River Örekilsälven

River Örekilsälven is the largest watercourse north of the Göta River on the west coast. Its catchment area is 1,338 km². The river flows from the source areas in Dalsland about 90 kilometers from the mouth through Munkedal and flows into Saltkällefjorden. The stretch downstream of Kärnsjön is a Natura 2000 site containing rapids and streams, with species such as salmon, trout, sand eels and caddisflies. River Örekilsälven has a native Atlantic salmon population and is important for eel recovery according to the national management plan.

The last few kilometers before the mouth are characterized by deciduous and coniferous forest with great biodiversity. The forest landscape contains ash, alder and oak, as well as plenty of dead wood, which benefits birds such as kingfishers. Beavers also occur in the area.

River Örekilsälven is the county’s most important salmon river and accounts for 7-8% of smolt production on the west coast.

New dam to improve
Torps power station regulates Kärnsjön according to a water judgment from 1990, which affects the flow dynamics in the river. A fishway and eel guides are in place, but they do not function optimally. The Swedish Environmental Protection Agency has purchased the power station and applied to demolish it under the national plan for environmental adaptation of hydropower. At the same time, a new dam with fish passage is planned to ensure water supply and improve water flow in the river. The dam is expected to reduce the risk of fish stranding and benefit salmon stocks.

The county’s most important salmon watercourse
River Örekilsälven has good spawning areas for salmon, but there are few nursery areas due to previous floodway clearance. In the past, there has been biotope restoration where stones and boulders were returned, and side channels were opened. River Örekilsälven is already the county’s most important salmon watercourse and accounts for 7-8 percent of smolt production on the west coast. After action, smolt production is expected to increase by another 50 percent. Torp power plant is thus an obstacle to fish migration, but when the migration barrier is removed, a 70-kilometer stretch of the river will be opened for free fish passage, which will benefit salmon and eel, among others.

Joint efforts have an effect
There are many past and ongoing projects in the Örekilsälven catchment area. Biotope restoration is planned downstream of Kärnsjön during the period 2025-2028 to restore floodplain cleared areas. Several wetlands in the upper catchment area that are affected by ditches, which negatively affect the hydrology, will be restored. These are restoration projects for which the County Administrative Board is responsible, with some measures starting in 2023-2024. In addition, within LOVA, proposals are being developed for measures to reduce the negative effects of land drainage.

Several fish species benefit
In the Munkedalsälven/Valboån tributary, biotope restoration has been carried out in the lower parts a few years ago. Within the national plan for environmental adaptation of hydropower, ten applications for environmental adaptation have been submitted, which will improve eel migration routes in particular. The cumulative effect of dam removals, floodway restorations and wetland measures will improve the ecological status of the Örekil River and benefit species such as salmon, sea lamprey, sea trout and eel.