Expert: Fix sewage, fix river
Posted on Saturday, September 23, 2006
An Oklahoma professor disagreed Friday with an Arkansas water-quality expert’s assertion that Oklahoma’s phosphorus limit for the Illinois River is impossible to reach.
Dan Storm, an Oklahoma State University professor in the department of biosystems and agricultural engineering, said his 125-page, phosphorus modeling study of the river between 1997 and 2001 shows it can reach Oklahoma’s mandated 0. 037 milligrams of phosphorus per liter.
Storm’s comments on his research came a day after Marc Nelson told the Northwest Arkansas Conservation Authority that Oklahoma’s water-quality mandate is unreachable.
“I’m giving you some bad news,” Nelson, director of the Arkansas Water Resources Center’s water-quality laboratory in Fayetteville, told the conservation authority Thursday. “It’s going to be very difficult to get there.”
Water experts, politicians and state employees in the two-state dispute have sided with their respective state’s view of phosphorus in the 99-mile-long Illinois River.
Gov. Mike Huckabee and others in Arkansas have never wavered in the view that Oklahoma’s goal is unachievable.
Those in Oklahoma, including former Gov. Frank Keating, never have strayed from their position that 0. 037 mg can be reached and want Arkansas entities to do more to meet that mark by 2012 as Oklahoma water-quality standards require.
Arkansas must ensure that the river, which has Oklahoma’s highest environmental protection, meets the 0. 037 mg limit at the state line. The river crosses from Arkansas into Oklahoma near Siloam Springs and empties into Lake Tenkiller near Tahlequah.
“It’s become state law, and it’s now the federal target for Oklahoma’s scenic rivers,” said Derek Smithee, water-quality chief for the Oklahoma Water Resources Board. “While achievability is a consideration in all our decisionmaking, it’s not the over-arching consideration.”
Nelson, who monitors water quality near the Arkansas 59 bridge across the Illinois River south of Siloam Springs, stayed true to the Arkansas view on Thursday.
The Illinois River won’t reach 0. 037 mg even if sewer plants decrease phosphorus discharges and farmers spread less poultry litter on cropland, he said.
That’s because there remains thousands of pounds of what Nelson called “background phosphorus” that’s stirred up from sediment by the fast-moving currents of the river and its tributaries. The same storms that increase the river’s flow carry more phosphorus-laden sediment into the river, Nelson said.
Between 10, 000 and 15, 000 pounds of phosphorus a year in background phosphorus is stirred up, raising the river’s phosphorus concentration, Nelson estimates.
Sewer plants in the Arkansas portion of the river’s watershed, which discharge about 50, 000 pounds of phosphorus a year, instead would have to discharge 2, 000 pounds of phosphorus annually to reach the 0. 037 mg maximum. That’s a level that’s not reachable for cities operating sewer plants, Nelson said.
At what’s called base flow — which is measured when rainfall is low and sewer plant discharges make up a higher percentage of water flowing in streams — Nelson’s monitoring station last year showed average phosphorus at 0. 10 mg per liter. That’s about three times the Oklahoma limit.
Baron Fork Creek, a scenic stream flowing from Arkansas into Oklahoma near the Washington County community of Dutch Mills, carries phosphorus of less than 0. 037 mg most of the time, Smithee said.
The watershed, which includes the Westville, Okla., sewer plant and poultry farms in both states, met the limit about 65 percent of the time water has been sampled since October 2000, Smithee said. Oklahoma law requires that the 0. 037 mg be met 75 percent of the time.
“I disagree with the assertion that if you removed all the manmade phosphorus sources that it wouldn’t be achievable,” Smithee said.
Storm’s research, published in June, shows the Illinois River can reach 0. 037 mg if sewer plants cut the amount of phosphorus they discharge into streams to 0. 25 mg per liter.
Under a federal Environmental Protection Agency-approved agreement with Oklahoma in December 2003, Northwest Arkansas cities must make sure sewer plants discharge 1 mg or less of phosphorus per liter into streams. Rogers had to comply by 2005, Springdale by 2007 and Siloam Springs by 2009. Fayetteville met the limit when the deal was approved by the EPA.
Poultry companies, which were sued last year by Oklahoma Attorney General Drew Edmondson when he accused them of polluting the river’s watershed with poultry litter, have improved their litter-spreading practices. They now encourage farmers to ship some poultry litter out of the Illinois watershed.
“It’s not as though exporting poultry litter out of the watershed isn’t important, but the point sources like sewer plants are what really dominate what’s going on in the rivers,” Storm said. “The poultry litter impacts the lake more than the rivers.”
Rene Langston, the Springdale Water Utilities director, heard Nelson’s report on Thursday. He didn’t know what it would cost to get his sewer plant in position to regularly discharge treated sewage that contains phosphorus near 0. 25 mg.
The city has beaten the 1 mg limit although it’s voluntary at this point. The average phosphorus discharged during the past 12 months was 0. 92 mg per liter. The plant averaged 0. 64 mg per liter from October 2004 to September 2005, Langston said.
“It would take an engineering evaluation of the current system, and we’d have to add some treatment components that would cost us,” Langston said. “I don’t know how much it would cost.
“ The 0. 25 ? I don’t know if that’s feasible. With the current facilities, you will not achieve it on a consistent basis.”
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