TAHLEQUAH — State and federal agencies in both Oklahoma and Arkansas are moving closer to reducing phosphorus and other nutrient levels in the Illinois River watershed, according to officials.

Representatives from the U.S. Environmental Protection Agency’s Region 6 Water Quality Division presented information about the data they’ve collected since beginning the development of a water quality model for the watershed during a public meeting  Thursday night.

In 2009, the EPA asked both Arkansas and Oklahoma to cooperate in developing the  model to reduce the Total Maximum Daily Loads of nutrients in the watershed, resulting in the adoption of the project that began last January.

Throughout 2010 the EPA hosted a number of public meetings and issued a call for scientific data relating to all factors affecting water quality in the both the Illinois River and Lake Tenkiller.

According to Miguel Flores, director of EPA’s Region 6 Water Quality Division, developing a comprehensive plan for the watershed is a complex undertaking.

“What is key is public participation, so we can take advantage of everyone’s input on how to reduce nutrient load levels,” said Flores. “A holistic approach is needed, and we need to look at all nutrients running through the watershed to arrive at the best solution. We’ve been at this for about a year, and lots of you have submitted data. About the time we think we’re through, we get more.”

Flores said Northwest Arkansas municipalities have invested both time and money nutrient reduction by incorporating green infrastructure to reduce natural runoff, and similar steps have been taken on the Oklahoma side of the watershed.

EPA representative Randall Rush said both states have developed two separate plans with common goals and objectives.

“The goal is restore water quality for all parameters, not just phosphorus,” said Rush.

The objectives of the project are to collect and analyze data submitted by state agencies, universities, stakeholders and others and develop specific strategies for reducing pollutants in the designated areas.

“Hopefully, our modeling efforts will identify sources of nutrients in the watershed and quantify the reduction needed to bring both states within safe limits,” said Quan Nguyen, work assignment manager for the EPA.

Some attending the meeting are concerned the EPA will set several sets of limits for TMDLs for varying points in the watershed.

“It looks like we might get more than one TMDL for the watershed,” said STIR member Kathy Tibbits. “Would we just divide it at the state line?”

Nguyen said it’s too soon to tell how TMDLs will be determined, but that the vast information received from participants is being analyzed.

“We’re talking about multiple TMDLs,” said Flores. “We have two very different systems in the Illinois River and its tributaries and then Lake Tenkiller. Both systems will be modeled separately.”

Tony Donigian, work assignment leader and project manager for Aqua Terra, the contractor for the EPA, said he’s been working on projects similar to this for over 40 years, and has never seen the quantity of data produced by participants in this project.

“We’ve spent over a year just collecting data,” said Donigian. “And we want to take advantage of that. We want to present ideas for models and ask how it sounds to you, and if we need to change things.”

After Donigian said once the data analyzation is complete, the EPA hopes to determine the best model for use in the watershed. In February, the selected models for the Illinois River and Lake Tenkiller will be calibrated and tested, which will allow them to determine flow and nutrient load at any given point in the selected bodies of water.

“The similation model is almost like a video game,” said Donigian. “By analyzing the model, we’ll be ably to get into the ‘what ifs’ and make adjustments to meet the TMDL standards.”

Learn more

To find out more about the EPA’s plan to institute a water quality model for the Ilinois River Watershed and Lake Tenkiller, visit www.epa.gov/region6/water/npdes/illinoisrive rwatershed/illinois_river_signature.pdf.