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The Division of Water began monitoring the water quality of Kentucky’s rivers, streams, and reservoirs over 40 years ago. Early monitoring consisted of 45 stations spread across the state.  Since then, the number of monitoring locations has grown considerably, and wetlands monitoring was added in 2010. The Division’s surface water monitoring programs are designed to meet the following federal Clean Water Act and state objectives:

  • Determining if the water quality of the Commonwealth’s rivers, streams, and reservoirs is protective of human health while supporting healthy aquatic communities;
  • Identifying waters that are not meeting water quality standards, and the causes and sources of the water quality impairments;
  • Supporting the development, review, and revision of state water quality standards;
  • Aiding in the development and implementation of water quality management programs;
  • Evaluating the effectiveness of water quality management programs; and
  • Providing data to inform public health advisories for recreation and fish consumption.

Learn more about the Division's surface water monitoring programs below.

Following enactment of the Federal Water Pollution Control Act of 1972 (i.e. the Clean Water Act (CWA)) and subsequent state legislation (e.g. KRS 224.10), the Division established a network of 44 stream stations for long-term monitoring in 1979.  These stations were sampled bimonthly (6 visits per year), with the goals of determining and tracking water quality conditions in larger streams throughout the Commonwealth over time. In 1998, the network was expanded to 72 primary ambient water quality stations and the sampling strategy shifted to a rotating five-year Basin Management Unit (BMU) approach, where extra effort is focused on one BMU during each project year.  While all primary ambient monitoring stations are sampled every project year, they are sampled monthly in BMU study years and bi-monthly in non-BMU project years.  These stations are located at mid- and lower watershed reaches of 8-digit HUC basins.  Stations also occur near the inflow and outflow of major reservoirs.

In addition to the 72 stations of the primary network, the Division established a rotating watershed network in each BMU in 1998.  The 106 rotating stations are situated within smaller sub-watersheds of each BMU.  They are monitored for the same suite of water quality parameters as primary stations.  The objectives of these stations include: 

  1. obtain an overall representation of the quality of each basin’s water resources; 
  2. determine water quality conditions associated with major land cover or land uses such as forest, urban, agriculture and mining; 
  3. characterize each basins’ least impacted waters; 
  4. collect data to assist with establishing total maximum daily loads (TMDLs) as required by Section 303(d) of the Clean Water Act; and 
  5. define water quality conditions in a watershed to answer special issues that may arise requiring long-term water quality monitoring.

The U.S. Environmental Protection Agency (EPA) began sampling the major reservoirs in Kentucky in 1973 as a part of the National Eutrophication Survey. Following enactment of the Clean Water Act in 1972, DOW established a network of lake and reservoir stations from 1981 to 1983.  This network of lakes and reservoirs were initially selected to satisfy a U.S. EPA Cooperative Agreement Award in 1980.  This award was the initial push towards the goal of Section 314(a) that each state shall prepare or establish:

  1. an identification and classification according to trophic conditions of all publicly owned freshwater lakes in the state;
  2. procedures, processes, and methods (including land use requirements) to control sources of pollution to lakes; and
  3. methods and procedures, in conjunction with appropriate Federal agencies, to restore the quality of impaired lakes. By 1984, there were 73 lakes/reservoirs in the state program. (Technically, most of the “lakes” in Kentucky are reservoirs.)

Currently, Kentucky lakes are sampled on a Watershed Management Framework Initiative approach.  A total of 108 lakes that are listed in the Division’s lakes inventory are sampled every five years by basin management unit (BMU).  Beginning in 1998, lakes have been sampled in the following sequential order : 1) Kentucky River; 2) Salt and Licking Rivers; 3) Four Rivers (included the Upper Cumberland, Lower Cumberland, Ohio River, Mississippi River and Tennessee River); 4) Green River and Tradewater River; and 5) Big Sandy River, Little Sandy River and Tygart’s Creek.  Ohio River minor tributary basins adjacent to the major river basins are sampled in the same year as the rest of the basin management unit. This data is primarily used for determining designated use support as defined by Kentucky’s water quality standards regulations.  Designated use support assessments are typically made for aquatic life (i.e. warm water aquatic habitat (WAH) and/or cold water aquatic habitat (CAH)) for each sampled water body.

The Intensive Survey Monitoring Program incorporates data collection activities that support the Success Monitoring Program, the development of Total Maximum Daily Loads (TMDL) or TMDL alternatives for 303(d)-listed impairments and monitoring for other special projects. The data collected by the Intensive Survey Program may be used by other programs within DOW for activities such as water quality standards development or water quality assessments for section 305(b).

