As beaver populations continue to increase, beavers are expanding into new areas and the problems they cause are increasing. The best solution to the problem of beavers damming culverts is to redesign and replace the culverts that beavers have dammed. Oversized culverts help prevent beavers from building dams. The culvert's location is another factor. Replacing culverts is expensive and is not an option in most cases. When replacing culverts is not an option, managers can consider:

• Installing devices that keep beavers from damming culverts. These devices can be grates or rebar installed in the culvert entrance, small wire mesh fences placed in front of the culvert, or wire mesh culvert extensions. Sometimes beaver will leave the area when these devices are installed. In other cases, they will build dams against them. Periodic maintenance can keep the culvert free of material. These techniques, especially the culvert fence, have been used successfully in almost all regions.
  
  
• Installing devices that allow water to flow through the culvert. These devices may keep beavers from building dams or they may limit the size of the dams. Many designs exist, but the main idea is to keep water flowing slowly and quietly through the pipe so beavers don't hear the sounds of rushing water that arouse their instincts to build dams. Devices using perforated tubing, the Clemson Beaver Pond Leveler, T-culverts, culvert blocks, and simple log drains can be effective. Routine maintenance is required to keep the systems from being clogged by debris.
  
  
• Trapping or shooting. Trapping or shooting can be an effective, relatively low-cost method of reducing beaver problems. Beavers can be trapped and relocated if suitable relocation sites exist. Trapping is prohibited in some States. All programs must be conducted in accordance with applicable regulations. Trapping and shooting may provide no more than a short-term solution because other beavers probably will show up if the habitat is good. Usually, systematic annual trapping or shooting programs are required.
  
  
• Using devices that frighten beavers. These devices attempt to make an area appear threatening. While most methods do not work for more than a few days, an electric fence with dangling loops was effective in one instance.
  
  
• Using repellants. Repellants are not effective in reducing culvert problems, but can be used to protect riparian areas. Commercial repellants do not offer much protection to larger trees, but can protect willow or cottonwood seedlings from beavers. Grit added to paint and applied to the base of trees was more effective than standard repellants.
  
  
• Installing fences. Fences up to 500 feet long can be placed in an area to effectively exclude beavers. The coated mesh or chain link fence does not need to be more than 2 feet high. The fence must be tight against the ground or buried a few inches to keep beavers from digging or crawling underneath it. This method is fairly expensive, but could be used to protect small areas.

Site conditions, habitat, and beaver populations will play a large role in determining whether any particular method will be successful.