Living With Beavers
Beavers play a very important role in our local environment. Beavers provide many benefits to our landscape, including slowing and storing stormwater, capturing excess sediments, recharging groundwater, creating wetlands, and providing critical habitat for threatened juvenile salmon and countless other plants and animals. While providing all these important functions, beaver activity can also occasionally cause headaches for landowners when their activities conflict with human land uses.
Beavers can be found in rivers, streams, lakes, wetlands, and sometimes even in roadside ditches and stormwater detention facilities. Any wet location that has adequate vegetation, which beaver use for both food and building material, can be a prime location for beavers to establish. Additionally, beavers prefer habitats with deep, calm water, which helps protect them from predators, and are known for creating those conditions by building dams, which back up water and creating ponds. This modification is at the root of the many benefits beavers provide to us and our environment, but it is also at the root of the conflicts that can occur when beavers establish in areas used by humans.
The primary conflict that can arise from the natural habitat-forming activities of beavers include flooding of yards, homes, driveways, and roadways. Beavers will also plug culverts and damage trees and other vegetation to use as food and building materials. Fortunately, there are management options available to help mitigate the impacts of beavers while often allowing us to live alongside them and continue to benefit from their presence on the landscape. In some cases, removal is also an option, although this is generally a temporary solution because if a beaver is removed from a preferred habitat, it is extremely likely that another beaver will move into the newly available habitat.
Tools for Preventing Conflicts
- Protect Vegetation
- Control Pond Levels
- Prevent Clogged Culverts
- Dam Notching/Removal
- Lethal and Live Trapping
Protecting vegetation can reduce the impacts of beaver and reduce their access to food sources and building materials. This can be accomplished by fencing off large areas of vegetation or by simply fencing individual plants. It is recommended to use a relatively heavy-duty material, such as welded wire fencing, to prevent beavers from damaging the fencing and then accessing the vegetation. Fencing should also be a minimum of 3 feet tall. Fencing or other vegetation protection methods should be inspected regularly to ensure they are not damaged and still functioning properly.
Control Pond Levels with Flow Control Devices
In some cases, flow control devices may be used to manage the level of a beaver pond, alleviating local flooding issues while allowing beaver and their beneficial habitat to remain on-site. These devices work by creating a notch in the dam, effectively lowering the height of the dam, and then excluding beaver from the notched area to prevent them from rebuilding the dam to the higher level.
The two most common flow control devices are Flexible Levelers (also known as Pond Levelers) and Notch Exclusion Devices (NEDs):
- Flexible Levelers consists of a long, corrugated pipe that is installed through a notch in the dam to allow water to flow through the dam at a lower level. Metal caging is installed around the pipe inlet to keep the beaver from clogging the pipe with debris.
- Notch Exclusion Devices are metal cages built around a notch in the dam which allows water to flow through the dam at a lower level. The metal caging is designed to keep beaver away from the notched area so that they cannot rebuild the dam.
Installation of flow control devices requires a permit from the Washington Department of Fish and Wildlife in most cases. To assess your site and determine whether a flow control device could be a viable solution on your property, request a free site visit from your Watershed Steward.
Prevent Clogged Culverts
Plugged culverts are a common type of beaver conflict. Beavers seek to plug up anywhere water is flowing out of their habitat, which often includes culverts that run under driveways and roads. Installing an exclusion device (often referred to as a Beaver Deceiver) around the inlet of the culvert prevents beavers from stuffing debris into the culvert opening in order to back up water. An exclusion device is a simple structure, which consists of metal fencing and posts to anchor the fencing around the culvert inlet. In some cases, a device may need to be installed on the outlet of a culvert as well.
Installation of exclusion devices requires a permit from the Washington Department of Fish and Wildlife in most cases. To assess your site and determine whether an exclusion device could be a viable solution on your property, request a free site visit from your Watershed Steward.
In general, dam notching or removal are considered very temporary solutions since beavers will typically rebuild within a day or two. However, these can be appropriate actions in certain situations. In particular, dam notching is often a valuable first action to immediately alleviate flooding issues while longer term management options are considered and implemented.
Removal of dam material can release large amounts of water and sediment, which can flood neighboring properties downstream, impair water quality, and harm aquatic life. As such, care should be taken to remove materials slowly as to not cause damage downstream. Landowners are encouraged to research your watershed and be aware of possible beaver activity downstream and especially upstream of your property.
Dam notching and removal requires a permit from the Washington Department of Fish and Wildlife in most cases. To assess your site and determine whether dam notching or removal could be a viable solution on your property, request a free site visit from your Watershed Steward.
Although the beaver management options discussed above can often be successful and cost effective, trapping and removing beavers from the site may be another option to consider in some cases. Trapping and removing all beavers in a colony can temporarily eliminate beaver impacts, but it is important to consider this can be a costly endeavor, and is unlikely to result in long-term relief. When a colony of beavers is removed from a given location, new beavers are likely to quickly move into the habitat made available by trapping.
Beaver trapping is regulated by the Washington Department of Fish and Wildlife, which maintains a list of certified trappers, called Wildlife Control Operators.
Most certified Wildlife Control Operators use “live” traps to capture and then euthanize trapped beavers on-site. Because trappers use different techniques and have a wide range of fees for service, finding a trapper that meets your needs may require contacting and interviewing multiple trappers.
Beaver trapping is regulated by the Washington Department of Fish and Wildlife, which maintains a list of certified trapper, called Wildlife Control Operators.
Live Trap and Relocation
Until recently, beaver relocation was not legal in Western Washington. However, recent changes to the Washington Administrative Code (WAC) make it conditionally legal to trap and relocate beavers. A special permit is required for a beaver to be released on property other than that on which it was trapped.
However, while many landowners prefer to relocate beavers rather than pursue lethal control, studies have shown that survival rates among relocated beaver are very low and animals that do survive rarely stay in the location they are released. Selecting appropriate sites for the release of beaver can be an intensive process which is critically important to ensure site conditions are appropriate, other beavers do not already occupy the site, and that the release will not create problems for other landowners. The Tulalip Tribes Wildlife Program traps and relocates beavers for habitat restoration purposes and is well equipped to trap and move whole families at once, which increases the chances of success. The Tribes occasionally trap and relocate problem animals from private property in Snohomish County when other methods of control haven’t been successful.
Content adapted from the Washington Department of Fish and Wildlife.