The Jackson area is home to a population of relatively genetically pure native cutthroat trout. In many other parts of the West, cutthroat trout have hybridized with rainbow trout. But a set of irrigation ditches off of Spread Creek have created a barrier for the Jackson area trout on their migrations. The fish get swept into irrigation ditches and eventually become stranded.
"That's pretty common to a lot of irrigation ditches. The velocity of the water coming through the headgate makes it so that they're not able to swim back out. Also, a lot of times, their natural instinct may be once they're in the ditch to keep going," said Trout Unlimited's Northwest Wyoming program director, Leslie Steen. "And so they would end up further down the ditch system and/or in lateral irrigation ditches, and therefore not really likely to ever get the hint to try to swim out until the end of the irrigation season when the water's shut off and they're essentially stranded."
Trout Unlimited has performed several fish rescues to collect the trout and bring them back to Spread Creek, but now they're working with Grand Teton National Park, Bridger-Teton National Forest, and the Wyoming Game and Fish Department to install a fish screen, which will automatically direct the fish back to the main creek.
"It allows water to pass through, down the irrigation ditch to the water users like it's intended. And then the fish and a certain section of the water will actually float on top of the screen, go into a fish bypass pipe, and the fish will go back into Spread Creek and they can keep migrating to where they were trying to get to," said Steen. "Our contractor's calling it a fish rocket."
She said there's very little impact on the amount of water that the end-users will have. They also specifically picked out a fish screen that won't require a lot of maintenance and won't likely get clogged with debris.
"But within reason. During certain times of year during runoff, when there's a lot of debris coming down the river and into the ditch, it's likely that the Park Service will have to send folks up there occasionally to brush the screen off," Steen said. "One of the neat things about the screen design though is that if, for example, it gets clogged on a weekend and someone can't get out there right away to brush it off, it actually will still continue to deliver water to water users."
Steen said they've been fortifying the irrigation ditches, building back after flood damage and adding erosion protection. This will help protect the fish screen once it's been installed, which is planned for the spring before irrigation season starts.
The fish screen is just part of the efforts Trout Unlimited and their partners have done to protect cutthroat trout migration in Spread Creek. In 2010, they removed the Spread Creek dam, which opened up over 50 miles of the watershed to migrating trout.
"We have this stronghold population of cutthroat trout, and with warmer climate predicted in the future, having access to upper Spread Creek, to these cold-water refuges, is going to be more and more important in the future," said Steen. "And I think this year's drought and high temperatures really drove that home."
