Urpalanjoki dam removal will reopen river to sea trout

A section of the Joutsenkoski dam on the Urpalanjoki river in Lappeenranta will be removed from August 2027, clearing the last barrier to migratory fish in the river. Yle reports that a natural fish passage will also be built.

The Southeast Finland Centre for Economic Development received a permit for the work from the Permit and Supervision Agency in September. The decision recently became legally binding after no appeal was filed with the administrative court.

The project will also replace the dam’s gates, which have been used to regulate water levels, with a bottom weir to stabilise the level of Suurijärvi upstream. Building the fish passage will require blasting bedrock. The work is scheduled for autumn because winter conditions, spring floods and summer recreation restrictions make other periods unsuitable.

The changes will end operations at the more than 70-year-old Joutsenkoski hydroelectric plant. The dam is the last barrier to migratory fish on the river.

The Urpalanjoki runs for just under 100 kilometres along the Finnish-Russian border, through South Karelia and Kymenlaakso, before flowing into the Baltic Sea at Vyborg Bay. Dams and other barriers, worsening water quality and river clearance work have almost eliminated sea trout from the Finnish stretches of the river.

Removing the dam is intended to improve conditions for the critically endangered sea trout. The fish can reproduce only in freshwater rivers, and the upper reaches are expected to offer better spawning conditions than waters nearer the sea, which are often too warm. Fishways have already been built at rapids downstream of Joutsenkoski. Salmon and migratory whitefish also occasionally enter the river from the sea, according to the centre’s waterway planning specialist Markus Tapaninen.