Validation of Model-Based Optimization of Reservoir Sediment Releases by Dam Removal

Abstract

Appropriate sediment management is required to improve the lifespan and productivity of reservoirs. Flushing operations to release part of the trapped sediment have therefore become increasingly common in practice. However, there is no clear methodology or guideline to assess their effectiveness. Numerical models are promising, but the lack of studies and data for validation presents a significant challenge. An opportunity to assess flushing operations is presented by the increasing number of dam removal interventions monitored for subsequent reservoir erosion and sediment displacement. Treating dam removal as an extreme case of sediment flushing, we use the case of the Marmot Dam removal to validate a two-dimensional morphodynamic model, which is then used for the study and optimization of sediment flushing operations. The results indicate that the software can be successfully used to design and optimize these types of operations notwithstanding some limitations in the quantification of released sediment volumes. Flushing appears to be more efficient if it starts just before the peak of a flood wave.