CLYDE PARK – The demands on Montana’s streams are many, but thanks to a law written almost a decade ago, Montana Trout Unlimited is helping ranchers help fish by reducing agricultural demand.

Last week, the Department of Natural Resources and Conservation approved a lease allowing a Bridger Canyon landowner to donate his water to the fish of Bridger Creek for the next 10 years.

It is the second such agreement to go through in the Bridger Range after years of negotiation and legal work by Trout Unlimited.

TU Water Project Director Laura Ziemer said the agreement allows landowners to keep their water rights without having to use the water. That means more water stays in streams to benefit fish, which is essential as climate change worsens and drought persists in southwestern Montana.

Normally, if a water-right owner doesn’t use all his allotted water, the DNRC could take back the unused amount, permanently reducing his water right in a “use it or lose it” scenario.

But under a hard-fought law passed in 2005, landowners can lease their unused water to Fish, Wildlife & Parks to maintain higher flows in Montana’s streams.

FWP has instream rights but it's sometimes not senior enough to override some water users. Leased rights can have higher priority because they often belong to ranches settled in the late 1800s.

Trout Unlimited has increased its outreach to encourage such leases, but few landowners will agree right away, said TU attorney and fisheries biologist Patrick Byorth. Years of negotiation are often needed to build the trust to get a landowner to sign a lease.

Most are 10-year leases, although the first permanent lease was recently approved.

TU makes the trade easier either by improving irrigation systems so ranches have water to spare or by bringing landowners together to share headgates and ditches so more water remains in the stream.

“Each deed is different. In some cases, we’ll reimburse landowners for not harvesting a second cutting of hay or pay for a spigot so they don’t flood irrigate,” Ziemer said. “In the long run, the work we’re doing is all about protecting sustainable ecosystems and quality of life that make for healthy communities.”

Flowing from the Bridger Mountains to the Shields River, Brackett Creek is running a little higher this year after Byorth was able to secure a lease last year.

Of the six historic stream diversions along the creek, ranch owner Greg Avis owned five and had water rights guaranteeing a significant amount of the streamflow.

“We started talking with him in 2006,” Byorth said. “He was pretty much ready, but it took long and careful work with his neighbors. It finally went through last year; now all his rights are instream.”

Over the past decade, Avis took the diversions out, removed ditches that drained his fields and is now allowing the high groundwater table to grow his hay. He harvests only one cutting of hay and allows his cows to graze the rest.

The three remaining water rights owners share one diversion.

Byorth knows exactly where Yellowstone cutthroat trout and whitefish now go to beat the heat, hugging the bottom of the creek’s pools, made deeper with Avis’ water.

“For a drought year, it’s looking pretty good. Looks like they’ll make it,” Byorth said.

Laura Lundquist can be reached at 582-2638 or llundquist@dailychronicle.com.