Mekong

The Mekong is one of the world’s major rivers in Southeast Asia. Roughly 4,350 kilometers in length, it rises on the Tibetan Plateau in China and flows generally south through Yunnan, then through Laos, Thailand, Cambodia, and Vietnam to the South China Sea. It supports millions of people as a source of water, food, and transport.

The river’s basin spans several climate zones with a pronounced monsoon-driven flood pulse. In Cambodia, the Tonlé Sap River connects with the Mekong and fills Tonlé Sap Lake during the wet season; in the dry season, water is released back to the Mekong, helping maintain flow into the delta. In the lower basin, the Mekong forms extensive distributaries that create the Mekong Delta in Vietnam, a densely populated agricultural heartland.

The basin is highly productive, hosting hundreds of fish species, including migratory taxa and several threatened forms. The river supports capture fisheries, irrigation, and transportation, underpinning rural livelihoods and regional economies across multiple countries.

Management and issues: The Mekong River Commission, formed in 1995 by Cambodia, Lao PDR, Thailand, and Vietnam, coordinates water resource management and development in the lower basin. China and Myanmar participate as dialogue partners. Upstream dam construction and climate variability alter flow regimes, affecting fisheries, sediment transport, and flood-dependent agriculture, leading to ongoing efforts to balance hydropower development with ecological and social resilience.