Installation of deflector in Colider Dam to minimize the percentual of total dissolved gases

ABSTRACT During voluntary or involuntary spills, the total dissolved gas (TDG) may increase with potential of causing gas bubble disease (GBD) in affected fish. Bubbles entrained during spill events in Colider are transported by plunging jets to deep, high pressure, regions in the tailrace where dissolution is enhanced increasing TDG concentrations. The most common alternative to minimize TDG supersaturation downstream of hydropower dams is to install deflectors on the spillway face. In order to reduce TDG levels downstream of the Colider's spillway, Copel retrofitted the four spillway bays with deflectors, finalizing the construction in November 2021. The design of the deflectors were assisted with two studies. The first study comprised the development of a physical model in 1:60 scale, and other study was a numerical model based on the open-source toolbox OpenFoam.