Mekong Dam Monitor (Update for August 12 - 18, 2024)

 

Update for August 12 - 18

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 Floodpulse is lagging significantly behind schedule Nearly 12 billion cubic meters of water restricted in upstream dams is causing the Mekong Floodpulse to lose energy and fall significantly behind for this time of year. In early August, only 11,500 square kilometers of seasonal flooding was observed in the lower Mekong floodplain. This was an increase of 650 square kilometers from late July, but well under normal for early August seasonal flooding levels of around 17,000 square kilometers. The green in the image shows what should be flooded at this time of the year compared to actual observed flooding (blue).

IMAGE OF THE WEEK Tonle Sap Lake levels are low for this time of year Compare current levels (left) of seasonal flooding at Kamphong Kleang Fishing Village along the Tonle Sap Lake in Cambodia to normal levels from 2018 (right). While the 2018 image might look like a disaster zone to some, this degree of flooding is actually welcomed by over two million people who live along the shores of the Tonle Sap Lake. During the wet season, the lake expands to five times its size and creates the world’s most productive inland fishery which underpins Cambodian food security. Lower than normal flooding translates to lower than normal fish catches, so fishers are likely worried about current conditions. Without dam restrictions upstream across the last month, the lake’s flooded expanse would be significantly larger.

Where is the water? Last week we tracked a large net cumulative restriction of flow of over 1 billion cubic meters of water across 10 dams all located in the downstream countries. China’s dams had no significant restrictions, likely due to a severe drought forming in the upper basin. Major restrictions came from Nam Ngum 1 (LAO, 427 million cubic meters) and Nam Ngum 2 (LAO, 698 million cubic meters). These restrictions have a devastating effect on the Mekong’s fisheries and agricultural outputs, which rely on high river levels throughout the wet season.

Reservoir Storage Over Time

River Levels Precipitation in northern Laos and northern Thailand is causing river levels above Vientiane to return to near-normal levels. However, river levels in Cambodia are now well below normal and trending downward due to a combination of dam restrictions and drier conditions downstream.

Chiang Saen Gauge Stung Treng Gauge

Weather & Wetness A severe drought is developing the Mekong’s headwaters and most of the lower basin. Much of southern Yunnan Province and northern parts of Laos and Thailand are experiencing extremely wet conditions from wet season storms. Flash flooding has been reported in these areas.

Mekong Dam Monitor in the News

• International Water Power highlighted the insights and impacts from the Mekong Dam Monitor annual reports, which provide deep-dive analysis into dam operations