Channel Control‐Based Ecological Flow Restoration by Combining Flow Supplementation and Flood Risk Prevention in the River‐Connected Lake

Global change‐induced lake water scarcity highlights the urgent need for targeted ecological flow restoration, but such restoration conflicts with lake flood regulation and undermines the performance of existing projects. Taking Dongting Lake as the study case, this study develops an integrated flow restoration strategy that systematically reconciles water replenishment demands and flood control requirements. The strategy is developed based on long‐term time‐series hydrological station observations and riverbed topographic datasets, leveraging generalized hydrological model simulations and machine learning algorithms. The results reveal that from 1955 to 2020, the runoff from the Yangtze River into Dongting Lake experienced a significant decline of 32.71%, which has become the dominant driver of the lake's water resource depletion. The average maximum flow rate of the “Three Channels” has decreased by about 729 m 3 /s over the years, while the annual interruption rate has significantly increased. Through scenario‐based river regulation simulations, this study demonstrates that targeted riverbed elevation lowering by 1.5 m at Shadaoguan, 1.0 m at Mituo Temple, and 0.5 m at Guanjiaopu can effectively maintain the synergistic balance between water resource supply security and flood control functional integrity. The proposed framework provides a replicable methodological reference for the ecological restoration of river–lake connected water systems, offering a viable solution to reconcile the long‐standing conflicting demands in water replenishment practices.