Humans vs. beavers: The battle of 1993

Throughout 2017, Minnesota Public Radio will celebrate 50 years on the air by sharing highlights from our archives, connecting Minnesota's past to its present. | This story originally aired in October 1993.

MPR marks 50 years
• More stories from the archives
• Join the celebration, tell us your story

As animals continue adapting to humans' habit of forcing modern conveniences into their habitat, people are going to keep creating ways to push harder.

One example of this man vs. beast dynamic is the culvert — a tunnel that lets water from a stream pass under a road.

But this human invention that can be easily plugged by a beaver dam.

In 1993, Leif Enger reported on a victory for mankind in this battle with beavers.

As the critters continued to make dams on man-made waterways — made even more dam-friendly by the skinny culverts — water would overflow from rivers and streams onto nearby roads, which then required constant repair.

"The frustration is you never get ahead of them," said Norman Moody, who was land commissioner for Cass County at the time.

Thousands of dollars were spent annually just on hauling the timber out.

Then, a modified length of 10-inch wide pipe entered the picture. Designed by Clemson University in South Carolina, the pipe goes through the dam, through the culvert and then drains out the other side. All the while masking the water movement using smaller holes in the pipe so beavers won't get wise to the workaround.

Dubbed the Clemson Leveler, the DNR hailed the invention as proof that human wits are a match for beaver persistence.

"It appears the beaver wars are over," Moody said.

Recently, MPR News checked in with Eric Thorson of the DNR to find out if the Clemson Levelers are still out-smarting beavers. He reports that in most cases, beavers have figured out how to dam culverts even if they are equipped with a leveler.

So, counties have resorted to hiring trappers each season to remove the furry dam builders.