Downstream Fish Passage Evaluation Using Barotrauma Detection Sensors

Experiments were carried out with sensors that were passed through the hydropower plants at Lanforsen and Ätrafors to measure the pressure conditions and blade strikes that downstream migrating fish can be exposed to during turbine passage.

At Ätrafors, different scenarios showed that pressure levels are maintained in the safe range for eels at the Nadir pressure. However, the number of strike events highlighted some possible risks. At Lanforsen, none of the scenarios (different turbine and discharge) showed pressure levels exceeding the critical thresholds for salmon safety. The rate of pressure change was also within safe limits, and no strike events were recorded.

The study shows that the risks for downstream migrating fish can be reduced through continuous monitoring and suggest that they could be managed through optimization of turbine operations.