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Living, working with beavers

Granddaughter Hayden asked, “What does ‘pesky’ mean?”

I’d just commented about “those pesky beavers” on our way to observe a Harris Center beaver-deceiver project in Stoddard.

I said it means rascally, as in little rascal beavers that are outsmarting humans.

Beavers at the Fremont conservation land in Peterborough have been outsmarting me for a month now. Hayden, Carl and I were going to observe installation of Phase II of the Harris Center beaver project. The beavers had thwarted Phase I.

The Harris Center objective is peaceful coexistence with beavers, but one that would maintain a certain water level that would not rise and flood Route 123.

“Beaver deceiver” pipes or conduits installed in a beaver dam allow enough water through to avoid flooding. That’s the concept.

Beavers had foiled the Harris Center’s first attempt. They detected one of two installed pipes, and soon figured out how to clog it up.

Carl and I had installed a similar Phase I at Fremont: A couple pipes embedded in the beaver dam that would allow enough water through to avoid overflow and trail washout — again.

Beavers have been moving around at Fremont for a long time, doing what beavers do: Damming a stream to create a beaver pond, building a stick and mud lodge with an underwater entrance, and creating in the process great wetland and open water habitat.

We like beavers. They’re one of a handful of “keystone species” that benefit a wide range of other wildlife species.

When they exhaust the local food resources, they move on, upstream or down.

Over the decades at Fremont Field, they’ve moved several times along two streams but never very far.

Their most recent impoundment resulted in flooding of the main trail during periods of heavy rain. Carl and I placed a boardwalk so people could cross the flooded lowland area. Hayden helped with that project. She was the first person to “walk the planks.”

Problem solved, we thought.

This spring we discovered the trail washed out.

One hot May day a stalwart Dublin School volunteer group shoveled a truckload of gravel, wheelbarrow by wheelbarrow, to the trail area and topped it with rich soil.

Crowned, rolled and seeded, the trail soon was grassy again. And flooded.

My new routine became an early morning visit to the dam to unclog the two beaver-deceiver pipes. It took the beavers one night to figure out the pipes, as well as the other small breeches I made in their dam to keep the water level down.

Mud, sticks and grasses patched each breech and clogged each pipe.

Each morning I cleared the two pipes and remade the breeches. Once I slipped on the muddy dam and fell in. I pictured the beavers finding that hilarious.

I did begin to worry that the beavers were having to spend too much time undoing my work and might not have enough time to forage.

Not to worry.

Carl and I visited the dam late one afternoon, a bit before dusk when beavers become active. Or so we thought. One beaver was already at work and had reclogged the two pipes and patched the breeches.

I pictured beavers whistling as they worked, “easy peasy” as Hayden likes to say.

One morning I found a waterlogged pole-sized tree some 15 feet in length laid next to one pipe. I have no idea how beavers managed to get that dead weight up and on the dam. I pictured angry beavers that time, leaving a message that they would not be deterred.

Also delivered was a beaver chew stick long enough that I could ram it up the main pipe on my morning routine of clearing the two beaver non-deceivers.

This Monday, Carl, Conservation Commission member John Patterson, and Eric Masterson from the Harris Center installed Phase II at the Fremont modeled after the Phase II system installed at the Harris Center’s Robb Reservoir property in Stoddard.

It’s a long stretch of 12-inch culvert pipe embedded in the beaver dam. It reaches well out into the pond and is circled by a wire cage that will be very difficult to clog.

As a diversionary ploy, I just might keep up my morning routine at Fremont with hopes the pesky beavers won’t associate the new thing in the middle of their small pond with the humans messing with their damworks.

It’s not a bad way to start the day: in the company of bluebirds; swamp roses abloom; blueberries ripening; a distant pileated woodpecker drumming. There’s always something going on at the Fremont.

Backyard Birder by Francie Von Mertens appears every other week in the Monadnock Ledger-Transcript.

Pipes alone are not enough—as the Backyard Birder has discovered, a large 5-foot diameter cage at the pipe inlet is necessary to prevent beaver plugging (For more on this, see http://beaversww.org/solving-problems/manage-flooding/). It's great that people persevered to find the right solution.

A well-installed flow device should allow you to keep the beavers and prevent flooding. My own city installed one 6 years ago which has continued to control flooding. Now because of our beaver-tended wetlands we regularly see otter, heron, kingfisher, steelhead and even mink in our tiny urban stream! If you can't do this work yourself you have regional experts that could help (Skip Lisle in VT and Mike Callahan in MA). Any city smarter than a beaver can keep a beaver! Heidi Perryman Worth A Dam www.martinezbeavers.org

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