State of New Mexico > Environment Department > Surface Water Quality Bureau

Surface Water Quality Bureau
Monitoring & Assessment

Biocriteria (biological criteria) are a way of expressing the qualities that must be present to support a desired condition of a waterbody. Biocriteria are narrative statements or numeric expressions that describe a reference biological condition (structure and function) of aquatic communities inhabiting waters of a given designated aquatic life use.

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The primary goal of the Clean Water Act is to restore and maintain the physical, chemical, and biological integrity of the nation's surface waters (Clean Water Act Section 101[a][2]).  Because this goal addresses physical, chemical, and biological integrity it can fundamentally be viewed as an ecologically based goal (Karr et al., 1986, Karr 1991, Yoder and Rankin 1998). The phrase biological integrity originated in Section 101[a][2] of the Federal Water Pollution Control Act amendments of 1972 (CWA) and has remained a part of the subsequent reauthorizations. The biological integrity language of the Clean Water Act, was eventually defined by Karr and Dudley (1981) as ". . . the ability of an aquatic ecosystem to support and maintain a balanced, integrated, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of the natural habitats of a region." The Environmental Protection Agency (EPA) adopted a similar version of this definition in the biological criteria national program guidance (EPA 1990).  In a review of EPA’s Ecological Monitoring and Assessment Program (EMAP) the National Research Council suggested that the definition of Biological Integrity be based on more useful, objective indicators such as “a community with a biological diversity, composition, and functional organization comparable to those of natural lakes and streams of the region.” This workable definition directly alludes to the measurable characteristics of biological community structure and function found in least-impacted waterbodies of a region. These measurable characteristics attempt to quantify the biological condition of a particular community (fish, macroinvertebrates, diatoms) and can be developed and refined into biological criteria.

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Biological Criteria

Understanding biological integrity and condition is essential for understanding biological criteria. Biological criteria are based on measurable and predictable characteristics of aquatic communities such as species richness, key taxonomic groupings, functional feeding and reproductive guilds, environmental tolerance, and evidence of stress. Measurable characteristics of a biological community have generally been termed "metrics". Examples of metrics include the Invertebrate Community Index (ICI) (DeShon 1995), Rapid Bioassessment Protocols (RBPs) (Shackleford 1988, Plafkin et al., 1989, Barbour et al., 1992, 1995, 1996, 1999, Hayslip 1993, Smith and Voshell 1997), and the benthic Index of Biotic Integrity (IBI) (Kerans and Karr 1994, Fore et al., 1996).The resulting numerical expressions reflect the health and condition of aquatic communities. There are numerous other, more recent, examples of Indices being developed by states such as Arizona, California, Colorado, Montana, Utah, and Wyoming.

Biological criteria are a way of expressing the qualities that must be present to support a desired condition of a waterbody. Biological criteria can be narrative or numeric expressions that describe a reference biological condition (structure and function) of aquatic communities inhabiting waters of a given designated aquatic life use.

Biological criteria are derived from biological monitoring and calculating indices (Index) of the composition, diversity, and functional organization of a reference aquatic community and comparison to stressed sites. Reference conditions should be the foundation for biocriteria. Reference conditions should represent unimpaired or minimally impaired conditions and the "high end" of the state's designated aquatic life use classification system.

Biological criteria scores (multimetric approach) or Observed vs Expected values (statistical approach) can be established for the different biological conditions characterized by the aquatic life use classification system. Biological assessments are then conducted to determine if a waterbody is attaining its specified designated aquatic life use by comparing the assessment results with the biocriteria established for that region and waterbody type.

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Biological Assessments

Biological criteria serve as the standard against which biological assessment (bioassessment) results are compared. Biological assessment is a method to evaluate the biological condition of a waterbody. Biological assessments consist of surveys and other direct measurements of riparian conditions and various aquatic communities such as aquatic vegetation and algae, fish, insects, crayfish, salamanders, frogs, worms, snails, mussels, etc., in the waterbody. The presence, condition, and numbers of aquatic communities along with other physical and chemical data are crucial for evaluating the overall health of a waterbody.

Biological assessments are a means to measure the cumulative impact of stressors such as toxicants, temperature, dissolved oxygen, sedimentation/siltation, and flow regimes as well as factors that influence the above parameters such as riparian conditions and physical stream characteristics (geomorphology). Biological communities integrate these stresses over time and provide an ecological measure of fluctuating environmental conditions. Biological assessments reflect the condition of overall ecological integrity (i.e., when the biological community is healthy, typically the chemical and physical components of a waterbody are also in good condition). Therefore, biological assessments directly and comprehensively assess the condition of ecosystem health (integrity), a primary goal of the CWA.

