Ohio State University Extension Bulletin

Nonpoint Source Assessment: User's Guide to Ohio's Surface Waters

Bulletin 873-98


The livelihood and health of Ohio's citizens is strongly connected to the abundance and quality of Ohio's water resources. Ohio's water resources include more than 29,000 miles of named and designated rivers and streams, a 451-mile border on the Ohio River, more than 188,000 acres among more than 450 lakes, ponds, and reservoirs (118,000 acres publicly owned), and more than 230 miles of Lake Erie shoreline. These resources are critical not only for drinking water, but also for much of the state's industry. Our ability to conserve and restore water resource integrity improves as we gain a better understanding of the environmental impacts of our actions. Over the last two decades, the most obvious point sources (PS) of pollution have been addressed, and now management efforts at the local, state and federal levels are addressing water quality concerns with a broader perspective that includes nonpoint sources (NPS) of pollution.

Ohio's Nonpoint Source Pollution Management Program includes a comprehensive water quality assessment of the nature and extent of NPS water pollution problems, as well as sources and causes of problems. This User's Guide was designed to help the reader identify a water resource of interest, whether stream, lake or ground water area, and obtain NPS monitoring and assessment information.

The assessment process involves assembling information received from over 200 local, county, state, federal, and regional agencies, including soil and water conservation districts, health departments and boards, municipalities and universities. The complexity of the information received varies from detailed site-specific chemical and biological monitoring conducted by the Ohio Environmental Protection Agency (Ohio EPA) and others, to field observation and best professional judgment.

The assessment places nonpoint source affected waters into four "classes":

  1. waters impaired by NPS pollution(not meeting established water quality standards);
  2. waters where an adverse water quality impact linked to NPS pollution is suspected;
  3. high quality waters (meeting established water quality standards); and
  4. waters with insufficient information to assess.

The first Ohio Nonpoint Source Assessment was prepared in 1988 as a single document detailing the entire state. The Assessment document was updated in 1990 with new information and reformatted to include a state overview volume, as well as five stand alone regional volumes. Records for individual water bodies have been updated as new information becomes available. While no formal assessment report has been produced since 1990, reports with updated information have been developed and distributed on an as-needed basis.

The NPS assessment is a database and planning tool that helps to both identify monitoring needs and direct NPS implementation projects. A primary use of the assessment is for identifying watersheds with the most critical need for pollution abatement funding. Assessment results should be helpful to any watershed resident seeking information, but particularly to NPS pollution program personnel, conservation and citizen groups, environmental planners and watershed management teams.

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