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Chapter 4 - Integrating Biological Criteria Into Surface Water Management
Integrating biological criteria into existing water quality programs will help to assess use attainment/nonattainment, improve problem discovery in specific waterbodies, and characterize overall water resource condition within a region. Ideally, biological criteria function in an iterative manner. New biosurvey information can be used to refine use classes. Refined use classes will help support criteria development and improve the value of data collected in biosurveys.
Implementing
Biological Criteria
As biological survey data are collected, these data will increasingly
support current use of biomonitoring data to identify water quality problems,
assess their severity, and set planning and management priorities for
remediation. Monitoring data and biological criteria should be used at
the outset to help make regulatory decisions, develop appropriate controls,
and evaluate the effectiveness of controls once they are implemented.
The value of incorporating biological survey information in regulatory programs is illustrated by evaluations conducted by North Carolina. In response to amendments of the Federal Water Pollution Control Act requiring secondary effluent limits for all wastewater treatment plants, North Carolina became embroiled in a debate over whether meeting secondary effluent limits (at considerable cost) would result in better water quality. North Carolina chose to test the effectiveness of additional treatment by conducting seven chemical and biological surveys before and after facility upgrades (North Carolina DNRCD 1984). Study results indicated that moderate to substantial in-stream improvements were observed at six of seven facilities. Biological surveys were used as an efficient, cost-effective monitoring tool for assessing in-stream improvements after facility modification. North Carolina has also conducted comparative studies of benthic macroinvertebrate surveys and chemical-specific and whole-effluent evaluations to assess sensitivities of these measures for detecting impairments (Eagleson et al. 1990).
Narrative biological criteria provide a scientific framework for evaluating biosurvey, bioassessment, and biomonitoring data collected in most States. Initial application of narrative biological criteria may require only an evaluation of current work. States can use available data to define variables for choosing reference sites, selecting appropriate biological surveys, and assessing the response of local biota to a variety of impacts. States should also consider the decision criteria that will be used for determining appropriate State action when impairment is found.
Recent efforts by several States to develop biological criteria for freshwater streams provide excellent examples for how biological criteria can be integrated into water quality programs. Some of this work is described in the National Workshop on In-stream Biological Monitoring and Criteria proceedings which recommended that "the concept of biological sampling should be integrated into the full spectrum of State and Federal surface water programs" (U.S. EPA 1987b). States are actively developing biological assessment and criteria programs; several have programs in place.
Biological
Criteria in State Programs
Biological criteria are used within water programs to refine use designations,
establish criteria for determining use attainment/nonattainment, evaluate
effectiveness of current water programs, and detect and characterize previously
unknown impairments. Twenty States are currently using some form of standardized
ambient biological assessments to determine the status of biota within
State waters. Levels of effort vary from bioassessment studies to fully
developed biological criteria programs.
Fifteen States are developing aspects of biological assessments that will support future development of biological criteria. Colorado, Illinois, Iowa, Kentucky, Massachusetts, Tennessee, and Virginia conduct biological monitoring to evaluate biological conditions, but are not developing biological criteria. Kansas is considering using a community metric for water resource assessment. Arizona is planning to refine ecoregions for the State. Delaware, Minnesota, Texas, and Wisconsin are developing sampling and evaluation methods to apply to future biological criteria programs. New York is proposing to use biological criteria for site-specific evaluations of water quality impairment. Nebraska and Vermont use informal biological criteria to support existing aquatic life narratives in their water quality standards and other regulations. Vermont recently passed a law requiring that biological criteria be used to regulate through permitting the indirect discharge of sanitary effluents.
Florida incorporated a specific biological criterion into State standards for invertebrate species diversity. Species diversity within a waterbody, as measured by a Shannon diversity index, may not fall below 75 percent of reference values. This criterion has been used in enforcement cases to obtain injunctions and monetary settlements. Florida's approach is very specific and limits alternative applications. Four States-Arkansas, North Carolina, Maine, and Ohio-are currently using biological criteria to define aquatic life use classifications and enforce water quality standards. These states have made biological criteria an integral part of comprehensive water quality programs.
- Arkansas rewrote its aquatic life use classifications for each of the State's ecoregions. This has allowed many cities to design wastewater treatment plants to meet realistic attainable dissolved oxygen conditions as determined by the new criteria.
- North Carolina developed biological criteria to assess impairment to aquatic life uses written as narratives in the State water quality standards. Biological data and criteria are used extensively to identify waters of special concern or those with exceptional water quality. In addition to the High Quality Waters (HQW) and Outstanding Resource Waters (ORW) designations, Nutrient Sensitive Waters (NSW) at risk for eutrophication are assessed using biological criteria. Although specific biological measures are not in the regulations, strengthened use of biological monitoring data to assess water quality is being proposed for incorporation in North Carolina's water quality standards.
