Chesterton Tribune

Nature's builders: Beavers busy along Chesterton streams

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By KEVIN NEVERS

If you’ve happened to stroll Coffee Creek Park in the last month or so, you probably noticed the destruction: clumps of stumps—of saplings mostly but of some more mature trees too—gnawed at ground level, chewed to perfect points as though shaved by some obsessive-compulsive whittler.

The beavers are back.

And there’s a reason why they’re proverbial for their industry. “I’ve knocked down a couple of dams,” Chesterton Park Superintendent Bruce Mathias told the Chesterton Tribune. “There were back in four days.”

For years Indiana was without any beaver population to speak of. By 1840 trapping had reduced their numbers to negligible levels, according to Mammals of Indiana Dunes National Lakeshore, a monograph published by the National Park Service in 1994, and as recently as 1990 it was news when fresh beaver cuttings were discovered along Derby Ditch. But in the last decade beavers have established a lodgment in Northwest Indiana, after swimming up the Ohio River, the Wabash, the Tippecanoe, then fanning out, said Linda Byer, a wildlife biologist with the Department of Natural Resources. “Beavers have been back for some time now.”

And they would appear to be here for the long haul. Duneland doesn’t have much in the way of predators to control their population—wolves and coyotes are especially fond of beaver—and there is not much market anymore more for their pelts (although beaver season opened Nov. 15 and they may be hunted or trapped through March 15). “The reason why things become a problem in urban areas is that urban areas don’t hunt or trap them,” Byer said.

Newcomers to the wilds of Chesterton may find the company of beavers appealing, in the same way they find that of deer appealing (until their garden is browsed to stubble or their windshield explodes one night on U.S. 12). And in fact there is something cool about beavers. They’re Nature’s own engineers and can construct dams so vast and sturdy—some have been measured at 100 feet in length—that they can only be dismantled with heavy excavation equipment. Beavers are, among other things, monogamous, herbivorous, and—just ask Chesterton Street Commissioner John Schnadenberg—relentless.

Early one morning in October Schnadenberg was summoned to Coffee Creek Bridge on East Morgan Ave., where a large tree, weakened by beavers, had given way across the railing from the creek bank below. Schnadenberg has also received at least one call from a business owner concerned about a tree on private property, currently under deconstruction by beavers, threatening to tumble onto his building. “We are keeping an eye on the areas where it could be a hazard to vehicles and pedestrians,” he said.

Their dams, on the other hand, present an entirely different problem. Beavers construct them in order to deepen shallow waterways and create ponds in which to build their lodges. In short, Byer observed, their instinct “is to stop the movement of water,” an altogether unnatural state of affairs in any stream and a potentially disastrous one in a vital receiving stream of a community’s stormwater drainage system.

“It’s all natural what they’re doing,” Mathias said of the beavers in Coffee Creek Park, “but it’s going to end up raising the creek water and backing it up. If it’s a foot higher here, it’s a foot higher a mile back.”

Several years ago, Schnadenberg recalled, beavers took up residence in Lake Griffin. “Their dams were causing flooding at a crucial point where water was backing up at Washington Ave. and 15th Street all the way to Duneland School property on 11th Street,” he said.

Now the beavers have constructed a dam under Coffee Creek Bridge across Indian Boundary Road, and it’s a big one, Schnadenberg said, the water on the south side of the creek two feet higher than the water on the north side. And Coffee Creek flows north. “That’s the concern. It’s backing water into our area. Typically each year—I don’t know if it’s our responsibility, the bridge is under the jurisdiction of the county—we try to free up dams because no one else is going to do it. Try to free up that water. But it seems like this year the problem’s a little worse. I don’t know why.”

Yet destroying dams is simply “ineffective because they build them right back,” Byer said.

Schnadenberg solved the Lake Griffin problem by hiring a trapper to live-catch the beavers and re-locate them. He and Mathias are considering that option right now. “That’s what we’re going to explore, if that’s feasible,” he said. “The fact that there are so many of them, I don’t know if it is feasible.”

And by feasible, of course, Schnadenberg means affordable. The cost of live-catching ranges from $75 to $100 per beaver, and with four to six beavers per lodge, the Street and Parks and Recreation departments are looking at a pretty good chunk of change. “That’s why the first thing we do is try to clear the obstruction and hope they move downstream somewhere,” Schnadenberg said.

But there are plenty of beavers upstream to take their place. They’ve been busy in the Coffee Creek Watershed Conservancy (CCWC), and CCWC Executive Director Steve Barker is beginning to cast about for his own non-lethal beaver-management strategy. To Barker’s knowledge beavers constructed a sizable dam in Shooter Ditch at the south end of the property, but they subsequently vacated it and the dam finally eroded away. More recently they moved upstream and there they’ve taken a bite out of a stand of “huge old-growth cottonwood trees,” he said, with “some erosion and flooding as a result this year.”

“It’s a delicate issue, just like the deer problem,” Barker said. “We’re keeping a close eye on it. The unfortunate fact is that there isn’t a whole lot of habitat left for them. Live-and-let-live has been our policy, but eventually we’ll have to do something. So it’s an interesting dilemma.”

Barker is considering a new product, one touted by Byer as a way for beavers and humans to co-exist peacefully. It’s called the Clemson Beaver Pond Leveler: a PVC pipe installed through the dam, well below the surface of the stream, allowing the current to flow from one side to the other, equalizing water levels and minimizing flooding. Beavers are unable to detect the flow, Byer said, they can’t hear the gurgle of the current, and so they’re content to leave well enough alone.

But the Clemson Leveler is a post-dam expedient and does nothing to prevent beavers from knocking down trees to construct one in the first place.

As Mathias observed, “They do what they do.”

 

Posted 12/1/2005