FRIENDLY TO FISH

Greybull river flows through new dam

2012-04-12T00:00:00Z Greybull river flows through new damBy MARTIN KIDSTON mkidston@billingsgazette.com The Billings Gazette

MEETEETSE, Wyo. — A stretch of the Greybull River turned muddy Wednesday when crews diverted water over a new $4.3 million irrigation dam designed to reunite Yellowstone cutthroat trout with native spawning grounds upstream.

At 9:30 a.m., a backhoe working against the backdrop of the Absaroka Mountains unplugged the river and sent a torrent of chocolate-colored water flowing back into the Greybull's historic channel. The dam's floodgates were raised and the river was whole again.

"A lot of fish over the years have been displaced by getting stuck below this thing and not being able to get upriver," said Cory Toye, director of the Wyoming Water Project for Trout Unlimited. "They'll be able to get upriver now for the first time."

Construction on the new dam began last fall when the Greybull was sent on a course slightly north of the new structure. Throughout the winter, the $4.3 million project, known officially as the Upper Sunshine Dam Rehabilitation Project, employed about 25 people.

While the dam was intended to provide irrigation water to a canal feeding the Upper Sunshine Reservoir five miles south of here, efforts by Trout Unlimited, the Shoshone National Forest and Wyoming Game and Fish, among others, helped incorporate a fish ladder into the project's design.

Built in the 1930s, the old diversion dam had essentially severed the Greybull River, blocking the migration of Yellowstone cutthroat up into the cold waters of the Shoshone National Forest.

The hope is that the fish will now use the ladder once runoff begins and the water rises. Reconnecting the upper and lower stretches of the river, biologists say, will help stabilize one of the purest populations of Yellowstone cutthroats in Wyoming.

"It's going to open up over 100 miles of fish habitat above this structure for unrestricted access, especially for Yellowstone cuts," said Ray Zubik, a fisheries biologist with the Shoshone National Forest. "They've been restricted and reduced to a fraction of their historical range for nearly 80 years."

Early Wednesday morning, a backhoe dug into the river bank while crews tinkered with the dam's flood controls, making final adjustments ahead of the release.

Shortly after 9 a.m., Bob Cooke, project superintendent with Groatehouse Construction, advised workers to cross the river -- the water was coming soon.

A slow trickle began, followed by a rush of muddy water, which quickly spread across the channel and filled in behind the dam.

"Any time you can reconnect as much traditional or historic habitat as you can for migratory requirements, you'll get a pretty good return on your investment," said Toye, watching the water flow.

"The Greybull above and below this dam is considered two of the best Yellowstone cutthroat populations left in the state. It's one of the best strongholds we have, and this will further secure that and make it better."

Wyoming Game and Fish also has high hopes for the dam and its fish ladder. The "fishway" allows operators to change the water level within each pool of the ladder, allowing fish to climb the elevation.

Erin Burckhardt, the agency's Cody region fisheries biologist, said the state will document how fish use the structure. As many as 50 cutthroats were captured and radio-tagged last year, and biologists will continue to track their movements up and down the river.

"Once a fish moved downstream of the diversion, it was lost to the population upstream," Burckhardt said. "There aren't too many spawning tributaries available to the fish downstream. Now, we're hoping to essentially have these two populations reconnect."

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