Integrated Water Regulation And Its Effects On Oasis Evolvement In Tarim River Basin

Tarim river is a typical inland river in arid area. With the social and economic development, the requirements of water resources for agriculture, industry and daily life increase significantly. Thus the main problems the river faces are the lack of water and deterioration of ecological environment. The source stream has been exploited in large-scale since 1950's. Both the utilization of water in the source area and the loss of overflow in middle reach increased, which resulted in the 320 kilometer-long cutoff from Daxihaizi Reservoir since 1972 and dramatically degenerating of oasis in downstream area. Consequently, it is important to protect the ecosystem of Tarim River for stability of society and sustainable development of economy. In 2001, the integrative harnessing project for Tarim River basin with an investment of 10.7 billion Yuan was started, which included water-saving transformation in source area, regulation in mainstream and construction of ecological sluices.In order to coordinate the water requirements between the source stream and the main river, upstream and downstream, and among industry, life and ecology, the integrated regulation schemes are studied. The evolvement rules of the oasis in the down stream under new engineering background and new regulating scheme are also presented. Both studies can provide theoretic and technological support for making strategies of ecology protection. The principles of water regulation and the rules of water consumption for vegetation are explored using induction method. Four regulation schemes of ecological sluices under different water inflow conditions are designed according to the water demand rules in the main river. Considering the circumstances of industry and agriculture, the integrated water regulation scheme of production, life and ecology is studied. An integrated water regulation model is developed based on self-adapting theory, decision-making theory and computer technology.The distribution rules of underground water depth along the cross section areexplored with the data of Yingbazha section. Considering the relationship between water content and the depth of underground water, a model which describes the yearly averaged response of underground water to water supply is established. Based on Logistic model, a yearly averaged response model of the area of oasis to water supply and the distribution of underground water is built up and verified by a typical test area with land use data in two periods and special analysis technology of GIS.The stability of 'Green Corridor' is predicted by these established models with 30 years hydraulic data. The results indicate that the ecological environment will improve gradually and the area of arbor woods with shade density larger than 30% will increase by 59.4%.The ecological environment of the test area is studied under continuously typical yearly inflow conditions. The results indicate that after the integrative harnessing project the ecological environment of 'Green corridor' can maintain or even improve a little under continuous low inflow. The water supply to improve, maintain and affect the ecological environment of 'Green Corridor' is given by 193.3, 166.0 and 77.8 million m3.