You’re sitting in a watershed right now, and you have probably contributed to the Illinois River Watershed and didn’t realize it. To make sure your actions are positive, learn more about the Illinois River Watershed. 

To learn more about the Illinois River Watershed Partnership's History and Mission, Board of Directors, and Sponsors, and to view IRWP Board Meeting Minutes, Illinois River Watershed Map, and IRWP Annual Reports, use the links on the left.

The Basics

Watershed: We all live in a watershed and our individual actions can affect it. It’s the area of land that receives rainfall and stormwater run-off that drains or seeps into a wetland, stream, river, lake or groundwater.

Headwater: The water from which a river rises; a source.

Stakeholders: A stakeholder is anyone who has a share or interest in any or all issues related to the watershed, including residents.

Point Source Pollution (PSP): Pollution that comes directly from a known source.  

Possible Point Source Pollution sources are:

  • Wastewater treatment plants
  • Industry (golf courses, commercial developments, factories)
  • Sewer overflows
  • Contained animal feeding operations
  • The end of a drainage pipe or any other means by which pollutants are discharged

Non-Point Source Pollution (NPSP): Pollution caused by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up and carries away natural and human made pollutants, discharging them into lakes, rivers, wetlands and ground water.

Pollutants include:

  • Excess fertilizer, herbicides and insecticides from agricultural lands and residential areas
  • Oil, grease and toxic chemicals from urban runoff and energy production
  • Sediment from improperly managed construction sites, crop and forest lands and eroding stream banks
  • Bacteria and nutrients from livestock, pet wastes and faulty septic systems
  • Contributing factors include urban non-point source pollution or rural non-point source pollution

The Facts

  • The Illinois River is a valuable natural resource that originates in Arkansas and flows into Oklahoma where it is designated as a Scenic River.
  • The Illinois River Watershed (Hydrologic Unit Area 11110103) covers 1,069,530 acres.
  • The Illinois River Watershed is in western portions of Benton and Washington counties with a very small section in Crawford County in Arkansas.
  • The Illinois River Watershed extends over Adair, Delaware, Cherokee and Sequoyah counties in Oklahoma.
  • The Illinois River Watershed encompasses 1,700 square miles.
  • The Illinois River Watershed has 119 miles of streams.
  • Nearly ¼ million residents live in the Illinois River Watershed.
  • The Illinois River Watershed includes 4 federally protected aquatic species.
  • All of the Illinois River headwater streams flow from Washington and Benton counties.
  • The main tributary streams in the upper basin are Osage Creek, Flint Creek and Clear Creek.

“Little drops of water, little grains of sand, Make the mighty ocean and the pleasant land.

- Julia A. Fletcher Carney