They call themselves the Beaver Patrol, and they’re on a mission to ensure that beavers coexist in balance with people and salmon.
The problem with beavers
Beavers, of course, intentionally dam streams to create their ponds. But when they block culverts in the wrong place it can cause problems, like flooding trails and keeping salmon from swimming upstream to spawn.
That’s what can happen in the Dredge Lake area near Mendenhall Glacier in Juneau — a network of trails and ponds connected by culverts.
One way to fix the problem is relocating or killing the offending beavers. That option was on the table well over a decade ago if other methods of managing them failed. (No one seems to remember it ever actually happening). But years ago, a group of volunteers stepped up with a plan to keep beaver dams from interfering with trails or salmon — without trapping any beavers.
Enter the Beaver Patrol
Mary Willson is a long-time member of the Beaver Patrol. She said the group came together around the idea of balancing all the competing interests.
“We said, ‘Wait a minute, no — we can manage this, and we can try to find a compromise,’” she said. “We can keep the beavers, keep the habitat they make for the fish, allow the spawners to come up, decrease the trail flooding — let’s try to do it all. It’ll never be perfect, but it’ll be a whole lot better.”
And so the Beaver Patrol was formed.
The trick is to let beavers keep building their dams, but make sure enough water is flowing to keep the trails from flooding and the salmon swimming through. In a natural environment, it’s easier for salmon to make their way through beaver dams — but when beavers jam sticks and logs into a narrow culvert, it can become impassable.
The Beaver Patrol says a beaver pond makes a good habitat that helps juvenile salmon survive — as long as the adults can reach the ponds to spawn in the first place.
Armed with saws and gardening tools, the Beaver Patrol trudges along the trails in the Dredge Lake area, checking the dams. Here and there, they dig out parts of dams that are at risk of raising the water level too high. It’s an ongoing task — the beavers are constantly building, so they come out twice a week during the summer to keep things under control.
“We have proved ourselves to be at least as stubborn as the beavers,” Willson said with a laugh.
But the real challenge is when the beavers get big sticks stuck in a culvert and debris starts collecting around it. The Beaver Patrol spent so much time clearing one area that they dubbed the site “Nemesis.”
Fortunately, the Beaver Patrol has technology on their side. They’ve built baffles and barricades out of metal mesh, stakes and netting — blocking culvert openings off from bigger sticks and debris, but letting water and salmon pass. Some were designed by outside experts, and some they came up with themselves — including the one that now guards the culvert opening at Nemesis.
It still takes regular work to clear smaller debris that gets caught in the mesh, but it’s a lot easier than crawling into a culvert to pull out a log.
Forest Service collaboration
The Beaver Patrol works closely with both the U.S. Forest Service and the Alaska Department of Fish and Game to make sure their designs and ideas have the desired impact on the beavers and their habitat.
Sometimes the Forest Service will pitch in to buy materials for a project (like when they spread gravel on the trails to mitigate the effects of flooding), but the Beaver Patrol is an independent nonprofit with its own funding and volunteers.
And it’s usually more about volunteer effort than money, said Chuck Caldwell, another member of the Beaver Patrol.
“It’s high physical effort per dollar spent, and some years we’re not spending any money, we’re just working,” he said. “The waders and everything we bought ourselves, the tools … we buy ourselves, so that’s pretty much from the members.”
He calls the Beaver Patrol the “gold standard” of volunteer organizations, because of their ongoing, twice-weekly commitment to have volunteers working in the area.
Thursdays and Sundays throughout the summer, you can usually find the Beaver Patrol clearing debris and designing baffles in the Dredge Lake area — helping maintain the balance between beavers, salmon and people.