Hierarchical Physical Classification of Western Streams: Predicting Biological Condition in Terms of Key Environmental Processes Bridging Local to Ecoregional Scales

EPA Grant Number: R828636
Title: Hierarchical Physical Classification of Western Streams: Predicting Biological Condition in Terms of Key Environmental Processes Bridging Local to Ecoregional Scales
Investigators: Bledsoe, Brian P. , Wohl, Ellen E. , Poff, N. LeRoy
Institution: Colorado State University
EPA Project Officer: Packard, Benjamin H
Project Period: January 15, 2001 through January 14, 2004 (Extended to January 14, 2005)
Project Amount: $788,144
RFA: Development of National Aquatic Ecosystem Classifications and Reference Conditions (2000) RFA Text |  Recipients Lists
Research Category: Water , Aquatic Ecosystems


Existing physical classifications for streams do not explicitly include considerations of how primary environmental drivers such as flow regime, geophysical setting, intermediate-scale geomorphic processes, and anthropogenic impacts interact and vary in importance across spatial scales in controlling stream environments and shaping biotic communities. To overcome these limitations, we propose to develop a hierarchical classification framework for stream environments in the western US that identifies the relative importance of key environmental constraints or "filters" operating across multiple spatial scales. Given the current emphasis on ecoregional and local scales in biomonitoring protocols, this approach will provide essential information on how environmental factors measured at intermediate scales (watershed, valley bottom / geomorphic process domain, and reach) can be used to understand and predict biotic condition at individual sites distributed across the landscape.


By integrating hydrologic regime, water quality, and critical geomorphic processes with reach classification, we will develop a flexible multi-scale framework that is user-friendly and designed to readily augment existing stream classification systems in the development of reference conditions and biological criteria.


We will utilize existing R-EMAP data on first through fourth order streams from six ecoregions in Colorado, Oregon, and Washington and new data as available from the EMAP Western Pilot Study to (1) link a multi-scale physical classification with expectations of taxa distribution and categorical abundance in western US streams and rivers, and (2) demonstrate the explanatory power and flexibility of the classification within and across diverse western US ecoregions. We will apply the classification in collaboration with the State of Montana to stratify diverse stream environments and systematically identify probable reference sites using multi-scale physical and chemical information. We will then examine the predictive utility of the classification by comparing the ecological health of these reference sites versus sites selected using less objective methods. This application will assist in further generalization of the classification, improving user-friendliness, and demonstrating practical applications. The proposed work provides a basic scientific foundation for: (1) determining the predictability of community compositions associated with different degrees of physical description; (2) interpreting biomonitoring information from diverse hydrologic, geophysical, and chemical settings; and (3) systematically selecting reference streams that are similar with regard to the most relevant physical drivers within an ecoregion.

Publications and Presentations:

Publications have been submitted on this project: View all 11 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 2 journal articles for this project

Supplemental Keywords:

scaling, aquatic, indicators, EPA Regions 8, 9, 10., RFA, Scientific Discipline, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Hydrology, Aquatic Ecosystems & Estuarine Research, State, Aquatic Ecosystem, Ecological Risk Assessment, Ecology and Ecosystems, biocriteria, EMAP, streams, Oregon, multiple spatial scales, ecoregional scale, Washington (WA), hierarchical physical classification, water quality, biological indicators, ecological classification, predicting biological condition, Colorado (CO)

Progress and Final Reports:

  • 2001 Progress Report
  • 2002 Progress Report
  • 2003
  • Final