By building dams in the Himalayas, Chinese engineers are tinkering with one of the world's great sets of watersheds. Five great streams-the Red River, the Yangzi, the Irrawaddy, the Salween and the Mekong-flow within about 180 kilometres (110 miles) of one another from the south-eastern edge of the Tibetan plateau, separated by parallel mountain ranges, before charging off to empty eventually in different seas. Yet research suggests that before this plateau began to rise, 50m years ago, at least two of these streams, and possibly more, were one.
展开▼
