Updated: 11/12/2012 11:50 AM KSTP.com By: Cassie Hart
Oxygen levels are up in the Minnesota River, a key indicator that one of the state's dirtiest waterways is getting healthier and that efforts to reduce pollution from wastewater treatment plants are working, the Minnesota Pollution Control Agency announced Monday.
MPCA staff monitored a 20-mile stretch of the lower river for three weeks in August to see if the hot, dry summer and low water flows would deplete dissolved oxygen levels. Such depletion had been a problem in previous droughts, but scientists were encouraged to find that oxygen levels remained high enough to support fish, bugs and other aquatic life despite the stressful conditions.
MPCA and Metropolitan Council officials announced the results at a news conference at the Blue Lake wastewater treatment plant in Shakopee.
They credit the success to major public and private investments to reduce phosphorous discharges all along the river, which starts at Minnesota's western border and cuts across the state to join with the Mississippi River just downstream from Minneapolis. Phosphorous promotes the growth of algae, which depletes oxygen in the water.
"It's about a quarter-billion dollars collectively when you look at all the investment from all the municipal and industrial facilities," Katrina Kessler, manager of the MPCA's water assessment and environmental information section, said in an interview.
The agency credits a 2004 phosphorous reduction plan that included several strategies, including upgraded wastewater treatment systems in 12 communities that had inadequate sewage treatment before.
"What it shows to us is a lot of the efforts that we initially designed are paying off, and the work of many small communities and wastewater systems across the Minnesota River watershed have added up to something pretty significant in terms of water quality improvement in the river," MPCA Commissioner John Linc Stine told The Associated Press.
Stine said they've met phosphorous reduction goals ahead of the agency's 2015 target date, and that's good for the entire food chain in the river.
"We're talking about all the critters, the bugs, the minnows, the fish - everything that relies upon dissolved oxygen to live," Stine said.
When those creatures thrive, so do ducks, egrets, herons and even eagles that live along the river, he said.
"That supports waterfowl and it supports feeding birds and up the food chain to birds of prey that feed on the fish," Stine said.
Stine cautioned that the river is still struggling with other serious contaminants, primarily sediments from runoff and eroding river banks that keep it muddy. And other pollutants such as nitrogen from farm runoff still need to be cut, he said. Bacteria levels also are still too high.
"This step forward is one good step forward but it's not the last step forward," Stine said. "It's going to take persistent efforts to address those contaminants and achieve water quality status that is no longer impaired."
Reducing those pollutants is going to require better agricultural soil and water conservation practices and better urban storm water management.
Stine and Kessler said the expense of the efforts so far has been worth it.
"We should all want to protect (the river) and invest in it so that we can have a swimmable and fishable Minnesota River," Kessler said.
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