Cascade effect: The Mekong River and China's Hydropower Ambitions

By building dams on the upper Mekong, China has triggered a revival in hydropower ambitions downstream, writes Philip Hirsch.
Much has been written on the downstream impact of China’s dams on the Mekong River, which flows through or along the borders of Burma, Laos, Cambodia, Vietnam and Thailand after exiting China (where it is known as the Lancang). The discussion largely focuses on the hydrological impact of impounding water in the eight dams along the mainstream upper Mekong River in Yunnan Province. The Mekong Cascade, as it is termed, has caused considerable controversy in downstream countries, most notably during the 2008 floods and the 2010 drought, which many blamed on China’s actions.

Clearly, the cascade has major implications for downstream hydrology, with the potential to exacerbate or ease both floods and droughts and impact on fisheries and other sources of income. (chinadialogue has published recent articles on the implications of altered river hydrology and China’s need for better public relations around its schemes). But China’s dams also have indirect ramifications, which receive less attention. Most notable of these is a revival of dam aspirations among downstream governments.

There are currently proposals for up to 11 dams on the lower Mekong mainstream, the section of the river below China. Some of these are in areas bordering or inside Laos, Cambodia and Thailand, three of the four countries that are member states of the Mekong River Commission (MRC), an inter-governmental agency formed in 1995. Dams have been planned for the lower Mekong since the 1950s, but the Cold War subsequently put development on hold. By the time mainstream dams came back onto the agenda in the early 1990s, environmental concerns over large dams had grown to the extent that simply dusting off these megaprojects designed a generation earlier was unpalatable and, until recently, it was widely assumed mainstream dams were off the agenda altogether.