Success Monitoring

The initial program of success monitoring in Kentucky began in the early 2000s, but didn’t develop into a defined program for several years. The Division of Water (DOW) nonpoint source program re-introduced success monitoring in 2013 with the onset of the National Water Quality Initiative Program through the Natural Resources Conservation Service.  The Success Monitoring Program was then refined with an intent to track effectiveness of Best Management Practices (BMPs) implemented through the watershed planning process.  Planning success monitoring for individual streams and watersheds was derived partly from the Environmental Protection Agency’s water quality measures, and through DOW’s mission statement.

Water quality improvement success can be demonstrated in a number of ways, but the monitoring will focus primarily on showing change in a designated use category (primary or secondary contact recreation, aquatic life, OSRW, etc.).  Ideally, data gathered from this program will influence decisions on types of BMPs that are most effective, remove streams from the 303(d) list, and allow the Division to demonstrate successful on-the-ground work to state and federal agencies.

TMDL or TMDL Alternative Monitoring

Once a lake, stream segment or other waterbody has been assessed as impaired and placed on the 303(d) a TMDL must be developed. The first step in developing a TMDL is to gather all existing data collected by the Division of Water.  Data generated outside of state government may be requested from the collecting agency if the data were collected under an approved quality assurance project plan (QAPP).  Once existing data have been compiled, it is frequently discovered that additional water quality, biological, bacteriological, and discharge data are necessary to develop TMDLs or to confirm use support.  In these cases, TMDL monitoring projects are initiated.

The Intensive Survey section uses an intensive approach to monitoring watersheds selected for TMDL development.  As a result, watershed monitoring occurs over two or three years.  During the first year of sampling, data collection focuses on confirming the nature of the impairments and possible sources of those impairments.  During the second year, targeted sampling for identified causes within the impaired segment(s) occurs.  The second year also can include data collection in smaller, un-assessed tributaries that were not sampled during the first year of monitoring but may be contributing to the identified impairment.  A third year of monitoring may be warranted if data gaps still exist.

Special Projects

The Intensive Survey Section can apply the intensive approach to monitoring in watersheds for other projects, as needed. Each intensive survey project has a detailed study plan that outlines the geographic boundary of the study, the field activities involved, the types and number of samples required, and the analyses and reports to be generated. Schedules for specific activities and goals for the project are included. The following types of samples or measurements may be collected depending on the specific goals of the intensive survey:

  • Water chemistry concentrations including: nutrients, metals, total dissolved solids, total suspended solids, chloride
  • Water quality multi-parameter meter readings: water temperature, specific conductance, pH, dissolved oxygen
  • Discharge measurements
  • E. coli concentrations
  • Habitat assessments
  • Fish, benthic algae, and macroinvertebrate collection and identification


The Probabilistic Stream Bio-assessment Program, first implemented in 1998, collects data from randomly selected stations across the state for use-support designations and to assess the health of Kentucky’s stream resources. Stations are randomly selected for sampling using a statistically-sound probability-based sampling design. The results from the random sample can then be applied to the entire region with a known level of uncertainty. This allows resources to be used efficiently to obtain valuable station-specific as well as entire study area condition information.

In the original plan, monitoring was conducted using a five-year rotating basin management unit (BMU) approach with all stations selected within a single BMU each year.  In 2017, two major improvements were integrated into the Probabilistic Stream Bio-assessment Program. First, the sampling design was modified from the traditional 5-year rotating BMU approach to a state-wide approach where streams across the entire state are included in the sample frame every year.  This change allows us to collect data from the sample frame from which we are interested in drawing inferences (i.e. stream condition across the entire state), provides consistent sample coverage across this sample frame each year, addresses issues in weather variations from year-to-year better than the BMU rotation, and will also still allow the detailed analyses of individual BMU’s as well. Second, stations representing large non-wadeable rivers, which were previously unsampled, were added to the sample frame over the five-year sample draw.

Currently, the Probabilistic Stream Bio-assessment Program is a statewide aquatic resource monitoring system in which a random sample of potential target streams is selected to assess stream conditions across the state. This approach to assessing stream health is used for numerous reasons:

  • It provides data that can be statistically applied to all statewide waters within the original sample frame in order to assess the condition of Kentucky’s stream resources over time.
  • It is inherently unbiased and provides a representative assessment of statewide stream health.
  • It provides an objective and repeatable method by which use support can be extrapolated to thousands of un-sampled stream miles.


The Reference Reach Program began in 1991, and the initial program goal was to determine a network of least-impacted streams within defined regions of the state.  Reference Reaches are not necessarily pristine streams, but represent streams least impacted by human activities in each region. As such, they can be considered to represent best available conditions and can be used as benchmarks for comparing water quality parameters with other streams in the same region.  Data gathered from the Reference Reach program were used primarily in the past to develop biological indices used for 305(b) assessments of aquatic life use support.

