Poster Presentation International Conference on River Connectivity (Fish Passage 2018)

Coanda Intake Efficiency Test on the downstream of trout
in a french river.

To ensure sediment transit and restore fish continuity, two Coanda-type water intakes with a 15mm inter-bar spacing were installed in Escouloubre and Aiguette in October 2015 on hydropower plants operated by EDF.

The objective of the monitoring presented here is to evaluate, by RFID technique, the efficiency of the system on the trout downstream.

The site of Aiguette (photo above) was equipped with 3 antennas :

• A first upstream of the sampling grid: recording of fish crossing the structure by the grid plan.
• A 2d at the outflowing outlet: detection of fish having taken this downstream path.
• A 3rd downstream of the water intake: detection of all fish leaving the system (photo below antenna and recorder)
• Sensitivity of detection is between 10 and 40 cm

The 279 trout were caught on 22/09/17 upstream of the site by electric fishing (see distribution chart below) and then anesthetized with eugenol, before Pit Tag operations.

The Trout between 50 mm and 90 mm (36%) were marked with 12 mm PitTag, those greater than 90 mm (64%) with 23 mm PitTag. (see photo). Emitters are placed in the abdominal cavity by surgical technique

No mortality was observed, the fish were then released upstream of the catch.

The other site of Escouloubre has been equipped in a similar system with 3 antennas and 302 trout.

Measurement studies were carried out at the beginning of 2017 and in the spring of 2018.

The poster will present the results of these studies.