The construction of a new dam at Eldforsen was completed in 2011. Legally Fortum was not required to release water in the old river bed, but after discussions with the local residents, sport fishermen and the municipality, Fortum decided to voluntarily create a bypass channel in the form of a bio channel, which would supply the old river bed with water.
A bypass channel for fish, animals, and plants
A bio channel is a more diverse version of a nature-like bypass channel with the idea that various animal and plant species, not only fish, can establish themselves in the channel. In traditional bypass channels, the main purpose is usually to enable fish migration. But the Eldbäcken project includes the construction of the bio channel, the design of suitable habitats, and research studies on the establishment of different animal and plant species in the channel.
The bio channel has a head of 5m and a length of 575m. To make the flow as natural as possible, the intake of the bio channel is constructed to create a variable flow regime. It also has other features, such as pools with low water velocity, islands and flood plains.
Eldbäcken is unique in Sweden and has employed researchers from mainly Karlstad's university for years. These studies contribute to various fields such as benthos, beach vegetation, large mussels, reptiles, fish, hydrology and flood fields. Stina Gustafsson from Karlstad university wrote her doctoral dissertation Dec 2017 on Eldbäcken with the title ”Habitat compensation in nature-like fishways: effects on benthos and fish”.
An underwater camera and fish-counter was installed in Eldbäcken, which monitors the fish and animals living in the bio channel. In the summer of 2018 the information was made public. The camera uses infrared rays to scan and register every single fish or animal that swims through Eldbäcken. The information is displayed on a website that collects statistics and video clips of the different species. In Eldbäcken grayling is spawning and otters seem to like the possibility to move through the bio channel searching for fish.
The project started up as voluntary, but is now part of the license for Eldforsen hydropower plant and the bio channel is on a probationary period for ten years.