Water Resources in the Hexi Corridor and Its Cycle

The Qilian Mountains are the cradle of all inland rivers in the Hexi arid region. The mountain glaciers are importantwater resources for this region. Changes in the mountain runoffs resulting from global climate warming will have important impacts on the development of human society and economy in the region. In this paper, the river runoffs from the Qilian Mountains and their dynamic changes are analyzed on the basis of instrumental data of precipitation, air temperature, and discharge from the weather and hydrological stations in the study area. The results show that the annual change in mountain runoffs is affected mainly by precipitation in the east of the region, but also by temperatures in the west of the region. There are some obvious regional differences in the influence of climatic change on surface runoffs in the Hexi region. River runoffs in the western part of the Hexi region have been increasing, whereas those in the eastern part have been decreasing. River runoffs in the central part, such as the Heihe River, present a slowly increasing trend,although it is not quite visible.