General

The Shiyang River Basin has an area of some 41,600 km2. Eight tributary stream from the Qilian mountains in the south and flow out over alluvial fans into the plain and towards the Badanjilin Desert in the north. To the east is the Tenggeli Desert. These eight streams all join the Shiyang River in the middle basin, which then flows through the Minqin oasis before terminating in the Quing Tu lake. The Quing Tu lake dried up in the early 1960s following construction of the Hongyashan Reservoir, and extension of irrigation in the Minqin oasis.

Precipitation occurs mainly over the mountains in the south, and is of the order of 600 mm annually. In the north of the Shiyang River Basin, average annual precipitation is of the order of 60 mm. Most runoff is thus generated in the mountains in the south, and much of it from snow and glacier melt in the spring and summer. In the mountains in the southwest there is natural vegetation cover, but north and east of the mountains vegetation exists only in the river corridors where there is