Ecological Design Across Interface: Ecosystem Restoration of Pengxi River/Reservoir in Three Gorges Reservoir Area, Chongqing

Riparian zone is a typical ecotone that connects terrestrial and aquatic ecosystems. At the same time, environmental stress magnifies here and the natural regulation of rivers is extremely active. In other words, the most dynamic and vibrant interactions between rivers and landscapes occur in riparian zones. However, the construction of dams and the operation of reservoirs have turned many riparian zones into river/reservoir alternation interfaces, influenced the shaping of hydrological and water environment, and the basin ecosystem as well. By introducing the definition and ecological characteristics of river/reservoir interface, this paper proposes the strategies and technical framework for the ecological design of river/reservoir interface. By studying the ecosystem restoration project of river/reservoir interface of Pengxi River in Three Gorges Reservoir Area of Chongqing, which emphasizes the comprehensive element design, structural design, functional design, and process design, this paper aims to provide a reference for related research and practice on river ecosystem restoration. The results of ecological performance analysis showed that the restored ecosystem of the Wuyangba river/reservoir interface has an obvious increase in habitat type diversity and biodiversity, a strong ability of plant communities to adapt to seasonal water level fluctuation, and an improvement in purifying non-point source pollution. The project demonstrates the coordination and symbiosis of interface ecological restoration and waterfront landscape construction and optimization. The project offers an innovative effort in exploring ecosystem restoration design and practice of river/reservoir interfaces. The design strategies and framework can be a reference for other ecosystem restoration cases that are affected by water level fluctuation in river/reservoir interfaces.