Two-dimensional simulation of flow hydraulics and bed-load transport in a mountain gravel-bed stream: The upper Spanish Creek

Sediment transport in a gravel-bed mountain stream, the Upper Spanish Creek, California, was simulated with a depth-averaged, two-dimensional hydrodynamic and sediment transport model. The hydrodynamic model is based on the solution of depth-averaged flow continuity and momentum equations with dispersion terms to account for the effect of secondary flow. The sediment transport model treats bed load and bed material as mixtures of multiple grain-size sediment. Changes in bed elevation are calculated by solving the sediment mass conservation equation. The model was applied to predict bed-load transport in the Upper Spanish Creek to identify areas of high-erosive potential that require bank protections. Results of this verification process demonstrated the applicability of the two-dimensional hydrodynamic and sediment transport model to assist river restoration designs for gravel-bed streams.