Beaver Dam Mapping App Now Available for Citizen Scientists

13 July 2014
Published in Environment
Written by  Ross Chambless
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Beaver Dam Mapping App Now Available for Citizen Scientists Wally MacFarland maps a beaver dam using the BRAT app on an iPad

Although western farmers and irrigators have long deemed beavers to be pests, scientists are studying how these dam building rodents could be used as a tool for stream restoration and mitigating impacts of climate change on Utah's water supply. Watershed scientists at Utah State University have created a smart phone app and are asking people out hiking in the wilderness to track these furry builders so they can better model which water ways would benefit the most from their help. This story is part of our "Follow the Flow" series that examines our relationship to watersheds in Utah.

Utah State University scientist Joe Wheaton studies forces that impact Utah's waterways – specifically beavers, those furry overgrown rodents with the buckteeth and the flat flapping tail.

"I doubt we'll see any today, unless we get lucky and sneak up on one," says Wheaton.

A few weeks ago he brought me up Logan Canyon to see what beavers are doing here. We've also come with some other researchers and a pair of eager black labs.

Though historically prized for their fur, in recent decades scientists have begun seeing beavers as ecological heroes. In 2010 the Utah Division of Wildlife Resources formulated a beaver management plan that sees beaver as a tool for restoring incised and degraded streams.

"Where we're standing now is on a little bridge across Spawn Creek, and... what this is, is an abandoned beaver dam," says Wheaton.

He points to what's left of a short wall woven with sediment and aspen branches – chewed like corn on the cob - about ten feet away. Here it once held back a shallow pool of stream water.

"What happened is they built a dam, roughly a meter high. And it's filled in with sediment."

This sediment, he says has raised the whole level of what was an incised and degraded stream in just a few years. Through the clear water you can see small round rocks – gravel. This stream is a stronghold for cutthroat trout, a protected native fish, and the sediment has created a safe place for the fish to lay their eggs, he says.

"It's like perfect spawning gravels, right. It's filled to the brim with sediment. And since that dam is breached and they've abandoned it, now what's left behind is really good spawning habitat," says Wheaton.

Currently most Utah streams struggle with sediment and nutrient overload. Only 30 percent of in-stream habitat for fish and other aquatic life in Utah's streams is considered "good", with most streams listed as "poor" or in "fair" condition, according to a preliminary Utah Division of Water Quality report this year. Here Wheaton and the other scientists are researching how beaver dams help sustain fish populations, and help trap sediment that recovers riparian habitat.

"Why do we want beaver dams? We don't one hundred percent care so much about the beavers," explains Greene, who is a researcher and educator at Utah State University Extension. "But what they're doing is they're taking the water and now connecting it to these other areas and they're pushing it out into the riparian zone. So now we have this really complex habitat that's good for the birds. It's good for the amphibians. It's good for the plants. So it makes really unique habitat."

Watershed scientists like Joe Wheaton are also assessing whether beavers - and the water-keeping dams that they build - could indeed help mitigate some impacts of a declining snowpack. Snowpacks in the Mountain West – including the Wasatch Range - provide millions of people with water, and recent studies suggest climate change is behind a withering trend over the last century.

"Certainly a number of people have speculated that if you have a bunch of beaver dams on the landscape, they're sort of providing a similar function to what a larger snowpack would, that provides this store of water that slowly releases it out over time," says Wheaton.

Hiking our way up along the stream, we cross over a cattle guard into a fenced area. About ten years ago the Forest Service, realizing this high elevation tributary was ideal habitat for cutthroat trout, set the area aside and fenced it off from cattle grazing and forbade beaver fur trapping, which still happens today, although with some regulations.

This recovering area now gives Wheaton and his team a chance to ground-truth a new mapping model called the Beaver Restoration Assessment Tool or BRAT, using an iPad. The BRAT predicts the capacity for beaver dams on every perennial stream in the state using nationally available satellite imagery of all the drainage networks. Wheaton's iPad is showing the stream we're walking along. It looks like a thread with different colored segments.

"Red means an area where you can't have any beaver dams. Orange is an area where it's not great, but where we might see up to one dam per kilometer. The yellow are occasional, we might see between one to four dams. Green we would see between five to 15. And blue is the best, is pervasive. Those are short reaches that could support up to 40 dams per kilometer. So that's like a dam every 40 or 50 meters," explains Wheaton.

