A recently completed fish barrier on Crooked Creek in the Pryor Mountains will benefit genetically pure populations of Yellowstone cutthroat trout.
   
Crooked Creek begins in the Custer National Forest, flows through Bureau of Land Management and private lands and then enters Bighorn Lake in Wyoming. The Crooked Creek barrier project protects and expands one of three genetically pure YCT populations on BLM-administered lands and one of six pure YCT populations on CNF-administered lands. These trout, a sensitive species in Montana, are native to Crooked Creek.
 
A naturally formed boulder barrier once protected the isolated headwater population of YCT from a nonnative salmonid invasion.  However, extensive debris flows after a high-intensity wildfire in July 2002 altered this barrier, making it possible for migrating nonnative salmonids to move upstream. Brook, brown, and rainbow trout survived the debris torrents and occupy the lower drainage, but the remaining YCT population is at a high risk of localized extinction.

To protect the YCT population, BLM’s Billings Field Office, CNF, and the Montana Department of Fish, Wildlife and Parks proposed building a concrete fish passage barrier to replace the natural one. Their goal was to isolate the YCT population to prevent competitive interaction and hybridization with nonnative salmonid species.

In August 2006, the group created a temporary barrier as a short-term solution but knew it would not be an effective obstruction during high flows. The barrier stayed intact, but it did not prevent brown trout from entering YCT habitat. One year after construction, they discovered 120 brown trout upstream of the temporary barrier.
  
The Custer National Forest funded a permanent barrier design contract with Great West Engineering of Helena, which completed the project spring 2007. The BLM Billings Field Office completed an environmental analysis at about the same time. Several issues affected the project in terms of the design and environmental analysis. First, the project is located in a wilderness study area, which limits disturbance and affects visual resources and construction activities. Second, the project is located in almost inaccessible terrain, typified by steep rimrock canyon walls. Third, cultural resources are located adjacent to the project area. As a result, the design was very complex and the cost elevated.

BLM awarded the contract to Bairco Construction Inc. from Lovell, Wyo., in early August 2007. Later that month, Bairco began work on the project, completing it in early October. Construction was challenging. It involved erecting a cable tram to haul materials and equipment into the project site, clearing the worksite and diverting the stream. Additionally, construction crews mixed concrete onsite, which involved heavy manual labor. Challenging, but worthwhile — the end product is excellent.

For more photos and video, go to http://www.baircoconstruction.com/CrookedCreekFishBarrier.html.