Save the Illinois River Inc. recently asked for and received a copy of a letter from the U.S. Environmental Protection Agency asking Oklahoma and Arkansas to cooperate in development of a water quality model for the Illinois River watershed.

The study will be conducted by EPA Region 6, and may finally result in development of one or more Total Maximum Daily Loads for the watershed.

According to Ed Brocksmith of STIR, TMDLs for impaired waters are required under the Federal Clean Water Act, but neither state has ever adopted a TMDL. Oklahoma reportedly made attempts at a TMDL for the Illinois River but was not satisfied with the product.

“Save the Illinois River members sued the EPA several years ago over its failure to insure that a TMDL was adopted for the Illinois River,” said Brocksmith. “However, unlike successful lawsuits in other states, the lawsuit was dismissed.”

Arkansas has refused to list the Illinois River as impaired by nutrients and bacteria, but the EPA added the Illinois River to Arkansas’ report on impaired waters. Oklahoma has established an instream phosphorus limit of .037 parts per million for the basin, effective in 2012. Oklahoma lists the Illinois River as impaired by phosphorus and bacteria. The U.S. Supreme Court has ruled that Arkansas must meet Oklahoma’s water quality standards.

“Since Arkansas has no phosphorus standard for the Illinois River in Arkansas, it rationalizes that the river is not polluted by the nutrient,” said Brocksmith. “Currently, there is a raging dispute over the phosphorus discharge limit for wastewater treatment plants in the Illinois River watershed.”

A new source of treated sewage is the Northwest Arkansas Conservation Authority’s Regional Wastewater Treatment Plant serving Bentonville, Ark., and several small communities. The EPA has required the facility to discharge no more that .1 parts per million effective in June 2012.

In the meantime, the facility can discharge at 1 part per million phosphorus according to a permit issued by the Arkansas Department of Environmental Quality.

According to Brocksmith, mayors of northwest Arkansas cities are alarmed at the .1 phosphorus limit, and are lobbying Congress and the EPA in Washington not to enforce the lower limit. Oklahoma is considering a challenge to the ADEQ permit for NACA’s regional facility which is now under construction.

According to a letter from Miguel I. Flores, acting deputy regional administrator for the EPA Region 6, the agency will take the lead in developing a TMDL for the Illinois Basin.

“We encourage active participation by both Oklahoma and Arkansas,” wrote Flores.

“Along with the modeling work we are now initiating, other factors may influence future TMDL decisions for the basin. Such factors include any resolution of ongoing litigation regarding activities which impact water quality in the basin and Oklahoma’s re-evaluation of the phosphorus criterion for scenic rivers.”