Study on urban scale in arid inland river basin based on water resources carrying capacity

Taking the typical oasis city Liangzhou District in arid inland river basin as research object, the connotations of water resources carrying capacity and urban moderate scale were explained. Based on available water quantity, water rights and water quality, the model of water resources carrying capacity and appropriate scale for urban were established. Moreover, computable model for distance coordination degree between urban appropriate scale and actual population was constructed, and the range of standard evaluation was given. Then, available water quantity, water allocation, and urban moderate scale in the future were predicted and analyzed. Urban scale threshold under different circumstances such as saving water, increasing water allocation, refunding farmland and etc. was analyzed in order to provide a scientific basis for decision-making to control the water resources. The results showed that: The level of urbanization increased by 1%, the per capita possession of water resources reduced by 5.4 m³. Obviously, there was a contradiction between population and water resources. The distance coordination degree between urban appropriate scale and actual population was in transition stage from verge of disorder yellow light zone to moderate disorders double-yellow light zone during 2000-2009, disorder degree annually grew 12.13% in average. However, it will reduce 2.49% during 2010-2030. using changing water consumption per capita index, increasing water allocation, refunding farmland and etc. to calculate different urban appropriate scale over the next two decades, we think that contradiction between population and water resources will be solved by the three measures implemented simultaneously.