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Bioassessment and Biocriteria Program Status for Florida: Streams and Wadeable Rivers

State Program Contact

Florida Department of Environmental Protection Exit

Water Quality Standards

WQS Information
The link to Florida's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
The state of Florida provided information and links to sections of their administrative code on designated aquatic life use, biological criteria, antidegradation as well as technical support documents and information on its bioassessment and biocriteria programs. These are included for your convenience and may or may not reflect the most recently EPA approved WQS. The following links exit the site Exit

Chapter 62-302, Florida Administrative Code, is the primary source for WQS in Florida. WQS impairments are addressed in Chapter 62-303, F.A.C. There are also some WQS provisions located in Rules 62-4.242, 62-4.243, 62-4.244, and 62-4.246, F.A.C.

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Designated Aquatic Life Uses
The default surface water classification is Class III with a designated use of “Fish Consumption; Recreation, Propagation and Maintenance of a Healthy, Well-Balanced Population of Fish and Wildlife.”  The “higher” classes (Class I or II) also include the aquatic life use (“propagation and maintenance…”).  There is also a sub-classification of Class III waters (Class III-Limited) that have a designated use of “Fish Consumption; Recreation or Limited Recreation; and/or Propagation and Maintenance of a Limited Population of Fish and Wildlife,” however there are currently no waters in this sub-classification. 

Biological Criteria
__X__ Narrative statement
__X__ Numeric
_____ No criteria

Narrative criteria
Rules 62-302.500 and 62-302.530(47)(b) F.A.C.
62-302.530(47)(b), “In no case shall nutrient concentrations of a body of water be altered so as to cause an imbalance in natural populations of aquatic flora or fauna.”
62-302.500, “free from” minimum criteria which state that all surface waters should be free from acute toxicity (to aquatic life).

Numeric biocriteria are contained in Florida’s water quality standards table, Chapter 62-302.530(10) and 62-302.531. They are also in Florida’s water quality assessment rule, Chapter 62-303, F.A.C

Antidegradation Policy
Rule 62-302.300 F.A.C. contains most of Florida’s antidegradation policies, including implementation of numeric nutrient standards (which, in turn, uses biological health assessment methods).

Antidegradation is primarily implemented during permitting of discharges to surface waters, and any lowering of water quality related to water quality criteria, including the biocriteria, due to a new or expanded discharges would have to meet antidegradation requirements, including a demonstration the degradation is in the public interest.

Biological Assessment

What biological assemblages are used in the bioassessment program?
Benthic macroinvertebrates, periphyton, and aquatic vegetation (including submersed)

Are bioassessments used to support 303(d) listings?
Yes. Listing methodology: The specific IWR rule sections include 62-303.330 and 62-303.430 for biological assessments, and 62-303.350 and 62-303.450 for nutrient impairments for streams, which incorporates bioassessment information.

How are assemblages used to make impairment decisions?
Benthic macroinvertebrate and lake vegetation communities can be found to be impaired under rule 62-303.430, F.A.C. The Implementation of Florida’s Numeric Nutrient Standards describes the application of the benthic macroinvertebrate, periphyton, and plant methods in the numeric nutrient standard for streams, which are applied independently.

Other uses of biocriteria or bioassessment within the water quality program:
Refining ALU, 305(b) surface water condition assessments, non-point source assessment, BMP evaluation, and restoration goals

Technical Support Information and Documents:

Reference condition:
Reference streams and lakes have been used for bioassessment development and nutrient criteria development, and the definitions of reference varied slightly among those purposes.  

Technical reference material:
Bioassessment Reports
Florida’s Technical Support Document for the freshwater NNC is available upon requests from the Florida Department of Environment Protection's Water Quality Standards Program.

Development of biocriteria involves the collection and interpretation of biological data –e.g. benthic macroinvertebrates, fish, and periphyton. During this process entities typically use biological metrics (usually aggregated into a multimetric index) and/or multivariate analysis to assess whether a waterbody is meeting its designated aquatic life use(s). The reference materials include standard operation procedures used in data collection, compilation, technical approaches used to develop biocriteria as well as its implementation procedures.

Technical reference material:
Bioassessment Reports
Florida's Bioassessment Program
Standard Operating Procedures
Surface Water Quality Standards
Surface Water Quality Support Documents

Stressor identification/causal analysis approach:
FDEP is currently drafting internal guidance for the review of bioassessment data to ensure adherence to SOPs and to determine cause of biological impairments (Stressor ID).

  1. A review of bioassessment data is completed to verify that they were collected in accordance with FDEP standard operating procedures (SOPs).  Variance from SOPs may include collection by unqualified staff, inappropriate sampling or subsampling, insufficient taxonomic level identifications, insufficient documentation, or inappropriate site selection (e.g., unrepresentative of water body, or tidal influence at a freshwater site), and can result in the exclusion of data from the assessment. 
  2. FDEP staff perform an evaluation of the potential causes contributing to the biological impairment. FDEP’s listing requirements for impaired waters include the identification of a causative pollutant(s), such as nutrients or BOD. Different biological communities are susceptible to different stressors, including water quality, habitat, and hydrology components. Ancillary habitat assessment, flow, and water quality data are evaluated to determine which stressor(s) were likely responsible for the impairments. If any water quality standards are exceeded in the waterbody, those are evaluated to determine if they could have led to biological impairment.
  3. For the Stream Condition Index (SCI) of stream macroinvertebrate health, FDEP uses a stressor identification model developed 2012-2013 as one tool to estimate relative importance of various water quality and habitat stressors at a given site. Two fully calibrated and validated models are available, and they contain slightly different variables, as follows: Riparian Buffer Width Model includes (factors in order of decreasing influence on SCI scores) Specific conductance  >> substrate diversity, DO > water velocity > excess TKN > riparian buffer width > excess temperature; Artificial Channelization Model includes Specific conductance  >> DO, substrate diversity > water velocity > excess TKN > artificial channelization > excess temperature. It is important to note the effects embodied in each coefficient are an average applicable to the expected response of the population. As a result, there may be some deviations in the response of a given site to a variable effect.  Thus, for sites which are impaired, examining the predicted effect of changing a particular site variable (e.g., excess TKN) on SCI can provide insight on whether such changes on average can lead to an effective mitigation strategy.

If habitat or hydrologic factors were the likely cause of impairment, then a water quality pollutant cannot be identified. If the likely causal factors of the biological impairment are identified to be nutrients or BOD (or other pollutant), then the waterbody can be listed as verified impaired and is scheduled for a Total Maximum Daily Load.

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