Removal of the dam in Vangselva will give lake trout access to approximately 25 km of river course and side streams, with excellent spawning opportunities upstream from the current dam, and help natural sediment transport to supply spawning gravel to the lower parts of the river.
Vangselva is located in Jevnaker municipality and flows into the southern end of Lake Randsfjorden. The Vangselva catchment area includes agricultural land, primarily grain fields, some grass production, livestock and pasture areas, forested regions, as well as scattered buildings and farmhouses. The dam, known as Vang Mølledam (Vang Mill Dam), is situated approximately 900 metres upstream from the river’s outlet into Lake Randsfjorden.
| Project status | Completed |
|---|---|
| Project type | Dam removal: demolition |
| Country | Norway |
| River | Vangselva |
| Removal date | Spring 2025 |
| Km opened | 25.6 km |
| Focal species | Lake trout |
| Organisation | Dokkadeltaet Nasjonale Våtmarkssenter AS (DNV) |
| Website | DNV's website |
In general, obsolete dams can have a wide range of impacts on the environment and local communities, including loss of biodiversity, blocking fish migrations, trapping sediment and nutrients that maintain habitat and estuary health, as well as altering flow patterns that drive the productivity of downstream floodplains and wetlands. These impacts can affect public safety, food and water supplies, livelihoods, recreation, and overall community well-being. This presents an opportunity to restore both wildlife and nature, while providing potentially significant benefits to the local community.
One of the main goals of the dam removal is restoring the river to its natural condition. The lake trout (Salmo trutta lacustris) will especially benefit from the dam removal, gaining access to approximately 25 km of river course and side streams with excellent spawning opportunities upstream of the current dam. Another key outcome of the dam removal is the restoration of natural sediment transport and the supply of spawning gravel to the lower parts of the river.
By removing waste and other unnatural materials that have accumulated at the site over the last 100 years, the project will contribute to reducing pollution and improving habitat quality for other organisms connected to the river, such as amphibians, reptiles, birds, and mammals. The removal of the barrier will also have positive effects on the agricultural land alongside the river, as water can flow freely without being dammed, reducing the extent of flooding during heavy rainfall events.
The barrier has now been removed, reopening the river for upstream fish migration. During the excavation period, a river ecologist from DNV was present on site daily. The dam was successfully removed without releasing sediment, minimised the site’s footprint, and restored the riverbed using local materials. Dead wood and other organic matter, preserved during the works, were reintroduced after excavation to support the recovery of biodiversity.
One of the most significant outcomes of the dam removal is the restoration of natural sediment transport and the renewed supply of spawning gravel to downstream sections of the river. Over the past 100 years, the dam had trapped waste, sediment, and other unnatural materials. Its removal will enhance habitat quality for a range of river-associated species, including amphibians, reptiles, birds, and mammals. Lake trout (Salmo trutta lacustris) in particular will benefit from renewed access to approximately 25 km of river course and side streams/tributaries upstream of the former barrier, offering excellent spawning conditions.
This project demonstrates that a combination of ORP funding, effective communication with local authorities, cooperation with the watershed coordinator, experienced and reliable contractors, and a project coordinator with strong ecological restoration expertise is essential for success.
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