Thesis – Trout passage behavior in an open and closed vertical slot fishway

at  Vattenfall

OM TJÄNSTEN

To comply with the European Water Framework Directive, which aims to achieve a “good” ecological status of all rivers, the national ongoing hydropower relicensing process (NAP) in Sweden works towards mitigating the environmental impacts of hydropower production. This, for example, includes the preservation and reinstatement of upstream and downstream river connectivity, necessary for many fish species to complete their life cycles.
Technical fish passes are one solution to facilitate upstream migration for a range of migratory species. One fish pass solution is the vertical slot fishway (VSF), which consists of a series of rectangular pools with cross-walls notched by vertical slots. While VSFs are suitable for many fish species of different swimming capabilities, the generally low slope of the fishways (<12.5%) presents a constraint, requiring large construction areas and causing high costs when installed at high-head dams.
To ease this constraint while maintaining suitable hydraulic conditions for fish passage, the fishway may be re-constructed to a closed system, like a closed culvert, eliminating the free water surface while preserving gravity-based flow. However, little is known about the fish response to such a closed fishway.

The following tasks shall be completed as part of the thesis:

• Review of literature on the hydrodynamics and fish response to conventional vertical slot fishways as well as closed/covered systems.
• Preparation and conduction of a life fish experiment.
• Review of video material recorded during the experiments and extraction of behaviour information.
• Statistical data analysis and data visualisation of the experimental data.
• Discussion of the observed fish swimming behaviour in relation to pool and slot hydrodynamics, extracted from a computational fluid dynamics (CFD) model.
• Discussion of the experimental results under consideration of fish passage requirements, fish passage performance, and hydrodynamics preferences.

DIN BAKGRUND

We are looking for a student to join our journey towards a fossil free future. You are soon to be graduated from your academic studies. You also identify yourself with our principles: active, open, positive and safe.

• Background in biology or a related field
• Experience in statistical data analysis and data visualization, ideally with R Studio
• Interest in fish migrations and ecology
• Proficiency in English is required

Please check with your course/module advisor/professor for suitability before applying for this thesis.

OM OSS

We have been electrifying industries, powering homes and transforming life through innovation and collaboration for more than 100 years. Empowered by our goal, we are determined to enable fossil free living. To succeed we, as one of Europe’s leading energy companies, must be fossil-free ourselves.
But that’s not enough. That’s why we are looking beyond our own industry, to see where we can really make a difference.
Join us in our journey towards a fossil-free life.
Power Climate Smarter living - that’s our purpose. We are looking for the brightest students to make this happen. Together you will contribute to a fossil free future. You will have a unique position to contribute to our purpose. All we ask from you is to use your Superpowers and share your energy to help us achieve our goal

• Review of literature on the hydrodynamics and fish response to conventional vertical slot fishways as well as closed/covered systems.
• Preparation and conduction of a life fish experiment.
• Review of video material recorded during the experiments and extraction of behaviour information.
• Statistical data analysis and data visualisation of the experimental data.
• Discussion of the observed fish swimming behaviour in relation to pool and slot hydrodynamics, extracted from a computational fluid dynamics (CFD) model.
• Discussion of the experimental results under consideration of fish passage requirements, fish passage performance, and hydrodynamics preferences