Mekong Basin Nature Nonprofits

The Mekong runs nearly five thousand kilometres from the Tibetan plateau to the South China Sea, and it feeds one of the largest inland fisheries on Earth. Tens of millions of people get most of their protein from this river. Its defining feature is the flood pulse: each monsoon the river swells so violently that in Cambodia it reverses the flow of a tributary and fills the Tonle Sap lake to several times its dry-season size, and the fish breed in the flooded forest.

Dams are dismantling that system. A cascade of hydropower on the mainstream and its tributaries traps the sediment that built and sustains the delta and blocks the fish migrations the flood pulse depends on. The Mekong Delta in Vietnam, which grows a large share of the region’s rice, is now sinking and salinating as the sediment fails to arrive and the sea pushes in.

The organizations here contest the dams, defend the fisheries and the communities that live on them, and work on a river governed by six countries that do not agree on much.