To engineer is human; doing it right might require beavers
Behold the concrete road culvert: straight and narrow and lifeless, having
whisked the previous day’s rains from oceans of hard-baked asphalt with
ruthless efficiency, swelling quickly to 6 feet deep with stormwater, then
receding to less than an inch of water hours later.
Now follow Erik Michelsen across the road, which is Maryland Route 2, a busy
four-lane traffic artery connecting Annapolis to Baltimore.
Until recently, the beavers would not have been embraced for their ecosystem
contributions. They’d have been removed, meaning trapped and killed. That’s
still too common around much of the Bay watershed.
Beavers are compelled to chew, to control their marvelous, self-sharpening
teeth that never stop growing; compelled also to dam, annoyed by the sound of
flowing water.
The beaver dams here were raising water levels, with a potential to flood
Ritchie Highway. The county responded by installing a simple, low-tech device
called a pond leveler. A sturdy metal cage toward the lower end of the pond
protects one end of an 18-inch diameter plastic drainpipe.
The other end of the pipe exits downstream of the beavers’ dam, carrying the
sound of flowing water far enough away so they are not motivated to plug it.
The whole affair is set up to keep the pond deep enough to make the beavers
feel at home, but not so deep as to flood the roadway.
Michelsen estimates there are hundreds of beavers now in Anne Arundel County.
Complaints about beavers typically run about “50/50, flooding and chewing down
peoples’ trees,” said Peter Bendel, with the Wildlife and Heritage division of
the state Department of Natural Resources.
“So now it’s a matter of education, teaching co-existence, offering solutions,
explaining beavers’ benefits,” Michelsen said.
We headed north up the highway toward where Cattail Creek meanders down from
big shopping malls and passes under the road by Joe’s Seafood and Precision
Auto Tune. Clambering down a slope, we picked up an improbable nature trail
that skirts several acres of beautiful pond and wetlands. Chisel-like beaver
chews are evident on sticks and felled trees as big as 18 inches in diameter.
Beavers feed on the bark and use the wood to construct dams and lodges.
The beavers have done the “restoration” here by themselves, Michelsen said. At
least twice, the county Department of Public Works trapped them out and tore
out their dam. The beavers just moved back in.
The problem was a fear of flooding that raised manhole covers, allowing access
to a major sewer line that runs along the creek floodplain. The solution was as
simple as pouring a bit more concrete to raise the manhole covers a few feet
higher, beyond the threat of flooding. It was a lot cheaper than never-ending
trapping, too.
Later that day, south of Annapolis on Flat Creek, a tributary of the South
River, we saw an expanse of beaver-wrought wild rice wetlands that looks
completely wild, save for twin pond levelers protecting Governor’s Bridge Road
from flooding.
No single-channel babbling brook here — just a broad and languid flow of water,
moving in braids across an expansive floodplain. This was water’s chosen way
back when both the watershed and the Bay were healthier.
The shift toward an ecological beaver ethic remains slow and uneven across the
watershed. Tools like pond levelers, abrasive paint and other techniques to
protect trees are available, notably from Mike Callahan’s Beaver Solutions in
Massachusetts. Callahan’s companion Beaver Institute provides both hands-on and
do-it-yourself training for organizations or individuals working for a peaceful
coexistence with the beavers.
We’ve scarcely begun to plumb the potential of beavers to restore water’s
rightful way throughout Bay landscapes. But Michelsen has high hopes. “I am
convinced that, even in a highly urban watershed, they can do wonders,” he
said, “if we just allow them to work.”
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Tom Horton
Tom Horton, a Bay Journal columnist, has written many articles and books about
the Chesapeake Bay, including Turning the Tide and Island Out of Time. He
currently teaches writing and environmental topics at Salisbury University.
