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Collar Gulch Creek – Just Below the Surface

photos and story by Craig Flentie, Lewistown Field Office

wall from stamp mill

A surviving wall from the old Collar Mine stamp mill of the early 1880s.

cutthroat health examination

Will Sheftall measures and gathers general health data on a Collar Gulch Creek westslope cutthroat trout.

men working on a rock wall

Mike Santuary of Confluence Consulting, Inc., and Mike Munsford of Kodiak Construction complete the rock wall portion of what will become a deeper pool in the newly diverted Collar Gulch Creek channel.

upper end of pool

Joe Platz’s left foot rests on the top of a rock wall at the upstream end of a deep pool in the new diversion channel. 

forming a shockline

Toby Tabor, Anne Tews, A.J. Donnel and Joe Platz form a shock and recover line in Collar Gulch Creek.

stunned fish

Joe Platz buckets a stunned Collar Gulch cutthroat.

Collar Gulch Creek is a short, clear, cold mountain stream that flows between steep mountain slopes and wind-swept grassy ridges in the Judith Mountains, about a dozen  miles north east of Lewistown, Mont.

It ripples its way through about two miles of public land managed by the BLM before it goes subsurface in the course-rock valley bottom.

In many stretches, a person can jump across Collar Gulch Creek or walk through it with several steps and not get wet much above the ankle. Most consider it small in size.

However, in recent years Collar Gulch Creek has become the focal point of a cooperative effort between the BLM and Montana Fish, Wildlife and Parks (MFWP) to benefit a rare fisheries gem that inhabits this relatively short piece of water.  

A genetically pure population of westslope cutthroat trout (an extreme rarity on BLM-managed land in central Montana, and increasingly rare across the Northwest) inhabits this two-mile stretch of Collar Gulch Creek. These trout were once common across the American West, but due to several factors (primarily habitat changes and hybridizing) the remaining pure strains are now largely relegated to a few isolated headwaters.   

The Collar Gulch Creek colony is the easternmost population of westslope cutthroat trout documented in the nation. The westslope cutthroat is a state species of special concern and the subject of continual discussions about its potential for listing under the Endangered Species Act (all of which tends to emphasize the uniqueness of this isolated population).

Needless to say, the presence of these westslope cutthroat trout has elevated Collar Gulch Creek’s stature far beyond its size.

Because of the sensitive nature of the westslope cutthroat and the habitat it requires, the BLM and MFWP are thinking beyond-the-envelope to ensure the continued existence of both in Collar Gulch Creek.

Since 1994, the BLM has managed this two-mile segment of Collar Gulch Creek and 1,618 acres of public land surrounding it, as an area of critical environmental concern (ACEC). An ACEC is a public land area that requires special management attention to protect specific resource values; in this case, the westslope cutthroat trout and its habitat.

The ACEC designation closed these public land acres to motorized vehicles and requires that any management activity be compatible with protecting the cutthroat habitat. The designation has certainly helped manage the area in a manner that protects this unique population of westslope cutthroat trout.  

However, the Collar Gulch cutthroats are not exactly secure and their future is complicated by a man-made structure that’s more than 125 years old.


For several years in the early 1880s, the Collar Mine, which was located near the creek in the canyon bottom, filled Collar Gulch with miners, equipment, ore, commerce, activity and noise common to the industry of the day. 

A year or so into the promising operation, miners built a log crib dam across Collar Gulch Creek to divert water to a nearby 20-stamp mill where the mined ore was crushed. About 15 feet long, five feet wide, six feet high, the dam is constructed of notched logs similar to a small, rectangular log cabin with the interior filled with rocks and other fill material. 

For a short time, the Collar Mine was quite a going concern in central Montana. It was a contributing factor in the development of other historical notables of the area such as the Carroll Trail and Fort Maginnis.

However, the mine was short-lived; the vein soon played out and the promise of riches fell drastically short. In 1885, the mine and its associated equipment were abruptly sold via a sheriff’s auction.

With closure of the mining operation, Collar Gulch fell silent of man-made noise; filled again only by the natural sounds of flowing water, wind rushing down the canyon, and the wild things that live there.

Time and weather have taken a toll on the mill and other remaining structures; 123 years later, portions of several walls and the foundation are about all that remain.

The condition of crib dam is another matter. While time, weather and water have all taken their best shots, it still stands today mostly intact in what was Collar Gulch Creek’s primary channel. However, as most streams will do with time, Collar Gulch Creek is cutting its way around the old dam and slowly creating a large head cut that’s creeping upstream.

The crib dam and the building remains are important cultural and historical reminders of that era in central Montana’s development. However, a flood event of even moderate proportions could blow out the old dam; greatly increase the sediment load downstream; and destroy a significant portion of the remaining westslope cutthroat population and habitat. In addition, the crib dam and the growing head cut around it limit the ability of fish to move upstream.

