Addressing Unwanted Morphodynamic Processes in Re‐Naturalization Projects

River systems worldwide are undergoing severe ecological and morphological degradation due to prolonged anthropogenic interventions, such as channelization and dam construction, which disrupt sediment continuity and natural flow regimes. In response, river re-naturalization projects have emerged as essential strategies to restore the dynamics of fluvial systems. However, these actions frequently encounter unintended morphodynamic consequences, including sediment erosion and deposition, altered flow patterns, and disrupted channel stability, which pose significant challenges to achieving ecological, navigational, and flood management objectives. This study addresses the critical challenges associated with secondary channel re-opening, a common practice in re-naturalization projects, focusing specifically on lowland river systems. By employing a combination of numerical modeling and theoretical analysis, we investigate how key design parameters, such as localized levee lowering, influence the equilibrium of a river reach. The research highlights how an inappropriate project design can amplify sedimentation in the primary channel branch, reducing navigability, increasing maintenance costs, and offsetting ecological gains. To support management authorities and project designers, this work emphasizes the need for a multidisciplinary framework that incorporates long-term morphodynamic projections alongside ecological restoration goals. The findings provide insights into balancing environmental sustainability with operational functionality, offering guidance for improving the resilience and success of future re-naturalization efforts worldwide.