There are two kinds of dam-builders – those that have two feet and those that have four. This report is about the four-footed ones.
Early after Europeans began populating North America beavers here went into decline thanks largely to fashion trends. Their fur was valued largely by hatmakers here and back in the Old Country.
There was also some culinary interest, the ultimate consequence being that the animal was almost entirely eradicated before animal protection and other conservation impulses turned things around in the 20th century – ultimately to the chagrin of settlers, roadbuilders and farmers whose own lives can be disrupted by ponds that show up where they aren’t planned.
Then, too, beavers tend to spread water-borne diseases, principally giardiasis, a diarrheal affliction carried by microscopic parasites that live in their intestines. Hence the term “Beaver Fever.”
From these inconveniences has emerged an industry in how to control beavers. Search the Internet for “How to Control Beavers” and prepare yourself for a lot of reading and also lessons in how resilient these mammals can be.
A study in Tennessee found that after hundreds of beavers were removed from one wetland area, an equal number moved back in within two years. As for the idea of demolishing beaver dams, the animals are quick to rebuild.
Hence, a wide range of alternative steps, including habitat alteration (meaning, remove the kinds of trees that beavers like to eat), fencing, repellants, frightening devices (firecrackers and strobes), trapping and shooting.
I’m inclined to the non-lethal solutions, among them water flow control devices that consist largely of underwater pipes that people install inside beaver dams that drain beaver ponds without causing any tell-tale noise that can alert beavers to a leak that needs to be plugged. A widely referenced design is the Clemson Beaver Pond Leveler.
Another non-lethal device that I particularly like is the Beaver Deceiver, a fencing system that was invented in Vermont. The New Hampshire Department of Transportation recently approved the use of the device near a busy road where flooding’s been a problem.
One of my principal findings while researching the book “Water Connections” is that water’s a place for inventive minds – whether in designing new hydropower technologies or water treatment methods or water-saving devices in household appliances.
Beavers can similarly get the creating juices flowing. So long as they are building dams and blocking culverts for their own purposes – and so long as we’re inclined to non-lethal responses -- there’ll be opportunity for invention.