- Maine has enacted a revised Water Quality Classification Law specifically designed to facilitate the use of biological assessments. Each of four water classes contains descriptive aquatic life conditions necessary to attain that class. Based on a statewide database of macroinvertebrate samples collected above and below outfalls, Maine is now developing a set of dichotomous keys that serve as the biological criteria. Maine's program is not expected to have a significant role in permitting, but will be used to assess the degree of protection afforded by effluent limitations.
- Ohio has instituted the most extensive use of biological criteria for defining use classifications and assessing water quality. Biological criteria were developed for Ohio rivers and streams using an ecoregional reference site approach. Within each of the State's five ecoregions, criteria for three biological indices (two for fish communities and one for macroinvertebrates) were derived. Ohio successfully uses biological criteria to demonstrate attainment of aquatic life uses and discover previously unknown or unidentified environmental degradation (e.g., twice as many impaired waters were discovered using biological criteria and water chemistry together than were found using chemistry alone). The upgraded use designations based on biological criteria were upheld in Ohio courts and the Ohio EPA successfully proposed their biological criteria for inclusion in the State water quality standards regulations.
States and EPA have learned a great deal about the effectiveness of integrated biological assessments through the development of biological criteria for freshwater streams. This information is particularly valuable in providing guidance on developing biological criteria for other surface water types. As previously discussed, EPA plans to produce supporting technical guidance for biological criteria development in streams and other surface waters. Production of these guidance documents will be contingent on technical progress made on each surface water type by researchers in EPA, States and the academic community.
EPA will also be developing outreach work-shops to provide technical assistance to Regions and States working toward the implementation of biological criteria programs in State water quality management programs. In the interim, States should use the technical guidance currently available in the Technical Support Manual(s): Waterbody Surveys and Assessments for Conducting Use Attainability Analysis (U.S. EPA 1983b, 1984a,b). During the next triennium, State effort will be focused on developing narrative biological criteria. Full implementation and integration of biological criteria will require several years. Using available guidance, States can complement the adoption of narrative criteria by developing implementation plans that include:
- Defining program objectives, developing research protocols, and setting priorities;
- Determining the process for establishing reference conditions, which includes developing a process to evaluate habitat characteristics;
- Establishing biological survey protocols that include justifications for surface water classifications and selected aquatic community components to be evaluated; and
- Developing a formal document describing the research design, quality assurance and quality control protocols, and required training for staff.
Whether a State begins with narrative biological criteria or moves to fully implement numeric criteria, the shift of the water quality program focus from source control to resource management represents a natural progression in the evolution from the technology-based to water quality-based approaches in water quality management. The addition of a biological perspective allows water quality programs to more directly address the objectives of the Clean Water Act and to place their efforts in a context that is more meaningful to the public.
Future
Directions
Biological criteria now focus on resident aquatic communities in surface
waters. They have the potential to expand in scope toward greater ecological
integration. Ecological criteria may encompass the ambient aquatic communities
in surface waters, wildlife species that use the same aquatic resources,
and the aquatic community inhabiting the gravel and sediments underlying
the surface waters and adjacent land (hyporheic zone); specific criteria
may apply to physical habitat. These areas may represent only a few possible
options for biological criteria in the future.
Many wildlife species depend on aquatic resources. If aquatic population levels decrease or if the distribution of species changes, food sources may be sufficiently altered to cause problems for wildlife species using aquatic resources. Habitat degradation that impairs aquatic species will often impact important wildlife habitat as well. These kinds of impairments are likely to be detected using biological criteria as currently formulated. In some cases, however, uptake of contaminants by resident aquatic organisms may not result in altered structure and function of the aquatic community. These impacts may go undetected by biological criteria, but could result in wildlife impairments because of bioaccumulation. Future expansion of biological criteria to include wildlife species that depend on aquatic resources could provide a more integrative ecosystem approach.
Rivers may have a subsurface flood plain extending as far as two kilometers from the river channel. Preliminary mass transport calculations made in the Flathead River basin in Montana indicate that nutrients discharged from this subsurface flood plain may be crucial to biotic productivity in the river channel (Stanford and Ward 1988). This is an unexplored dimension in the ecology of gravel river beds and potentially in other surface waters.
As discussed in Chapter 1, physical integrity is a necessary condition for biological integrity. Establishing the reference condition for biological criteria requires evaluation of habitat. The rapid bioassessment protocol provides a good example of the importance of habitat for interpreting biological assessments (Plafkin et al. 1989). However, it may be useful to more fully integrate habitat characteristics into the regulatory process by establishing criteria based on the necessary physical structure of habitats to support ecological integrity.