Illinois River timeline
1970: Oklahoma designates the Illinois River a scenic waterway (among others) as part of the 1970 Oklahoma Scenic Rivers Act.
1988: Environmental Protection Agency permits Fayetteville, Arkansas, to dump treated wastewater into a tributary of the Illinois River; Oklahoma sues.
1992: U.S. Supreme Court rules Arkansas may dump treated sewage into the Illinois River watershed, but that it must meet Oklahoma water quality standards.
1993: Oklahoma begins gathering data on phosphorous and other pollutants in the Illinois River.
1996: State of Oklahoma issues report detailing high levels of contaminants in Lake Tenkiller.
2003: Arkansas and Oklahoma agree to work together to reduce pollution in the Illinois River watershed.
2004: Poultry companies submit plan to reduce chicken litter application in Oklahoma river watersheds. Oklahoma Attorney General Drew Edmondson calls the plan “lacking.”
2005: Edmondson files a federal lawsuit against 14 poultry companies, accusing them of polluting the Illinois River watershed with chicken litter and seeking damages.
2007: Citing data obtained through water and soil samples, the state seeks preliminary injunction banning the use of poultry litter in the Illinois River watershed.
September 2008: Judge rejects state’s request for a preliminary injunction to prevent land application of poultry waste.
October 2008: Poultry industry seeks to have case dismissed because Cherokee Nation has water rights in the watershed.
July 2009: Judge rules that state can’t seek millions in damages because it failed to properly include the Cherokee Nation, which claims water rights in the watershed.
September 2009: Federal trial begins in Judge Gregory Frizzell’s courtroom.
2010: Final arguments in chicken poultry case. After more than eight years, no decision has been rendered.
2013: Oklahoma and Arkansas announce a joint three-year study of water quality in the Illinois River watershed as a continuance of the 2003 agreement as a “Second Statement of Joint Principals and Actions.” The Scenic Rivers Joint Study Committee, with three members each from Arkansas and Oklahoma, is established.
2015: Environmental Protection Agency makes available for comment a proposed Illinois River Watershed Modeling Program.
2016: The Joint Principals agreement yields the Oklahoma-Arkansas Scenic Rivers Joint Phosphorus Study, which is adopted by the Scenic River Joint Study, affirming a scientific basis for standards sought by Oklahoma since 2003.
April 2018: The EPA approves working models for the Illinois River watershed based on the Oklahoma-Arkansas Scenic Rivers Joint Phosphorus Study. State agencies begin meeting to discuss how to implement the models.
November 2018: Oklahoma and Arkansas announce completion of a Memorandum of Agreement to “chart a path forward” in joint agreement on a .037 ppm water quality standard at the state line overseen by an Illinois River Watershed Steering Committee with state secretaries or directors, EPA and Cherokee Nation represented and overseeing implementation of the agreement.
Sept. 8, 2020: Limited by the coronavirus pandemic, the Oklahoma Water Resources Board commences Zoom webinars in place of public meetings to introduce the idea of “critical flow,” a new water quality standard criteria to monitor the .037 ppm standard as ordered under the 2016 Joint Principals Agreement.