Projects>Redwater River Fish Passage Feasibility Study

Confluence evaluated two crossings over the Redwater River north of Circle, Montana. The Redwater River is a tributary to the Missouri River in eastern Montana. The connection of the Redwater River to the Missouri River is indicated by the presence of 10 native fish species that use the Missouri River for part of their life cycle. These species include goldeye, western silvery minnow, emerald shiner, flathead chub, river carpsucker, smallmouth buffalo, bigmouth buffalo, channel catfish, longnose sucker, and stonecat. Of these 10 species, only one species (emerald shiner) is commonly captured in fish surveys. Improving the fish passage conditions at road crossings in the Redwater River Basin has increased the upstream distribution and abundance of these species. The general stability of the river bed and banks were also evaluated in the vicinity of each of the crossings.

The first crossing on Nickwall Road consisted of a low concrete structure with 24 inch diameter concrete culverts spaced across the channel. The second crossing was 25 miles upstream and was a low concrete structure with four 18 inch diameter CMP culverts clustered in the center of the channel. Confluence completed an assessment of both crossings, noting swimming velocities of fish, channel and structure conditions, water flow, culvert hydraulics, and potential recommended alternatives. Design alternatives included a bridge, low arch or box culverts, and a larger diameter pipe culvert. Cost estimates were developed for each proposed solution.

Redwater River downstream of Nickwall Road crossing

Redwater River downstream of Nickwall Road crossing