Reconciling the regulations and conservation of the Lhasa River, Tibet

Excerpt

The Lhasa River of Tibet (figure 1), flowing through the Lhasa City with a main stream length of about 555 km (345 mi) and a mean gradient of 0.29%, is the largest tributary of the Brahmaputra River, which is traced back to the Pangtso Lake at the southern face of the Nyenchen Tanglha Mountain. Lhasa, the long-standing capital of Tibet, plays a particular role in the life of Tibetans with regard to history and customs. The Lhasa River critically supports agricultural irrigation, township water supply, and even the formation of certain traditions of local Tibetans. As a consequence, any regulation/conservation activities imposed on the river may also cause unexpected (or potential) threats to the fragile surrounding environments. Thus, conservation practices for the Lhasa River should incorporate and reconcile multiple objectives, such as concerns about flood prevention, safety, ecological health, aesthetics, and ethics.

Flood prevention has been a challenge for the Lhasa River for a long time (Wangdui 1988; Xu 2001). As early as 1562, heavy storms flooded Lhasa (Fang 1996), causing a long-standing fear of flooding threats. The new China has made flood preventions of the Lhasa River a priority. In the summer of 1962, several lasting storm events resulted…