Local contractors are teaming up with Montana conservationists to preserve a population of genetically pure Yellowstone Cutthroat Trout indigenous to the upper Crooked Creek area north of Cowley.


A concrete fish-passage barrier is being built in Crooked Creek on BLM land, about three miles north of the Montana-Wyoming border to thwart efforts of non-native species of trout that are trying to make their way upstream.


BairCo. Construction of Lovell is handling the construction of the fish barrier along with subcontractors Workman Concrete of Lovell.


“It’s a fun project but everything is a challenge,” Project Manager Devin Bair said.


One challenge is getting equipment to Crooked Creek, which is surrounded by rocky cliffs on all sides and accessible only from a road that sits about 700 feet above the job site.


The original plan was to airlift concrete pallets, an excavator, skid loader, cement mixer and other equipment into the canyon, but Bair and crews at BairCo. devised a pulley system instead. They spent many hours in their shop, welding the pulley system together. A tower was mounted on the rocky top above Crooked Creek that anchors a cable for the pulley system.


The cable is capable of carrying as much weight as a helicopter in a single load, the heaviest item being a 3,400-pound excavator, Bair said. The system is also less costly than using helicopters. Hydraulic winches powered by auxiliary power from a bobcat skid-steer raise or lower equipment to the job site below.


After the equipment is sent on its way, workers begin their own descent into the canyon, traveling on a sketchy footpath over rocks and dirt. Bair said the trip to the work site, including drive time from Lovell, takes about 1 ½ hours.
“Its not bad going in, but it’s marching out of here after a day’s work,” Bair said.


BairCo. Construction, inc. began work on the project Aug. 14 and plan to be finished Oct. 15. Funding was provided by the National Fish and Wildlife Foundation, the U.S. Forest Service, the Montana Bureau of Land Management office and the Montana Dept. Fish Wildlife and Parks.


Another challenge is making sure the fish barrier isn’t an eyesore.


Jim Sparks, Assistant Field Manager of the BLM, Billings, said it was important that the fish-barrier construction did not impair any qualities that make it acceptable as a wilderness area.


“They [BairCo.] have done a great job minimizing impact at the site,” Sparks said.


The barrier has been designed to look like bedrock to blend in with surroundings.

Crooked Creek feeds into Big Horn Lake, which is home to many non-native fish species. The upper three miles of Crooked Creek has maintained a population of genetically pure Yellowstone Cutthroat Trout because of a natural barrier of boulders that prevented non-native species from entering.


But that changed in 2002 when the high-intensity Red Waffle Fire burned headwater hill slopes in the upper Crooked Creek drainage. A massive downpour of 2-3 inches put out the fire overnight and eroded Crooked Creek, rerouting the stream channel around the natural barrier.


Darin Watschke, Fish Biologist at the Custer National Forest, said the debris that followed resulted in a “fish kill,” saturating a portion of the creek with debris from the fire. This caused the population of Cutthroats in upper Crooked Creek to be cut in half, but it also continued to prevent non-native species from entering upper Crooked Creek. Since then, the water has cleared and several non-native trout species began making their way upstream. A temporary fish barrier was put in place to keep them out of the Yellowstone Cutthroat Trout indigenous waters.
Watschke has been spending time on the job site to oversee the project and maintain the temporary fish-passage barrier until the permanent structure is complete. He proposed the idea for the barrier in 2004 after discovering the natural barrier was no longer functioning.


The site, about 3 miles north of the Montana-Wyoming border on BLM property, was selected for construction because it provided bedrock on either side for the concrete barrier to be affixed to so that a rain event will not cause water to bypass the barrier.


 Watschke said the barrier will function in two ways. At low flows, it will act as a leap barrier; fish won’t be able to jump over it. At high flows, it will be a velocity barrier and the high pressure of water flowing over the barrier will prevent fish from approaching it. The barrier is designed to withstand a 100-year runoff event, which is equivalent to 900 CFS.


Currently the creek is at five or six CFS, Watschke said.
The barrier is being built about five miles south of where the natural barrier was, giving the cutthroats more room to repopulate.


Watschke said that competition, predation and hybridization from non-native trout species is a leading cause of the extradition of Yellowstone Cutthroat Trout from historical waters. He explained how the differing spawning periods of cutthroats and other species allows them to be edged out of their native waters.


“When these non-native aggressors get into isolated populations, after a few years, Yellowstone Cutthroat populations are often diminished and ultimately replaced,” Watschke said.


While Yellowstone cutthroats spawn in early summer and their eggs hatch in late August to September, brown and brook trout spawn in the fall. Brown and brook trout eggs sit nestled in the creek bed until they hatch the following spring, which means they are already a few months old when cutthroats hatch. The bigger, non-native fish dominate the newborn cutthroats, eating them and out-competing them for food and habitat. Rainbow Trout exert these same stressors, but can also hybridize with Yellowstone Cutthroat Trout and taint the pure population.