Protecting Road Culverts and Drains
Imagine having half of your house already built for you at the beginning of construction. That's exactly how beavers see road culverts and drains. With little effort, beavers fill in culverts and drains with sticks, mud, or rocks to create a large pond. Thankfully, there are ways to protect these manmade structures from these busy beavers. What method is most effective depends upon the terrain and site characteristics
Culvert Protective Fences
There are a variety of ways to build these fences depending upon the topography of the stream, water depth, and stream flow. Culver Protective Fences work by making the entrance of the culvert or drain structure, which should be the easiest place to build the dam, into the hardest. Since it becomes more difficult for beavers to create a dam, they tend to look elsewhere for an easier habitat. Upkeep these structures are around one hour per year and have a success rate of 95%. The ideal area for these are shallow waters that cannot be impounded.
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Fence and Pipe Device
Similar to flood mitigation strategies for beaver dams, fencing can be built around the culvert. This allows beavers to make a pond by only damming a small part of the fence at the entrance of the structure. A Pond Leveler pipe is then inserted through the fence to control the height of the dam. It is important to note that the Pond Leveler pipe requires a depth of 3 feet to be effective. This method is the most common, has a success rate of 99% when installed properly, and requires less than 1 hour of maintenance a year.
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Diversion Dams
Diversion dams encourage beavers to dam upstream of the culvert rather than in it, keeping the culvert unblocked and allowing us some control as to where the beaver dams. Diversion dams work best in places where ponding upstream will not be a nuisance and requires little to no maintenance. They can be created with fencing, rocks, wooden posts, and/or branches. This is the most simple and easiest device to install and is the most wildlife and fish friendly flow device.
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