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Chapter 2: Summary of Findings (cont.)

Table 1. National summary of bioassesment programs for streams and wadable rivers in 2001.

Figure 2c. Numeric biocrtieria development. Four entities (FL, OH, OK, DRBC) have numeric biocriteria incorporated into their WQS (Figure 2c-right). And of the 11 entities for which numeric biocriteria is categorized as "under development," Maine and Wyoming have developed and incorporated numeric biocriteria into other program documents, such as SOPs and monitoring guidance manuals, and have been using the numeric limits to maintain designated uses.Four entities (FL, OH, OK, DRBC) have numeric biocriteria incorporated into their WQS (Figure 2c-right). And of the 11 entities for which numeric biocriteria is categorized as "under development," Maine and Wyoming have developed and incorporated numeric biocriteria into other program documents, such as SOPs and monitoring guidance manuals, and have been using the numeric limits to maintain designated uses.

The three major groups of biological organisms or assemblages monitored as part of comprehensive biological assessment programs are fish, benthic macroinvertebrates, and algae (periphyton). Macroinvertebrates are the most common indicator assemblage used by state water quality agencies and are a part of all but Hawai`i's bioassessment program, where it is currently under development (Figure 3a). The second most common assemblage monitored is fish, followed by periphyton (Figures 3b and 3c - below). Forty-five entities monitor for at least two assemblages, and another five (AK, HI, NV, UT, WY) currently use one, but are developing the capability of using a second (Figure 3d).

Figure 3b. Map of fish assessment status in programs.

Figure 3a. Fish assessment programs

Figure 3c. Map of periphyton assessment status in programs.

Figure 3c. Number of assemblages assessed. The three major groups of biological organisms or assemblages monitored as part of comprehensive biological assessment programs are fish, benthic macroinvertebrates, and algae (periphyton). Macroinvertebrates are the most common indicator assemblage used by state water quality agencies and are a part of all but Hawai`i's bioassessment program, where it is currently under development (Figure 3a). The second most common assemblage monitored is fish, followed by periphyton (Figures 3b and 3c - below). Forty-five entities monitor for at least two assemblages, and another five (AK, HI, NV, UT, WY) currently use one, but are developing the capability of using a second (Figure 3d).

One of the key elements in bioassessment programs is the establishment of reference conditions to help discern human impacts from natural variation. The two types of reference conditions currently used in biological surveys are regional and site-specific. The Ecoregion Concept, a common regionalization approach, recognizes geographic patterns of similarity among ecosystems and the subsequent distribution of biological communities grouped on the basis of environmental variables such as climate, soil type, physiography, and vegetation. Forty-two entities have adopted this method of stream stratification/ characterization in developing reference conditions (Figure 4 - below). Site-specific reference conditions typically consist of condition measurements taken upstream of a point source discharge or from a "paired" watershed. However, their usefulness is limited since they have only site-specific value (USEPA 1999). Only nine entities primarily use this approach to determine reference conditions.

Figure 4. Status of use of multimetric indices in bioassessment programs. Of the 54 entities that select and calculate biological metrics, 41 aggregate these metrics into a multimetric index (such as fish or macroinvertebrate IBIs) to assess biological condition and water quality, and to discriminate between impaired andunimpaired conditions (Figure 5- left). Finally, all entities with bioassessment programs also assess the physical habitat quality at their sample sites, usually employing visual based methods (such as QHEI and RBPs) in combination with other measurements.
Figure 4

Figure 5. Status of the use of ecoregional reference conditions in programs. Of the 54 entities that select and calculate biological metrics, 41 aggregate these metrics into a multimetric index (such as fish or macroinvertebrate IBIs) to assess biological condition and water quality, and to discriminate between impaired andunimpaired conditions (Figure 5- left). Finally, all entities with bioassessment programs also assess the physical habitat quality at their sample sites, usually employing visual based methods (such as QHEI and RBPs) in combination with other measurements.Biological metrics and multivariate analysis are two types of data analysis tools/methods used to reduce a wealth of raw data into workable indicators of biological condition. Nearly all of the entities with bioassessment programs have developed biological metrics. In addition, just under half use multivariate analysis (techniques that look at the pattern of relationships among several variables simultaneously, such as principal components analysis (PCA) and non-metric multidimensional scaling (NMS). Of the 54 entities that select and calculate biological metrics, 41 aggregate these metrics into a multimetric index (such as fish or macroinvertebrate IBIs) to assess biological condition and water quality, and to discriminate between impaired andunimpaired conditions (Figure 5). Finally, all entities with bioassessment programs also assess the physical habitat quality at their sample sites, usually employing visual based methods (such as QHEI and RBPs) in combination with other measurements.

 

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