Multimetric Bioassessment
and Habitat Assessment
Over the past two decades, multimetric indices of biological condition have been widely adopted as part of a suite of tools for comprehensive monitoring of ambient water quality. Increasingly, these indices are being incorporated into regulations in the form of numeric, biological criteria. Forty-two states now use multimetric assessments of biological condition, and an additional six states are developing biocriteria programs. Indices of habitat quality have also become widely used tools for environmental assessment. Langhei Ecology and its members have been involved in these approaches to ecological assessment over the last decade, both in implementation of the available tools and in evaluation of these tools from both conceptual and applied perspectives. Our combination of experience with these and other ecological assessment tools give us an uncommon understanding of the opportunities and limitations of the various multimetric assessment approaches.
Evaluation of multimetric bioassessment for application
to § 316(b) of the Clean Water Act
Presently, biocriteria are central to a proposed draft regulatory framework that the U.S. Environmental Protection Agency is developing under a consent decree to implement § 316(b) of the Clean Water Act (CWA). The proposed framework will address the potential adverse environmental impacts from cooling water intake structures (CWIS) at power plants and other industrial facilities. While biocriteria and their assessment tools have been embraced by the regulatory agencies and incorporated within many of their water programs over the past decade, EPA's tentative decision to make biocriteria an integral part of its framework for regulating CWIS under § 316(b) places biocriteria in a new regulatory context. That is, it extends the application of biocriteria principles and methods from small-scale systems, for which biocriteria were originally developed, to larger scale, more open systems where power plants are typically located. In this project, Langhei Ecology performed an evaluation of strengths, weaknesses, and research needs surrounding multimetric bioassessment and biocriteria, both generally as an assessment approach and specifically in the context of regulation of cooling water intake structures under § 316(b) of the CWA. For the first part of the report, we developed a primer on multimetric bioassessment. For the second part of the report, we identified strengths that can be exploited, potential weaknesses that should be addressed through targeted research, and inherent limitations that must be acknowledged and accommodated as multimetric biocriteria are developed to implement § 316(b). In separate sections, we examined several general issues and other more specific concerns that may arise in various water body types for which EPA has, or is planning to develop, guidance (e.g., streams, lakes and reservoirs, estuaries and coastal marine waters, and large rivers). This research was funded by the Electric Power Research Institute.
Assessment of Spawning and Nursery Habitat: Review and Evaluation of Methods Potentially Applicable to Regulation of Cooling Water Intake Structures
The U.S. EPA is currently developing regulations implementing § 316(b) of the Clean Water Act (CWA). Section 316(b) of the CWA requires that the design, construction, location, and capacity of cooling water intake structures (CWIS) minimize adverse environmental impact (AEI). The location of a CWIS in relation to important spawning and nursery habitat for fish will be an important consideration when assessing the potential for AEI. In this project, Langhei Ecology identified and reviewed a wide variety of habitat assessment approaches, including biologically-based methods such as density or abundance measurements, physiological indices, and multi-species biological indices, and habitat-based methods such as habitat suitability models, habitat classification, and mechanistic models. Evaluation of these methods focused on state of development, information requirements, transferability, and relevance to § 316(b).
Feasibility of an IBI-approach to Synthesizing Data from the Maryland Biological Stream Survey
The Maryland Biological Stream Survey is an ongoing, state-wide survey of biological resources in non-tidal first-, second-, and third-order streams throughout the state (M1). The survey encompasses fish, benthic macroinvertebrates, limited water chemistry, and physical habitat variables. Dr. Jacobson led a team that investigated the feasibility of using an approach similar to Karr's (1981) Index of Biotic Integrity (IBI) for reduction and interpretation of data obtained from the survey. Relationships among instream physical habitat, landuse, water quality characteristics, and biological assemblages were examined in western Maryland and the Piedmont region. Additionally, a trial multimetric index for western Maryland fish was tested using available data. Biologically-based metrics were found to have some ability to discriminate sites with respect to anthropogenic influences; thus, it appeared feasible to devise an aggregated measure for detecting anthropogenic stress in streams of the Appalachian Plateau and Piedmont regions of Maryland. Two remaining challenges were identified: to improve the sensitivity of the metrics, and to develop a sufficient understanding of land use effects on biological communities in acid-sensitive regions of the state to discriminate their effects from those associated with acidic deposition.
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