Beavers

Nature's engineers, flooded streamgages, beaver deceivers, hydroacoustics, and a lifetime of turning down trails to see what they built.

Always Fascinated by Beavers

During my four decades in New England, I was always fascinated by beavers and the ponds they built. I even bought a very light Kevlar kayak, only about 20 pounds, largely so I could haul it down trails and paddle remote beaver ponds. I spent countless weekends hiking into the woods to look at dams and lodges and see how the ponds had changed.

Nature's Engineers

Beavers are incessant builders. The sound of running water seems to trigger them to patch holes and keep working on their dams, expanding ponds and reaching more trees for food and lodge building. I took courses on beavers through local wildlife organizations, and the more I learned, the more amazing they seemed. Their ponds create incredibly rich habitat for waterfowl, wading birds, turtles, snakes, fish, and all kinds of other wildlife. For someone who loved nature watching, a beaver pond was a perfect place to spend a day.

Beaver
Beavers were always one of my favorite animals and their ponds were some of my favorite places to explore.

When Beaver Ponds Meet People's Property

Of course, the same engineering that creates wonderful wildlife habitat can create real problems when water backs up onto someone's yard, road, or property. During my years on the Conservation Commission, beaver flooding became one of our biggest recurring issues. We received calls from people whose land was flooding and from others reporting that someone was tearing into a dam. Massachusetts regulated alteration of beaver dams and lodges, so these situations often required investigation and permits rather than a homeowner simply ripping out a dam.

Beavers and USGS Streamgages

Beavers also caused a completely different problem in my USGS work. We measured rivers and streams, and many streamgages depended on a relationship between water level and flow. Unfortunately, the places that worked well for a gage sometimes also looked perfect to a beaver. A new dam could back the water up and destroy the normal relationship between stage and discharge. Suddenly the water level was no longer a reliable indicator of how much water was actually flowing.

Tearing Out a Dam

I remember spending a full day with two colleagues tearing out a huge beaver dam because my boss told us to do it. We did not have the permits, and I realized we could potentially be fined even though we were federal employees simply following directions. It was one of those moments when the conflict between field work, regulations, and a determined beaver colony became very real.

Trying Beaver Deceivers

We eventually looked toward flow-control devices, often called beaver deceivers or pond levelers. The idea was to build a pipe or flow device into the system so the pond could remain, but the water would not rise above a certain level. The intake was arranged so the beavers could not simply find the running water and plug it. Professionally installed systems could be expensive, so people in our office tried building versions ourselves. We had rather limited success, but the concept was an excellent way to think about living with beavers instead of constantly fighting them.

Historic beaver flood-control booklet
An image from my original 1999 beaver page, when I was collecting information on beaver flood-control systems.

Acoustics Changed My USGS Career

Around the same time, newer acoustic technology was becoming available for streamgaging. Instead of depending only on water height, we could use acoustic signals to measure velocity and combine velocity and channel area to estimate flow. The equipment cost thousands of dollars and was complicated to install and operate. At first, the calculus, Excel formulas, ratings, and regression analyses were way over my head. But I stuck with it, went to courses and trainings around the country, learned the equipment, and eventually passed that knowledge on to others in the office.

Learning the New Technology

That decision became one of the best things I ever did in my USGS career. Many of the old-timers understandably stayed with methods they had used successfully for years, but I could see that the newer technology was the future, especially at sites affected by backwater and other conditions where the old stage-discharge relationship did not work well. Becoming one of the people willing to learn the new systems opened the door to new duties and a much better life for me at USGS.

Falling Through a Beaver Pond

For all the work problems beavers caused, I still loved their ponds. One winter I was out taking pictures on a snow-covered beaver pond when I suddenly heard the snow and ice beneath me give way. I dropped into water about five feet deep. Luckily my elbows caught the ice, just as they had once before when I fell through a river. I managed to get out, but I was completely covered in beaver-pond mud. My winter clothes, boots, and everything else were soaked and filthy. Somehow I saved my expensive camera, and I still have the photos from that day. It is an awesome memory now, although it was a little less awesome at the time.

Still One of My Favorite Animals

I do not see beavers where I live in Florida the way I did in New England. In Massachusetts, beavers had once been nearly eliminated by the fur trade, but they returned and became a familiar part of the landscape again. They are still one of my favorite animals. Even after years of flooded properties, streamgage problems, permits, dam removals, and muddy boots, I cannot see a beaver pond without wanting to stop and see what is living there.