In 1970, the Clean Water Act established a goal that our waterways should be “fishable and swimmable” and made it the obligation of every state to monitor and assess the chemical, physical and biological conditions of their streams and rivers.

In the U.S., the State of Ohio is at the forefront in the field of biological assessment.  This form of assessment, refined and “personalized” to our state by Ohio EPA, presents a particularly comprehensive and meaningful monitoring approach, as the animal communities in these aquatic systems effectively integrate a wide range of conditions and environmental variables over time.  In a grossly oversimplified description: If sources of degradation are present, sensitive species decline and tolerant or more adaptable species prevail.  The composition of the fish and invertebrate communities therefore reflect the relative health of the waterway.

To gain a better understanding of the process of developing biological assessment programs and to understand all the work that has gone into Ohio’s and other states’ programs, Rapid Assessment of Stream Health (Edited by D.L. Hughes, M.P. Brossett, J.A. Gore, John R. Olson, 2010) is a worthwhile read.  This book is not for the casual reader with an interest in stream health, however.  It is specifically geared toward the practitioner or environmental professional with a keen interest in understanding or even developing a regional bioassessment protocol.

The book starts with a basic introduction of concepts and the history of bioassessment, including discussions of Karr’s (1981) Index of Biotic Integrity Rapid Bioassessment Protocol (RBP) by Barbour et al. (1999), Hilsenhoff’s biotic index, and other related but lesser known indices.  It then compares and contrasts these methods and their ability to detect impairment of aquatic resources.  The author concludes through a summary of other published studies that their approaches show little difference in their ability to detect impairment, but stresses that methods should be selected with a full knowledge and understanding of the advantages and limitations of each.

In a very general sense, a regional bioassessment program requires the development of a robust baseline of data from reference sites (sites that have experienced no or only minimal degradatation) to which study sites may then be compared.  The goal is to get to a point where the knowledge of regional reference streams will allow biologists to establish an expected condition (E) to which observed conditions (0) at other potentially impaired sites may be compared (O/E).

The text highlights numerous aspects of rapid bioassessment development in an extensive material and methods section.  The book leans heavily on examples from the State of Georgia to demonstrate the process, although these methods could be used in any state or region – the same basic rules apply.  Reference sites should be selected with a solid understanding of degradation sources and processes, so that the least impacted sites may be identified as reference sites.  Sampling should follow standardized protocols to ensure the validity of future O/E comparisons, and supplemental physical and chemical data should also be collected in order to interpret potential influences on the biological components of the stream system.  And throughout the process, careful data analysis, database development, metric calculation and multi-metric index development should be used to establish appropriate and meaningful metrics and scoring breaks for the RBP being developed.  GIS mapping can be an extremely beneficial tool in this process.

The authors go into considerable detail regarding the calibration of metrics and numeric rankings, the importance of sample size and taxonomic resolution (should invertebrates be identified to species? Or is genus or family level identification sufficient?), the cost effectiveness of various approaches, and QA/QC procedures.

The final two chapters address the use of RBPs to assess stormwater best management practices (BMPs) for urban streams and implementation of RBPs by state agencies, which may be more topical given the emerging emphasis on stormwater management.  The book includes extensive data-rich appendices, comprising nearly 40% of the book, which could be useful to a practitioner planning a RBP program for their state or region (though I must confess, I did not spend much time with these appendices).

For any environmental professional wishing to improve their comprehension of rapid bioassessment, I would recommend this text.  If nothing else, it will give you a new-found respect for the biologists, planners, program managers and agencies that are leading these important efforts across our country.  But for the lay person or casually-interested citizen scientist, this book will be more than you bargained for.

~Mark

http://www.environmentalconsultingohio.com/