Montana Fishery Project
Evaluating sediment and nutrient contributions from unpaved forest roads to headwater streams
August 2016 - September 2019
- US Forest Service
- Northern Rocky Mountain Science Center
Unpaved forest roads remain a pervasive disturbance on public lands. Mitigating sediment from road networks remains a priority for management agencies. Restoring roaded landscapes is becoming increasingly important for many native coldwater fishes that disproportionately rely on public lands for persistence. However, effectively targeting restoration opportunities requires a comprehensive understanding of the effects of roads across different ecosystems. The Southwestern Crown of the Continent (SWCC) is an area of over 6,070 square kilometers in western Montana. Within the SWCC over 1,200 km of roads are currently being considered for restoration by the US Forest Service. A recent study in the SWCC indicated considerable variability in sediment production from roads. Specifically, recent findings suggest considerable variability in sediment production across road segments and relatively low sediment production from the majority of roads in the SWCC. However, relatively high suspended sediment within streams and high nutrients in local lacustrine environments remain, rendering some uncertainty in how sediment from roads may be affecting aquatic ecosystems. Furthermore, additional uncertainty remains in how road use and the interactions with precipitation may lead to sediment and nutrient pulses. As activities in the SWCC increase in the near future, a unique opportunity exists to evaluate how such increases in travel (and probably sediment production) alter our current understanding of the importance of roads and road restoration in the SWCC and elsewhere. We are conducting an in-depth field study in the SWCC to monitor and refine our understanding of how roads and sediment delivery from increased use (and other activities and disturbances) influences sediment and water quality in aquatic habitat. The project specifically builds off of existing data to establish a set of treatment and control sampling locations for suspended sediment and nutrient and streambed sediment data collection. Furthermore, we are capitalizing on existing data from the SWCC to effectively design a suspended sediment study that complements existing data.