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Bioassessment and Biocriteria Program Status for Oregon: Streams and Wadeable Rivers

State Program Contact

Oregon Department of Environmental Quality Exit

Water Quality Standards

WQS Information
The link to Oregon's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
The state of Oregon provided information and links to sections of their administrative code on designated aquatic life use, biological criteria, antidegradation as well as technical support documents and information on its bioassessment and biocriteria programs. These are included for your convenience and may or may not reflect the most recently EPA approved WQS. The following links exit the site Exit

You may need a PDF reader to view some of the files on this page. Refer to EPA’s about PDF page to learn more.

Designated Aquatic Life Uses
They vary by basin and include:
  • Salmon and Steelhead Migration Corridors
  • Salmon and Steelhead Spawning through Fry Emergence
  • Shad and Sturgeon Spawning and Rearing
  • Redband or Lahontan Cutthroat Trout
  • Cool Water Species (No Salmonid Use)
  • Redband and Hybrid Trout
  • Lahontan Trout
  • Borax Lake Chub
  • Bull Trout Spawning and Juvenile Rearing
  • Core Cold Water Habitat
  • Salmon and Trout Rearing and Migration

Biological Criteria
__X__ Narrative, with quantitative implementation procedures or translators
_____ Numeric
_____ No criteria

340-041-0011 Biocriteria
Waters of the State must be of sufficient quality to support aquatic species without detrimental changes in the resident biological communities.

Antidegradation Policy
Use of biocriteria or bioassessment not included in antidegradation policy.

Biological Assessment

What biological assemblages are used in the bioassessment program?
Benthic macroinvertebrates, fish, and amphibians

Are bioassessments used to support 303(d) listings? 
Yes. Listing methodology: Methodology for Oregon’s 2018 Water Quality Report and List of Water Quality Limited Waters (PDF) (109 pp, 3 MB)

How are assemblages used to make impairment decisions?
Only macroinvertebrate data is used to make impairment decisions.

Other uses of biocriteria or bioassessment within the water quality program:
TMDL development and assessment, non-point source assessments, BMP evaluation, 305(b) surface water condition assessments, and restoration goals

Technical Support Information and Documents:

Reference condition:
The paper below describes the approach the Oregon DEQ Watershed Assessment Section uses to select reference condition sites. The purpose of selecting reference condition sites is to establish an objective and systematic method for finding water bodies minimally disturbed by human activities.

Technical reference material: 
An Approach for Biological Criteria and Watershed Assessment

Development of biocriteria involves the collection and interpretation of biological data –e.g. benthic macroinvertebrates, fish, and periphyton. During this process entities typically use biological metrics (usually aggregated into a multimetric index) and/or multivariate analysis to assess whether a waterbody is meeting its designated aquatic life use(s). The reference materials included below include standard operation procedures used in data collection, compilation, technical approaches used to develop biocriteria as well as its implementation procedures.

Technical reference material: 
PREDATOR: Development and use of RIVPACS-type macroinvertebrate models to assess the biotic condition of wadeable Oregon streams (November 2005 models)

Stressor identification/causal analysis approach:
Not applicable.

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