Beyond Single‐Species E‐Flows: A Multi‐Species Eco‐Hydrodynamic Framework for Sustainable Dam Operations in the Yangtze River

Abstract The preservation of aquatic ecosystems in dam‐regulated rivers requires balancing environmental flows (e‐flows) requirements for multi‐species conservation. This study proposes a novel, multi‐species eco‐hydraulic framework to optimize dam operations at the Three Gorges Reservoir, aiming to sustain aquatic biodiversity while meeting human water demands. Unlike conventional e‐flows approaches that focus on single species, our framework integrated hydraulic modeling, hydrological alteration, and habitat suitability analysis to balance the divergent requirements of three distinct species guilds‐larval/juvenile fish, macroinvertebrates, and hydrophytes‐across three riparian river segments. The framework employs an analytic hierarchy process to evaluate habitat satisfaction rates (SR) and hydrological overall alteration degree (OAD) under four operational strategies, incorporating real‐time hydraulic data and seasonal ecological thresholds. The results showed that operations based on eco‐hydrodynamic principles achieved optimal balance, reducing flow homogenization (OAD < 33%) while maintaining high habitat suitability (50%–70% SR) for multi‐species habitats at all three segments. Seasonal flow thresholds were identified, including base flows of 3,100–7,600 m 3 /s in Yichang, 3,000–10,000 m 3 /s in Jianli, and dual‐peak ranges in Daijiazhou (6,000–14,000 and 39,000–53,000 m 3 /s), which align with critical life‐cycle events. Compared to traditional e‐flows, the proposed framework improved habitat suitability by 10%–40%, resolving dam‐induced disruptions to hygrophyte communities. This approach offers a transferable paradigm for eco‐informed reservoir operation in large regulated rivers.