Ecological water level regulation based on aquatic plant restoration in large reservoirs: A case study of Wangying Reservoir

Abstract

The regulation of water levels based on water level requirements at different life-cycle stages of aquatic plants is a crucial measure for the restoration of aquatic plants. Based on the current situation of aquatic plants in the reservoir and the requirements for the water level of aquatic plants in different life cycle stages, the present study proposes the best ecological water level under different plant coverage restoration targets for the Wangying Reservoir. There were 184 species of aquatic plants in the Wangying Reservoir belonging to 142 genera in 61 families and 32 orders, with an average biomass of 2.35 kg/m² and average density of 227 plants/m². The total coverage of aquatic vegetation was 26 %, which included 15 % hygrophytes and emergent plants and 11 % submerged plants. The hygrophytes, emergent, and submerged plants have experienced discrepant life history stages and water level requirement even for the same life history stage. The fluctuations in the water level required for hygrophytes and emergent plants (2 m) were relatively more stable across different life cycle stages than for submerged plants (5 m). These results offer valuable guidance for the recovery of aquatic plants and reservoir management for the lentic water bodies.