“…Water is one of the most important natural resources on which living things depend, the survival and development of human society cannot be achieved without the support and use of water resources [1] .China's water resources are scarce, and the regional distribution is very uneven, with more water in the south and less in the north, and the quarterly and interannual variations of rainfall and river runoff are great [2] .With the development of economy and society, China's demand for water resources is increasing day by day. In recent decades, the large-scale development and utilization of water resources has made great achievements, but it also has a certain impact on the ecological environment, which has aroused wide concern of people.…”