Importance and vulnerability of water towers across Northwest China

Abstract

High mountains (known as water towers) in the arid areas of Northwest China (ARNWC) are major suppliers of water resources for the downstream oasis region, where large populations and economic activities are concentrated. Studies on both water supply and water demand in central Asia including ARNWC have been explored in recent decades, but a precise study on the importance and vulnerability of fine-scale water towers still needs to be conducted, because oases are isolated each other and each oasis has its own specific tower(s). Here we ranked the importance of water tower units (WTUs) using a simplified water tower index (WTI) based on water amount of supply/demand side at a fine river basin scale. Then the vulnerability of these WTUs is assessed with the consideration of future changes in climate, population, GDP, water stress, etc. We concluded that the WTU of the Mid-branch Rivers of the Junggar Basin is the most important with the highest WTI, while the Yarkant River Basin is the most vulnerable. The WTUs such as the Yarkant, Hotan and Kaxgar of the Tarim River Basin as well as the Hei River of the Hexi Corridor are important at present and vulnerable under a considerable pressure from future climate change scenarios. To respond to these opportunities and risks, it is better to reduce the proportion of the primary industry appropriately, improve the efficiency of water use and strengthen the supervision of water resources utilization, especially in the industrial and urban planning as well as ecological engineering projects.

Keywords

• Water towers
• Oasis-human vulnerability
• Cryospheric service