Beavers meet their match in Newry
After a year-long standoff between Newry officials and beavers, the humans recently called in reinforcements.
Last year beavers built a dam in a culvert near the Sunday River Schoolhouse that carries a brook under the Sunday River Road. The dam plugged the culvert and filled much of the nearby roadway with water.
Last summer, after consulting with the Department of Inland Fisheries and Wildlife, contractor D.A. Wilson cleaned out the culvert. A beaver was also trapped.
But early this summer, at least one of nature’s engineers again began construction in the culvert.
Wilsons again cleaned it out. And this time, rather than wait again to see how persistent the critter(s) were, wildlife biologist Chuck Hulsey came up with a construction plan of his own. Brian Maxham of Dixfield was hired to carry it out. He is licensed by the state to do such projects.
Just upstream of the culvert, Maxham built a U-shaped wire fence, with the bottom of the U facing upstream.
“Beavers will build a dam against the fence,” said Maxham. “They follow its shape.”
Beavers instinctively build dams in a U-shape, the strongest design. (Many man-made dams mimic the beavers.)
If the beavers relocate the dam there, it would pose no threat to the culvert. Maxham said he is waiting to see if they will build against the fence. If that happens, he can also adjust the size of the pond behind the dam, if needed. “I can put pipes through part of it,” he said, to allow more water through.
Maxham also built a straight wire fence just below the culvert to block access from that direction.
As of Monday, there was no sign of rebuilding, which would also suit Newry officials just fine. A short distance below the culvert, another dam has been in place all along, and the animals may simply be operating from there, Hulsey said Tuesday.
He also said the brook generally is not ideal beaver habitat. "The beaver may have built in the culvert just because he could, not because he needed to impound the water," said Hulsey. In that case, there's not a lot of incentive to rebuild, he said.
"Beaver deceivers" and other tactics
The fence combinations can vary depending on the location.
In the Newry situation, a relocated dam would not be a problem. But in other circumstances, beavers must be prevented from rebuilding anywhere in the area they have chosen.
For example, Maxham said, beavers built a dam on a Dixfield property, and the water backed up and flooded the owner’s septic system leach field.
The solution: Maxham built a square-shaped fence in the brook. Beavers will try to build against it, he said, but their building materials can’t get a good grip against the corners.
Discouraged, they may leave the area or learn to live with the ineffective dam, which will often let enough water flow through to solve the property owner's problem, Hulsey said.
The square-fence design is sometimes known as a “beaver deceiver.”
Depending on the time of year, the animals can also sometimes be trapped and relocated.
If it’s at least early August, the young, or kits, have grown enough in their underwater lodge to be safely trapped, Maxham said.
But if it’s springtime, “we’d rather leave them alone,” said Maxham. “And they don’t do much damage in the spring. They eat grass and vegetation. It’s the fall when they start cutting trees for their winter food supply.”
Hulsey said he recommends against trapping generally, and only considers it as an option if the site is a particularly poor beaver habitat. If it's good habitat, he said, another beaver will likely find it and use it not long after the first ones have been relocated by trapping.
Maxham said he deals with beaver dam problems two or three times a year.
He occasionally sees the animals as he works in a stream. They’re not usually aggressive, but, he said, “sometimes they’ll slap their tails against the water (the beaver alarm for danger).”