Restoring Rattlesnake Creek: Using Citizen Science to Assess the Ecological and Morphological Impacts of Small Dam Removal

As dam removals increase in frequency across the U.S., most research has focused on the impact of larger dam removals, despite the removal of small dams being much more common. Given the hundreds of small dams in Montana, this research uses citizen science data collected over seven years spanning before and after a 2020 small dam removal in Rattlesnake Creek, Montana, to investigate impact on stream ecology and morphology. We analyzed pebble count grain size distributions and aquatic macroinvertebrate biotic indices from 2017 to 2023 to assess changes in sediment transport and macroinvertebrate population as well as evaluating the efficacy of citizen science for long-term stream monitoring. Our analysis includes comparisons of pre- and post-dam removal data collected from above and below the dam site. Our findings revealed no statistically significant changes in grain size distribution or macroinvertebrate diversity between upstream and downstream reaches post-dam removal. This suggests that the removal of this particular small dam had minimal detectable impact on sediment transport or macroinvertebrate communities within the study period. Our study also demonstrates the capacity for citizen science programs to effectively collect robust and valuable datasets. This study underscores the importance of meticulous data management along with the potential for and challenges of citizen science for environmental research. We provide recommendations for “best practices” to improve future citizen science monitoring and informing decision-making for future dam removals, particularly for the nine dams further upstream within the Rattlesnake Creek watershed.