Project background: Liaohe River Basin is short of water resources and has a high degree of exploitation and utilization and insufficient environmental flow guarantee; and Liaohe River mainstream has serious water ecological degradation, with a wide gap with the restoration goal of Liaohe River Reserve and large difficulty in the restoration of water ecology. Liaohe River Basin is facing the scientific and technological demands of enhancement of environmental flow guarantee. In view of the above scientific and technological demands of Liaohe River Basin, the study on key technologies for environmental flow of Liaohe River Basin and application demonstration should be carried out to provide support for environmental quality up-to-standard and environmental flow management in Liaohe River Basin.
Main content: Firstly, in view of the dilemma of numerous calculation methods of environmental flow and unclear environmental protection objectives and water demand, based on the water ecological function regionalization and according to the current situation and future restoration needs of river basins, the “four-aspect” environmental flow standard calculation method has been constructed, including environmental flow management regionalization, classification of environmental protection objectives, stages of different water periods and level years and grading of implementation and early warning, solving the problem that the bottom line of environmental flow in response to river ecological process can hardly be determined scientifically. Secondly, combined with supply, consumption and drainage pattern of water resources in the river basins, a model of integrated coordination between regulation characteristics in runoff, evaporation, water demand of all trades, water use of all trades and water source projects and environmental flow in the river basin scale has been developed, which is guided by the standard guarantee of environmental flow. The verification scheme of environmental flow management applicable to highly artificially controlled rivers has been formulated, realizing the organic integration of multi-criteria environmental flow scheme system into the daily management of water resources and breaking through the problem of decoupling between environmental flow theory and practice management.
Scale and Distribution of demonstration and popularization: Aiming at the disadvantageous problems of water resources shortage and prominent and long standing contradiction of water use in life, production and ecology and around the scientific determination of environmental flow, the graded environmental flow verification technology has been put forward and the technology chain for determination of environmental flow of “environmental flow management regionalization-classification of environmental protection objectives and key flow components- ecohydrological rhythm and different level year staging-grading of implementation and early warning+ upstream and downstream coordination and coordination of water use in life, production and ecology” has been proposed and the scientific and applicable monthly Environmental Flow Management Scheme for Liaohe River Basin has been proposed, which are adopted for the management of water resources in the basin and support the implementation of “Action Plan for Prevention and Control of Water Pollution” in Liaoning Province.
Main scientific and technological innovations and contributions: [Regionalization] According to the characteristics of the nature-society complex system, the study put forward the coordinated technologies for environmental flow management regionalization, such as natural/social attributes; [Classification] Combined with the functional classification of water ecological function regionalization, the study proposed the technical method for identification of river functional targets, component structure of environmental flow corresponding to functional target and the applicable standard calculation method for classified environmental flow; [Grading] Combined with the functional protection requirements, the environmental flow grading technology for early warning grades is set up; [Staging] According to the eco-hydrological rhythm in the flood season-dry season in a year and requirements for ecological protection and restoration planning in different level years, the monthly environmental flow standards are proposed; [Coordination] Based on the overall model technology of river basin environmental flow, the upstream and downstream coordination and basic coordination of water use in life, production and ecology are realized.
Achievement and scientific and technological output: A series of achievements in river basin environmental flow management have been obtained, including zoning, classification, staged and graded environmental flow calculation technologies, environmental flow management scheme based on integrated coordination model of river basin environmental flow and river basin environmental flow guarantee management system, which further consolidate the research foundation of water quality target management scheme for river basins and further strengthen the technological innovation ability in the aspects of key technologies for operational management and guarantee scheme of environmental flow.
Economic benefits: The environmental flow guarantee management system of Taizi River Basin developed in this project has been applied to the water resources management of Taizi River Basin in Liaoning Province by Liaoning Provincial Bureau of Hydrological and Water Resources Survey, effectively improving the work efficiency of the management department.
Social benefits: The study on key technologies for river basin environmental flow is based on the main content of common technologies for comprehensive management of water quantity and quality in water ecological function regions of the river basins and river basin environmental flow guarantee scheme and vocational operation of demonstration areas are of great supportive significance to the prevention and control of water pollution and water resources protection in the representative basin economic society.
Environmental benefits: The results of the study based on environmental flow and reservoir ecological regulation scheme including Joint Regulation Scheme for Large Reservoirs and Water Conveyance Projects in Liaohe River Basin, Technical Guidelines for Ecological Regulation of Water Projects of Liaohe River Basin and Guidebook on Ecological Regulation of Reservoirs and Gate Dams in Liaohe River Basin provide ecological regulation basis and technical support for relevant departments, such as Liaoning Provincial Water Supply Authority, Liaoning Administration of River Basins, Liaoning Administration of Liaohe River Basin and so on, especially the water conveyance technical scheme for winter and related work provide support for the improvement of water quality of Liaohe River mainstream in winter.
Ecological benefits: The regulation demonstration based on joint regulation scheme for environmental flow and water quantity and quality and its implementation makes each water phase of main control sections of Huntai River Basin meet the requirements of environmental flow management objectives and ecological environment and water quality in the river channel improved. Through the research and demonstration, this project provides technical support for the construction of ecological civilization in the river basin and provides the river ecological environment with clean water and green bank for the public.