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New Mexico's Benthic Macroinvertebrate & Bioassessment Program

The SWQB established a Biological Monitoring Program in 1979.  Early programs were site specific or intensive monitoring which concentrated on point-source discharges in high quality mountain streams such as the Rio Hondo, Red River, and Chama River.  Ambient monitoring stations were first sampled throughout the state in 1979.  The SWQB now uses a basin network of monitoring, scheduled on a yearly rotation and prioritization.  A core team of Monitoring and Assessment Section staff provide the technical resources to conduct the monitoring.  Biological data are necessary to assess the condition of New Mexico’s surface waters and to measure the attainment of biological integrity goals as directed by EPA and characterized by the state of New Mexico. This monitoring has been used extensively for establishment and refinement of designated aquatic life uses and more recently for the development and application of biocriteria.

New Mexico has made substantial progress towards the development of benthic macroinvertebrate biological thresholds for perennial, wadeable streams using a regional reference condition approach. In September 2002, the New Mexico Biocriteria Development Team (NMBDT) was formed.  This technical team was composed of several SWQB staff, local academicians/consultants Drs. Gerald and Donna Jacobi, Tetra Tech consultants, as well as a representative from NMED Department of Energy (DOE) Oversite Bureau, and Los Alamos National Laboratory (LANL). NMBDT compiled benthic macroinvertebrate and site data collected from streams and rivers of New Mexico over the past 20+ years (796 discreet samples from 420 sites) and transferred these data to New Mexico’s previous version of the Ecological Data Application System (EDAS), a data analysis system developed for EPA and used to calculate indices and provide a mechanism for integrating biological and physicochemical data.

The resulting EDAS database was used by Tetra Tech and the Drs. Jacobi to develop a provisional Stream Condition Index (SCI) for New Mexico’s perennial, wadeable streams in the Mountain Ecoregion. The Mountain Ecoregion is composed of Omernik Ecoregions 21 (Southern Rockies) and 23 (Arizona/New Mexico Mountains). A report (Jacobi et al., 2006) was completed in April 2006 detailing the SCI to date, including site scoring, reference site selection, metric selection, and index calculation. The SWQB envisions continuation of data acquisition and technical analyses.

Potential future steps towards completing a benthic macroinvertebrate wadeable stream condition index for all ecoregions in New Mexico may include the following:

1) Refine SCI through improved site scoring and classification – This may be accomplished through incorporation of improved Land Use/Land Cover information, stream order, geology information, water quality parameters, and regional delineations, and the development and application of a Human Disturbance Gradient.  Metric values and scores may be aggregated into an index to calculate impairment thresholds for each site class based on the biological data.
2) Refinement of a River InVertebrate Prediction And Classification System (RIVPACS) model – Using the same data as used for the multimetric development and refinement, a preliminary RIVPACS-type predictive model was developed and tested for perennial, wadeable streams. A final family level and operational taxonomic unit (mostly genus level) model were built, however both models were fairly imprecise. A draft report was completed in June 2008 detailing the preliminary results, but Tetra Tech recommended against using either of these predictive models until further refinements can be made. The classification developed with this model may be used in step 3.
3) Completion of final SCI and Report – This peer-reviewed report may detail indices for perennial, wadeable streams in the other two ecoregions (Xerix and Plains) in New Mexico and will form the basis of SWQB’s assessment protocol for impairment determinations due to “Benthic-Macroinvertebrate Bioassessments” (i.e., Cause of Impairment as defined in ADB v.2).
4) Customization of NMEDAS – A new in-house water quality database (NMEDAS) was developed in 2010.  Once the final SCI is developed, NMEDAS must be revised to generate the final SCI score for impairment assessment.
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New Mexico's Diatom Bioassessment Program

SWQB is currently in the process of developing a regional stream condition index (SCI) and assigning tolerance values for diatom communities of New Mexico. Once a SCI has been developed for New Mexico and organism tolerance values are verified, these biological indicators may be used in the weight-of-evidence nutrient assessment. Additional information on nutrient threshold development is available on SWQB's website at:

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New Mexico's Fish Bioassessment Program

New Mexico has been collecting fish community data from select streams, lakes, and reservoirs since 2000. SWQB has collated available data to begin exploring the feasibility of biological assessment techniques using fish assemblages in select water body types. Cold water streams tend to be lacking in variety of species, making development of fish assemblage-based biological assessment challenging. Therefore, biological assessment development efforts will initially be focused cool and/or warm water streams.

