Bioassessment and Biocriteria Program Status for Idaho: Streams and Wadeable Rivers
State Program Contact
Water Quality Standards
The link to Idaho's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
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Designated Aquatic Life Uses
- Cold water (COLD): water quality appropriate for the protection and maintenance of a viable aquatic life community for cold water species.
- Salmonid spawning (SS): waters which provide or could provide a habitat for active self-propagating populations of salmonid fishes.
- Seasonal cold water (SC): water quality appropriate for the protection and maintenance of a viable aquatic life community of cool and cold water species, where cold water aquatic life may be absent during, or tolerant of, seasonally warm temperatures.
- Warm water (WARM): water quality appropriate for the protection and maintenance of a viable aquatic life community for warm water species.
- Modified (MOD): water quality appropriate for an aquatic life community that is limited due to one (1) or more conditions set forth in 40 CFR 131.10(g) which preclude attainment of reference streams or conditions.
__X__ Narrative, with quantitative implementation procedures or translators
_____ No criteria
Idaho’s antidegradation implementation procedures uses the integrated report, which relies largely on Idaho’s biological assessments, for identification of high-quality waters. In addition, Idaho’s antidegradation procedures use biological and habitat parameters to identify waters as high-quality waters even when certain numeric criteria may be exceeded - IDAPA 58.01.02.052.05c.i (PDF) (190 pp, 3 MB).
What biological assemblages are used in the bioassessment program?
Benthic macroinvertebrates and fish. In addition, physical habitat is an important line of evidence on assessment.
Are bioassessments used to support 303(d) listings?
Yes. Listing methodology: Monitoring and Assessment
How are assemblages used to make impairment decisions?
Refer to detailed explanation in Water Body Assessment Guidance (PDF) (118 pp, 2 MB)
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:
The reference condition concept is one in which the acceptable indicator conditions are defined by the conditions observed in sites with minimal disturbance (Barbour et al. 1999, Stoddard et al. 2006). Reference sites were defined using measures of the intensity of human activity in the watersheds (such as GIS derived land use intensity), and were selected in order to have representative reference sites distributed spatially throughout Idaho.
Technical reference material:
(PDF) (229 pp, 2 MB)
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 include standard operation procedures used in data collection, compilation, technical approaches used to develop biocriteria as well as its implementation procedures.
Technical reference material:
Water Body Assessment Guidance (PDF) (118 pp, 2 MB)
Stressor identification/causal analysis approach: