Mekong Dam Monitor (Update for February 3-16, 2025)

 

Update for February 3-16, 2025 Notable changes on the Mekong in the last week. Visit the Monitor home for more, including Burmese, 中文, Khmer, ພາສາລາວ, ไทย, and Tiếng Việt translation.

SPOTLIGHT Dry season river levels are generally higher than normal so far in 2025. Between December and January, river levels were unusually high at Chiang Saen as a result of higher-than-normal surface wetness from rain and/or glacial melt in China. When combined with dam releases, river flow was 23% and 43% higher than normal in December 2024 and January 2025, respectively. Farther downstream, the river returned to closer to normal levels. At Nakhon Phanom, dam releases helped the river achieve normal levels in December 2024 and 16% higher than normal levels in January 2025. In December at Stung Treng, Cambodia, drier than normal conditions in the lower basin created 10% lower than normal flow, and subsequent dam releases buoyed river flow to 20% higher than normal in January.

IMAGE OF THE WEEK Dam Releases Raise the River 20% higher than normal in January. At Stung Treng, Cambodia we estimate the January natural flow would have been normal without dam releases, when historically compared to how the river flowed prior to dams. Dam releases raised flow about 20% higher than normal levels. About half of those releases came from dams in China where flow from China accounted for 44% of total observed flow to Stung Treng. We haven’t observed this high of a monthly flow contribution from China since May 2019. The higher-than-usual flow contributions in China come from a combination of dam releases and wetter than usual surface conditions in the upper Mekong.

Where is the water? Last week dams throughout the basin released a large cumulative total of 1.799 billion cubic meters of water. During the dry season, releases from dams for hydropower production artificially raise the level of the river. Nearly half of dam releases last week came from Xiaowan (PRC, 874 million cubic meters). Other significant releases came from Nuozhadu (PRC, 332 million cubic meters), Nam Ngum 1 (LAO, 235 million cubic meters), and Ubol Ratana (THA, 130 million cubic meters).

Most Impactful Dams

River Levels River levels throughout the basin are slightly higher than normal.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness Excess wetness continues to accumulate in the upper basin in China. Parts of northern Laos and more than half of Cambodia’s Mekong are much drier than normal. Northeast Thailand, central Laos, western Cambodia, and Vietnam’s portions of the Mekong basin are wetter than normal.