We're now entering an area the BRAT model identifies as a blue segment, or "pervasive" along the stream. And sure enough, here we've entered into a complex chain of ponds and beaver dams. The shallow stream water is spread out everywhere, and fresh groves of aspen, willow and green grasses are all growing up around us. Wheaton points out the telltale signs of an active colony of beavers living here: a mound of sticks that's their lodge; a skid trail that marks where the beavers drag the aspen trees into the water; and a network of underground tunnels.

"You're standing right above the tunnel to their lodge. See there's an underwater entrance, and it goes to the great big mound of sticks, which the dogs have smelled that there's probably some beaver in there."

None of this beaver activity was here ten years ago, according to Wheaton. Given time, and a stream protected from overgrazing, he says beavers will move downstream, which could mean more water gets stored on the mountain for longer periods.

"What we have done with the model is try and predict where in the landscape could beavers be. Even in places they are not now. What's the capacity of these different streams to support what sort of densities of dams," says Wheaton.

For these scientists, checking every perennial stream in Utah for beaver dams will be a time consuming job. That's why they've also made a smart phone app to enlist help from volunteer citizen scientists – basically anyone out hiking or fishing in Utah who might encounter beaver activity.

"It allows them to very easily take a photo and send us the GPS coordinates of beaver activity," says Greene.

"If we're getting a lot of volunteers reporting back that we're seeing lots of beavers in this area and the model predicted that's a good area for beavers, then that means the model is working well. If they're finding lots of beavers in areas the model says there shouldn't be beavers, then maybe the model isn't as accurate as we'd like it to be," Greene adds.

Still, not everyone thinks beavers belong everywhere. Historically beavers have been reviled – and often killed – for being pests that cut down trees, stop up creeks and culverts, cause floods, or take water from farmers downstream. A few years ago Wheaton says he was asked to help water managers in Park City resolve a problem with beavers in their city.

"They just did what everyone did with beaver if there were any. You'd blow up their dams with dynamite and kill 'em, right. And this wasn't a policy. It was just what they did as routine maintenance. And roughly five years ago some local residents, there was some beaver ponds that were built. And the residents liked it, and all the wildlife that came around it. And then they complained to the city when the city went in to do what they normally do."

So the Park City workers left the beaver dams alone, and they didn't kill the beavers. Soon the number of beaver dams grew, and the beavers built their dams higher. This eventually caused flooding of roads and houses. And the beavers upset neighbors by harvesting ornamental yard trees. So in 2013 Park City officials asked Wheaton to help them draft an adaptive beaver management plan.

"For example, you could go in and put in a 'pond leveler', or a 'caster master', and that would lower the water level, and alleviate the flooding, and still allow the beaver to be there," says Wheaton. "Or fencing around ornamental trees, etc. And then the worst case scenario is, OK, we've tried these living with beaver strategies or we're in an area that's so sensitive, like a canal diversion, we absolutely cannot allow beaver. So that's when we'll live trap nuisance beaver and relocate them to areas, either within the city limits or beyond, where they want beaver for restoration or the ecosystem services they provide."

We're now approaching a dam that Wheaton says has been here since the 1940's. If this were near a road or housing, it surely would've have been destroyed by now. It's over a meter high, like a fortress wall of sun-baked sticks holding back an Olympic-sized pool of water. And nearby is a giant lodge.

That is the mother of all lodges. It looks like a damn two-story beaver lodge.

I'm just in the middle of asking Wheaton another question, when we see him.

"There he is! He's swimming around right by the lodge. You see his nose," asks Wheaton. "Oh yeah, that's a beaver! And the dogs are in pursuit."

The beaver swims at the surface just for a moment, before splashing down his tail and disappearing.

These beaver buffs hope interested citizens will help to document beaver dams - and beavers - when they find them all across Utah. They also hope this information will help people to better manage and appreciate what the beavers do for our fragile water systems... that is, even if they'd rather stay out of sight.

This story was made possible by iUTAH, a National Science Foundation Funded statewide effort to maintain and improve water sustainability.

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