Mekong River group urges more data sharing on hydropower operations

The changes in water levels have affected navigation, river ecosystems and riverbank stability in the region, where tens of millions depend on the Mekong for their livelihoods.

In a report released on Wednesday, the MRC said hydropower dams were holding back water at the start of this year’s dry season, but releases were partially triggering higher-than-average water flows in the first five months of this year.

Dry conditions in the past two years continue to adversely impact seasonal water flows and interrupt the flooding cycles on the Tonle Sap lake, which much of Cambodia’s population relies on for agriculture, fishing and transportation.

And while parts of Thailand and northern Cambodia saw record rainfall in April to May, the river flow did not register a significant increase in the period, the report said.

The MRC - of which Laos, Thailand, Cambodia and Vietnam are members - also said that while hydropower water releases could be beneficial for agriculture and combating seawater intrusion, the management of the river basin could be improved with more data sharing.

"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," said An Pich Hatda, MRC Secretariat Chief Executive Officer.

China last year agreed to share year-round water level and rainfall data with the MRC and pledged to notify the commission and its member countries of any abnormal changes in water levels.

Chinese Foreign ministry spokesman Wang Wenbin said it was providing data that was "fully open and transparent" to the Lancang-Mekong Cooperation (LMC), another platform of international cooperation set up in 2016.

"China has provided the Mekong countries with real-time hydrological information...and has taken the initiative to report major changes in the discharge flow," Wang told a briefing.

The report also forecast higher-than-average rainfall in June compared to the past two years, but lower than normal rainfall in Cambodia, the Central Highlands of Vietnam and southern Laos in July.