干旱区生态环境知识资源中心

The City of Urumqi is situated in northwestern China in a semiarid environment with an extremely continental climate. It is located in a narrow green grassland corridor between the Gurbantunggut Desert and semi-desert lowlands in the north and the glaciated Tianshan Mountains in the south. The annual precipitation is about 200 to 300 mm with most of the water necessary for human activities provided by the mountainous surroundings. Urumqi represents one of the most dynamic city developments of the last 50 years, shifting from a traditional Central Asian city of less than 100,000 inhabitants in 1950 to the most important economic growth pole of northwestern China with approximately 4 million people in the greater Urumqi region. In the 1950s, the central government began to transform solely the extensively used peripheral areas of the northwestern basins into areas with more intensive utilisation, thereby facilitating first agricultural and later also industrial expansion. Not surprisingly, this successful economic development resulted in a rise in water demand in this ecologically sensitive dryland environment. Rivers and smaller streams supply the greater Urumqi region with mountain and glacial water throughout the year. On the foothills, the surface runoff seeps into and infiltrates the alluvial fan, in which surface and groundwater are in an intensive exchange. Therefore, it is difficult to differentiate between surface and groundwater bodies in and outside of the urban area and to determine and specify the consequences of human activities on its quality and quantity. Despite the topographical advantage of the city, Urumqi faces several water-related challenges: 1) high evaporation rates due to storage and transportation in open canal systems as well as flood irrigation, 2) low water quality due to intensive usage and general salinisation, 3) very high water consumption rates, and 4) overexploitation of groundwater resources. Additionally, global climate change affects the sensitive water balance in the region. The quantity of precipitation tends to increase and to lead to a more variable and concentrated runoff regime. Additionally, rising temperatures cause the glaciers and snowfields in the mountains to melt and reduce the storage capacity, which originally provided melt water during the vegetation and planting period. Therefore, adaptation to the changes includes increasing the efficiency of water usage, thereby decreasing the overall consumption, securing the water supply by enhancement of the storage and transportation system, and improving the water quality by means of better water treatment and management. However, these investments and changes have to be made without compromising the overall economic development, which is probably the greatest challenge. Future research will have to analyse the exact consequences of climate change and anthropogenic activities in order to develop feasible measurements and interventions as well as to monitor the results of technical implementation.