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The Baltimore Sun

Dan Rodricks: Why not recruit the ‘weird rodent’ to help the Chesapeake Bay? | COMMENTARY

By Dan Rodricks, Baltimore Sun,

2023-03-14

Ever come across a place and try to imagine what it was like 300 or 400 years ago? It’s not something you do every day, when you have errands to run, work to do, children to care for, meals to fix, politics to abhor. But sometimes and some place, you surrender to the moment and try to squint away all the clutter of the modern world — office buildings in the distance, plastic bags in trees, the board fence on the edge of a pasture.

You apply what you know, what you’ve learned about the natural history of a place, to imagine what it was like in, say, the time of Captain John Smith, who explored the Chesapeake Bay. Next year will mark 400 years since Smith published his map of the region. Maybe you can imagine that time before colonization, before colonists cleared forests for farms, before they built roads and bridges.

And so you might be hiking, as I was on Saturday, along a creek in Baltimore County, and you know that it was not always like this: Low water in March, a series of dry gravel beds, large stone blocks placed against the banks to slow its erosion, a single-stream creek, essentially a drainage ditch.

To most people, Minebank Run in Cromwell Valley Park looks like any suburban creek, degraded by time, development and stormwater runoff upstream; low water after the non-winter of 2023 is probably what you’d expect to see there.

Except once there were beavers, and once there were beaver ponds — if not along Minebank, then along thousands of other creeks and rivers throughout North America.

Before beavers were almost trapped out of existence, they shaped the American landscape. They built dams and ponds, and the ponds became habitat for waterfowl and fish, aquatic insects, amphibians and reptiles. The pond and the land around the pond stored water so that many of the creeks ran cold, providing year-round habitat for the Eastern brook trout. Water filtered slowly through the dams and flowed downstream to the bay.

“Beavers need water, so they cut down trees and flood forests to create ponds,” writes Leila Philip in “Beaver Land: How One Weird Rodent Made America,” a new book on the subject. “In doing so, they kill trees but create new habitat for hundreds of animal species that rely on those new waterways. Once they abandon a dam, having determined that life there is no longer manageable due to lack of food, [the pond] begins to drain and grows back as meadow, then underbrush, then eventually forest, the soil enriched by years of accumulated pond rot and muck.”

So I try to imagine what it would be like if, at Minebank Run and other places, we encouraged beavers to do their thing again.

What if we planted trees and native plants that attract beavers to places like that? What if, instead of seeing them as a nuisance, we let them build the dams their ancestors would have built. What if, instead of a gravelly ditch, we saw a series of ponds and lush wetlands, with water slipping through the beaver dams on its way to the Chesapeake?

We could probably achieve what we’ve been after for years now — reduced erosion and sediment control, the restoration of wetlands and habitats — at a fraction of the cost we now spend on stormwater control and stream restoration.

In her book, Philip devotes a chapter to what she learned from Scott McGill, the founder of a Harford County-based environmental restoration company and now a champion of the beaver. I’ve known McGill for years and, while he doesn’t expect beavers to put companies like his and engineering firms out of business, he believes there are places where they could be a huge benefit.

Minebank, running through a public park with a nature education center, would be a great demonstration project.

There’s a growing naturalist movement behind the beaver, more so in Europe than in the United States. There’s a recognition that climate change causes more extreme weather — from floods to drought — and their advocates believe beavers can play a role in softening the effects of both.

Three years ago, Pickering, a town in the north of England long prone to flooding from a nearby river, reintroduced beavers for protection during heavy rains. Since then, the busy rodents have built what is reportedly the largest dam in the country, at nearly 80 yards, along with a series of smaller dams to further protect Pickering.

It was as inexpensive and as unobtrusive a flood management plan as you can imagine. Conventional projects to protect river towns are hugely expensive. (In Howard County, the Ellicott City flood mitigation project has received more than $160 million in local, state and federal funding in recent years.)

If we were to ever incorporate beavers, even in a small way, into government-sponsored flood control — if we could allow them to create ponds from the small streams that feed the rivers that feed the Chesapeake — it would have to be carefully managed.

There’s also the possibility of mimicry — that is, having humans create from logs, brush and mud the kind of small dams that beavers are known for. In other words, we could take a lesson from the “weird rodent” and restore streams to their historic best, the way they were in the time of Captain Smith. Imagine that.

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