How to Tackle Conflicts Caused by Beaver Dams
Beavers build dams to support their territories, create sufficient water depth to protect themselves from predators and provide access to foraging resources. While beaver dams create and support a wide range of ecological and hydrological benefits, there may also be challenges such as localised flooding and potentially delaying fish migration. Beaver dams are ephemeral and a watching brief is always recommended to start with to understand why the dam is there and its likely permanence. If you do need to manage a beaver dam, you should seek professional advice from the relevant regulatory authority, as the work must be carried out in a way that considers beavers and other protected species, doesn’t cause pollution or smothering of sensitive aquatic habitats and maintains fish passage where required.
Management Methods for Resolving Damming Conflicts
Dam Notching / Removal
- In some cases, it may be necessary to notch or even remove a dam.
- Dam notching is the partial removal of a small section of the middle of a beaver dam, usually by hand or with hand tools. This increases water flow over that section and reduces the water level behind the dam to reach a compromise level.
- Notching a dam will immediately reduce water levels, but one-off management such as causing a breach may be ineffective as beavers can repair dams within a matter of hours if they are determined. Therefore, dam-notching may be required regularly to maintain the upstream water levels.
- Similarly, dam removal may simply result in the dam being re-built by beavers within 24 to 48 hours in active beaver territories.
- Some dams are more important to beavers than others. These are likely to require more persistent management. Frequent monitoring and management are required for dam notching and removal to achieve their desired outcomes.
Flow Devices
- In some specific circumstances, where other options, including making space in the riparian zone, are not feasible, a flow device is a potential, semi-permanent solution to beaver damming that involves reducing and maintaining the water level behind the dam to a compromise level.
- This involves inserting artificial piping through the dam. The device’s inflow pipe is submerged upstream and away from the dam and protected from blockage by beavers with a wire-mesh cage. Submergence masks the sound and feel of water leaving the pond from the beavers.
- The outflow pipe installed in the dam allows water to pass through it, lowering the water level enough to limit or prevent flooding of the land around it while facilitating the territory to remain viable.
- A permit is always required for flow devices, and fish passage will need to be considered. Flow devices should not be installed where salmonid passage is required.
- Flow devices may not be effective in all landscapes, as beavers can build new dams further along the watercourse. Therefore, ongoing monitoring of the flow device and the surrounding area is recommended.
Culvert Protector
- In some locations, beavers may dam a culvert, causing a blockage.
- Culvert protection, such as a grill or in-stream fencing, prevents culverts from becoming blocked by beaver activity.
- In-stream fencing is a temporary measure that involves installing a fence made from fence posts and wire mesh around the culvert to prevent beavers from accessing and damming it. This can be installed either with or without a flow device, but it is worth considering that beavers may attempt to create a dam on the fencing system. Ongoing monitoring and management will likely be required.
- Where it is desired that beavers and other animals need to use the culvert for passage, a T-pipe can be mounted within the fence that allows animals and beavers to pass through whilst preventing them from carrying sticks and other materials in.
- In areas where the water level fluctuates substantially, a roof can be fitted to the culvert protector to prevent beavers bypassing the fencing during periods of high water flow.
- Where deemed necessary, a grill could be installed on the upstream entrance to the culvert. Grills can be designed in a way that allows mammal passage but limits potential blockages.
- A permit is always required for culvert protection and fish passage will need to be considered in the designs.
Tips and Additional Considerations
- Making space for water and beaver activity is the best and most effective way to avoid challenges.
- Beaver dams are a legally protected feature and removing an established dam (over 2 weeks old, or of an unknown age) requires a licence in England and Scotland.
- Where possible, dams should be left in place and a watching brief carried out before any action taken. The options above should only be considered where there is a need to manage water levels or to maintain the functionality of a culvert.
- Interfering with dams can increase tree felling as beavers are more likely to forage for fresh construction materials. It is therefore essential to consider whether any important or valued trees nearby require protection.
- The purpose for which beavers built the dam (natal or forage access) will influence the level of beaver motivation to repair a notched dam or re-dam where one has been removed.
- The hydrology of the system will influence the level of damming and dam maintenance.
- Seek professional advice before undertaking any dam mitigation and consult national regulations, especially regarding species protection and obstacles in the water course. See the licensing information below.
Licensing in Each Country
In Scotland
As of 1st May 2019 beavers are recognised as a European Protected Species in Scotland.
Removing, notching or installing a flow device in a beaver dam < 2 weeks old does not require a licence but removing notching or installing a flow device in a beaver dam > 2 weeks old does require a licence under the current management framework.
If you own or manage land that is affected by beaver damming visit NatureScot’s website.
In England
As of 1st October 2022 beavers are recognised as a European Protected Species in England.
Removing, notching or installing a flow device in a beaver dam < 2 weeks old does not require a licence but removing notching or installing a flow device in a beaver dam > 2 weeks old does require a licence under the current management framework.
If you own or manage land that is affected by beaver damming, visit the Government’s website.
In Wales
As of 4th March 2026, beavers are recognised as a European Protected Species in Wales.
If you own or manage land that is affected by beaver damming contact the Welsh Beaver Project for support on beaver.afanc@
Other Management Techniques
Mitigate Beaver Impacts
Choose from a range of well-established mitigation and management techniques