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Literature Cited

Bulleted item Barbour, M.T., J.L. Plafkin, B.P. Bradley, C.G. Graves, and R.W. Wisseman. 1992. Evaluation of EPA’s rapid bioasseessment benthic metrics: metric redundancy and variability among reference stream sites. Environmental Toxicology and Chemistry 11(4):437-449.
Bulleted item Barbour, M.T., J.B. Stribling, and J.R. Karr. 1995. Multimetric approach for establishing biocriteria and measuring biological condition. Pages 63-77 in Biological assessment and criteria: tools for water resource planning and decision making. W.S. Davis and T.P. Simon (editors). Lewis Publishers, Boca Raton, Florida.
Bulleted item Barbour, M.T., J. Gerritsen, G.E. Griffith, R. Frydenborg, E. McCarron, J.S. White, and M.L. Bastian. 1996. A framework for biological criteria for Florida streams using benthic macroinvertebrates. Journal of the North American Benthological Society 15(2):185-211.
Bulleted item Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling. 1999. Rapid Bioassessment Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish, Second Edition. EPA 841-B-99-002. U.S. Environmental Protection Agency; Office of Water; Washington, D.C.
Bulleted item DeShon, J.D. 1995. Development and application of the invertebrate community index (ICI). Pp. 217-243 in Biological assessment and criteria: tools for risk-based planning and decision making. W.S. Davis and T. Simon (editors). Lewis Publishers, Boca Raton, Florida.
Bulleted item Environmental Protection Agency (EPA). 1990. Biological Criteria: National Program Guidance for Surface Waters. EPA-440/5-90-004. April 1990.
Bulleted item Fore, L.S., J.R. Karr, and R.W. Wisseman. 1996. Assessing invertebrate responses to human activities: evaluating alternative approaches. Journal of the North American Benthological Society 15(2):212-231.
Bulleted item Hayslip, G.A. 1993. EPA Region 10 in-stream biological monitoring handbook (for wadeable streams in the Pacific Northwest). U.S. Environmental Protection Agency-Region 10, Environmental Services Division, Seattle, Washington. EPA-910-9-92-013.
Bulleted item Jacobi, G.Z, M.D. Jacobi, and M.T. Barbour, 2006.  Benthic Macroinvertebrate Stream Conditions Indices for New Mexico Wadeable Streams.  New Mexico Environment Department, Santa Fe, New Mexico. /swqb/documents/swqbdocs/MAS/Biology/M-SCI2006Report.pdf
Bulleted item Karr, J.R. and D.R. Dudley. 1981. Ecological perspectives on water quality goals. Environmental Management 5:55-68.
Bulleted item Karr, J. R., K. D. Fausch, P. L. Angermeier, P. R. Yant, and I. J. Schlosser. 1986. Assessment of biological integrity in running waters: A method and its rationale. Illinois Natural History Survey, Champaign, Illinois. Special Publication 5.
Bulleted item Karr, J. R. 1991. Biological integrity: A long-neglected aspect of water resource anagement. Ecological Applications 1:66-84.
Bulleted item Kerans, B.L. and J.R. Karr. 1994. A benthic index of biotic integrity (B-IBI) for rivers of the Tennessee Valley. Ecological Applications 4:768-785.
Bulleted item Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M. Hughes. 1989. Rapid bioassessment protocols for use in streams and rivers: benthic macroinvertebrates and fish. EPA/440/4-89-001. U.S. Environmental Protection Agency, Office of Water, Washington DC.
Bulleted item Shackleford, B. 1988. Rapid bioassessments of lotic macroinvertebrate communities: biocriteria development. Arkansas Department of Pollution Control and Ecology, Little Rock, Arkansas.
Bulleted item Smith, E.P. and J.R. Voshell. 1997. Studies in benthic macroinvertebrates and fish in streams within EPA Region 3 for development of biological indicators of ecological condition. Virginia Polytechnic Institute and State University, Blacksburg, Virginia.
Bulleted item Yoder, C.O. and E.T. Rankin 1998. The role of biological indicators in a state water quality management process. Environmental Monitoring and Assessment 51:61-88.
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Our Favorite Links

Biocriteria Factsheet
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Bioindicators and Climate Change
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Environmental Monitoring and Assessment Program
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Watershed assessment of river stability and sediment supply
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Dragonflies and Damselflies of the United States
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Stoneflies of the United States
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Mayflies of the United States
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Rapid bioassessment protocols for use in streams and wadeable Rivers: Periphyton, benthic macroinvertebrates, and fish
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North American Benthological Society
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National survey progress report
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Monitoring and assessing water quality
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National rivers and streams assessment
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bulleted item Bureau Contacts
Bulleted item Seva Joseph
Monitoring, Assessment & Standards Section
(505) 827-2921
Bulleted item Lynette Guevara
Monitoring, Assessment & Standards Section
(505) 827-2904


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