Multiscale Analysis of Water Area, Level and Flow and Their Relationships for a Large Lake Connected to Rivers: A Case Study of Dongting Lake, China

Exploring the different characteristics of water status at different time scales is essential for the understanding of the complex hydrological processes in lakes connected to rivers. Taking Dongting Lake, a large-scale lake connected to the Yangtze River, as an example, this study employed wavelet analysis and multiple models to explore the temporal characteristics of water area, level, and flow and the water level–area and flow–area correlations from 2000 to 2021 on annual, seasonal, and monthly scales. The results show that the interannual variations in annual, seasonal, and monthly water area anomalies demonstrated rather consistent overall trends, but there were differences in the variation ranges at different temporal scales. The dominant amplitudes for annual and seasonal area anomalies were close, while for monthly anomalies, they were sometimes much larger. The dominant amplitudes of the water level and flow anomalies generally followed the order annual < seasonal < monthly. The water level–area and flow–area correlations are strongest at Chenglingji station and on the seasonal scale. This study provides a multiscale perspective on hydrological conditions and will support the management of water resources and the prevention of drought and flood disasters.