Motivation

Sediment management in

river systems with hydro-power dams is of crucial importance, both for economic as ecologic reasons. Sedimentation in reservoirs upstream the dams 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. Together with J-Power, the largest electric utility in Japan,

we are carrying out the current research project to jointly develop knowledge and techniques to improve

the gate operation for better management of the sediment trapped in

reservoirs and spread of sediment downstream.

Goal

The goal of this research project is to expand the knowledge on sustainable sediment management in rivers with 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.

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).

Research activities

1. Literature survey on sediment management in reservoir
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
3. Development: Improve the numerical tools by including the dam operation (Delft3D and RTC) for modelling the behaviour of sediment up- and downstream of hydropower dams