• Chemical and narrative water-quality criteria and standards can be more appropriately applied and take into account the integrated dynamics of the receiving waters when relevant biological assessment information is available (Yoder, 1991a,b).
  • The biological results provide a legal basis for enforcement against entities discharging chemicals for which there are no existing water-quality standards or effluent guidelines (or at least provide the impetus to designate new chemical criteria or whole-effluent toxicity limits).
  • The results provide a basis for regulating nonchemical environmental degradation (e.g., certifications of dredging permits [Section 401 water-quality certifications], non-point-source management).

Remaining Challenges

We have demonstrated how biological criteria can be developed and used within a state water-resource-management framework. Nonetheless, some important challenges remain. The cumulative costs associated with environmental mandates, many of which consist of prescription-based regulations, have recently come into question. Both the regulated community and the public desire evidence of real-world results in return for the expenditures made necessary by federally and state-mandated requirements. Biological criteria seem particularly well suited to address these concerns because the underlying science and theory is robust (Karr, 1991), and biocriteria directly assess the biological condition of aquatic habitats.

Although no single environmental indicator can do it all, biological criteria have a major role to play. A lack of information from or an overreliance on any single class of indicators can result in environmental regulation that is inaccurate and either under- or overprotective of the resource. Accounting for cost is not only a matter of dollars spent but also of program effectiveness. A credible and genuinely cost-effective approach to water-quality management should include an appropriate mix of chemical, physical, and biological measures, each in their respective roles as stressor, exposure, and response indicators. The public must come to see comprehensive monitoring designs using such cost-effective indicators as a part of the cost of doing business, perhaps at the expense of other programs when new evidence suggests that the resources allocated are disproportionate to the magnitude of the present problems (e.g., point versus nonpoint sources).

Based on our experience over the past 17 years, it is evident that including biological criteria in a state's monitoring and assessment effort has multiple benefits: It can foster a more complete integration of important ecological concepts, better focus water resource policy and management, and enhance strategic planning. Some specific examples include:

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