An introduction to the research on "Evolutionary Laws and Dualistic Evolutionary Model of Water Resources in the Yellow River Basin"

The paper describes three main results obtained in the second project of the Yellow River 973 Program,i.e.,National Development Program for Basic Key Science Research entitled Evolutionary Laws and Sustainable Maintaining Mechanism of Water Resources in the Yellow River Basin.The three main results are:(1) establishment of a dualistic evolutionary model of water resources;(2) multi-criterion and dynamic assessment of water resources in the Yellow River Basin;(3) evolutionary laws of water resources in the Yellow River Basin under the impact of human activities.The dualistic evolutionary model of water resources is established by coupling a distributed hydrological model for large basins(WEP-L) and a water allocation and regulation model(WARM).Concepts of special water resources and general water resources are proposed,and an approach for multi-criterion and dynamic assessment of water resources is suggested.The water resources assessment results under present underlying surfaces are compared with those under the historical underlying(land covers),and the water resources assessment results under no water use condition are compared with those under water use condition as well.By contrast,it is shown that the quantity and compositions of water resources changed distinctly under the impact of intensive human activities.The two main variations are as follows:(1) the surface water resources reduced but the groundwater resources which are non-overlapped with the surface water resources increased;(2) the special water resources reduced but the general water resources increased accompanied with increase of the effective evaporation,namely effective utilization of precipitation.