Computational Modeling of Fine Sediment Relocation Within a Dam Reservoir by Means of Artificial Flood Generation in a Reservoir Cascade

Sediment relocation is a process where water turbulence moves deposits from shallower to deeper zones of a lake or reservoir. Additionally, in the context of a reservoir cascade relocation is a one of the possible sediment management strategies used to maintain the operational capacity of reservoirs. Numerical modeling tools applied to sediment dynamics can help to better understand the reservoir sedimentary processes and enhance the design of management strategies. This paper describes the detailed analysis of the cohesive sediment dynamics within a reservoir and a methodology for the calibration of numerical models for the management of sediment deposits through dam operation and upstream generation of artificial floods. The calibration process was based on an accumulated sediment volume curve and the usage of simplified models for an initial parameter estimation. The calibrated model has been applied to analyze different possibilities of sediment relocation strategies. Plain Language Summary This paper describes the detailed analysis of the sediment dynamics of a reservoir and how the analysis can be used for model calibration. Furthermore, it presents a methodology to build and calibrate a two‐dimensional (2‐D) model for reservoir sediment dynamics and a case study of cohesive fine sediment management in a reservoir. Sediment relocation consists of the resuspension of sediments in shallower zones by waves and water currents with subsequent transport to and settling in deeper zones. In this work, we suggest a simple procedure to graphically represent the relocation processes. The proposed calibration process is based on the usage of simplified models for an initial parameter estimation. The method has been exemplified with a real case in the Riba‐roja reservoir in the Ebro River (Iberian Peninsula). Key Points The relocation processes of fine sediment in a reservoir are measured and analyzes A numerical model for prediction of reservoir sediment dynamics is calibrated Different management strategies to enhance sediment‐relocation processes are analyzed