Understanding sediment transport protects against climate change effects
Transport of sediment in rivers, estuaries and along the coast can result in significant morphological changes that increase the occurrence of floods and storm surges. In addition, morphological changes in reservoirs and in the vicinity of man-made structures may damage water supplies and energy networks, and dramatically increase the risk of structural failure. This will result in economic losses, threaten human life, disrupt the social fabric and damage natural ecosystems. Impacts on sediment transport will also be exacerbated by climate change; therefore it is vital to have advanced knowledge of sediment transport and to train future engineers in this field. The EU-funded project SEDITRANS (Sediment transport in fluvial, estuarine and coastal environment) formed a European network to coordinate research and training activities that addressed the challenges posed by sediment transport. The network comprised 6 academic and 4 industrial partners and provided a comprehensive interdisciplinary training-through-research programme to 12 early-stage and four experienced researchers. This included workshops, winter and summer schools, conferences, the drawing up of guidelines and secondments with industrial partners. Researchers focused on coastal and river flows and reservoir sedimentation and interactions with man-made structures. ‘The goal was to deepen knowledge of sediment transport mechanisms and their relationship with flow hydrodynamics in order to better understand and predict the evolution of river, estuarine or coastal morphology,’ says project coordinator Professor Athanassios Dimas. Better models developed through partnership Project partners developed algorithms for modelling sediment transport in river and coastal flows and for inland and offshore turbidity currents or debris flows. Models were created along three paths, beginning with a two-phase continuum model and a resolved particle motion model for bed sediment transport. Suspended sediment transport was modelled using advanced coupled fluid-flow/sediment-transport models where the large-eddy simulation approach was applied for the closure of turbulence. Lastly, two-layer modelling of open-channel flows or gravity currents was coupled with sediment transport and bed morphodynamics. ‘Modelling was based on advanced numerical methods, for example the immersed-boundary method for the imposition of boundary conditions on complex geometries and the use of parallel computations,’ explains Prof. Dimas. Experiments were also conducted for sediment transport in rivers and coasts and for sediment-laden density undercurrents in reservoirs and submarine canyons. These, together with high performance computing, were explored jointly by academic and industrial partners in real engineering applications. Accurate prediction tools benefit society Results were integrated into morphology predicting tools for use in the engineering realm by well-trained practitioners. In addition, results from the field experiments enabled crucial advances to be made in the conceptual models upon which the simulation tools were built. According to Prof. Dimas engineers will benefit directly from the new models and experimental data. ‘The frequency and magnitude of disasters associated with or caused by excessive morphological dynamism are likely to increase due to climate change,’ he comments. ‘Hence, the prediction tools developed by the project for planners will have profoundly positive societal impacts.’ SEDITRANS supported the coordination of research and educational activities in sediment transport at a European level, increasing Europe’s competitiveness in these important technical and scientific fields. Prof. Dimas concludes: ‘The emphasis on numerical models and experimental data will advance research and engineering in sediment transport, addressing large-scale problems concerning planning and protection against floods and erosion.’
Keywords
SEDITRANS, sediment transport, river, climate change, coastal, estuarine, hydrodynamic, algorithms
