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Statewide Biological and Water Quality Monitoring and Assessment

Ohio is a water-rich state, bounded on the south by the Ohio River and the north by Lake Erie. These water bodies, as well as thousands of miles of inland streams and rivers and thousands of acres of lakes and wetlands, contribute to the quality of life of Ohio's citizens. Ohio EPA's Division of Surface Water supports a diverse set of programs that monitor inland lakes, Lake Erie, primary headwater streams, and wetlands, in addition to its comprehensive watershed studies.

Each year, Ohio EPA collects data from 400 to 450 stream and river sites around the state to support watershed assessment. During these studies, Ohio EPA scientists collect chemical samples, examine and count fish and aquatic insects, and take measurements of the stream. There are three major objectives for the studies:

  • To determine how the stream is doing compared to goals assigned in the Ohio Water Quality Standards (WQS);
  • To determine if the goals assigned to the river or stream are appropriate and attainable; and
  • To determine if the streams condition has changed since the last time the stream was studied.

The data gathered by a field survey is processed, evaluated and synthesized in a biological and water quality report. The findings and conclusions of each biological and water quality study may factor into regulatory actions taken by Ohio EPA and are incorporated into Water Quality Permit Support Documents (WQPSDs), total maximum daily loads (TMDLs), State Water Quality Management Plans, the Ohio Nonpoint Source Assessment and the Ohio Water Resource Inventory (305[b] report). This information also provides the basis for the list of impaired and threatened waters required by Section 303(d) of the Clean Water Act.

Watershed Surveys

Watershed Survey Background

In 1990, Ohio EPA initiated an organized, sequential approach to monitoring and assessment. One of the principal objectives of this approach was to better coordinate the collection of ambient stream and river monitoring data so that information and reports were available in time to support water quality management activities such as the reissuance of wastewater discharge (NPDES) permits, development of watershed Total Maximum Daily Load (TMDL) documents, and periodic revision of the Ohio Water Quality Standards (WQS).

Further refinement of the monitoring approach occurred in the early 2000s in response to Ohio EPA's decision to embark on a progressive watershed-based monitoring, assessment, and reporting approach to facilitate the collection of data to support development of TMDLs. To this end, Ohio EPA adopted as basic watershed assessment units the U.S. Geological Survey 11-digit Hydrologic Unit (HUC-11), eventually transitioning to HUC-12s during the 2008 survey year. Beginning with the 2010 Integrated Water Quality Monitoring and Assessment Report, 1,538 HUC-12 watershed assessment units (WAUs) became the primary reporting unit for watershed survey monitoring and assessment, as well as TMDL development and implementation.

The HUC-12 WAU scale is used to categorize and assess stream and river sites draining watersheds up to 500 square miles. For Ohio's largest rivers—greater than 500 square miles—large river assessment units (LRAUs) were developed to report independently on these large water bodies, since they are unique in their importance and cannot be readily included and effectively assessed in small HUC-12 watersheds. At this size, rivers generally are impacted more by the character of and activity in the accumulated drainage area and less by what is happening adjacent to the channel (i.e., on the stream bank) or in the immediate adjacent landscape. Currently, 45 LRAUs have been established for the 30 largest rivers in Ohio.

Environmental Indicators

Ohio EPA's approach to surface water monitoring and management essentially serves as an environmental feedback process taking "cues" from environmental indicators to effect needed changes or adjustments within water quality management. This hierarchy is essentially in place within the technical support document (TSD) process and represents, from a technical assessment and indicators framework standpoint, a watershed approach. The environmental indicators used in this process are categorized as stressor, exposure, and response indicators.

  • Stressor indicators generally include activities that impact but may or may not degrade the environment. This includes point and nonpoint source loadings, land use changes and other broad-scale influences that generally result from anthropogenic activities.
  • Exposure indicators include chemical-specific, whole effluent toxicity, tissue residues and biomarkers, each of which suggest or provide evidence of biological exposure to stressor agents.
  • Response indicators include the direct measures of the status of use designations. For aquatic life uses, the community and population response parameters that are represented by the biological indices that comprise Ohio EPA’s biological criteria are the principal response indicators. For human body contact uses (e.g., primary contact recreation), fecal bacteria (e.g., E. coli) are the principal response indicators.

The key to having a successful watershed approach is in using the different types of indicators within the roles that are the most appropriate for each.

Monitoring for Status and Trends

An assessment of the impact of multiple sources on the receiving waters of a watershed includes an evaluation of the available chemical/physical (water column, effluent, sediment, flows), biological (fish and macroinvertebrate assemblages), and habitat data that have been collected by Ohio EPA. Other data evaluated includes, but is not limited to, NPDES permittee self-monitoring data, effluent and mixing zone bioassays conducted by Ohio EPA, the permittee, or U.S. EPA, spills data compiled by Ohio EPA, and fish kill information from the Ohio Division of Wildlife.

The integration of this information into a report for each study area is accomplished via the TSD process. Besides reporting on status and trends for the applicable designated uses, the TSD also identifies and describes causal associations of use impairments with the predominant causes and sources of impairment. The completion of this process enables the structured use of the output from the TSD (i.e., the assessment of water bodies) to support virtually any Ohio EPA program where surface water quality is a concern.

Resources and Guidance

Study Plans

2022

Routine Monitoring

2021

Special Monitoring Projects

In addition, we will be monitoring the following waters for special projects. Click on the links to view the study plans.

Special Monitoring Projects

2020

Routine Monitoring

Special Monitoring Projects

2019

Routine Monitoring

Special Monitoring Projects

2018

Routine Monitoring

Special Monitoring Projects

2017

Routine Monitoring

Ohio's long-term monitoring schedule is revisited every two years in the Integrated Report process.  See the Integrated Report page for more information.

Special Monitoring Projects

2016

Routine Monitoring

Ohio's long-term monitoring schedule is revisited every two years in the Integrated Report process.  See the Integrated Report page for more information.

Special Monitoring Projects

2015

Routine Monitoring  

Ohio's long-term monitoring schedule is revisited every two years in the Integrated Report process.  See the Integrated Report page  for more information.

Special Monitoring Projects

2014

Routine Monitoring

Ohio's long-term monitoring schedule is revisited every two years in the Integrated Report process.  See the Integrated Report page  for more information.

Special Monitoring Projects

2013

Routine Monitoring

Special Monitoring Projects