The Mekong, one of the world's major rivers, starting in Tibet and flowing through south China, Burma, Thailand, Laos, Cambodia, and Vietnam, provides sustenance through irrigation and fishing to those living in its basin. But it also provides hydroelectric power through dams, three of which were built in China, with more planned. And it is precisely these dams that are now threatening the water supply, the livelihood of those living downstream, and the relations between China and its southern neighbors. A fourth Chinese dam, Xiaowan, that should generate 4,200 megawatts of power, could affect the level of fish stocks in Cambodia and water supply for Vietnam's rice fields. But China contends controlling the water flow will prevent the adverse effects of erosion caused by the Mekong's flooding cycle and will supply renewable energy. Winning the debate or coming to a workable compromise is further complicated by China's refusal to join the Mekong River Commission, an inter-government agency whose members include the four of the downstream countries. And though the global financial crisis has put on hold other dams being planned by the downstream countries, China is moving ahead with its plans.