Develop Refined Designated Aquatic Life Use
Classifications
Refinement of Ecologically-based Uses
Data collected from biosurveys, as part of a developing biocriteria
program, may reveal unique and consistent differences among aquatic
communities inhabiting different waters with the same designated
use. Measurable biological attributes could then be used to separate
one class into two or more classes. For example, in Arkansas the
beneficial use Fisheries "provides for the protection and propagation
of fish, shellfish, and other forms of aquatic life". This
use is subdivided into Trout, Lakes and Reservoirs, and Streams.
Recognizing that stream characteristics across regions of the State
differed ecologically, the State further subdivided the stream designated
uses into eight additional uses based on regional characteristics
(e.g., Springwater-influenced Gulf Coastal Ecoregion, Ouachita Mountains
Ecoregion). Within this classification system, it was relatively
straightforward for Arkansas to establish detailed
narrative biological criteria that list aquatic community
components expected in each ecoregion.
Refinement of Management-based Uses
States can also refine very general designated uses such as high,
medium, and low quality to specific categories that include measurable
ecological characteristics. Maine,
for example, has developed four levels of use from Class AA
through Class C. The condition of the aquatic community that is
required to be maintained at each of the four levels of use has
been specifically described.
Goals for Stratified Designated Aquatic Life Use Classifications
Developing stratified designated aquatic life use classification
should accomplish three related objectives:
- States and Indian tribes further develop, standardize, and apply
biological assessments as part of their water quality programs
- States and Indian tribes will gain experience and build a data
base to support development or refinement of an aquatic life use
classification system based on biological measures, indices, and/or
criteria, and
- The effectiveness of controls and best management plans can
begin to be evaluated over successive monitoring cycles.
Developing stratified designated aquatic life use classifications
will result in a long term, field validated data base needed to
more accurately characterize designated aquatic life uses. It also
will assist in formally developing scientifically sound narrative
and numeric biological criteria for adoption into state or tribal
water quality standards.
Steps to develop stratified designated aquatic life use
classifications include:
- Develop standardized bioassessment methods
- Establish regional reference conditions
- Develop ecological database to support stratification (biological
expectations, level of condition)
- Evaluate the effectiveness of controls and best management practices
over successive monitoring cycles
Although these steps can occur outside water quality standard setting
and be contingent upon available Federal and state or tribal resources,
a state or tribe can proceed in adopting narrative biological criteria
during this phase.
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