干旱区生态环境知识资源中心

This paper describes the characteristics of water resources utilization in the Tarim River basin in terms of both its quality and quantity. It is found that the water cycle and water qualities have changed greatly because of human activities in the last 50 years. Many canals have been built to transfer almost all stream waters for irrigation and farmland desalinization. As a result, about 37% of stream waters were Ca2+HCO3- type and more than 40% were either Na+Cl- type or Na+SO42- type. The former can be found in natural hydrological conditions, while the latter was affected by agriculture activities. The relationships between water use, desertification and salinization are discussed, based on the water table, soil water content and evaporation in the study region. When the groundwater table is 4 m below the surface, evaporation almost stops. Soil moisture will decrease without supply by groundwater. It is therefore possible to cause desertification when the groundwater table is deeper than 4 m in the Tarim basin. Therefore, water resources issues concerning desertification and salinity must be dealt with at the same time with respect to water and mass balances.