Author(s): Y. Jia; C. Niu; N. Wei; F. Wang; J. You; Y. Qiu
Keywords: Environmental flow; Hydrological processes; Eco-environmental function zone; Water resources regulation; Weihe River
Abstract: As the biggest tributary of the Yellow River, the Weihe River with a command area of 134800 km 2 is now confronting serious competition between social-economic water use and eco-environmental water use because of local economic development and water resources decease. Instream flows at some key sections of the Weihe River are frequently disappeared at drought season, which leads to serious eco-environmental issues. Although the local government is implementing 60 billion RMB to carry out a comprehensive treatment plan of the river, there are 3 questions remaining to be answered: How much eco-environmental flow is required? Where is the source of eco-environmental water? What kinds of regulation measures can be adopted to guarantee the eco-environmental flow? In this study, we try to answer the above 3 questions. The holistic method (combining fish habitat analysis, water environmental design flow method, hydrological method and stakeholders seminar etc. ) is adopted to calculate eco-environmental flows at 5 key sections of the Weihe River, a distributed hydrological model is applied to produce the naturalized daily river flows in the past 50years at the 5 sections, and a water resources regulation model is used to perform regulation schemes at present and planning years (2020). As study results, target values of eco-environmental flows at the 5 sections are suggested and their rationalities are discussed, the water sources for the environmental flows are identified, and regulation measures are proposed from 7 aspects including hydropower generation control, water-saving and trans-watershed diversion etc. It is concluded that restoration of eco-environmental flows in the Wei River and balancing of economic and ecoenvironmental water uses can be gradually realized, though the target is very challenging. Although a further study is desired, the results are believed to be of an important referential value to a sustainable development in the basin.