Characterization Of Groundwater Storage In The Heihe Headwater Watershed, Qinghai-Tibet Plateau, China
Evans, Sarah 1 ; Ge, Shemin 2 ; Zhou, Min 3 ; Liang, Sihai 4 ; Chen, Jiangwei 5
1 University of Colorado Boulder
2 University of Colorado Boulder
3 Peking University
4 China University of Geosciences
5 China University of Geosciences
A warming climate has led to decreases in permafrost extent and water insecurity in the Qinghai-Tibet Plateau in China. It is speculated that this will cause large-scale changes water resource availability. These speculations bring up questions: At what amount does groundwater storage contribute to stream flow in headwater watersheds? How is groundwater flow affected by permafrost? To address these questions, we have developed a three-dimensional, groundwater flow model for the Hulugou Watershed, the headwaters of the Heihe River located on the northern edge of the Qinghai-Tibet Plateau (Figure 1). Headwater watersheds such as the Hulugou Watershed are of particular interest due to their direct impact on the water resources of downstream regions.
Model results suggest that stream discharge is primarily from groundwater contributions in the form of base flow (54%). Results also highlight the effect permafrost has on groundwater flow (Figure 2). In the higher elevation permafrost region, the majority of flow (56%) is in the 3 m thick suprapermafrost zone, disrupting the typical topographically-controlled nested flow that is observed in most headwater watersheds. These results have direct consequences for aquatic system health, water resource availability, and the efficiency of geomorphic and sedimentological processes.