Numerical simulation and application of nature based solutions to solve bank erosion in hydrosystems

• NBS are essential for enhancing the resilience and protection of river ecosystems. • Numerical simulation allows for describing the alterations in systems affected by human activities. • The OpenFOAM model is a tool to assess small local processes that exacerbate erosion in lotic systems. • NBS simulation allows for an effective assessment of eroded bank restoration interventions. Nature based solutions (NBS) have been successfully applied in developed nations. Its application in developing countries is however still incipient to some extent. Moreover, very few studies have addressed its implementation in the domain of large river systems, which have been exposed to ever increasing anthropogenic pressure in the last decades. The Magdalena River is the main waterway in Colombia, and it exhibits one of the largest sediment loads in South America. This contribution presents the successful operationalization (i.e., hydrological and hydraulic analysis, as well as numerical simulation) of sediment traps for sedimentation control and bank stabilization of the right bank of the Magdalena at Magangué Municipality (lower Magdalena) through wooden sustainable alternatives. The NBS simulation and intervention assessment indicates that the traps effectively restored the bank shore in the critical sector of the study area. To the best of our knowledge, the intervention in question is one of the first of its kind in the region. The numerical results indicate that these traps were able to reduce the exposure of vulnerable communities, not only to floods, but also to negative hydrodynamic changes associated to climate change. Thus, the contribution currently described can potentially provide for practitioners and decision makers a guide for the application of NBS in river engineering, and, for scientists, valuable insights into processes associated with NBS in different environments. We posit that the operationalization of NBS in developing countries needs to be institutionally encouraged through, for example, the construction of a database of successful interventions, and the establishment of methodological guidelines.