Damned if you do

THE greatest of all South-East Asia’s waterways and the world’s 12th-longest river, the Mekong, is a natural wonder that ties together the destinies of half a dozen countries. Born from snowmelt at over 17,000 feet (5,200 metres), it bolts off the Tibetan plateau like a runaway horse; by the time it leaves China it is starting to slow and spread. When it reaches Cambodia, via Laos, it is tropical and ample and, with the monsoon rains, parts of it curiously change the direction of their flow. Farther down, it reaches the South China Sea through a filigree delta. The Mekong watershed nurtures extraordinary biodiversity, with new species of plants and animals discovered every year. It has also nurtured humans. Tens of millions of people—much of the population of Laos, Cambodia, Thailand and Vietnam—depend on the Mekong. Its fish are their protein and its delta is the world’s rice basket. No wonder its name, in Thai or Lao, means “mother of rivers”.

Planners think the mother has one more gift to give: hydropower. China has 14 dams planned or under construction on its stretch of the Mekong in Yunnan province, joining six already built. Today the river is undammed below China, but that will soon change. Laos has nine dams planned or under way; Cambodia has two. Dozens more dams for tributaries are on the drawing board.