Mekong Dam Monitor (Update for July 29 - August 4, 2024)

 

Update for July 29 - August 4

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 Mekong Dam Monitor adds three new dams, increasing tracked reservoir storage by 3.67 billion cubic meters This week we began tracking reservoir storage levels at three dams which became operational after the launch of the MDM. The Tuoba Dam, China’s 12th and newest Mekong mainstream dam (258 million cubic meters of active storage), became operational in February 2024. Nam Ou 7 (2021) is the largest of a cascade of seven dams in Laos with an estimated active storage of 1.4 billion cubic meters. Nam Theun 1 (2021) in Laos has an estimated active storage of 2.02 billion cubic meters and ranks 6th largest in the Mekong. Their combined active storage (3.67 billion cubic meters) increases the estimated total storage capacity of the Mekong’s largest reservoirs by 7%. Currently we estimate the 60 largest dams in the Mekong Basin hold 54.5 billion cubic meters of active storage. Learn more about these dams on the MDM platform’s Virtual Gauges tab.

IMAGE OF THE WEEK Significant restrictions at the Nam Theun 1 dam in Laos The image shows the Nam Theun 1 Dam in Laos increased its reservoir level by an estimated 25 meters over the last five weeks. Last week alone, we estimate that the reservoir restricted over 900 million cubic meters of water. These severe restrictions drive the river to lower levels along the Thai-Lao border and even Cambodia and reduce the positive benefits of the Mekong floodpulse.

Where is the water? Last week we tracked a cumulative restriction of flow of 5.6 billion cubic meters of water across 23 dams. This is the largest restriction of flow estimated for one week since the MDM launched in December 2020. Nearly half of the restrictions came from Xiaowan (PRC, 2.58 billion cubic meters). Other significant restrictions were observed at Nam Ngum 1 (LAO, 566 million cubic meters), Nam Theun 1 (LAO, 907 million cubic meters), Xepian-Xenamnoy (LAO, 635 million cubic meters), and Lower Sesan 2 (CAM, 520 million cubic meters). These huge restrictions have a devastating effect on the Mekong’s fisheries and agricultural outputs, which rely on high river levels throughout the wet season.

Most Impactful Dams

River Levels Significant precipitation in China and the Golden Triangle caused the river level to rise more than four meters last week in a matter of days. This pulse of water is moving down through the Mekong mainstream. Currently, this pulse has caused river levels above Vientiane to rise to above normal levels. River levels below Vientiane are currently below normal but are expected to rise to over the coming week as the pulse moves downstream. According to the MRC, river levels are currently not predicted to exceed flood stage.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness Wetness levels well above average were observed in much of China’s Yunnan province and the Golden Triangle last week. Eastern portions of Laos and the highlands of Vietnam remain wetter than usual. Most parts of Thailand and Cambodia are experiencing drought conditions. Vietnam’s delta was much wetter than usual.

MDM in the News

• Nirmal Ghosh interviews Brian Eyler in the Green Pulse Podcast about impacts on local Mekong communities and ecosystems from upstream dam development
• WION highlights a recommendation from Australian Strategic Policy Institute that India and partners implement an open source satellite monitoring platform similar to the Mekong Dam Monitor on the Brahmaputra river basin