Culverts are installed to allow water to flow under a road or trail. This is an "easy" dam for Beavers, as they only need to plug the culvert to back up the water and create a pond. The growing pond can potentially flood the road, trail, and nearby areas, making it impassable and sometimes damaging the infrastructure. A solution to this problem is a culvert protector (or exclusion fence) that prevents beavers from plugging the culvert.
While some culvert protectors allow beaver and other wildlife passage through the culvert, beavers are not able to bring sticks and building materials into the culvert to plug it. Typically, a culvert protector consists of metal t-posts, and panels of hog wire that form a trapezoidal shape around the culvert opening (Figure 1, left photo). The trapezoidal shape forces any debris or building materials placed by the beavers to flow to the sides of the culvert protector so they are unable to obstruct flow.
The bottom right photo shows a different style of culvert protector, sometimes called a 'beaver-proof culvert,' which adds a t-junction piece to the end of a culvert, with grates on the top and bottom. The t-junction funnels the sound of running water upwards, decreasing the beaver's desire to plug the culvert, and the grate allows water to flow but no sticks or debris can be placed in the culvert.
*Please note that prior to the installation of any coexistence tool, it is important to check for permitting requirements with your local, provincial/state, and federal departments*
Please see the following resources to learn more about this coexistence tool:
1 Callahan, Mike. n.d. "The Keystone Fence." Beaver Solutions LLC. https://www.beaverinstitute.org/wp-content/uploads/2017/07/TheKeystoneFence.pdf.