Mekong River Basin

The Mekong River Basin is the drainage basin of the Mekong, the world's twelfth-longest river and the third-longest in Asia at about 4,350 kilometers, covering roughly 795,000 square kilometers and discharging about 475 cubic kilometers of water a year. The river rises at Lasaigongma Spring on Mount Guozongmucha in Qinghai province at an elevation of 5,224 meters and flows through China, Myanmar, Laos, Thailand, Cambodia and Vietnam before emptying through the Mekong Delta into the South China Sea. Only the Amazon basin has a higher level of biodiversity, and the Mekong basin is home to about 20,000 plant species and 850 freshwater fish species. Extreme seasonal variation in flow, along with rapids and waterfalls, makes navigation difficult despite the river's importance to regional trade.