|
|
||
 farmer who has cows with access to a reservoir inflow may not ever fish or swim in the lake
downstream and, therefore, has no real opinion about the local water quality. If swimming is impaired,
due to decreased visibility, the connection between the algal bloom and the farmer's cows may not be
easily conveyed to the farmer.
2.1.2 WATER QUALITY BIOCRITERIA AND INDICATORS
Relating actual water quality data to user perceptions may be a reasonable approach defining
water quality problems and developing enhancement techniques. Heiskary and Walker (1988)
developed a method for establishing phosphorus criteria in Minnesota Lakes that took traditional
predictive techniques for phosphorus, chlorophyll, and water clarity for establishing criteria and
calibrated the method to include user perceptions. This approach suggests that criteria be applicable to
user perceptions and regional differences in water quality.
More recently, the EPA and others in the scientific community, developed an approach for
conducting a bioassessment of lakes and reservoirs and establishing biocriteria (USEPA 1998). In this
approach, bioassessment is defined as an evaluation of the biological condition of a waterbody that uses
biological surveys and other direct measurements of resident biota in surface waters. Biological criteria
(biocriteria) are numeric values or narrative expressions that describe the reference biological condition
of aquatic communities inhabiting waters of a given designated aquatic life use (USEPA 1998).
Once a biological survey has been conducted and biocriteria are established the information can
be used for:
Problem screening and identification
Assessing the effectiveness of implemented water resource management practices
Determining attainment of designated aquatic life uses
Refining aquatic life use categories
Identifying impact sources.
Clearly, collaboration among users and resource agencies is required in this process. Much of the data
used in determining biocriteria come from the state's monitoring programs, federal data collection
efforts, and studies/monitoring conducted by academic institutions and the private sector. Additional
information on biocriteria is available in USEPA 1990, 1991, 1992, 1996a, 1996b, and 1996c.
Indicators of water quality problems may be defined by paraphrasing a definition by the
Intergovernmental Task Force on Monitoring Water Quality (ITFM 1995, Appendix E) which defines
environmental indicators as, "... measurable feature or features that provide managerially and
scientifically useful evidence of environmental and ecosystem quality or reliable evidence of trends in
quality." Characteristics of indicators include technical considerations such as validity, sensitivity, and
representativeness (i.e., one indicator for a whole system may not be appropriate), practical
considerations such as cost and logistical difficulty, and programmatic considerations such as
understandability and relevance. Indicators may be classified as those that provide information for
2.1-2
|
||
|
||