Another challenge to the Collar Gulch cutthroats is that the creek lacks several important structural characteristics. There are few deep pools which allow fish to grow to a larger size, and the creek generally lacks large overhanging cover to protect fish from predators and increase the number of fish surviving from one year to the next.


Public resource managers are often challenged with conflicting issues and values such as this: the historical importance of the crib dam vs. the wildlife importance of this population of westslope cutthroat trout. Finding all inclusive solutions--and the money to fund them--often requires partnerships among resource managing agencies and the private sector.     

Securing and improving the westslope cutthroat trout habitat in Collar Gulch Creek is a good example of such a partnership.

In 2004, the BLM and MFWP began joint studies to refine the information at hand concerning the Collar Gulch cutthroats.

Over the next 24 months, Joe Platz, a BLM fisheries biologist who was stationed in Miles City; Fred Roberts a BLM wildlife biologist in Lewistown; and Anne Tews, a fisheries biologist with MFWP in Lewistown made numerous visits to Collar Gulch Creek. They documented and monitored the condition of the old crib dam and head cut, and conducted fish population studies.

Their findings supported their suspicions. They found that the Collar Gulch cutthroats were at best hanging on, and that a large portion of the existing cutthroat population consisted of small fish.

Platz, Tews and Roberts began formulating ideas for solving the issues facing this isolated population of westslope cutthroat trout and involved other agency managers and staffers at the onset of their discussions.

The BLM felt that installing wooden stream structures (logs roughly 12 inches in diameter and long enough to extend across the creek) at select locations in this stretch of Collar Gulch Creek would be an inexpensive, yet effective first step toward increasing the number and depth of pools.

The biologists also roughed out a somewhat more exotic idea. They felt re-channeling approximately 300 feet of the creek around the old crib dam would help prevent a potentially catastrophic blowout, stop additional head cutting and would certainly improve the odds of keeping this cutthroat population stable. Re-channeling would also help ensure the stability of the historical crib dam.

There was room in the canyon bottom to parallel the original channel with a new water-route about 30-40 feet to the west, and the more the biologists refined their re-channeling concept, the more feasible it appeared.

Agency managers greeted the re-channeling idea with unanimous, but measured enthusiasm, pending more detailed analysis. In March 2006, the BLM completed an environmental assessment analyzing the impacts of constructing such a bypass.

The assessment found that with the exception of felling approximately 40 Douglas-fir trees to clear a path for excavating a new channel, there would be no detrimental impacts as a result of the effort. To mitigate the impact of cutting these trees, the assessment recommended using all of the fallen Douglas-fir to create wooden stream structures; placing them as overhanging cover along the new channel; installing them in the stream bank to increase stability; or spreading them as ground cover across the potential worksite.

In 2006 and 2007, the BLM installed nearly 30 wooden stream structures in this two-mile stretch of Collar Gulch Creek. Each one required placing two or three sections of Douglas-fir across the creek in strategic locations. Installation required chainsaws, a winch, block and tackle and the most basic of construction equipment: strong backs. The structures paid immediate dividends by increasing the number and depth of pools available for the westslope cutthroats.  

Then in 2007, the BLM and MFWP successfully secured the funds necessary to award a contract for the design and construction work on the 300-foot creek diversion around the crib dam. 

Confluence Consulting, Inc. out of Bozeman, Mont., was awarded the contract for the project design and oversight assistance on the actual construction work. Confluence offers a variety of water resource planning and restoration services throughout the Northwest and has completed a number of water and habitat improvement projects in Montana, Wyoming and Idaho.

Mike Santuary, a stream restoration specialist with Confluence Consulting, Inc., was assigned the task of completing the design for the new diversion channel, which would include constructing six deep pools along the new 300-foot water route. Each pool would provide valuable habitat (similar to cutthroat condominiums) and would serve to slow the water velocity during runoff events. Mike would also be onsite during the contract to direct the work and to help construct the rock walls that would form the upstream portion of each pool.

The excavation portion of the construction work was subcontracted to Bridgeford Industries/Kodiak Construction in Lewistown, Mont. In September 2007, Clint Huck and Mike Munsford, equipment operators with Kodiak Construction, walked a small backhoe and a skid steer down the steep slopes sheltering Collar Gulch Creek and into the worksite. Kodiak left the equipment in place through the duration of the project to avoid disturbing the creek with daily crossings.

Earthen plugs (about three feet of undisturbed soil between the original channel and the upstream and downstream ends of the newly excavated channel) were left in place to prevent water from running into the work area. This allowed the equipment operators to work in dry conditions. 

It only took about four days for Huck and Munsford to excavate the new channel diversion in the thinly-soiled, rocky canyon bottom. On average, the new bypass is six feet wide by two feet deep and 300 feet long. 

According to Mike Santuary, “both equipment operators were extremely capable and the excavation work could not have gone better.”


