As unlikely as it may seem this year, it's time for streams to receive a reservoir boost.
The Montana Department of Natural Resources will begin releasing water from the Painted Rocks Reservoir Wednesday at the request of the Montana Department of Fish, Wildlife and Parks.
DNRC engineer Larry Schock said the reservoir is still overflowing, sending about 200 cubic feet per second into the spillway. He'll augment that with another 50 to 75 cfs, which will continue and increase until the end of the season on Oct. 1.
Montana FWP owns the water rights to close to half of the 32,000 acre-feet stored in the reservoir that they can call on to keep flows high enough to provide good habitat for fish.
Fisheries biologists have been making water calls on the reservoir since a study in the late 1980s demonstrated the amount of water needed to sustain fish populations, Shock said.
The Painted Rocks Water Users Association also owns rights to close to one-third of the reservoir water that they call on for irrigation.
In the past, biologists have measured the Bitterroot River at Bell Crossing and have called for water when the mid-valley flows fell below about 400 cfs, said FWP fisheries biologist Chris Clancy. But occasionally when the mainstem flow remains sufficient, the West Fork runs low, at least for recreationists.
"I anticipate that this is another year where the mainstem will stay full," Schock said.
So Clancy said FWP is taking advantage of a high-water year to try something different.
This year, Clancy is using the West Fork flows, based upon gauges at Conner and Darby, as his target for water requests.
"This year, we have the luxury of enough water that we can experiment with flows in the West Fork," Clancy said. "We would like to keep it high enough for floaters, but not so high that fishermen can't wade. It will be a balancing act."
The high water in the West Fork lasted until June 25 this year. Since then, with less rainfall and higher temperatures, it has dropped by a factor of 10. It's now flowing past Conner at 255 cubic feet per second, although it's still running at more than the 70-year average of around 190 cfs.
Clancy said he'll try to maintain close to the current level in the West Fork, which means increasing water releases as the tributary flows decrease. He'll poll floaters throughout the season to fine-tune the releases so the information can be used in the event of another good water year.
Reach reporter Laura Lundquist at 363-3300 or firstname.lastname@example.org.