Assessing the impact of nutrient enrichment in the Henry’s Fork River Headwaters




Western U.S. rivers are experiencing changes in nutrient flux from urban development and changes to migratory fish populations, which could influence productivity of ecologically, economically, and culturally important trout populations. The Henry’s Fork of the Snake River in east Idaho is experiencing rapid development due to excellent recreational opportunities, including fly-fishing, nonmotorized boating, and proximity to Yellowstone National Park. An increase in development will require new avenues of wastewater disposal and changes in the management of stocked migratory salmon, resulting in nutrient flux changes in the river. We seek to understand how the ecology of the Henry’s Fork will respond to anthropogenically-driven nutrient flux change, including: 1) understanding the effect of nutrients on primary productivity and whole-stream metabolism 2) linking changes in primary productivity to changes in stream ecosystem structure and food webs, focusing on trout growth and habitat, and 3) developing a nutrient budget for the Henry’s Fork under various climate and development scenarios. Methods will include observational comparative studies among different reaches of the Henry’s Fork, a nutrient addition experiment, and statistical and systems modeling. Our results will assist local resource managers in mitigating human development for the benefit of the Henry’s Fork ecosystem and the trout that call it home. We aim to advance the field of stream and fish ecology by more closely examining how nutrients can affect stream ecosystems, including concepts such as the paradox of enrichment, the river continuum concept, and the management usefulness of ecosystem metabolism.


  • Henry’s Fork Foundation
  • Utah State University – The Ecology Center
  • United States Geological Survey – Utah Cooperative Fish and Wildlife Research Unit (In-kind)


  • Dr. Phaedra Budy, Principle Investigator, USU – Dept. of Watershed Sciences
  • Jack McLaren, PhD student, USU – Dept. of Watershed Sciences, and The Ecology Center
  • Dr. Soren Brothers, Principle Co-Investigator, USU – Dept. of Watershed Sciences
  • Dr. Rob Van Kirk, Henry’s Fork Foundation

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