Examples of Flow Devices

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Fence and Pipe Pond Levelers

A beaver pond leveler, or fence and pipe flow device, creates a permanent leak in the dam to keep water flowing despite the presence of beavers. It controls the beaver pond level to allow humans to coexist with beavers without conflict. The pipe outlet elevation determines the pond level. This end of the pipe can be adjusted up or down if a higher or lower pond level is desired.

The domed intake fence prevents beavers from hearing or feeling the flow of water into the pipe. Therefore they ignore the intake end of the pipe, and only dam on the culvert fence where they hear the water flowing.

Source: The Beaver Institute

Keystone Fences

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Keystone fence are effective at protecting culverts from beaver damming for three reasons. 

  1. Damming 30 to 50 feet of fence is a lot more work for the beavers than plugging a narrow culvert, discouraging damming.

  2. When beavers begin to dam near the culvert, the fence forces their damming away from the culvert which also discourages them.

  3. As beavers dam out on the fence, the opening that the water flows into becomes wider and wider. Therefore, less water is moving through the fence where the beavers are damming. Less water flow through the fence further decreases the damming stimulus for beavers.

Source: The Beaver Institute

Flexible Pond Levelers

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When flooding from a beaver dam threatens human property, health or safety, a Flexible Pond Leveler™ pipe system can be a very effective solution. This flow device will create a permanent leak through the beaver dam that the beavers cannot stop. This eliminates the need for 
repeated trapping despite the presence of beavers.

In order for these pipe systems to be effective, they must be designed so that beavers cannot detect the flow of water into the pipe. The Flexible Pond Leveler™ does this by surrounding the submerged intake of the pipe with a large cylinder of fencing which is placed in as deep water as possible. This prevents the beavers from detecting the flow of water into the pipe. As a result, the beavers do not try to clog the pipe, and a safe water level can be maintained. 


The height of the pipe in the dam determines the pond level. Water will flow through the pipe unless the pond level drops below the peak of the pipe. The pipe is set in the dam at the desired pond level, and can be adjusted up or down if necessary. Unlike road culverts, Flexible Pond Leveler™ pipes do not need to be sized to handle catastrophic storm events because heavy storm runoff will simply flow over the top of the dam. Following the storm the pipe will return the pond to the normal level. When installing a pipe system it is very important to lower a pond only enough to protect human interests. The more a pond is lowered the more likely it is beavers will build a new dam to render the pipe ineffective. Lowering a beaver pond by up to one vertical foot is generally not a problem. 

Source: The Beaver Institute

Culvert Diversion Dams

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A Culvert Diversion Dam (CDD) inexpensively protects road culverts from beaver damming by encouraging the beaver to dam immediately upstream of the culvert instead of inside it. This keeps the culvert open and works well when some ponding upstream of the road is tolerable.

The CDD is constructed 10 to 15 feet upstream of the culvert so when the beavers dam upon it the inlet of the culvert is not blocked. The CDD creates a small, noisy waterfall that will attract the beaver’s attention. They will then dam on top of your CDD instead of the road culvert.

Source: The Beaver Institute

Fact Sheets on Flow Devices from Beaver Solutions