NEW FISHWAY AT LYCKEBY POWER PLANT
The Lyckeby River in southeastern Blekinge is an important waterway with rich biodiversity. Species such as vimba, tench, crucian carp, and the increasingly rare European eel thrive here. The river also has great potential as a spawning and nursery area for sea trout, thanks to its excellent stream habitats and high water quality. About one kilometer upstream from its mouth in the Baltic Sea, fish encounter their first migration barrier — the Lyckeby Dam. This historic dam, built in the early 1700s and designed by the renowned engineer Christopher Polhem, has long been a barrier for fish to reach their natural spawning grounds further upstream.
FROM WOODEN LADDER TO MODERN SLOT PASS
Previously, there was only a steep wooden pool ladder here, through which only strong swimmers like sea trout could pass. For most other species, it has been an impossible task to get through. To restore migration opportunities in the river and increase connectivity in the watercourse, Fiskevårdsteknik AB, on behalf of the Karlskrona municipality, has constructed a modern fishway in the form of a slot pass at the dam. The slot pass consists of a series of pools, connected by vertical slots, allowing fish to gradually move upwards, resting in the pools between the slots. This design, with a low gradient and reduced turbulence, also benefits weaker swimming species that previously couldn’t pass.
MONITORING AND FOLLOW-UP
To assess the effectiveness of the new fishway, we have installed our TiVA FC fish counter, enabling precise monitoring of fish migration. So far, we’ve observed a wide variety of species passing through, including many weaker swimming species like bleak, crucian carp, and tench. Encouragingly, we’re also seeing many small, upstream-migrating eels using the fishway extensively. The eel is one of the specially prioritized target species, and it’s very positive to see that the smaller, juvenile individuals are successfully passing through the fish counter. The sea trout, another key target species, has also begun migrating in large numbers during the autumn. This indicates that the new fishway is working as intended, helping to strengthen populations of these protected species. See some of these fish passages in the video to the right!
FISH SCREENS
In addition to the fish counter, we at TiVA have also supplied a fish-friendly intake screen to safely protect and guide downstream migrating fish past the dam and the still-operating power plant. The screen is made of specially bent metal profiles, providing a cost-effective solution while also having a hydraulically advantageous profile that minimizes head loss through the screen. Read more about the screens.
Passages from the fishway at Lyckeby Power Plant, July and August 2024.
The new slot pass at Lyckeby Power Plant.
A TiVA FC mounted in the fishway.
Fish-friendly intake screen.