Nature-based hydraulic engineering

This sub-project focuses on hydraulic engineering and examines the extent to which the aspects of drought and heat are taken into account in various bodies of water in the canton of Aargau. Bern University of Applied Sciences Burgdorf (Civil Engineering Division, Chair of Hydraulic Engineering) is providing scientific support for the sub-project. It explores the following questions:

• How must hydraulic-engineering interventions for flood protection and revitalisation be implemented in view of the climate scenarios, so that in particular the increasing drought and warmth do not become an existential problem for cold- and oxygen-loving fish (especially brown trout and grayling) in the medium to long term?
• What measures already exist and which if any of these can be implemented in the canton of Aargau, and where?
• What statements and specifications can be derived from existing principles of hydraulic engineering?
• Which already implemented projects serve as showcases with regard to cold- and oxygen-loving target species in the canton of Aargau and which would be implemented differently today?
• What recommendations can be formulated for the future based on today's findings in the light of climate change?

The canton of Aargau is represented in the sub-project by the Landscape and Waters Department, the Hunting and Fishing Section and the Cantonal Fishing Commission as well as the Aargau and Swiss national fishing associations. Adrian Aeschlimann (SKF) heads up the sub-project.

The second sub-project is looking into the question of how an existing trout river can be preserved as such despite global warming, based on the River Ergolz in the canton of Basel-Landschaft. In the pilot region, solutions are being sought for the expected temperature trend over the next few decades so that the river from Liestal upwards will remain primarily a home to trout, despite the expected climatic developments. In addition to any habitat upgrades and the provision of sufficient shade, particular attention is being paid to sufficient water flow to compensate for periods of low precipitation.

The sub-project involves the Hunting and Fishing Administration as well as representatives from the Department of Construction and Environmental Protection and the Basel-Landschaft Cantonal Fishing Association. The sub-project leader is Barbara Berli (University of Basel, member of the Canton Basel-Landschaft Fishing Commission).

The cantons of Bern and Fribourg are jointly implementing the third sub-project on the River Sense.  As a study from 2018 shows, most of the brown trout there have disappeared due to excessively high temperatures and fish diseases below Zumholz near Plaffeien, despite near-natural conditions. The fishing authorities have therefore decided to limit the stocking of juvenile fish to the area above Zumholz.
Working with the cantonal authorities and associations as well as the affected angling clubs, the SKF is investigating the following questions:

• What does it mean for anglers when established species disappear and new species appear?
• Should anglers resign themselves to this situation and give up fishing on the Sense or should they specialise in the new species?
• Can they help to improve the situation?

The sub-project involves the fishing authorities of the cantons of Bern and Fribourg, one representative each from the cantonal fishing associations of Bern and Fribourg, one representative each from local fishing associations of both cantons, and technical experts. The sub-project is headed up by Adrian Aeschlimann, SKF.

The anticipated climatic changes will also have an impact on the work of the fishing authorities in the cantons. The fourth sub-project explores the following questions:

• How can developments be foreseen and how can the cantonal authorities learn from each other?
• Which elements of current practice provide appropriate responses to climate change and which need to be reconsidered?
• To what extent is the practice of the cantons changing and what impact does this have on current organisational structures (e.g. operation of farming facilities)?
• What knowledge gaps need filling and what decision-making bases need developing (e.g. how fish adapt to warmth, effects of fish harvesting, etc.)?

The sub-project is being implemented by the SKF in close consultation with the FOEN and the Cantonal Hunting and Fishing Wardens’ Conference.

Another sub-project led by the Swiss Fishing Federation (SFV) has set itself the aim of adapting anglers’ fishing practices to climate change and the expected developments. The pilot programme seeks to show anglers and authorities the importance of connected and dynamic bodies of water. It provides an opportunity to place fishing-related messages and position the “Fischer schaffen Lebensraum” (“Anglers create habitats”) guide. It aims to answer the following questions:

• What opportunities does this development offer anglers?
• What do the changes mean for the life of angler associations? Which fish conservation activities on rivers and lakes are effective and sensible?
• What interventions make sense to maintain local populations (e.g. cold-water zones, freshwater supply, fisheries, etc.)?
• Are there any other possible options with respect to brown trout and grayling than those already practised today?
• What modifications to training courses are needed (e.g. module on global warming in SaNa training)?

The sub-project is headed up by Philipp Sicher, Managing Director of the Swiss Fishing Federation (SFV).