Turbulent eddies to create paths for safe downstream migration for salmonids and eel past hydropower intakes
Fish on their downstream migration in rivers often encounter hydropower dams and intakes and tend to follow the main flow into the turbines where they may be injured or killed.
While some alternative guiding rack systems have shown promising results, there is a need to develop next generation systems that are cost-effective and easier to operate. In FishPath we aim to find a completely new way of guiding fish past the water intake of power plants.
Create eddies to lead fish
Via their sensory systems, fish can detect turbulent movements (eddies) in the water and respond either by avoiding them or by exploiting the eddies for swimming. In FishPath we will utilize these abilities to develop turbulent eddies based guiding structures for salmon, trout and eel. To do so we first need to further explore the shapes and behavior of eddies created by different objects (e.g. cylinders and hydrofoils) in the flow and how the fish species respond to different types of eddies. The behavior of the eddies will be studied by data modelling and experiments in a small flume. The responses of fish to different turbulent eddies will be explored in a series of fish flume experiments. Next, we need to align the objects that produce the desired eddies to create fish path that the fish will follow, also explored by modelling and experiments.
Develop practical guidelines
Once the candidate guiding systems have been developed their ability to guide fish will be tested, first in a relative small laboratory flume, next in a large flume and finally the most promising in a full scale prototype test in a river with a relatively large hydropower intake.
Results will be compiled in a practical guideline for eddy based guiding system, where we will also explore how the knowledge on turbulence and fish can be used in mitigation of other migration challenges (e.g. upstream migration).