Physical integrity: The missing link in biological monitoring and TMDLs

Brenda Asmus, Joe A Magner, Bruce Vondracek, Jim A Perry

Research output: Contribution to journalReview articlepeer-review

10 Scopus citations


The Clean Water Act mandates that the chemical, physical, and biological integrity of our nation's waters be maintained and restored. Physical integrity has often been defined as physical habitat integrity, and as such, data collected during biological monitoring programs focus primarily on habitat quality. However, we argue that channel stability is a more appropriate measure of physical integrity and that channel stability is a foundational element of physical habitat integrity in low-gradient alluvial streams. We highlight assessment tools that could supplement stream assessments and the Total Maximum Daily Load stressor identification process: field surveys of bankfull cross-sections; longitudinal thalweg profiles; particle size distribution; and regionally calibrated, visual, stream stability assessments. Benefits of measuring channel stability include a more informed selection of reference or best attainable stream condition for an Index of Biotic Integrity, establishment of a baseline for monitoring changes in present and future condition, and indication of channel stability for investigations of chemical and biological impairments associated with sediment discontinuity and loss of habitat quality.

Original languageEnglish (US)
Pages (from-to)443-463
Number of pages21
JournalEnvironmental Monitoring and Assessment
Issue number1-4
StatePublished - Jan 2009

Bibliographical note

Funding Information:
The Minnesota Cooperative Fish and Wildlife Research Unit is jointly sponsored by the US Geological Survey, the University of Minnesota, the Minnesota Department of Natural Resources, and the Wildlife Management Institute.

Funding Information:
Acknowledgements We thank David E. Andersen, Richard L. Kiesling, and John Swartz who read an earlier draft of this manuscript and provided thoughtful and constructive comments. We also thank an anonymous reviewer who edited the manuscript and offered suggestions that better defined the scope of this article and increased clarity. This paper was written in support of a broader research project funded by the United States Protection Agency and the Minnesota Pollution Control Agency. Although the research described in this article has been funded wholly or in part by the United States Environmental Protec- tion Agency through grant/cooperative agreement RD-83136601-1 to the University of Minnesota, it has not been subjected to the Agency’s required peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred.


  • Biotic impairment
  • Channel stability
  • Habitat assessment
  • Low-gradient alluvial streams
  • Sediment


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