Aah, those beavers, one must deceive them to avoid flooding the trail and our neighbors property along Rt 7 in Sheffield. See Adam Brown's report on the mucky business below.
ATC was approached in late fall of 2011 by a business
owner whose property abuts National Park Service AT land in Sheffield, MA. He reported that beavers on the NPS side were
flooding his construction yard and threatening to inundate his septic
mound. Both ATC and the AT Committee
were aware that flooding was happening on the trail itself and had been in to
take a look at the area to see if any immediate solution was available, but
were not aware that a neighbor was being affected. After some discussion between NPS and MA Fish
and Wildlife, we came up with several options: do nothing, hire a trapper to
remove the beaver and kill it for its pelt (the state does not allow for
relocation), or hire a contractor to install a flexible pond leveler (also
called a “beaver deceiver”) device. The
first option was likely to alienate the neighbor; the second was harmful to the
beaver, so we settled on the third option in hopes of being able to co-exist
peacefully with the beaver.
ATC and the AT Committee pursued a grant through MA
Society for the Prevention of Cruelty to Animals (MSPCA), as well as the
appropriate town/state Wetlands Protection Act permits, that would allow for
cost-free construction and installation of the device by Mike Callahan of
Beaver Solutions. Below is a diagram and
description of the device we installed.
We will plan to monitor the area over the fall and into next spring to
see if it works. When we installed it on
Friday, water was very low due to the dry summer and the fact that the railroad
company had recently replaced their culvert upstream in a way that prevents
water at the current level from passing onto NPS land. This will likely not be the case in a rainy
year.
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Mostly Empty Pond, Beaver dam far side of mud hole! |
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Assemblying the Deciever |
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Floating the whole shebang into position |
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Submergence, ready for deception...
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Readying the pipe for burial in the dam
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So, here's how the whole thing works:
The Flexible Pond Leveler™
Courtesy of Beaver
Solutions LLC
Where
flooding from a free-standing beaver dam threatens human property, health or
safety, a Beaver Solutions Flexible Pond Leveler™ pipe system can be an
extremely effective solution. If properly designed and built, a Flexible Pond
Leveler™ will create a permanent leak through the beaver dam that the beavers
cannot stop. Our Flexible Pond Leveler™ devices are so effective we guarantee
them. They eliminate the need for repeated trapping despite the presence of
beavers.
Sorry folks, just can't figure out how to get the diagram to print in this space!
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. Beavers cannot get close enough to the intake to detect
water movement. As a result, the beavers do not try to clog the pipe, and
maintenance is rarely needed. A minimum pond depth of 3 feet is needed for the
Flexible Pond Leveler™ to function properly.
The
height of the pipe in the dam determines the pond level (see diagram). 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 desired.
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. Some mild pond fluctuations are possible following very wet periods, but
the pond will be controlled at a safe level since the dam height is controlled
by the pipe.
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.
Whenever
a pond must be lowered by more than one foot, a single round of trapping may be
necessary prior to the flow device installation. When new beavers without the
memory of the higher water level relocate to this area they are more likely to
tolerate the smaller pond. Most Flexible Pond Leveler™ failures are due to new
downstream damming in response to a dramatic lowering of the water level.
So, there you have it! Let's hope it works, and Adam, if you get a picture of the pond refilled with our recent rains with the elevation limited by the Beaver Deceiver, send it along and we'll add it to this post!
Great fun in the muck and mire!
Posted by Jim for Adam Brown