Mekong Dam Monitor (Update for May 27 - June 2, 2024)

 

Mekong Dam Monitor

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Update for May 27- June 2 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 2024 Dry Season Releases Were the Lowest in Three Years Last week marked the end of the 2024 dry season. If you’ve been following our reporting over the last six months, you’ll know that river levels have been much lower than previous years due to relatively low dam releases of water for hydropower production. The chart below shows just how much lower total dam releases were throughout the basin this year compared to the previous two dry seasons. Most of the difference is coming from China, where hydropower production was much more muted than previous years due to a drought in 2023 and where a new mainstream dam has almost completely filled its reservoir during the dry season. As a result, parts of the river closest to China were running at relatively closer to normal levels. Dam releases from the large dams in central Laos exceeded China’s, and releases from dams in other parts of the Mekong were about the same as previous years. The operations of China’s 12 dams have a significant impact on the downstream, but that impact is lessened when they release less water as they did in 2024.

IMAGE OF THE WEEK Nuozhadu Reservoir Continues to Rise The largest dam in the Mekong, Nuozhadu, continues to restrict Mekong flow as it fills unseasonably early. Since late April, its reservoir has increased more than 15 meters, restricting more than 4 billion cubic meters of water. The reservoir has exceeded its maximum 2023 level and is approaching 2022 levels. Early June is a critical time for the river to be rising downstream. Now that Nuozhadu has filled somewhat adequately, it would be most useful for the Nuozhadu dam operator to moderate or limit further filling until later in the wet season to allow important downstream ecological processes to initiate.   Nuozhadu Reservoir Continues to Rise

Where is the water? Like clockwork, the start of the wet season saw a huge net flow restriction of 2.27 billion cubic meters last week. The most significant restrictions came from Huangdeng (PRC, 175 million cubic meters) and Nuozhadu (PRC, 2.19 billion cubic meters). Major restrictions like these are extremely damaging to early wet season ecological processes.

Reservoir Series Over Time

River Levels In the Golden Triangle along the Thai-Lao border, river levels are lower than normal. Downstream from Vientiane, river levels are at normal or slightly higher than normal levels for this time of year.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness A major snow melt event in China increased the river’s natural flow, but most of this was restricted behind China’s Tuoba and Nuozhadu dams. A drought pattern is emerging once again throughout much of the Mekong with some extreme wetness observed in the lower 3S Basin and Cambodia’s Cardamom Mountains. Vietnam’s delta remains wetter than normal for this time of the year, largely due to irrigation.

Upcoming Webinar

 June 10 from 9 - 10:30 PM ET | June 11 from 8:00-9:30 AM Asia/Bangkok
The Mekong’s wet season is underway after a dry season marked by extremely high temperatures and some of the lowest river levels observed in recent years. A new dam (Tuoba) is filling its reservoir, and Nuozhadu the largest reservoir in the Mekong is filling unseasonably early! How did all of this plus regular water releases from dams for hydropower generation across the basin impact the Mekong? How might the 2024 wet season play out in terms of potential La Nina impacts and the operations of over 100 dams?

Join the Mekong Dam Monitor team and outside experts for a discussion about what the data shows about the previous dry season and forecasting about how dam operations and weather will impact the hydrology and ecology of the river this coming wet season. Simultaneous translation will be available for 6 local Mekong languages (Burmese, Khmer, Lao, Thai, Vietnamese, Chinese).  RSVP today!