Fish passage |
A typical small river in the Nepalese Himalayas – the focus of much current hydropower interest
No one-size approach
Toby Coe is the Managing Director of Fishtek in the UK. Here he describes how the challenge to fish migration presented by hydro schemes must be assessed and appropriately mitigated afresh each time
Below: The channels at Khone Falls provide ‘real world’ examples of the kind of hydraulic features to incorporate in large natural bypass channels
FISHTEK IS A MULTIDISCIPLINARY, technical consultancy that specialises in the field of fish migration, including the design of fish passage facilities. We are based in the south-west of the UK, but have delivered projects all over the world. Our team is comprised of fisheries biologists, scientists, civil, structural, electrical, mechanical and hydraulic
engineers, and CAD technicians. Much of the focus of our work has been on the practical mitigation measures that can be integrated into a hydropower or dam project and how and when these should be used. By definition, a dam or hydropower project creates an impermeable ‘wall’ in a river, with the flow of water through this wall then controlled for reasons of power generation, navigation or irrigation. Fish passage facilities that are incorporated into these structures aim to provide a degree of permeability into this structure for fish that are migrating in the river. From a fish passage perspective, the fundamental considerations that we take into account from the very start of our involvement in a project are as follows: Fish migration is bi-directional. It is critical to ensure that fish can migrate past a dam in both directions. Historically, significantly more effort and cost has been devoted to the issue of upstream migration, however this is now changing.
When considering fish passage facilities (for either direction of travel), the underlying basis should be “FLOW”:
Facility location – where should the fish passage facilities be located? In particular, where should the entrance(s) be?
36 | June 2025 |
www.waterpowermagazine.com
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