Mekong Dam Monitor (Update for Dec. 11 - 17, 2023)

 

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Update for December 11-17 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 MDM Annual Report Highlights Dam and Climate Change Impacts We’re proud to publish our annual Mekong Dam Monitor report, which for the first time shows the monthly impacts of dams and climate at multiple locations along the river’s course. Our analysis demonstrates that dams can reduce wet season flow by almost 20% downstream in Cambodia and double river flow there during the dry season, leading to significant environmental and social impacts. The report also sheds new light on how the Tonle Sap Lake expands during the wet season and makes a case for greater conservation of Southeast Asia’s largest lake. The report provides useful policy and planning recommendations to conserve the Mekong’s natural resource base and help tens of millions of people who rely on the Mekong better adapt to change around them. Click here to read the full report.

IMAGE OF THE WEEK Mekong Floodpulse continues to reduce as the dry season progresses Seasonal inundation in the Lower Mekong floodplain decreased from 14,500 square kilometers at the end of November to 12,500 square kilometers in mid-December. This reduction is normal for this time of the year and progression of the dry season. However, note how the map shows several new reservoirs on the periphery of the Tonle Sap. We counted at least five in Cambodia and three in Thailand. These reservoirs are full with water from the wet season. Little is known about how these reservoirs operate or their impacts on the Mekong Floodpulse.

Where is the water? We tracked a net release of 417 million cubic meters last week with the largest release coming from Nam Ngum 1 (172 million cubic meters, LAO). This total release would have been higher if the Xiaowan Dam did not restrict over 200 million cubic meters of water. It is unusual for large dams in China to increase their storage at this time of the year. The upper basin is experiencing wetter conditions than normal, and this created conditions for a rare dry season restriction. Most Impactful Dams

River Levels Eyes on Earth estimates there is 15% missing water at the Chiang Saen gauge as a result of a recent flow restriction at the Xiaowan Dam. River levels along the Thai-Lao border are lower than normal for this time of year, while levels from Stung Treng downstream are normal.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness The lower basin, especially Laos, is experiencing extremely warm temperatures for this time of year. The upper basin in China and the lower basin in Thailand, southern Laos, Cambodia, and Vietnam are wetter than normal. Southern Yunnan, Myanmar’s Shan State, and northern Laos are drier than normal.