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

State Program Contact

Kentucky Division of Water Exit

Water Quality Standards

WQS Information
The link to Kentucky's WQS that are in effect for Clean Water Act purposes is provided. These are the WQS approved by EPA.
The state of Kentucky 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

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Designated Aquatic Life Uses
WAH, CAH and OSRW (outstanding state resource water)

WAH (warm water aquatic habitat) is the default DU (designated use) in the Commonwealth. WQS have been developed and adopted to protect both WAH and CAH (cold water aquatic habitat) for all surface waters. Chemical water quality criteria and flow are in-place to protect the chemical and hydrological integrity of each; additionally, biological community (macroinvertebrates and fishes) thresholds are utilized in wadeable and headwater streams for evaluation and assessment.

Biological Criteria
__X__ Narrative, with quantitative implementation procedures or translators
_____ Numeric
_____ No criteria

Antidegradation Policy
The Commonwealth’s Antidegradation policy is adopted into WQS. This policy is implemented through a tiered waterbody system and each tier is primarily dependent on biological and chemical integrity of the surface water (i.e. assessment or survey results). Tier 3 waters can have nothing more than a temporary lowering of water quality that does not have a measurable impact on the designated uses. Tier 2.75 water bodies cannot be lowered to a point the OSRW designated use is not supported.  Tier 2.5 water bodies (Exceptional/Reference Reach) and Tier 2,high quality surface waters, can only be lowered via demonstration implemented in 401 KAR 10:030 Section 1(3)(b). Tier 1 surface waters are protected at the minimum by applicable designated use WQS.

Biological Assessment

What biological assemblages are used in the bioassessment program?
Benthic macroinvertebrates and fish

Are bioassessments used to support 303(d) listings?
Yes. Listing methodology: Standard Operating Procedures

How are assemblages used to make impairment decisions?
All monitoring programs that collect biological community data (fishes or macroinvertebrates) additionally collect in-stream habitat and water quality data (most conventional parameters and many nonpriority parameters) at time of the biosurvey. When only one biological community is sampled, preference is given to macroinvertebrates as the single most reliable biological community indicator of good in-stream habitat and water quality conditions. If conflicting results occur between the two biocommunities, macroinvertebrates will be given preference, but this is contingent on evaluation of water chemistry results and how those results may indicate stress or potential degradation of biological community structure and integrity.

The algae (diatoms) community may be sampled for supplemental or supporting data to increase the rigor and confidence of assessment decision and cause identification, but the index for this community is not developed and tested for independent determination of water quality conditions for use assessment.

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

Technical Support Information and Documents:

Reference condition:
Both the fish and macroinvertebrate multimetric indices were developed by a regional reference reach approach.  These locations were both foundational to identifying responsive metrics for given bioregions, and themselves represent bioregional expectations for least impacted surface waters. The criteria for metric development and stream characteristic qualities are discussed in the Index Calculation Documents. A list of Reference Reach surface waters are promulgated into WQS – Antidegradation policy (Table 2).

Technical reference material:
Index Calculation Documents

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 included below include standard operation procedures used in data collection, compilation, technical approaches used to develop biocriteria as well as its implementation procedures.

Technical reference material:
Division of Water Standard Operating Procedures
This website provides access to SOPs (standard operating procedures) to assist in interpreting narrative criteria such as habitat integrity. The CALM (Consolidated Assessment and Listing Methodology) discusses the procedures of implementation and interpretation of narrative criteria. The multimetric numeric indices development documents, technical information, and tools to calculate numeric thresholds for fish and macroinvertebrate (primarily aquatic insects) communities, are available on the same webpage. Note, that these criteria are not adopted into WQS 401 KAR 10:031, but are adopted by reference into the Antidegradation policy in 401 KAR 10:030 (PDF) (25 pp, 359 K).

Stressor identification/causal analysis approach:
Stressor analysis is an element of each individual index that represents, for example, the MBI. When a community structure indicates stress, each index may be examined for confirmation of suspected pollutant stressor/s. These likely stressors may be observed in chemical or habitat data results, or combined with cause-relationship responses for water quality impairment. For example, nutrient related stresses may be observed in the chemical dataset by pollutant magnitude, pH and dissolved oxygen diurnal swings. These stressors are paired with biological information, such as the mHBI (modified Hilsenhoff Biotic Index), percent chironomids (midges) + oligochaetes (aquatic worms), and then individual taxa or taxa groups are looked at more closely for linkage of the stressor to the causes (pollutants). This example would then be incorporated into the 402 (surface water permitting) program. If a stream was listed as impaired for nutrients/eutrophication, or a positive reasonable potential analysis was identified, a facility permit would get a limit for nutrients (total phosphorus) discharge and additional monitoring.

Taking measurements of quality indicators for multiple media data (water column, habitat quality, biological community) are necessary for aquatic life designated use assessment, and essential to linking stressors with causes (pollutants).  The strength of implementing biomonitoring and criteria with water quality monitoring is foundational toward understanding not just the causes, but to address the stresses to the habitat.

Technical reference material:
Division of Water: refer to the CALM and the macroinvertebrate and fish (KIBI) index documents

Wastewater Discharge: The dovetail of 304(a), 305(b), 303(d) and 402 is both implied and certain elements explicit in K(N)PDES procedures and each facility permit (e.g. reasonable potential).

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