Scott County says it's being snared by new rules to clean up Minnesota's rivers and is running out of options to stop the drastic costs they could someday entail.

Last week, county commissioners unanimously agreed to dispatch a letter to the Minnesota Pollution Control Agency (MPCA) that disputes its placement in the more heavily regulated Central River Nutrient Region.

That region, which includes the Mississippi River, drains less natural sediment into its rivers than those in Scott County. That means that in the future, the county could be on the hook to reduce more runoff than is necessary, said natural resources manager Paul Nelson.

"It'll take 10 to 20 years before you see a lot of costs in this," he said, but added that when the county finally has to comply with the new water quality standards, it will be unduly expensive and "unachievable."

He cited a figures indicating that more than $1 billion has already been spent on reducing sediment in the Minnesota River alone.

The new draft standards for rivers are the state's answer to meet federal requirements first planned through the Clean Water Act more than a decade ago. In 2008 the state created standards for lakes to meet the requirement.

In the last several years, Nelson said, he has tried to get the MPCA to redraw Scott County rivers and watersheds in the South River Nutrient Region, which allows more runoff. Because the county's tributaries were formed by the same geologic forces as the Minnesota River, he said, they should be part of the same regulatory region. The MPCA, he said, "didn't think critically about where [the] lines should go."

In a response to his comments in January, the agency said the county's rivers were "mapped appropriately," and that its regions were based on a practice recommended by the federal government.

"We're not seeing his comments as a reason to change the general approach," said Shannon Lotthammer, who manages development of water quality standards for the MPCA.

She said that "we absolutely are listening," and the county can apply for a looser standard, based on scientific evidence, if and when the state's rules are approved by the feds.

If they are approved, Nelson said the only way to stop them is a lawsuit. He did not propose a lawsuit at the recent meeting, but he did plan to testify before the vote takes place this week.

If the rules pass and are sent to the federal government, Nelson said, he doesn't know if other groups will pursue a lawsuit. But he said nearly two dozen groups skeptical of the MPCA's proposals have written a letter asking for an independent review.

Graison Hensley Chapman is a Northfield freelance writer.