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Key Concepts for Using Biological Indicators

Using USEPA’s Comprehensive Assessment and Listing Methodology guidelines as the basis, the USEPA biological criteria program, Regions and states have piloted a review procedure to examine the technical attributes of State and Tribal biological assessment programs and how biological assessment information is used in conjunction with chemical and physical assessments to support water quality management. Increasingly, biological assessments are being used and formalized in State and Tribal programs to more precisely define designated aquatic life uses, develop biological criteria, and support development of numeric criteria for nutrients and aquatic life protection, TMDL targets for waters impaired by stormwater, and 303(d) listing decisions. With this increased interest in using and formalizing biological assessments, the need to recognize and communicate technically sound approaches takes on increasing importance and urgency. It is important to provide detailed guidelines and milestones by which States, Tribes, and USEPA can evaluate progress when developing and improving biological assessment programs.

The program review methodology was first developed in Region 5 and most recently applied and refined in Region 1.  Regions 1 and 5 have supported all of their states in evaluating the technical strengths and needs of their biological assessment programs in context of each state’s water management program policy and water quality standards.  The states have used the evaluation results to target resources and prioritize actions to strengthen their technical programs and the use of their assessments to support critical water management decisions.  First, a 13-element technical element review includes selecting indicator assemblages, calibrating regional reference conditions, choosing appropriate index points, and addressing important methodological questions.  Second, a water management program review analyzes the flow of biological information through the agency, e.g., designation of aquatic life uses, integration with other uses and criteria, assessment and listing protocols, TMDL development, and permitting.

In sum, the quality and level of rigor of a bioassessment program is dependent upon the quality and level of resolution of each of its technical elements, which are categorized as 1) survey design (the extent of temporal {index period} and spatial coverage, natural classification, characterization of reference conditions, and reference site criteria), 2) methodology (number of assemblages, field sampling, sample processing, and management of the data), and 3) quality of the interpretation (ecological attributes, biological endpoints, diagnostic capability, and professional peer review). Certain aspects of monitoring and assessment, particularly quality assurance/quality control (QA/QC), are inherent in several technical elements of a viable bioassessment approach. An explanation of the key attributes of each element is presented in the following links.

Key Technical Elements

Design
1. Index period
2. Spatial coverage
3. Natural classification
4. Criteria for reference sites
5. Reference conditions

Methods
6. Taxonomic Resolution
7. Sample collection
8. Sample processing
9. Data management

Interpretation
10. Ecological attributes
11. Biological endpoints
12. Diagnostic capability
13. Professional review

For more information on evaluation of state and tribal biological assessment programs, please contact:

Susan Jackson, US EPA Office of Science and Technology, Office of Water, jackson.susank@epa.gov
Edward Hammer, US EPA Region 5, hammer.edward@epa.gov
Diane Switzer, US EPA Region 1, switzer.diane@epa.gov

Biological Indicators | Aquatic Biodiversity | Statistical Primer

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