Strutdammen, Sweden

The removal of Strutdammen, the last big barrier at Hjuksån

The Hjuksån Catchment

Hjuksån is a tributary to Vindelälven and is part of the Natura 2000 network. It is located in Vindeln municipality in Västerbotten county and extends to 380 km2 (Figure 1). It springs from the lakes Krokvattnet and Struten and runs for about 33 km before flowing into Vindelälven. Hjuksån is inhabited by several fish species, including seatrout and trout (Salmo trutta), salmon (Salmo salar) and grayling (Thymallus thymallus).  

Figure 1. Hjuksåns catchment area in north-eastern Sweden. The red dot indicates the location of Strutdammen

Hjuksån has historically been very affected by the log-driving era, including high levels of fragmentation by longitudinal river barriers. Strutdammen was the last big barrier in Hjuksån, and the river will soon be free-flowing as the last small barrier currently in place located upstream in the Lake Krokvattnet outlet is set to be removed in 2026. Hjuksån still has large restoration needs, which will be addressed in the upcoming years, following the complete restoration of the river’s connectivity. 

The Strutdammen

Strutdammen was built in 1927 to supply water for log driving, and remained in use until 1970 (Figure 2). Strutdammen was since a “stray dam”, as it was in a bad state, leaking and eroding, and there was no documentation of the original or the most recent owner who could take the responsibility of maintaining it. It was a full barrier to the migration of fish and other aquatic animals, but its removal is expected to restore the migration routes, especially for trout that will be able once again to reach Lake Struten. 

Figure 2. Strutdamen at Hjuksån in north-eastern Sweden © Oscar Lundgren

Barrier removal

In Västerbotten county there are ~1400 dams/barriers mostly originated back to the flotation era. About half of these structures are barriers to fish migration. In cases where a barrier is located within the property of a landowner, they are the responsible ones for its removal. However, identifying the owner of a lot of those dams/barriers is quite complicated, as they were built a long time ago by timber floating associations that no longer exist and/or are located on land of unresolved/unclear ownership status. Thus, these dams/barriers are no one’s responsibility, which is very problematic as many of them are in bad state and at risk of collapse.

The project to remove Strutdammen started in January of 2024 (Figure 3, Video 1) and was completed in late November of 2025 (Figure 4). It was part of a bigger project called “Herrelösa dammar I värdefulla vatten I västerbottens län” (obsolete dams in valuable waters in Västerbotten county), aiming to remove 19 barriers in Västerbotten county between 2024 and 2027. 

Figure 3. Removal works of the Strutdammen © Oscar Lundgren

Video 1. Removal works of the Strutdammen © Oscar Lundgren

The removal works cost about 13500 euros (excavator and the hydraulic hammer costs) while the works to acquire the necessary permits and documentation from consultants was 1200 euros. Work management and project management cost is harder to calculate since this project was part of a bigger one. The removal was founded by the European Maritime and Fisheries Fund. 

Figure 4. The restored site following the removal of Strutdammen © Oscar Lundgren

Regarding the time needed for the preparatory works, it took approximately three weeks to meet with the interested shareholders and with the cultural environment department at the county administrative board, to decide on the best action plan and to visit the site a couple of times with and without the presence of the involved stakeholders. The removal works lasted about two weeks.  

The dam was located in a rural part of Västerbotten and thus there were only a few stakeholders involved, and they were mostly positive towards the project, mainly because the dam was in a very bad condition and the consequences of a breach would have been devastating for the lake upstream. So, they accepted the proposed plan of action to remove the dam and restore the natural lake outlet. Only one of the stakeholders was very skeptical at first, because of sentimental reasons, but in the end, he was persuaded of the benefits of the dam removal and river restoration activities. 

Challenges

The biggest challenge was to get the excavator down to the water since it is quite far from the nearest road. The issue was overcome by finding an old overgrown road that had been used in the 60s, and with the permission of the landowner was used to access the river. A smaller excavator (16 tons) with wider tracks was also used to avoid damaging the vegetation. The original skepticism of the landowners was also a challenge, which was resolved through lots of discussions clarifying the shared benefits for all the involved parties. 

Ecological and community benefits

The dam removal is expected to restore the upstream migration towards Lake Struten of many fish species, especially trout. However, it might take a few years to see measurable increase in the populations’ numbers because Hjuksån is in need of major restoration actions which are already planned for the next few years. 

Watch a live interview from the former Strutdammen site:

Before & After photo pairs

The restored site at Strutdammen (left) before and (right) after the removal works © Oscar Lundgren

With many thanks to Oscar Lundgren from Västerbotten County for providing the information and the visuals presented herein.

Prepared by Foivos A. Mouchlianitis