Water Storage Changes of Lakes and Reservoirs Across Asia (2018–2023) and Their Effects in Flood Control

Abstract Monitoring lake and reservoir water levels is critical for water resource management and flood risk mitigation. We integrate Sentinel‐3A/B and ICESat‐2 altimetry to reconstruct monthly water levels (2018–2023) for 7,433 lakes and reservoirs (>5 km 2 ) across Asia and estimate their storage variations. Reservoirs exhibit a median annual water level change of 0.36 m/yr, far exceeding the 0.05 m/yr observed for lakes, highlighting their dominant role in surface water dynamics. Eight Asian basins flood events reveal that insufficient self‐regulation capacity of lakes is the primary flood trigger, while large reservoirs effectively mitigate flood frequency and intensity through regulation. These findings emphasize the importance of high‐precision satellite altimetry in surface water assessments and the critical role of reservoirs in modulating hydrological extremes under climate change.