Environmental flow assessment in a lake‐marsh system with reverse seasonal hydrological patterns

Abstract

Environmental flow (e-flow) assessment is essential for the ecological protection and restoration of lake-marsh systems. Previous studies on e-flow assessment for lakemarsh systems focused on lake-marsh systems with natural seasonal hydrological patterns (i.e., low water level in winter and high water level in summer). However, they have not considered lake-marsh systems with reverse seasonal hydrological patterns (i.e., high water level in winter and low water level in summer). The reverse seasonal hydrological patterns impose seriously negative impacts on waterbirds, because the hydrological patterns could lead to limited plant germination in spring and massive plant death in summer, leaving few plants available as food for waterbirds in winter, and could consequently reduce the sheltering and forageable areas for waterbirds. This study took Hongze Lake Wetland National Nature Reserve in China as the study area. Based on the habitat requirements of waterbirds, the sheltering and forageable areas for waterbirds under different water-depth and aquatic plant distribution scenarios were calculated. By exploring the impacts of reverse seasonal hydrological processes on waterbird habitats, we determined the necessary e-flows for lake-marsh systems with reverse seasonal hydrological patterns to meet the needs of waterbird habitat. The results showed that the water level of Hongze Lake should be controlled to 13.0-13.1 m in March, 12.5-12.6 m in July, and 12.9-13.0 m in October, which can meet the needs of waterbirds for both shelter and foraging.

Changes in Lake Inundation and Shrinkage Within the Framework of Coevolutionary River-Lake state

“…Changes in water bodies directly contribute to wetland degradation, making them an indispensable factor in wetland ecological issues. Additionally, the hydrological changes in lake wetlands vary dynamically over spatial and temporal scales, leading to inevitable errors in ecological analysis and restoration strategy formulation (Qin et al, 2021). Thus, our approach to analyzing the temporal and spatial evolution of lake water bodies through the context of river-lake relationships provided a comprehensive understanding of the changing trends in low-water events and the spatial distribution of water body degradation in DTL.…”

Environmental flow mechanism and management for river–lake‐marsh systems

“…The reverse seasonal hydrological patterns in lake‐marsh systems will lead to the degradation of waterbird habitat. Based on the habitat requirements of waterbirds, the sheltering and forageable areas for waterbirds under different water‐depth and aquatic plant distribution scenarios, Qin et al (2021) established a new method for e‐flow assessment in lake‐marsh systems with reverse seasonal hydrological patterns.…”

Spatio‐temporal patterns and quantification of lake–groundwater interaction determined in a large water transfer lake

“…There is a case study targeting the Hongze lake located in eastern China, the fourth largest freshwater lake in the country and is as the largest lake along the east route of the South to North Water Diversion Project (Sheng & Webber, 2018) is presented here. The impacts of temporal tasks like water transfer, reverse seasonal water storage (Qin et al, 2021) and flood drainage (Yin et al, 2013) on spatial lake–groundwater interaction would be are considered.…”