![[logo] US EPA](https://webarchive.library.unt.edu/eot2008/20081014083425im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Aquatic Life Use Support (ALUS)
Biocriteria Links
The EPA/State 305(b) Consistency Workgroup has begun to implement the Intergovernmental Task Force on Monitoring Water Quality (ITFM) recommendations including how to integrate the results of biological, habitat, chemical and toxicological assessments in making a determination of aquatic life use support (ALUS). This approach includes consideration of assessment quality as indicated by levels of information of the different data types in evaluating the degree of impairment (partial support vs. nonsupport) when there are differences in assessment results.
Level of Information
In 1994, the 305(b) Consistency Workgroup concluded that descriptive information characterizing the level of information, or rigor, in the method is needed to more fully define an assessment of use support. Documenting this information is important because users often need to know the basis of the underlying information. The Workgroup recommends that assessment quality information become a part of State assessment data bases. Consequently, the Workgroup has developed guidance for evaluating the level of information of methods used in making ALUS.
Data types are grouped into four categories: biological (Table 1), habitat (Table 2), toxicological (Table 3) and physical/chemical (Table 4). A hierarchy of methods corresponding to each data type and ordered by level of information is summarized in the tables. The rigor of a method within each data type is dictated by its technical components, spatial/temporal coverage, and data quality (precision and sensitivity). In the data type tables, Level 4 data are of highest quality for a data type and provide relatively high level of certainty. Level 1 data represent less rigorous approaches and thus provide a level of information with greater degree of uncertainty. Data in Levels 1 through 4 vary in strengths and limitations, and, along with site-specific conditions, should be evaluated carefully for use in assessments. Data not adequate for ALUS determinations should be excluded from the assessment.
At the Workgroup's recommendation, EPA is applying levels of information to wadeable streams and rivers where EPA's Rapid Bioassessment Protocols or other comparable methods can be applied. This is because, at this time, monitoring methods for wadeable streams and rivers are better documented and standardized than for other surface water resources such as lakes and estuaries.
EPA asks States to document the level of information that characterizes their methods for biological, habitat, toxicological, and chemical evaluations. The approach may be extended to ALUS determinations in other types of waterbodies as well as other designated uses in future 305(b) cycles based on the experience with ALUS in streams and rivers and as methods for other waterbody types are standardized. The Waterbody System will contain fields to track level of information for each data type (first columns of the tables).
Additional Information on Bioassessment of ALUS got Wadeable Streams and Rivers