Hydraulic analysis of technical solutions for improved connectivity at hydropower dams

The project aims to investigate the hydraulic effects of technical solutions for creating guidance flows for downstream migrating fish.

Passage solutions for downstream migrating fish, especially for large-scale hydropower, are typically designed to guide small fish that tend to move passively with the near-surface stream. If the surface flow is guided away from the main channel, ideally the smaller fish will follow and encounter a point-of-no-return where they are no longer able to deviate from the divided stream to the dedicated passage. Larger fishes have stronger swimming capabilities, and they can navigate around guiding walls, louvres and bar racks, designed to guide the surface flow to dedicated passage routes, if the fish encounter hydraulic conditions that are unfavourable. This project will conduct full-scale tests at Edsforsen hydropower plant in the Swedish river Klarälven where technical solutions are used to create guidance flows for downstream migrating fish and the efficiency of these guiding solutions will then be evaluated by monitoring the fish responses via sonar and acoustic telemetry. The project also aims to gain further understanding of the coupling between hydraulic parameters such as velocities, accelerations, or shear stresses at the study site and fish responses. The final aim is to develop behavioural rules that can be applied to future modelling tools to predict the downstream migration of kelts at arbitrary locations with and without passage solutions.