The Mekong River Cruise in Vietnam is one of the world's great rivers. It is the world's 10th-longest river and the 7th-longest in Asia. Its estimated length is 4,909 km, and it drains an area of 795,000 km2 (307,000 sq mi), discharging 475 km3 of water annually. From the Tibetan Plateau this river runs through China's Yunnan province, Burma, Laos, Thailand, Cambodia and Vietnam. Laos, Thailand, Cambodia and Vietnam established the Mekong River Commission in 1995 to assist in the management and coordinated use of the Mekong's resources.
In 1996 China and Burma became "dialogue partners" of the MRC and the six countries now work together within a cooperation framework. It then flows across Cambodia and southern Vietnam into a rich delta before emptying into the South China Sea. In the upper course are steep descents and swift rapids, but the river is navigable south of Louangphrabang in Laos.
From the point where it rises to its mouth, the most precipitous drop in the Mekong occurs in what is referred to as the 'Upper Mekong Basin' (see below), a stretch of some 2,200 km (1,367 mi). Here, it drops 4,500 metres (14,764 ft) metres before it enters the Lower Basin where the borders of Thailand, Lao PDR, China and Burma come together in the Golden Triangle. Downstream from the Golden Triangle, the river flows for a further 2,600 km 2,600 km (1,616 mi) through Lao PDR, Thailand and Cambodia before entering the South China Sea via a complex delta system in Viet Nam.
In Yunnan province China, the river and its tributaries are confined by narrow, deep gorges. The tributary river systems in this part of the basin are small. Only 14 have catchment areas that exceed 1,000 km2 (0 sq mi). In the south of Yunnan, in Simao and Xishuangbanna Prefectures, the mekong river changes as the valley opens out, the floodplain becomes wider, and the river becomes wider and slower. The Mekong River is a transboundary international waterway that traverses six countries. The land, water, forest and ﬁ sh resources are shared in a number of senses and at a number of scales among the riparian countries in the region.
Thus, water used by an upstream country may become unavailable to a downstream country on a temporary, seasonal or even permanent basis. Many transboundary environmental issues, such as the upstream-downstream watershed dynamics of water quantity, quality and timing, the trade in timber and non-timber forest products, and air pollution, have begun to receive attention as regional issues. Similarly, some actors and decision-makers in the region have begun to consider issues such as livestock movements, labour migration and public health as being of importance to the regional environment.