Mekong Dam Monitor Weekly Update for May 12-June 1: Spotlight: 2026 Dry Season Flow Would Have Been Normal. Dam releases from throughout the Mekong Basin prevented the Mekong from having a normal dry season flow pattern. From Chiang Saen, Thailand to Stung Treng Cambodia, the top of the blue bars show how monthly flow would have mostly matched the pre-dam flow conditions along the course of the Mekong for the entire dry season particularly for the critical months of March and April when the river should achieve its natural low point. Instead, dam releases for hydropower production raised the river to unnaturally high levels. In March at Chiang Saen, dam release from China doubled natural flow—from February to May overall, these releases doubled natural flow. From March to May at Nakhon Phanom, dam releases from China and northern Laos nearly doubled natural flow. These impacts carried through to Stung Treng, Cambodia where flow from March to May also doubled. Significantly higher water levels during the dry season are extremely harmful to local ecologies and natural resource provisions that rely on consistently low river levels during the dry season. Image of the Week: Most of 2026 Dry Season Flow came from China. The map shows that among the five sub-basins, China contributed 37% of dry season flow to Stung Treng, Cambodia from December 2025 through May 2026. Flow includes releases from dams and the natural flow of the river. This is slightly below average (38%) for the 2008-2026 time period when dams have significantly altered river flow. Prior to 2008, China contributed about 32% of flow to Stung Treng. Total dam releases for the dry season are estimated at 27.03 cubic kilometers. Natural flow for the dry season is estimated at 58.7 cubic kilometers— about 13% higher than pre-dam average flow of 51.3 cubic kilometers. Therefore, under natural conditions, the river would have been slightly higher than normal for the 2026 dry season, and dam releases raised the river by an additional 50%. Where’s the Water: Last week saw a mix of releases and restrictions throughout the basin with a final net change of 300 million cubic meters of water added to the river system through dam releases. Nuozhadu (PRC) was the only dam to release a significant amount of water with 280 million cubic meters. This is the time of the year when dams begin to restrict flow and fill their reservoirs, so relatively low changes to the natural hydrological cycle are expected. River Levels: Levels throughout the Mekong are between 1 and 1.5 meters higher than the long-term average mostly due to upstream dam releases still making their way through the basin. Learn more at mekongmonitor.stimson.org.