Blackfoot River Wildlife Management Area

The Blackfoot River Wildlife Management Area (WMA) is a property owned by the Idaho Department of Fish and Game (IDFG) in Caribou County, Idaho, approximately 18 miles northeast of Soda Springs and several miles upstream of the Blackfoot Reservoir. The project reach is 5.5 miles long and has historically supported a high-quality cutthroat trout fishery, but fish numbers have declined since the 1960s due to land-use practices and other impacts that have degraded habitat. Willow eradication and extensive cattle grazing have contributed to bank instability, channel incision, areas of sediment deposition, unstable bed forms, and a disconnected floodplain and have created conditions conducive to fish predation, especially by pelicans.

Eroding banks with very little vegetation along the Upper Blackfoot River.

The Upper Blackfoot River has little riparian vegetation, over-widened channels, and poor floodplain connection.

Reference reach Campanula Creek in Yellowstone National Park features sinuous channel, varied riparian vegetation, off-channel features, and well-connected floodplain.

IDFG contracted Rio ASE and Quadrant Consulting to conduct a geomorphic assessment to summarize existing channel forms and processes, identify geomorphically appropriate target conditions, and recommend potential treatments suitable for creating and maintaining those conditions. Rio ASE first assessed the existing conditions in the reach, identifying geomorphic forms, hydrology, hydraulics, and river processes. Then, Rio ASE examined reference reaches of similar elevation, gradient, confinement, and basin size to help develop the target conditions for the project reach, scaling the targets based on bankfull discharge and width. Treatment recommendations to improve habitat conditions were provided at the reach-scale, with high-level guidance for future planning and design efforts. Based on the analysis of the stream in this area, Rio ASE developed concepts for the reach, many of which have subsequently been designed and constructed by IDFG.

Conceptual restoration treatments for the Upper Blackfoot River showing areas of fill and excavation, riffles, boulders, willow weave fencing, and various sizes and types of wood structures.