Fish screens: Keeping trout in the river and water in the ditch

This past spring, a teacher from Helmville School contacted us asking about an irrigation ditch behind the school that had some trout swimming in it. The kids were excited about "rescuing" the fish and putting them back in the river and she wondered if I knew anything about this particular ditch. After doing a little research, it turns out that this ditch was one we were already working with the landowners on with plans for a fish screen to be installed in the fall.

Over the past 31 years, we've had the opportunity to work with many different landowners on projects that upgrade their irrigation diversion to make them more fish-friendly. These projects involve installing new head gates, building new instream structures that allow them to pull water while ensuring fish can still migrate upstream and installing fish screens to prevent trout from being entrained down irrigation ditches and lost to the river.

To date, we have installed 36 different screens in the valley and have seven different models that we've worked with. We have three different screens right here in Seeley Lake on important native trout streams and the goal of these projects is to ensure irrigators can continue to pull their important water right, while ensuring trout remain in the river and can move freely to important habitat.

Our most recent project involved working on an irrigation diversion on Nevada Creek over near Helmville. We spent three years developing the project with two different families who own ranches first settled in 1867. Both ranches are now being run by fourth and fifth generations. The irrigation diversion is an important water source for their operations, but the setup of the diversion in Nevada Creek consisted of tarps, boards and fence posts and did not allow fish to move upstream while it was in place.

Working with the US Fish & Wildlife Service Partners for Fish and Wildlife Program and Montana Fish, Wildlife & Parks, this past October we were able to remove the old diversion across Nevada Creek and replace it with a rock cross-vane that maintains an elevation for irrigation while also restoring fish passage. A new fish screen, called a Farmers Screen, was installed in the ditch which funnels water into the ditch and sends trout back to the river. River Design Group out of Whitefish did the design work, and TNT Excavating from Ovando constructed the project.

"We used to spend hours each week trying to keep water running down the ditch and in the process the creek became impassable for native cutthroat trout and entrained them in the ditch," said irrigator Kyle Graveley. "This project has enabled us to become more efficient and conservative water users while still benefitting the ecosystem and fishery. This project has been a win-win for both the watershed and our ranches."

Next spring, BBCTU and partners look forward to taking Helmville School children out to the diversion to show them the project and talk about how working together on these types of projects allows irrigation to continue and fish populations to improve.

For more information on how you can get involved, visit us on our Facebook page at Big Blackfoot Chapter of Trout Unlimited or send Ryen Neudecker an email: ryen@montanatu.org