High-resolution Numerical Simulation of Flow Through a Highly Sinuous River Reach

Abstract

River dynamics involve complex, incompletely understood interactions among flow, sed- iment transport and channel form. The capacity to predict these interactions is essential for a variety of river management problems, including channel migration, width adjustment and habitat develop- ment. To address this need, high-resolution numerical models increasingly are being used by river engineers, fluvial geomorphologists and river biologists to explore the complexity of river dynamics and to predict fluvial behavior. This paper presents numerical simulations through a natural meader- ing river using two different models: a depth-averaged numerical code with secondary flow correction and a fully 3-D, state-of-the-art, Computational-Fluid-Dynamics (CFD) code. Models predictions are compared to high-quality 3-D velocity data collected in a highly sinuous reach of the Embarras River in Central Illinois, showing a successful simulation of the main flow features. Implications for sediment transport, planform development and habitat structure throughout the reach are analyzed, demonstrating the potential use of the models as a tool for river management.