Beaver-related problems and solutions
Beavers activities benefit the natural environment in numerous ways. Problems arise because humans live in and travel through areas where beavers live and sometimes have an impact. This page discussions problems and presents many of the potential solutions to living with beavers.
How beaver problems develop
Beavers were nearly extirpated (made extinct) in the mid- to late 1800s in Washington from wide-scale trapping. Their fur was sold to make hats in England and other places. In the early to mid-1900s, beavers were being relocated to various places in Washington so they could re-establish populations, primarily so they could continue to be trapped for their fur.
As beaver populations continued to make a come-back, trapping continued. But in 2000, voters in Washington State approved a ban on "body gripping traps." Body-gripping traps are lethal traps that were by far the most commonly used traps for beavers and many other furbearers. Trapping continues in Washington, but the non-body gripping traps are expensive and burdensome. The value of fur has also declined. The decline in trapping is resulting in beaver populations continuing to grow and expand into areas that have not had beaver present since the area was first being settled by Europeans.
The human landscape we have created was not built with beavers in mind.
Beaver activity does not always mix well with human infrastructure and property. Beavers are excellent engineers, but people can be quite ingenious as well. More beavers in the Pacific Northwest means more potential problems and more opportunities for solutions.
What are the solutions?
If your problem is flooding, one or more "engineered solution" may be available to alleviate the problem. Water level control devices allow the beavers to remain present while water continues to flow downstream. If beavers are cutting your trees and shrubs, there are a few different solutions that may allow you, your vegetation, and the local beavers to all co-exist. We created this table to provide a summary of possible solutions to different beaver issues, give the pros and cons of different solutions, and show a rough estimate of cost.
Engineered solutions to flooding
If a beaver is making a dam on your property and the water is causing property damage or safety issues, you have a few options to consider:
- You could get a permit to remove the dam. But the beavers will likely rebuild the dam, sometimes overnight.
- You may consider hiring a trapper to remove the current beaver family. But unless the surrounding land cover changes dramatically, you can expect more beavers to move in and take their place. If one beaver family currently finds your property a good place to live, so will another.
- You may install a pond-leveler or culvert fencing. The idea behind these devices is to allow the beaver to stay on location while water levels are kept at a preferred maximum height. See our Resources page for more information.
To do nearly all in-stream work in Washington, you need to get a permit from the Washington Department of Fish and Wildlife. WDFW has a web page describing Hydraulic Project Approvals, which are required under the "Hydraulic Code" (Chapter 77.55 RCW) passed in 1949. In many instances a permit from the King County Department of Permitting and Environmental Services is also required. Beavers don’t need the same permits, so they have an advantage over people in their response times.
Our Resources page includes a list of various types of hydraulic solutions to beaver flooding.
Protecting trees from beavers
Beavers are experts at removing trees and other vegetation. Here are a few options for protecting your vegetation from beavers:
- A mechanical barrier, such as fencing, between your vegetation and the beavers may be very effective.
- Plant species beavers like to avoid. They prefer willows, cottonwood, alder, vine maple, and aspen. They generally avoid cascara, especially the young sprouts. See our Technical Paper #1 for detailed species information.
- Decrease the palatability of your plants. An exterior latex paint mixed with sand and applied around the base is one method that's proven fairly successfully.