Currently, priorities for Reference Reach Monitoring center on characterizing the natural variability within the reference condition in each region, identifying new reference reach locations, and monitoring the condition of existing reference reaches as identified in 401 KAR 10:030.  A firm understanding of the inherent biological variability and natural potential of the streams in a region is needed to address levels of impact to any given stream. This is accomplished using a regional reference approach, which is based on the range of natural conditions found in a population of stations or streams with similar physical characteristics and minimal human impact. The reference condition collectively refers to the range of quantifiable and naturally occurring ecological elements (i.e., chemistry, habitat and biology) present in an area.

In many regions of Kentucky, finding reference quality streams can be a difficult task because of the prevalence of human disturbance across the landscape. First, staff members identify least-impacted waters representative of geographic regions of the state known as ecoregions. Typical reference reach watersheds contain a high proportion of natural vegetation and have minimal human disturbance such as point-source discharges, agricultural land, mining and urban development. Then, data on chemical water quality, sediment quality, habitat condition and biotic communities are collected to define the quality of the streams of a particular ecoregion, and allow other streams in the same ecoregion to be compared to the reference condition.

​The primary purpose of the Fish Tissue Contaminant Monitoring Program is to inform the public of the potential health risks associated with consuming wild-caught fish in Kentucky.  Secondarily the program provides monitoring support in fulfillment of Federal Clean Water Act requirements.  Samples are collected from many sites across the Commonwealth to determine if fish are safe for human consumption.  Fish samples are collected once every five years from all lakes and reservoirs that are greater than 65 acres and have an publicly accessible boat ramp.  In addition, all water bodies with current advisories are visited once every five years in order to evaluate the advisory.  Streams and rivers are visited as resources are available, generally associated with other Department monitoring programs.

Fish are analyzed for metals (i.e. mercury and selenium), PCBs, chlordane, pesticides and herbicides.  Results are used to determine if there are contaminants in fish tissue and data from this analysis is then provided to the Fish Consumption Advisory Committee so consumption advisories may be issued when warranted.  This committee is comprised of the Kentucky Departments for Environmental Protection, Public Health and Fish and Wildlife Resources. 

The Wetland Monitoring and Assessment Program began in 2010, and the initial program goal was to develop an assessment method for rapidly determining wetland condition to inform permitting decisions. Since then, the program has expanded to include development of indices of biological integrity (IBIs) and evaluation of Kentucky’s Surface Water Criteria for wetlands, which will be used to inform permitting decisions, serve as tools for ambient monitoring and assessment of wetlands, and validate the Kentucky Wetland Rapid Assessment Method (KY-WRAM). Currently, three IBIs are under consideration or development for use in the Wetland Monitoring and Assessment Program. These include IBIs for vegetation (VIBI), avifauna (AIBI), and amphibians (AmphIBI). The VIBI and AIBI methods were completed in December 2017, and completion of the AmphIBI is expected in June 2020. Data collection for IBI development has primarily occurred in riverine wetlands across the Commonwealth. These IBIs are expected to characterize wetland condition for other wetland types; however, further testing will be needed to confirm this.

At present, the primary priorities of the Wetland Monitoring and Assessment Program are to continue building a network of least-impacted wetlands within defined regions of the state.  Reference wetlands are not necessarily pristine, but represent wetlands that are least impacted by human activities in each region. As such, they can be considered to represent best available conditions and can be used as benchmarks for comparing water quality parameters with other wetlands in the same region. Data gathered will be used primarily to continue development and/or evaluation of biological indices and evaluate Surface Water Criteria used for 305(b) assessments of aquatic life use support. In addition, these studies will allow for characterization of natural variability within the reference condition in each region, identifying new reference wetland locations, and monitoring the condition of existing reference wetlands as identified in 401 KAR 10:030.  A firm understanding of the inherent biological variability and natural potential of the wetlands in a region is needed to address levels of impact to any given wetland. This is accomplished using a regional reference approach, which is based on the range of natural conditions found in a population of stations or wetlands with similar physical characteristics and minimal human impact. The reference condition collectively refers to the range of quantifiable and naturally occurring ecological elements (i.e., chemistry, habitat, and biology) present in an area.

In addition, a significant priority of the Wetland Monitoring and Assessment Program is to collaborate with federal and state agencies, as well as private entities, to adopt the wetland assessment tools that have been developed. Through these collaborations we strive to improve the regulatory decision-making process, and to support voluntary restoration and protection of wetland habitat. Currently, we are working with the US Army Corps of Engineers to adopt the KY-WRAM for pre- wetland impact permitting decisions, and to identify mitigation wetland sites for preservation. If adopted, the DOW will provide training for the KY-WRAM to regulators and the regulated community by 2020.


Other helpful links:

 Wetland Program Plan [PDF, 990 KB]

Wetland Story Map


Permits for Wetland Fill or Alterantion

National Wetland Condition Assessments