Fish pass through Lippenannerl weir at the Alm/Upper Austria

The Fishcon lock was installed in the course of the revitalisation of the Lippenannerl diversion power plant parallel next to the newly built residual water screw turbine and overcomes a height difference of approx. 2 m. The system is operated with an attraction flow rate of 100 l/s, which results in a reduction of more than 50% compared to a conventional slot pass.

In spring and autumn 2019, video monitoring was carried out by the University of Natural Resources and Life Sciences, Vienna to check the fish-ecological function at the site. The Fishcon lock was rated as fully functional with a rating of 1 according to Austrian guidelines.

In addition to the total of 683 fish ascents, 305 fish descents were also documented in the study period of 104 days, despite a poor fish population of around 10 kg/ha in downstream water. The largest migrated fish was a brown trout, 420 mm long. The largest fish when fishing was 370 mm in length. The migration of all fish species identified during fishing and monitoring could be verified.

   Facts:

  • Fish region: Metarhithral
  • Lead fish: Brown trout 50 cm height
  • Height difference: about 2 m
  • Attraction flow rate: 100 l/s
  • Water saving: 140 l/s compared to slot pass
  • Assessment: fully functional according to Austrian regulations

 Facts:

  • Fish region: Epipotamal medium
  • Lead fish: Barbel 60 cm
  • Height difference: about 1,5 m
  • Attraction flow rate: 125 l/s
  • Water saving: 145 l/s compared to slot pass
  • Assessment: fully functional according to Austrian regulations

Fish pass Leumühle on the Aschacharm

The Fishcon lock was built at the site after an unused ballast lock, overcomes a height difference of approx. 1.5 m and is operated with an attraction flow rate of 125 l / s. The connection to the water is via a bypass channel, which was already there, but is not optimally designed.

The weir monitoring at the site was started in autumn 2019 and completed at the end of June 2020. The migration of a total of over 5,300 fish from 27 native fish species has been verified. Including the migration of schools of fish (noses, bleaks …), sole hikers (stone loach) and weak-swimming fish species (bitterling, rudd).

The largest fish was a 700 mm eel. The migration of a pike measuring 601 mm and a pikeperch measuring 610 mm could also be documented. Due to the very positive results, the Fishcon lock was rated as functional “Grade 2” according to the new and old Austrian guidelines by the company Blattfisch.

Research facility of the University of Natural Resources and Life Sciences, Vienna

The true-to-scale research facility of the Fishcon lock was comprehensively examined by the University of Natural Resources and Life Sciences, Vienna in 2017. The aim of the research project was to determine the application potential of the new technology through theoretical, technical and fish-ecological studies and to be able to derive optimisation potentials.

In the course of the technical investigation, several measurements and tests were carried out on the research facility. In tests with leaves, grass and wood, it was found that the fine screens clean themselves automatically as a result of the changing flow.

In the fish ecological studies, the fish ascent and descent were analysed at the experimental facility using brown trout. Different test conditions were implemented (throttle and turbine with flow rates from 50 l / s to 120 l/s). It could be demonstrated, for example, that the fish can pass the lock in both directions without injury under all test conditions and that the turbine has no negative impact on fish migration.

   Facts:

  • Fish region: Epirhithral
  • Lead fish: Brown trout 40 cm
  • Height difference: about 2,5 m
  • Attraction flow rate: 50 to 120 l/s
  • Operation with throttle and turbine
  • Project shows great potential

Fish pass

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