Streamflow Characteristics of the Eastern Qinghai Plateau
Yang Zhenniang (Lanzhou Institute of Glaciology and Geocryoiogy, Chinese Academy of Sciences) Woo Ming-Ko (Department of Geography, McMaster University, Hamilton, Ontario, Canada)
The eastern Qinghai Plateau is the headwater area for many large Asiatic rivers. Permafrost occurs above 4 200 m and glaciers occupy the summits and high valleys of the east-west trending mountain chains. Annual runoff generally increases with precipitation which is augmented southward by the rise in topography. Rainfall, snow melt, glacier melt and groundwater are the primary sources of streamflow, and the presence of permafrost enhances the flashiness of runoff respons to rainfall and snowmelt events. Peak flows are concentrated between June and September. And winter is the low flow season. Three types of runoff patterns may be distinguished according to their primary sources of water: snowmelt and rainfall, glacier melt and snowmelt, and groundwater. Large rivers generally drain more than one environment and their runoff regime reflects an integration of the various flow patterns found on the plateau.