Abstract: The seasonal fluctuation of water level after the impoundment of the Three Gorges Reservoir has brought great environmental stress to the water level fluctuating zone. How to restore the water level fluctuating zone and optimize its ecosystem service function? Nature-based solution is an important approach. In this paper, the design strategy and technical framework of ecosystem restoration for the water level fluctuating zone of Pengxi River Basin in the Three Gorges Reservoir Area were expounded as a case study. In line with over a decade of practice in ecosystem restoration of water level fluctuating zone, the comprehensive application and effectiveness of nature-based technologies were analyzed. Such technologies include: the selection of flood resistant plant species, the establishment of plant provenance bank, the construction of near-natural plant community, multi-functional dike ponds, wetland woods complexity, multi-dimensional wetlands and collaborative restoration technology involving terrain,sediment,plants and animals in the fluctuating zone. The results manifested that the selected plants had good flood resistance and survival status, plant community structure in the restored fluctuating zone was stable, biodiversity was improved and non-point source pollution was reduced significantly. The nature-based practice of ecosystem restoration in Pengxi River Basin has solved the problem caused by large-amplitude water level change and deep-water inundation in winter, and creatively constructed a technical system of ecosystem restoration in the water level fluctuating zone of reservoir. The research findings offer a popularized and reproducible technical method and practical model for the ecological restoration of fluctuating zone of large lakes and reservoirs.

Key words: water level fluctuating zone, ecosystem restoration, nature-based solutions, Pengxi River, Three Gorges Reservoir Area