On the hydrological changes and their attribution analyses in the Dongting Lake Region in the past 60 years

The Dongting Lake Region (DLR) of the middle Yangtze River, China. The controlling mechanism of the hydrological changes in the DLR is still unclear, though which are of great concern for ecological environment and water resources management. The runoff coefficient ( R c ) of DLR and water level ( wl ) at the Chenglingji station were selected to represent hydrological changes. The changes of climate( E 0 , P , I , T ), runoff( Q ) and river channel characteristics change( Bias ) were evaluated and then taken into considered in attribution analyses. Finally, the contribution of each factor to hydrological changes was quantified. The runoff coefficient R c increased by 45.37 % (from 0.34 to 0.50) in period 2012–2020 related to period 1961–1997 and the wl raised since 1980, which increased 1.12 m in period 1983–2020 related to period 1961–1982. The wl is mainly controlled by river channel characteristics change induced by sediment load changes ( Bias c lj ), precipitation intensity ( I ), runoff of Jianli station ( Q jl ) and runoff from the four river ( Q fr ), the dominant factors are Biasc lj and Q jl .The R c is mainly controlled by precipitation intensity I , Q jl and Q fr , the dominant factors are I and Q jl . The change of Q jl not only contributes to wl change but also to R c change. In addition, the impacts of Q jl on R c may be related to the groundwater interactions between the main channel and DLR. • The changes of runoff and sediment load in and around Dongting Lake Region were analysed in the past 60 years. • The runoff yielded in DLR increased by 45.37 % compared to 1961–1997 and water level increased 1.12 m related to 1961–1982. • Impacts of river channel characteristics changes and runoff changes on water level change were equally important. • The changes of main channel runoff played a critical role in hydrological changes in Dongting Lake Region.