Mekong River water in the dry season of 2002 increased and decreased dramatically compared to the natural flow forecast index," Basist said.

After 2012, when the No Trac Do dam was operated, the natural flow of the Mekong River was significantly adjusted.

In the Monitoring of water flows through the upper Mekong, Basist and colleagues point out that between 1994 and 2008, the flow data of the Mekong River was measured at Chian Saen station and the flow estimate data.

Basist said that the natural flow of the Mekong is essential, to maintain the vitality of the river and the integrity of the basin.

Further explaining the impact when China changes the natural flow of the Mekong, Brian Eyler, Director of the Southeast Asia Program, Stimson Research Center, USA, said the ecosystem of the Mekong plays an extremely important role.

Eyler said China for decades kept confidential information about the operation of hydroelectric dams and the amount of water discharged downstream, not shared with related countries.

"Now is the time for China to share data with other countries. It is the best step for Beijing to become a constructive partner in the region," Eyler said, answering VnExpress's question about data.