Prickly Pear Land Trust close to completing Sevenmile Creek project, after Birdseye Fire burned area

Posted at 2:41 PM, Nov 26, 2020
and last updated 2020-11-26 16:41:24-05

HELENA — After nearly five years of planning and construction, a major stream restoration project outside Helena is nearly complete – in spite of September’s Birdseye Fire burning directly through the project area.

Prickly Pear Land Trust acquired a 358-acre property along Sevenmile Creek in 2016. Their goal has been to return the creek and its historic floodplain to a more natural condition.

On Sept. 2, high winds blew the Birdseye Fire east into the Helena Valley. Much of what burned was on the Sevenmile property. PPLT estimates the fire destroyed vegetation on about 330 acres – though they noted the areas where they had already completed stream work were less affected.

Nate Kopp, PPLT’s program director, said the fire actually presented them with an opportunity, by giving them a chance to help establish native vegetation in the grassland areas.

“We weren’t planning on doing this, but because the fire cleared everything out, we kind of have a blank slate,” he said. “Our hope is to add some good native grasses that can take hold – and hopefully keep some of the more noxious and invasive species off the property.”

Last week, PPLT staff seeded about half of the property with a mixture of native plants, including wheatgrass and needlegrass. They used a tractor to spread the seeds, then dragged a harrow behind a truck to break up the soil.

“It allows the seed to infiltrate into the upper inch or two of soil, so it’s got some cover, it’s not going to blow away in the wind, and then when it rains it’s got that protection and it can work on its root structure,” said Kopp.

Fire is a natural part of the life cycle for grasslands. Kopp said they believe the native vegetation would return relatively quickly even if they didn’t seed the areas, but that seeding could help give those plants a head start and limit the chance of cheatgrass and other invasive species becoming established.

This week, crews reached another milestone in the restoration of Sevenmile Creek itself – redirecting water on a roughly 1,000-foot section of the creek into a newly constructed channel.

Over the last 100 years, the Sevenmile property has been used for agricultural activities like grazing and hay production. Farmers and ranchers rechanneled the creek, making it flow straighter and faster and pushing it toward the edge of the valley. Mike Sanctuary, of the firm Confluence Consulting, says those changes disconnected the stream from its floodplain and led to increased erosion.

Confluence worked with PPLT on designing a more natural channel, built to include meanders and pools. On Tuesday, they blocked the current creekbed and allowed the water to start filling that channel.

As part of the redirection, Montana Fish, Wildlife and Parks staff was on hand to move hundreds of fish out of the existing channel before it dried up.

Web Extra: Nate Kopp, PPLT’s program director on Community Support

“The fish know when the channel gets closed, and so they instinctually move downstream as the water lowers in the old channel,” said Adam Strainer, FWP’s Helena area fisheries biologist. “But what we’re doing is basically moving as many fish as we possibly can to benefit the stream as a whole.”

They used a technique called “electrofishing” – using a low-voltage electric shock to stun the fish, then scooping them up with a net and placing them in a bucket. PPLT staff then carried those buckets about 1,000 feet upstream to release the fish back into the creek.

“Today the water clarity was poor, and so just being able to see the fish as you’re electrofishing them is probably the most difficult part,” said Strainer.

They relocated several dozen rainbow, brook and brown trout, along with many more small prey fish like mottled sculpin. Strainer said, at this time of year and with cooler temperatures, they are able to handle the fish for longer periods without doing them any harm. They’ll return in the coming days to check for any additional fish stuck in pools on the old channel.

PPLT says they still have to complete one more stretch of the new channel further downstream. They plan to redirect water into that section next month, wrapping up work on the Sevenmile Creek restoration.

Kopp said seeing the next section of creek filling with water is always a good feeling.

“It really puts kind of an exclamation point on the success of the project,” he said. “You’re able to see the good we’re doing right away. It’s a tangible addition to the work that we’ve done.”