Don’t knock down that beaver dam! Beaver ponds provide important rearing habitat for young fish, especially coho salmon. Beaver ponds also store water during heavy rains, reducing downstream erosion. They release water slowly during the dry season, ensuring year-round streamflow.
If you are troubled by beavers, the best long-term solution is to learn to co-exist with beavers. Trapping is a short-term, and expensive, solution because new beavers almost always re-populate vacant habitat, sometimes within just a few months. However, there are several techniques available to manage the negative aspects of beavers, while still taking advantage of their many benefits.
If the beavers are not causing problems: Wait for a warm spring day. Around dusk, take a lawn chair, a pair of binoculars, your favorite drink and your best friend to your creek or beaver pond. Sit back, relax, and enjoy the show!
If the beavers are causing flooding problems: There are ways to control water levels in beaver ponds and still keep the beavers. For example, a beaver deceiver is a cage or rack around the end of a culvert or pipe to discourage the beavers from plugging the culvert. A trickle tube or pond leveler can be installed to regulate the water level after a dam is constructed.
These devices are tricky to install and are best done by someone with experience. They all require a permit from the State Department of Fish and Wildlife. Contact one of the resources in the How To Get Help page for advice.
Snohomish County Beaver Management Web Page.
If the beavers are cutting down your trees: Beavers have to eat! Their diet mostly consists of aquatic plants. Since some aquatic plants are unavailable for parts of the year, they supplement with the tender bark of young trees and shrubs. Willow is by far their favorite, but cottonwood, cedar, cherry, and apple are popular as well. Beavers also cut trees to supply their dam-building habits.
There are several options to protect your favorite ornamental trees. Not all options are fool-proof (beavers are clever!) but they can help you co-exist with these beneficial, yet challenging, critters.
Option 1: Make sure they have enough to eat. Planting lots of willows will provide a food source and can offer an alternative to your prized ornamental apple tree. Expect the willows to be eaten. You may need to protect some of the willows for a few years to mature. Once they are well-rooted, they will re-sprout if the beavers cut them.
Option 2: Loosely wrap your prized trees with wire fencing. Wrap loosely so that the tree has room to grow. You'll need to check the wire every year to make sure the fencing is still loose. Beavers can chew through chicken wire. Two wraps with horse fence works well. Horse fence is the 12-14 gauge fence with a 2x4" grid. The fence needs to be at least four feet tall. On rare occasions, beavers have climbed the fence and cut the tree off four feet above the ground!
Option 3: Paint the tree with a repellant. We've tested Plantskydd and Deer Away Big Game Repellent on our sites with some success. They need to be re-applied periodically. The first one lasts about 6 months.
No. Removing beaver dams actually eliminates more salmon habitat than it helps. Beaver dams that prevent salmon from migrating are extremely rare. Beaver ponds are like nurseries to young salmon, providing them with food, shelter, calm water, and protection from floods. Coho salmon and cutthroat trout, in particular, rely on beaver habitat.
You should also consider the impact of removing a beaver dam to people. Some people who remove beaver dams drain the pond and are left with an unsightly mud-hole for years afterward. Draining a beaver pond has downstream impacts as well. The high flows of water created as the pond drains can cause severe erosion and deposit significant amounts of sediment on neighboring properties. You could be held liable for damage to downstream properties resulting from your removal of a beaver dam.