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

State Program Contact

Wisconsin Surface Waters Exit

Water Quality Standards

WQS Information
The link to Wisconsin's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
The state of Wisconsin 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

In addition to the links to WQS, Wisconsin provided links to its Department of Natural Resources website, which includes a summary of efforts to revise/create sections of their administrative code on designated aquatic life use, biological criteria, and antidegradation. More information will be posted on these site as it becomes available.

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
Since the 1970s, Wisconsin has had ALU subcategories based on temperature and the associated fisheries expected.  The five ALU subcategories are:

  1. Coldwater – Salmonids and some sculpin species
  2. Warm Water Sport Fish – game fish and some important forage species
  3. Warm Water Forage Fish – forage fish communities intolerant to low dissolved oxygen
  4. Limited Forage Fish – forage fish communities tolerant of low dissolved oxygen
  5. Limited Aquatic Life – communities with non-fish species (invertebrates, etc.) that are tolerant of low dissolved oxygen.

WDNR is currently undergoing a rulemaking process to revise its ALU categories.

Proposed ALU Categories:
  • Macroinvertebrate communities
  • Cold water communities
  • Warm water communities
  • Wetlands

Under the proposed rules, waterbodies in the above categories could additionally be designated as “altered” if the department demonstrates through a use attainability analysis that the aquatic life use is unattainable due to certain human-caused factors.

Biological Criteria
_____ Narrative
_____ Numeric
__X__ No criteria (in progress)

Wisconsin is currently undergoing rulemaking to establish biocriteria for streams, rivers, and lakes.  The stream/river biocriteria are as follows:
  • Narrative biocriteria language to prevent declining trends and loss of species;
  • Combined criteria for phosphorus that use biological metrics as phosphorus response indicators.  The phosphorus response indicators for streams are benthic algal biomass and diatom taxa; for rivers the indicator is the frequency of moderate algae levels (suspended chlorophyll a).
  • Wisconsin is also working with EPA on refining numeric biocriteria thresholds for fish and macroinvertebrates for each stream/river type. These may be part of a future rulemaking effort.

Antidegradation Policy
The antidegradation rule is implemented in Chapter NR 207 of the Wisconsin Administrative Code.

Wisconsin expects to begin rule package to update the existing antidegradation rule. In addition, the proposed biocriteria rule package contains narrative biocriteria in NR 102 that would address antidegradation principles.

Biological Assessment

What biological assemblages are used in the bioassessment program?
  • Benthic macroinvertebrates and fish are currently used for assessing streams and rivers. The thresholds used for these assessments are currently under revision.
  • A set of phosphorus response indicators for rivers and streams (including diatoms and suspended chlorophyll a) is being proposed for rulemaking.

Are bioassessments used to support 303(d) listings? 
Yes. Listing methodology: Surface Water Quality Assessment Process

How are assemblages used to make impairment decisions?
Applied independently for impairment assessments if minimum data requirements (2 yrs) are met. If fewer biological samples are available, can use in conjunction with TP for an impairment decision. If rules are promulgated establishing biocriteria and phosphorus response indicators, assessment protocols would be updated. Biocriteria and algal abundance metrics would be applied independently. A new set of phosphorus response indicators (a.k.a. combined criteria) would be applied to waters exceeding the statewide phosphorus criteria but within a certain range, to determine whether the waterbody is exhibiting a biological response to phosphorus. This bioconfirmation process would contribute to phosphorus listing decisions.

Other uses of biocriteria or bioassessment within the water quality program:
Refining ALU, TMDL development and assessment, antidegradation, non-point source assessments, BMP evaluation, 305(b) surface water condition assessments, restoration goals, evaluation of discharge permit conditions, fishery assessments, and FERC re-licensing decisions, etc.

Technical Support Information and Documents:

Reference condition:
Wisconsin has a least-impacted reference site dataset for wadeable streams. This dataset was used in setting proposed biocriteria for streams. These sites were selected based on 26 human disturbance variables, and span different stream sizes, flows, and ecoregions.

Not applicable.

Wisconsin has a draft Technical Support Document that covers biocriteria and phosphorus response indicators, among other components of the Water Quality Standards rules under discussion.

Stressor identification/causal analysis approach:
Not applicable.

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