Hydrologic variability and sediment bypass efficiency

Sediment bypass strategies endeavor to pass as much sediment as possible around the reservoir storage to minimize sedimentation while minimizing impacts on beneficial uses such as water supply and hydropower. The percent of the load that can be bypassed depends on site-specific hydrology, the sediment rating relationship, and sediment bypass tunnel (SBT) capacity. The interplay of these factors determines the degree of control that can be achieved as a function of bypass hydraulic capacity. This interplay of factors is examined by simulating sediment exclusion efficiencies for rivers in three distinct hydrologic environments: Caribbean, Andes, and Himalaya. Analysis of these datasets shows that hydrology variability tends to be more important than variation in sediment concentration as a predictor of potential sediment bypass efficiency.