Aanleiding van het project
Sediment management in hydropower dams is of crucial importance, both for economic as ecologic reasons. Sedimentation in reservoirs may lead to loss of active storage and blockage of the inlets and consequently loss of economic value. For the ecological value (e.g. fish habitat) a proper mix of sediment is important. Many hydropower companies around the world are therefor interested to improve the sediment management of the reservoirs. J-Power, the largest electric utility in Japan, is actively seeking to jointly develop knowledge and techniques to improve their gate operation for better management of the sediment trapped in the reservoirs and spread of sediment downstream.
Doel van het project
Expand the knowledge on sustainable sediment management in reservoirs and generate generic tools, like numerical models (Delft3D). With these knowledge and tools reservoir operators can be advised on how to optimize their sediment management.
In the current project the Funagira dam will serve as a case study on how the gate operation can help to improve the sediment management. Currently the gate operation is optimized by trial and error. By setting up a numerical model (Delft3D), including the gate operation (Real Time Control Module (RTC)), the gate operation pattern can be optimized.
The case study will be elaborated to investigate:
– the mobilization of sediment in the reservoir in the upstream part (lifetime of the reservoir).
– the influence of the jet of water coming across the dam on sediment transport downstream (erosion sedimentation problems downstream)
– behaviour and sorting mechanisms of graded sediment (ecological purposes).
1. Literature survey on sediment management in reservoirs.
2. Case study Funagira dam:
Numerical model setup and runs to study the influence of the gate operation pattern on the sediment flow through the dam and the sediment behaviour downstream (NB. Results will be compared with scale model tests and field data).
3. Improve the numerical tools by including the dam operation (Delft3D and RTC) for modelling the behaviour of sediment up- and downstream of hydropower dams.
4. Study on the mobilization of sediment in the reservoir, the flow over the dam and the sorting mechanisms downstream of the dam.
Numerical model with which sediment behaviour in the reservoir, across the dam and downstream of a hydropower dam can be studied for different gate operations. This will be done with Delft3D in combination with the RTC module.
Scientific paper on the results, together with JPower and to be presented in one of the international conferences (e.g. International Symposium on River Sedimentation, ICOLD annual meeting, Hydro conference, RCEM)
Animations to provide insight on the sediment behaviour across and downstream of the dam
PS. J-Power and Deltares (previously WL-Delft) have a long collaboration of 15 years. In March a meeting will be held on continuation of this collaboration. A TKI grant will help to further strengthen and improve the collaboration, which gives the ideal opportunity to combine their field data and scale model results with our numerical modelling tools.
State of the art models that simulate the complex sediment behaviour around hydropowerdams in combination with the gate operation rarely exist. Setting up models which can simulate all these aspects and by improving the modelling suits (Delft3D and RTC module), we will be 1) at the forefront of modelling sediment in hydropower dams and reservoirs 2) able to train operation managers how to optimize their dam operation. These models and knowledge can subsequently be generalized and used in future projects on sediment management in reservoirs.
Results will be published in a scientific paper, together with JPower. The knowledge will furthermore be shared with the client/ dam operators via reports, movies and possibly trainings. As Delft3D is open source, all improvements made for modelling sediment behaviour in reservoirs will automatically be available to the world wide community of Delft3D. Last but not least, gate operation managers can optimize their gate operation for better sediment management based on the knowledge and models from this project. Optimizing the sediment management will reduce maintance costs and may improve the ecological values downstream, for the Funagira (this project) and other hydropower dams (future projects).