UC Davis

Despite studies showing that dams have significant effects on the sediment dynamics and evolution of a river upstream of a dam, the knowledge on relationships between river topography and sediment transport in the dam’s backwater zone has been poorly applied in reservoir sedimentation management. Therefore, this study evaluated the benefits that topographic control might have on reservoir sedimentation. To do this, three test scenarios were applied to explore the hydraulic and sediment transport regimes in the Middle Yuba River. A two-dimensional hydrodynamic model was employed to simulate the stream hydraulic response to topographic controls. The results indicate that adding a topographic constrictions and expansion sequence can change a river’s capability of entraining sediment and control the spatial distribution of sediment transport regimes by either accelerating sediment flushing near the dam or ponding the sediment farther upstream from dam. Topographic controls perform best for the low and medium flow.