INVENTORY AND ASSESSMENT OF A PORTION OF ROCK CREEK IN THE UPPER BIG HOLE RIVER DRAINAGE NEAR WISDOM, MONTANA

The Environmental Field Studies class at the University of Montana Western conducted an inventory and assessment of Rock Creek, a tributary of the Big Hole River near Wisdom, Montana from September 24^th through October 17^th, 2012. The project included analysis of stream morphology, in-stream macroinvertebrates, riparian vegetation and stream habitat. The purpose of the project was to assess riparian restoration efforts started in 2006 to improve habitat for fluvial Arctic grayling in the upper Big Hole River watershed. The study area included a total of eight cross sections located upstream from the confluence of Rock Creek and the Big Hole River. Restoration work conducted by the U.S. Fish and Wildlife Service and Montana Fish, Wildlife and Parks on this segment of Rock Creek starting in 2006 included the diversion of the stream into its historic channel, installation of riparian fencing, in-stream water level agreements, willow planting and the installation of fish ladders.

The data show that Rock Creek is functioning as a Rosgen C4b stream, and is evolving into an E4b stream. In-stream macroinvertebrate diversity and richness have improved and riparian vegetation diversity and density have increased. Stream habitat surveys shows that pools are short and deep, while riffles are long and shallow, optimal conditions for grayling reproduction and survival. Stream bank vegetation is dense, with abundant willows and sedges and little exposed ground. Cattle were allowed to graze the upstream reach of Rock Creek within the study area during the summer of 2012, which reduced vegetative stability of stream banks and liberated significant sediment into the channel. It is recommended that grazing not be allowed on Rock Creek, especially since it is such an important tributary for reproduction of fluvial Arctic grayling living in the main stem of the Big Hole River.