The Arkansas-Oklahoma Arkansas River Compact Commission learned that phosphorus levels in the Illinois River basin continue to decline.
"I am real pleased to see the continued drop of phosphorus levels," Randy Young, an Arkansas-appointed commissioner said during an annual meeting Thursday in Rogers. "We had higher rainfall, and typically you would see higher levels."
The river compact includes representatives from Oklahoma and Arkansas. The compact works to define water use by each state along with encouraging the maintenance of an active pollution-abatement program, according to its website.
Oklahoma and Arkansas officials have been disputing phosphorus levels in the Illinois River for decades. Oklahoma imposed a 0.037 milligram-per-liter limit on phosphorus concentration as a standard for the river.
Phosphorus is a nutrient that affects algae growth in the waterway. Contributing sources include poultry litter spread in the watershed and area wastewater treatment plants, among others.
Testing on Flint Creek in Oklahoma near Kansas showed the water flow at 121.2 cubic feet per second in 2013. It was up 73 cubic feet per second from 2012's flow. The flow in 2012 was 48.1 cubic feet per second.
Kenneth Brazil, engineer supervisor with the Arkansas Natural Resources Commission, of which Young is the director, said that because of the higher flow there was a larger load of phosphorus in the creek at 10,070 kilograms a year. There were 4,598 kilograms of phosphorus in the creek in 2012.
Despite the flow more than doubling in 2013, the phosphorus load did not, data from the compact show.
Brazil said this is because the concentration of phosphorus decreased. Phosphorus levels were at 0.093 milligram per liter in 2013. It is the lowest the level has been at the creek in more than 30 years. The phosphorus level in 2012 was 0.107. In 1993, it was 0.156, and in 1983, it was 0.284.
"We increased the flow this year," Brazil said. "You would expect us to also increase phosphorus levels. The inference from that is the concentrates are continuing to decrease. The trend is still going down."
Julie Chambers, Oklahoma Water Resources Board lake monitoring coordinator, said both Arkansas and Oklahoma have made efforts in recent years to reduce phosphorus.
"You aren't going to see a rapid change," Chambers said. "It is going to take some time."
Water treatment plants have continued to increase standards in both states, Chambers said. She said farmers in the two states have also worked to implement strategies that reduce nutrients.
Some of these efforts can be seen in data in recent years, Chambers said.
The average phosphorus level from 2009 to 2013 was 0.14. The average level from 2004 to 2008 was 0.191.
Steven Patterson, restoration ecologist for BioxDesign, talked to the commission about another strategy that can be used to lower phosphorus in the river. He said Lake Frances in Siloam Springs is holding nutrients that could be adding to the phosphorus levels downstream.
A workshop was held in 2013 with the purpose of finding solutions for Lake Frances, Patterson said. He said several ideas came out of the workshop, including the construction of wetlands around the lake.
Wetlands could help filter nutrients flowing into the lake, Patterson said. He said this project could cost between $5,000 to $50,000 an acre. He said the land could also be used for recreational purposes, which would include boardwalks.
Patterson said another option would be to treat the lake with alum. Alum breaks down the nutrients and cuts the phosphorus release. He said the cost would be about $1,000 an acre.
Metro on 11/01/2014