How Fish Screens Help Farmers And Save Fish

Jun 3, 2013

Children examine a fish screen.
Credit Courtney Flatt / EarthFix

If proper equipment isn’t installed on irrigation pipes and pumps, fish can get sucked into farmers’ fields and drainage ditches. That clogs pipes and kills fish. A new fish screen was just installed on a Central Washington River to prevent this from happening. It's the first of its kind in the state.

When migrating fish and debris get sucked into farmers’ pipes and ditches, it’s bad news for farmers and for fish.

“If a fish goes into a ditch, it’s unlikely it will turn around and get out. It typically will die there.”

That’s Les Perkins. He’s with Farmers Conservation Alliance. The company has helped develop a new solution to keep irrigation pipes clear -- a horizontal fish screen.

Fish screens are more complex than screens on your windows. Mesh wire lays flat across a cement canal. Fish and debris flow quickly across the top and back into the stream. Irrigation water flows slowly through the mesh and into the farmer’s ditch.

“The fish don’t even know they’ve gone through a diversion,” Perkins says.

Washington and Oregon require fish screens when water is being pumped out of streams, rivers, and lakes. In Idaho, fish screens are mainly in place for migrating salmon and steelhead, although some streams have screens to protect resident fish.

There are still hundreds to thousands of diversions in each state that don’t have fish screens.

Typically fish screens look like a rotating mesh drum. Think of an old mill wheel. Fish and debris flip over the drum. Perkins says these screens have one problem: moving parts.

“It was a constant maintenance issue for the irrigation district and for the Department of Fish and Wildlife," Perkins says.

This new screen is like an extension of the stream. And there are no moving parts. Oregon’s Hood River farmers came up with the idea after a massive flood in 1996.

Perkins says this design won’t work everywhere. Streams must slope downhill. It also takes up much more space than a typical screen.

Michael Tobin is the district manager for the North Yakima Conservation District. He says fish screens are important, no matter the design.

“They protect the resource," Tobin says. "They enhance the community by having a good ecosystem balance. At the same time, economic considerations of maintaining agriculture are kept in place.”

This fish screen will serve 85 landowners and 1,700 acres of farms. Over its lifetime, it will save thousands of fish.

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