Perhaps the most time-intensive portion of this habitat improvement project was constructing the six pools. Designed to provide deeper water, the pools will allow the Collar Gulch cutthroats to live longer and grow to a larger size. 

Each pool was built by first excavating a large rectangular divot (about 12 feet long, seven feet wide and 3-foot deep) along the new water course. The next step was to construct a slightly curved rock wall 10-12 feet long at the upstream end of each depression. The top of each wall was constructed to a grade that will allow water to flow over the top and into the excavated divot.

Mike Santuary selected specific rocks for these walls. Each rock was placed by hand to ensure the walls would appropriately channel water at normal and peak flows.  Natural fill material (gravel, small rock and dirt) was packed among the rocks in each wall to seal them and ensure that water would run over the wall and into the pool rather than seeping downstream through the wall. 

The new channel, rock walls and pools were designed to blend naturally with the other geologic features of the canyon. However, with no water in or around them, they appeared somewhat like abstract works of art in the canyon bottom. 

Flowing water would be the litmus test for the entire project.    


The day before diverting Collar Gulch Creek into the newly excavated route, Anne Tews and Toby Tabor from MFWP, and Joe Platz, A. J. Donnell, and Will Sheftall with BLM, set about shocking, collecting, measuring and moving the cutthroats from the section of the Collar Gulch Creek that would soon be bypassed.

After carefully measuring the conductivity of the water and setting the backpack electrofishing unit to deliver a mild electronic shock to temporarily stun the fish, the crew set about their task. The shock crew consisted of one person operating the electrofishing unit and sweeping the probe from side to side through the water; two people with dip nets to collect the stunned fish; and a fourth person bringing up the rear with a bucket of water to hold the captured fish, where they regained their composure.     

With scattered rocks ranging in size from a baseball to a microwave in the creek bed and a variety of overhangs, the Collar Gulch cutthroats had plenty of places to escape the mild electric shock that would temporarily render them immobile. After a fish was shocked, it usually floated to the surface, but only for a five-count or so before it gathered its senses enough to dart back beyond the reach of the dip nets.

After a stunned fish was netted and placed in the hold bucket, it took less than a minute for it to fully recover from the predictably unsettling experience.

The shock crew made four sweeps through the original channel to be confident they had captured the vast majority of the cutthroats present. On their first trip they captured 38 westslope cutthroats; 21 on their second trip; 12 on their third trip; and 10 on their fourth sweep through the creek.

The fish ranged from 2-7 inches in size and all appeared to be in good condition. After being measured they were released back into the creek, either above or below the new diversion channel. Containment nets reinforced with straw bales across the creek above and below the new diversion prevented fish from moving back into the water that had just been shocked.  

About six days into the construction project, the new diversion channel was finished, the pools had been constructed and the Collar Gulch westslope cutthroat trout had been moved from the section of creek to be dewatered. 

The next step was to open the new channel to water.

The individual components of this project looked great. The engineering and design were solid, the construction work went by the text book, and shocking and relocating the westslope cutthroat trout had been successful. Still, everyone involved with this project felt a little anxious when it was time to remove the upstream plug and let this section of Collar Gulch Creek run down its new course. Like many endeavors in life, work and habitat improvement projects, all the individual components have to work well together to be successful.

As the small backhoe clawed out the upstream plug, Collar Gulch Creek quickly ran down about 60 feet of its new channel, over the rock wall and into the first pool. When that pool had filled, the water again rushed down the next segment of the new channel, over the rock wall, and into the second pool. This process repeated itself until all six pools and the new channel were flowing water from top to bottom, where it re-entered the original creek channel. 

In a matter of minutes, the presence of water converted the new channel, the rock walls and pools from somewhat abstract features to a natural appearing segment of Collar Gulch Creek.

The research, ideas, analysis, design and the newly excavated bypass were working perfectly together and Collar Gulch Creek was flowing comfortably down its new route. The short-term turbidity created by water rushing thorough a new channel soon settled out or was caught by straw bales that were staked into position where the diversion re-entered the original channel. 

After pausing for a brief moment to enjoy the efficiency of their work, it was time for Mike Santuary and the contractors to start closing up this project.

The disturbed area was broadcast seeded, mulched and hand planted with water-birch seedlings. The containment nets and straw bales, at the upper and lower end of the construction project, were removed. After a couple of trips over the worksite to dress it up, the contractors, equipment, and biologists scrambled their way up and out of Collar Gulch; confident that the Collar Gulch cutthroat trout would soon be exploring their new habitats.

With the closure of this habitat improvement project, Collar Gulch fell silent of man-made noise; filled once again only by the natural sounds of flowing water, wind rushing down the canyon, and the wild things that live there.

However, this time as the people and equipment pulled out of Collar Gulch Creek they left behind a more secure habitat for its most sensitive of wild things, the westslope cutthroat trout.  



Last updated: 06-28-2012