‘Beaver Deceiver’ New Weapon In Long-Running Battle

By Andrew Gorosko

In a joint effort to promote peaceful co-existence between man and beaver, the town and a wildlife advocacy group are installing several “beaver deceivers” at local beaver trouble spots to allow beavers to enjoy their aquatic habitat, while preventing the flooding problems caused by beaver dam construction.

Debra Gode, who heads The Fund for Animals, Inc.’s urban wildlife program in Connecticut, and Skip Hilliker, a beaver control consultant, waded into the shallow waters of Limekiln Brook in Dodgingtown September 27 to install a “beaver block” in front of the headwall of a triple culvert which carries the brook beneath Cemetery Road, near Flat Swamp Road. The brook drains an extensive swamp, which is prime beaver habitat.

The beaver block consists of two sections of flexible plastic six-inch diameter drainage pipe and three blocks of steel-wire grid, which serve as frames for the drainage pipe. When in place against the headwall of the triple culvert, the beaver block allows water to continue flowing through the culvert. Beavers typically dam up culverts to raise the water level in a swamp, allowing them to build beaver lodges.

Joseph Tani, head of the town’s highway department, observed as Ms Gode and Mr Hilliker, both in fishing waders, wrestled the components of the beaver block into place in the brook just upstream of the culverts.

The town has spent much time and effort over the years undoing the work that beavers have done to construct dams, Mr Tani said. The town dispatches a work crew twice a month to make the rounds of several beaver trouble spots to open up beaver dams and control flooding problems, he said.

In Dodgingtown, beavers repeatedly have plugged up the culverts beneath Cemetery Road, requiring repeated trips by town workers to Limekiln Brook to unplug them, Mr Tani said.

“Its just something you’ve got to keep doing,” he said of the need to repeatedly reopen blocked culverts.

Besides Limekiln Brook, the animal advocacy group will be installing beaver blocks at sites along Old Hawleyville Road, Boggs Hill Road, and Brennan Road.

Materials for the four beaver block construction projects are expected to cost the town about $2,300, Mr Tani said. Mr Hilliker designs an individual beaver control device for each site, based on the site’s characteristics. The animal fund contacted the town about installing the beaver blocks.

“They are very industrious animals,” Mr Tani said, noting the town has wrestled with beaver-related problems for years, with the problems worsening about 10 years ago.

Up until now, the town has placed heavy steel gratings in front of culverts to deter beavers from damming up culverts and creating flooding problems. But that arrangement requires frequent, repeated cleanings of the gratings, Mr Tani said.

Mr Tani said he hopes the beaver blocks are more effective and require less maintenance than the gratings.

 “I hope it lasts forever,” he quipped.

 Beaver Deceiver

The beaver block acts to deceive beavers about water flow, Ms Gode said.

 The two intake pipes, which extend about 20 feet upstream of the culvert headwall, have ports on their submersed undersides. The design is intended to eliminate the sound of flowing water – the sonic cue which instinctively tells beavers to build a dam, Ms Gode, said.

“The beauty of the system is that it foils the beavers’ instinctive response to plug any spot where they hear the sound of running water. Because of its design, the beaver won’t be able to plug up this device, built in front of the culvert to protect it,” according to Ms Gode.

“Thanks to this simple and inexpensive device, we can outwit the beaver, stop the flooding, and help the town and beavers co-exist,” she added.

Beaver habitat will attract beavers, according to Mr Hilliker. Killing beavers and trapping beavers is ineffective because as soon as one set of beavers is removed from beaver habitat, new beavers will move in, he adds.

Ms Gode said the beaver block is a cost-effective way to manage beaver activity, allowing the beavers to exist and preventing flooding problems. The device must be inspected and cleaned at least twice a year to ensure it works properly, she said.

The device allows the water level in a brook upstream of culverts to remain high enough to allow beavers to build their lodges, but low enough to prevent flooding problems, she said.

“If this works the way they say it’s going to work, then it [flooding] won’t be a problem,” Mr Tani said.

 Mr Tani said he expects he will know whether the four beaver blocks are effective in controlling flooding within several weeks.