Floating islands in Dalälven
Water levels in regulated rivers can change rapidly, making it challenging to provide stable shallow water habitats that are required for birds to find suitable nesting spots.
Short facts
- Älvkarleby
- Nesting birds, fish, invertebrates and aquatic plants
- Create nesting platforms and aquatic habitats both above and below
- Continuous
One solution to this can be to build floating islands, which we explored and tested as part of Vattenfall Hydropower’s biodiversity programme.
Floating islands adjust with shifting water levels but remain stable, offering a reliable surface for plants and animals. In 2025, Vattenfall launched two large floating islands of approximately 90 square metres, along with several smaller ones, in the river Dalälven upstream of the Älvkarleby hydropower plant. The islands were designed and constructed at Vattenfall’s research laboratory in Älvkarleby and planted with vegetation native to local shores and aquatic habitats.
Over the coming years, the function and stability of these structures will be evaluated, and different designs will be constructed and deployed at different locations in regulated rivers.
More about biodiversity
Biodiversity and nature protection are a priority at Vattenfall. It is one of the focus areas in our environmental policy and therefore also a central part in our environmental work.
How we make a difference for nature
Biodiversity is an important and integrated part of our work. Here, we show concrete examples of how we care for nature through our projects.
See also
Testing “dancing rods” in practise
Vattenfall is testing new, behavioural guiding-methods to improve fish migration past hydropower stations.
Restoring riparian vegetation in Umeälven
In regulated rivers with a high degree of hydropeaking (rapid, short-term fluctuations in river flow), natural erosion and sedimentation processes are altered resulting in unnaturally high e...
Coexisting with capercaillie: innovative forestry methods at Bruzaholm wind farm
At the Bruzaholm wind farm in Sweden, a new approach for balancing wind power and capercaillie conservation was developed.