The Arctic grayling population was historically widespread in the Missouri River basin above Great Falls, Montana but has declined significantly.  Beyond water stewardship itself, one of the most important action partners can take to improve Arctic grayling’s conservation status is to solve landscape connectivity problems.  Approximately 40 Denil fishways, have been installed at irrigation diversions in the Big Hole Watershed to provide habitat connectivity, with more planned for the future.  There is a need to determine if the restrictors installed in Denil fishways achieve the combined objective of passing fish and reducing water flow.  Through this project, the research team will design and test retrofits to traditional Denil fishways that will optimize the passage of Arctic grayling while minimizing flow.  This approach is essential to restoring Arctic grayling in Montana while helping conservation partners ensure access to water rights.