BEST OF 2013: Reconstructing a River for Wildlife

Looking down the central part of the Platte River. (Photo by Ariana Brocious, NET News)
Crane Trust Habitat Manager Brice Krohn. (Photo by Ariana Brocious, NET News)
One of the agricultural disks the Crane Trust uses to remove invasive weeds, shrubs and young trees from the river channel and banks. (Photo by Ariana Brocious, NET News)
Two larger disks in the dry river channel. They tear out vegetation to create open, wide channels migrating birds prefer. (Photo by Ariana Brocious, NET News)
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December 23, 2013 - 6:30am

Every spring, millions of birds migrate through the Platte River in central Nebraska on their way north. They’ve been doing it for thousands of years. But as man-made demands on the river increase, year-round work is required to maintain that quality habitat, especially for endangered species.

Getting down to the edge of the central Platte River can be hard work. Brice Krohn, habitat manager for the Crane Trust, leads the way through a dense thicket until we arrive at a huge mechanized hoe. The disks’ massive, rotating metal blades have ground to a halt. And no wonder. It’s uprooting thick stands of invasive weeds, shrubs and young trees on the river’s edge. Krohn said the plants’ deep roots cause problems because they block the natural ebb and flow of water and sand that keep this river wide and shallow. Those plants also suck a lot of water out of the river.

“We’re going to help Mother Nature by going in and disking, tearing up the roots on some of these plant species, which will let the vegetation to die and sand will be more able to move around. If they stay there and grow, it would channelize the river,” Krohn said.

Deep channels aren’t good for birds, Krohn said. They prefer a shallow, braided river with bare sandbars. That matters because we’re in prime crane territory. Millions of birds spend a few weeks here every spring, resting and fattening up on the surrounding grasslands and fields before continuing their migration north.

“Cranes like a wide river, wide field of view, unobstructed view. They feel safe from predators when they’re roosting overnight in wide, shallow channels,” Krohn said.

They’ve been migrating through the central Platte for thousands of years. But more recent demands from irrigators and cities have substantially changed the river. Krohn said today’s flows are only about a quarter of what they were historically.

“The old premise was a mile wide and a foot deep. So if we look now we’re sitting at, in some spots, 100 yards wide and three and four foot deep,” Krohn said.

That powerful, much bigger river used to scour vegetation from the banks and channel—even more than it did during the recent flood that swept down from Colorado. Other factors played a role, too, “Historically, we know fires came through the area, we know the river was a broader scheme, bison used to graze through here,” Krohn said.

The Crane Trust is hoping to mimic those natural forces on about 10,000 acres of river habitat on the big bend of the Platte. They’re tearing out trees and weeds, setting controlled burns and applying pesticides to rid the area of dense foliage. In addition, nearby landowners are grazing cattle on the banks and the Trust is reintroducing its own small herd of bison to help thin the vegetation. Krohn said without these efforts, we’d be losing more habitat every day.

“If we don’t do anything today for it, the way the river is today will not be here for future generations,” Krohn said.

But the Trust isn’t the only group working on the river. A little further downstream, Jerry Kenny watches two huge disks churn through a dry channel of the Platte.

“The more water there is in the river the more challenging it is to operate the equipment,” Kenny said. Kenny is the executive director of the Platte River Recovery Implementation Program, which formed as a way to avoid lengthy court battles between Colorado, Wyoming and Nebraska over water rights and endangered species. The program is a collaborative effort between those states, the federal government, water users and conservation groups. It works to protect land and water for the threatened and endangered species in the Platte Basin: the whooping crane, interior least tern, pallid sturgeon and piping plover.

“The river wasn’t able to take care of itself under the constraints that we imposed upon it. At least to create the habitat that we think the species need—we need to step in and help restore that,” Kenny said.

The six year-old program manages about 10,000 acres of habitat along the central Platte. And they’re working with Nebraska, Colorado and Wyoming on getting more water back in the river. One tactic is using federal funds to lease Platte river water from willing irrigators. Then, the Program can divert that water into reservoirs and release it back to the river at critical times when certain species need it—like during whooping crane migration—through what Kenny calls retiming: “You store water in a surface water reservoir when it’s a time of excess, you release it when it’s a time of shortage.”

They’re working on a new reservoir to do that. Another way to get more water is paying people to use less of it. Kenny said that’s harder to quantify, and admits the program has been criticized by the community for spending a lot of money “on just a few birds.” He disagreed, “It’s not just for benefit of species, benefit of people who live in basin as well.”

Kenny said by managing the river for the endangered species, they’re helping the states and water users avoid legal conflicts and further regulation over water rights in the future. And the Program is studying the most effective ways to manage land and water for species. Kenny said their research helps them understand the natural and man-made forces that shape the Platte—and the species that depend on it.

This story is part of our QUEST Nebraska science reporting project.  QUEST is a collaboration of six public broadcasters across the country, including NET News.  Funding for QUEST is provided by the National Science Foundation.  For more stories on the science of sustainability, visit the QUEST Nebraska website.



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