Thirty-one states feed phosphorous and nitrogen into the Mississippi River and eventually into the Gulf of Mexico. Those nutrients are the primary foods for a tide of red algae that defines the dead zone. Currently, the dead zone is the size of Massachusetts. It's an area devoid of marine life.
Under the EPA plan, by 2015 Minnesota and other states hope to shrink the dead zone by one third.
"We realize that is probably too aggressive of a date," says the MPCA's Wayne Anderson.
The Environmental Protection Agency started this project in 2000. Since then the hypoxic zone has grown, so it's unlikely the region will shrink substantially in the next ten years.
Grow the Future of Public Media
MPR News is supported by Members. Gifts from individuals power everything you find here. Make a gift of any amount today to become a Member!
It's still worth trying, Anderson says. He points that two regions of Minnesota are the biggest contributors of nitrogen and phosphorous.
The area that shows up as the biggest source (of pollutants) is the Minnesota River Basin and that's not surprising. It's one of our strongest agricultural regions. The other is the southeast Minnesota
"The area that shows up as the biggest source is the Minnesota River Basin and that's not surprising, it's one of our strongest agricultural regions. The other is the southeast Minnesota," he says.
Run-off from ag land is the biggest contributor of phosphorous and nitrogen in Minnesota's lakes and rivers too, though cities are also a big contributor.
The EPA plan calls for farmers to cut back the amount of phosphorous they use on their field. That will decrease the amount of nutrient run-off.
"You do want to lay a good background of education. People are not going to change something if they don't understand that it's a source of a problem or what the solutions are," Anderson says. "But then you can do a lot through incentive. And I think that's been the traditional approach with agriculture."
The state also hopes to restore more agricultural land to wetlands, and increase the number of buffer zones that could absorb nutrients like phosphorous before they flow into Minnesota's rivers, Anderson says.
The MPCA has also developed plans to reduce pollutants in Lake Pepin and in the Lower Minnesota River Valley.
The group, Friends of the Minnesota Valley, is helping address phosphorous run-off in the urban areas. In Bloomington, for example, residents cleaned up leaf debris and litter along roadways, says executive director Lori Nelson.
"In the last six years or seven years we've reduced pollution into the Minnesota River, phosphorous, by 6,000 lbs, which translates into six million pounds of algae," she says.
But farmers are considered the biggest contributor of pollutants.
Minnesota Farm Bureau president Kevin Papp wants to make sure farmers get credit for what they've already done to reduce run-off. Farmers have cut their use of fertilizers partly because fertilizer prices have sky rocketed, Papp says.
"The agriculture community has clearly reduced its use of nutrients in our fields. And yet we see the hypoxic zone increase in size. We don't understand why that correlation is like it is," Papp says.
Partly, it's due to heavy rains. The MPCA says floods like the ones we've seen in the last three years increase run-off and that ultimately feeds the dead zone.