Mekong Dam Monitor (Update for July 15 - 21, 2024)

 

Update for July 15-21:

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 Upstream river levels are low, but downstream river levels are high This week the Mekong’s upstream looks entirely different from its downstream. At Chiang Saen, Thailand, river levels are much lower than average due to major restrictions from dams in China like Xiaowan (see image of the week below). We estimate river levels at Chiang Saen would be slightly above the average line without dam restrictions. However, far downstream at Stung Treng, Cambodia, river levels are far above normal due to recent precipitation outpacing the negative effects of dams. A tropical storm currently hitting Vietnam’s border with Laos will likely drive the Stung Treng gauge even higher over the next week, promoting a strong flood pulse that will help drive the expansion of the Tonle Sap Lake and the productivity of its fisheries.

PHOTO OF THE WEEK Significant restrictions at China’s Xiaowan Dam Over the last month, the Xiaowan Dam in China (the 2nd largest in the Mekong) has restricted an estimated 1.31 billion cubic meters of water, driving the river along the Thai-Lao border to lower than normal levels. These large restrictions pull down the mighty Mekong flood pulse and deliver significant impacts to the river’s ecology upon which tens of millions of people rely on for their livelihoods.

Where is the water? We tracked a large cumulative restriction of flow (1.77 billion cubic meters) at 19 dams across the basin last week. The most significant restrictions came from Xiaowan (PRC, 713 million cubic meters), Nam Ngum 1 (LAO, 324 million cubic meters), Nam Ngiep 1 (LAO, 107 million cubic meters), Theun Hinboun Expansion (LAO, 202 million cubic meters), Ubol Ratana (THA, 183 million cubic meters), and Sirindhorn (THA, 121 million cubic meters). These restrictions are common at this time of the wet season but have a negative effect on the Mekong’s fisheries and agricultural outputs which rely on high river levels throughout the wet season.

Most Impactful Dams

River Levels Above Savannakhet river levels are trending below normal levels. Below Savannakhet, river levels are now above normal.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness Drought conditions mostly improved throughout the basin last week. Most of southern Laos is currently experiencing above average wetness (blue), which will likely continue into next week due to a recent tropical storm. Pockets of extreme drought (red) are still persistent in northern Laos and parts of Cambodia, despite recent storms there.