Air Quality
Ozone Alert! Program
Water Quality
  The Role of INCOG
  Regional Water Quality
  Pollution and Impairment
  Total Maximum Daily Loads (TMDLs)
  Resources and Links
Green Country
Stormwater Alliance
Energy Programs
Tulsa Area Clean Cities
Hazard Mitigation Planning
Metropolitan Environmental Trust (M.e.t.)





There are many reasons why we Oklahomans treasure our excellent water resources: fishing, swimming, boating, water skiing, industrial and agricultural uses, hydropower, wildlife habitat, and high quality drinking water to name a few. Oklahoma water quality standards protect the various uses of our water resources. These “Beneficial Uses” are defined in the Oklahoma Water Quality Standards. Each beneficial use has its own standard for protection.

Some waterbodies in Oklahoma deserve a higher level of protection. These include Outstanding Resource Waters (ORW) (e.g., all of the Oklahoma Scenic Rivers), High Quality Waters (HQW), specially designated waterbodies listed in Appendix B of the Oklahoma Water Quality Standards, Sensitive Water Supplies (SWS), and Culturally Significant Waters (CSW). For more information on the state’s water quality standards, visit the Oklahoma Water Resources Board (OWRB) website.

Every two years, the State of Oklahoma submits a biennial report to Congress and the EPA on the condition of Oklahoma’s streams and lakes. The Oklahoma Department of Environmental Quality (DEQ) report, called the “Oklahoma Integrated Water Quality Assessment Report”, lists the water quality status for many of the waterbodies in Oklahoma, including impairment status. DEQ is the primary water quality regulatory and permitting authority for Oklahoma, and they work closely with the Oklahoma Water Resources Board (OWRB) and the Oklahoma Conservation Commission (OCC).

The Role of INCOG

In October 1972, Congress passed Senate Bill S. 2770 putting into law the Clean Water Act amendments of 1972. In passing this law, Congress established the national goal that, “…wherever attainable, an interim goal of water quality which provides for the protection and propagation of fish, shellfish, and wildlife, and provides for recreation in and on the water be achieved by 1 July 1983.” This statement is often referred to as the “fishable/swimmable goal” of the Clean Water Act.

The 1972 law authorized formation of planning areas in each state for the purpose of ensuring attainment of Clean Water Act goals. On September 17, 1974, Governor David Hall designated INCOG as the water quality management planning agency for Creek, Osage, Tulsa, and parts of Rogers and Wagoner Counties.

Beginning in the 1970s to the present, INCOG has managed numerous EPA grant-funded projects to collect environmental and water quality data to support the state’s 208 Water Quality Management Plan. These studies have assessed the existing water quality of area streams, employed computer modeling to calculate point source wastewater treatment plant load limits for discharge permits, and supported state agency decisions on waterbody impairment status.

Within the past 15 years, INCOG has established additional programs to address the growing problem of stormwater pollution from urban sources. INCOG’s Green Country Stormwater Alliance (GCSA) brings together many of the stormwater permitted cities and counties in Oklahoma and provides a wide range of technical support, public outreach and employee training to support stormwater permittees and programs.

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Regional Water Quality Programs
In 1990, EPA finalized regulations requiring stormwater discharge permits for many types of “industrial activities” and for cities over 100,000 population. In 1999, EPA passed “Phase II stormwater regulations” requiring stormwater discharge permits for many smaller cities and some counties in Oklahoma. The purpose of these discharge permit programs is to control pollutants in stormwater runoff from urbanized areas, still considered to be a major source of water quality pollution.

To help its municipal membership, INCOG created the Green Country Stormwater Alliance (GCSA), a coalition of many of the state’s stormwater permitted cities and counties.

Formerly grant-supported, GCSA is now sustained by annual dues. INCOG provides employee education and training, research of technical and legal issues facing permittees, prepares document templates and guidance, and provides local assistance to staff and elected officials on the complexities of the permit program.

For more information about GCSA or membership, contact

INCOG continues to participate in many state work groups and committees which address 303(d) impairments, Total Maximum Daily Load (TMDL) strategies, water quality standards, wetlands and groundwater issues, nonpoint source pollution, wasteload allocations for point source dischargers, and development of nutrient criteria.

INCOG also sits on committees and participates in work groups addressing the water quality aspect of local economic development initiatives and participates in regional water planning activities.

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Pollution and Impairment
The Oklahoma Department of Environmental Quality (DEQ) must report to EPA every two years all updates on the water quality status of all Oklahoma waters. DEQ’s biennial “Oklahoma Integrated Water Quality Assessment Report” includes the 303(d) List of impaired waterbodies. Most waterbodies on the 303(d) List will eventually have a special type of pollutant load study prepared called a Total Maximum Daily Load (TMDL), or alternatively, a Watershed Plan will be prepared in lieu of a TMDL.

In years past, most load studies focused on point sources, and most of these dealt with oxygen-demanding substances. However, TMDLs have expanded to include pollutants associated with non-point sources, such as turbidity, pesticides, nutrients and bacteria. The DEQ Water Quality Division Programs website provides a great deal of information about the state’s water quality and regulatory programs intended to assess and improve our natural resources.

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Total Maximum Daily Loads (TMDLs)
Point Source vs. Nonpoint Source
In the past 10 years, wasteload allocation studies have become more complex by adding nonpoint source load assessments. Nonpoint sources are different from the discrete single pipe discharges of point sources that come from a treatment facility. Nonpoint sources have no discrete discharge pipe, and they are from pollutant sources that do not undergo any type of waste treatment. Nonpoint sources are usually associated with rainfall runoff, so under dry conditions, nonpoint sources are usually minimal or non-existent.

Characterizing and calculating nonpoint source loads is very difficult, and the scientific investigations and modeling of nonpoint sources is still actively evolving. Also, most nonpoint sources do not have permit limits and are not regulated. Exceptions are discharges from Concentrated Animal Feeding Operations (CAFOs) and stormwater discharges from designated Phase I and II municipal stormwater systems, both of which are regulated as point sources in TMDLs.

A study that incorporates point source wasteloads, nonpoint source loads and includes a margin of safety calculation is called a Total Maximum Daily Load (TMDL). TMDLs set daily maximum limits on all point source and nonpoint source load discharges. A TMDL can address bacteria, dissolved oxygen, turbidity, metals, pesticides or any other type of pollutant. Hundreds of TMDLs have been prepared across Oklahoma for bacteria, turbidity, dissolved solids, dissolved oxygen and nutrients.

Identifying and calculating nonpoint source loads is very difficult, and the scientific investigations and modeling of nonpoint sources are still evolving. Also, most nonpoint sources do not have pollutant discharge permits and are therefore not regulated. Exceptions are discharges from Concentrated Animal Feeding Operations (CAFOs) and stormwater discharges from permitted municipal stormwater systems, both of which are included as point sources in TMDLs with mandatory TMDL compliance obligations.

Treatment plants must meet numerical effluent limits. Their discharge permits have mandatory compliance requirements with penalty provisions for failure to comply. Stormwater permitted cities and counties within TMDL watersheds must implement Best Management Practices (BMPs) to control pollution in runoff when called upon by DEQ or EPA.

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Resources and Links
INCOG’s Green Country Stormwater Alliance (GCSA) Internet Resources website maintains a comprehensive list of resource links on water quality, including links to state and federal agencies and water quality programs in Oklahoma. Also, contact INCOG at for more information about water quality programs within the INCOG area and State of Oklahoma.

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For more information, contact:
Vernon Seaman
Environmental and Energy Planning Manager