A Little Goes a Long Way

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A Little Goes a Long Way FWP, landowners, and private conservation groups are working to keep just a bit more water in spawning tributaries—the natural “hatcheries” of Montana’s storied trout rivers.

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JULY–AUGUST 2019

FWP.MT.GOV/MTOUTDOORS

CLOCKWISE FROM TOP LEFT: DARYL DRAKE; TOM DICKSON/MONTANA OUTDOORS; JOHN LAMBING

PHOTO ILLUSTRATION BY LUKE DURAN/MONTANA OUTDOORS

By Tom Dickson

or years, Alan Carroll and his wife inadvertently irrigated their apple orchard and hay field with tens of thousands of baby rainbow trout. The couple pumped water from an irrigation ditch that ran along the hill above their cabin near the Jefferson River, a few miles north of Twin Bridges. The ditch drew water from Hells Canyon Creek, a small tributary of the Jefferson River. The Carrolls had no idea that tiny trout fry were part of the mix. Then in the mid-1990s, Montana Fish, Wildlife & Parks biologists met with the couple to explain that, each April, rainbow trout moved up Hells Canyon Creek from the river to spawn. When the eggs hatched into trout fry, more than one-third of the little fish were drawn into the irrigation ditch and spewed onto the couple’s alfalfa fields and orchard. “That didn’t seem right to us,” Alan Carroll, a carpenter, says. There was another problem: Most of the water drawn from the creek did not reach their crops. “We diverted three cfs [cubic feet per second] but were lucky if we got even one,” Carroll says. Like other earthen irrigation ditches across Montana, theirs leaked. Precious water soaked into the arid sagebrushstudded hillside where the ditch had been dug decades earlier. Because this forced the Carrolls to pull more water to get what they needed, they typically drained lower Hells Canyon Creek by late summer. That was another blow for baby trout, says Ron Spoon, an FWP fisheries biologist in Townsend who has devoted much of his career to restoring the Jefferson trout population. “Not only were they being entrained in the ditch, but the ones that remained in the creek were stranded and couldn’t make their way down to the Jefferson,” he says. Trapped in shallow pools, the young trout became easy prey for kingfishers and other birds. Hells Canyon is one of only three spawning tributaries on 40 miles of what was once one of Montana’s premier trout rivers. As Hells Canyon went, so went the Jefferson’s rainbow population. To solve the creek’s chronic dewatering dilemma, FWP, Carroll, and two other water rights holders signed a lease agreement in 1996. State and federal agencies paid to replace the ditch with a $200,000 gravity-fed

pipeline. They also installed a fine mesh selfcleaning screen that allows water into the pipe but keeps young trout out. Carroll used some of the water saved by the new system to irrigate his land more efficiently. He and the other landowners leased the rest of the water to FWP, which kept it in the creek to benefit trout. “It was totally win-win,” Carroll says. The Hells Canyon Creek lease, recently renewed until 2029, is a good deal for all parties. But consider this: Of the more than 300 other chronically dewatered streams across Montana that FWP has identified, the agency has secured only a handful of water rights leases like the one on Hells Canyon. If leasing can help improve trout reproduction

on vital spawning tributaries, why isn’t the agency doing more of it elsewhere? NATURE’S “HATCHERY TRUCKS” Montana trout rivers are the superstars of fishing videos and tourism brochures. But with some exceptions—a few rivers below dams with ample main stem spawning habitat—it’s not the rivers but their tributary streams that produce most of the trout that end up in those renowned waters. Each year, trout swim up tributaries to lay their eggs: rainbows in late spring, cutthroats in midsummer, and bull and brown trout in the fall. They use their fins to create dishshaped spawning pads, known as redds, in

DRAINED Above left: Tiny Hells Canyon Creek, shown here in early spring, is a major spawning tributary for the Jefferson River (below). Above right: Ron Spoon, FWP fisheries biologist, says chronic dewatering in late summer prevented the creek from producing rainbow trout.

MONTANA OUTDOORS

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