Lost Opportunities in Sustainable Hydropower: The Overlooked Role of Sediment Management and Coordinated Dam Operations

Abstract Balancing hydropower development with river sediment connectivity is essential for meeting energy demands while mitigating impacts on river ecosystems and delta communities. Here, we introduce an integrated modeling framework to jointly explore water and sediment release strategies alongside dam planning, addressing the complex interplay between sediment transport, hydrology, and reservoir operations. Applied to the 3S river basin, a critical tributary of the Mekong River, the framework provides novel insights into optimizing sediment connectivity and hydropower production. By analyzing spatio‐temporal sediment dynamics and employing multi‐objective optimization, we assess how coordinated reservoir management can reconcile competing objectives. Our results show a fundamental shift in sediment transport dynamics, with hydropower infrastructure replacing hydro‐climatic variability as the dominant control. Since 2018, sediment loads at the basin outlet have dropped from an average of 25 Mt/yr to less than 10 Mt/yr, primarily due to Lower Sesan 2 dam. Optimizing flushing and sluicing strategies, we reveal the importance of coordinated reservoir operations: 57% of the identified Pareto‐optimal solutions outperform current dam management practices in all the objectives considered. This study highlights the importance of integrating sediment management with hydropower development and operations, providing a transferable framework for sustainable river basin management globally.