People along the Clark Fork River are still getting used to the removal of Milltown Dam. But as far as the fish are concerned, it's history.
"Over the last few years, almost 3 million cubic yards of sediment has gone, and remediation is almost complete," Montana Fish, Wildlife and Parks biologist Dave Schmetterling told a crowd of fishing guides at the Clark Fork Coalition's third annual state-of-the-fishery gathering Wednesday evening. "And it's almost immediately had an effect on the watershed. The impacts of the dam removal are now behind us by a couple years."
Drawing down the reservoir in 2007, followed by breeching Milltown Dam in 2008, sent a lot of sediment down the river. And while another big load got released in 2009, Schmetterling said the river is settling into a healthy state.
Some preliminary research hints that the bug population along the Missoula reach of the Clark Fork has bounced back after suffering through 2007 and '08, according to Clark Fork Coalition science director Chris Brick. While the study is not yet published, she said the draft report shows improvements from Warm Springs to the confluence with the Bitterroot River west of Missoula.
The bug picture will continue to evolve as the river's bottom changes, Schmetterling said. That's because a century's worth of sand, gravel, rocks and other material is finally able to be redeposited below the dam site. Different bugs like different sizes of sediment to breed and feed in, and those critters will re-colonize the area quickly.
"We're going to see lots more diversity, and not just the pollution-tolerant insects or the ones that were limited to certain substrates," he said.
In addition, past studies showed about 200,000 adult fish a year were unable to travel above the dam to where they spawned. Now those fish - trout, suckers, pike minnows and others - are all able to use the entire watershed.
Guides are having to learn lots of new river geography. Peter Bring, who's been taking clients on the Clark Fork for 13 years, said he's seen lots of new sandbars and gravel banks between Kelly Island and Frenchtown.
"That's water where we've always guided, and it's always been good fishing," Bring said. "Pools have filled in, and the structure of the river has changed. We still don't know how connected they are."
FWP biologists have been doing lots of population surveys in the upper Clark Fork as well. That area is scheduled for major Superfund cleanup work starting this summer - a continuation of the river repair necessitated by a century of accumulated toxic waste from Butte and Anaconda smelters.
"What we're dealing with is primarily a brown trout fishery," biologist Jason Lindstrom told the guides. In the 60 miles of river between Warm Springs and Jens, there's a strong population of fish 12 inches and larger.
There are extremely few rainbow trout in that area, Lindstrom said. But the dozen or so he found in his electro-shock population survey last year were impressive. He showed one photo of a rainbow measuring 27 inches and 13 pounds.
"Did he eat a dry fly?" someone asked.
"No," Lindstrom replied. "About 5 amps."
Reporter Rob Chaney can be reached at 523-5382 or at email@example.com.