Minnesota regulators have proposed adding more than 580 water bodies to its list of polluted waters, including a new section of the St. Croix River.

The Minnesota Pollution Control Agency said Tuesday the river didn’t meet limits on phosphorus and chlorophyll, nutrients that cloud the water and affect aquatic life. The nutrients don’t affect the safety of swimming or eating fish.

The announcement comes as the MPCA finishes a 10-year assessment of the state’s water quality, finding 56 percent of streams and lakes either don’t meet standards for healthy bug and fish communities or are marred by a range of pollutants such as mercury, nitrogen, phosphorus or bacteria. 

The state has been working to evaluate all of Minnesota’s watersheds, paid for by the Clean Water, Land and Legacy Amendment, a 25-year sales tax passed by voters in 2008 dedicated to environmental protection and cleanup and arts and cultural projects. The research has resulted in updates to its list of “impaired” waters, which is required by the federal Clean Water Act. To date, more than 3,400 bodies of water have been listed, with a total of 5,774 impairments.

The MPCA is hosting four meetings around the state on its draft 2020 list and gathering public comments before it submits a final product to the Environmental Protection Agency for approval.

Here’s what we learned from Tuesday’s milestone, and what comes next in the state’s drive for cleaner water:

St. Croix gets added to the list

While the St. Croix is one of Minnesota’s most protected waters, the MPCA has proposed adding a lengthy section of the river between the dam near Taylors Falls and Lake St. Croix to the impaired list for the first time. The state has known of pollution in Lake St. Croix “for many years,” said Miranda Nichols, the water quality assessment coordinator at the MPCA, and has a strategy in place to improve it. But the MPCA hadn’t yet assessed the St. Croix river itself.

The new reading is significant. First, it means the lake’s issues aren’t new or isolated, Nichols said. “Something didn’t happen over the last two years for this water body to degrade to that point,” she said. But it also means the St. Croix — a popular recreation destination — is still susceptible to flagging water quality, Nichols said.

By contrast, the MPCA this year found the Rainy River near International Falls, another popular fishing water, was not impaired, Nichols said.

Greg Seitz, founder of St. Croix 360, an online publication focused on the river, said the news was “disappointing,” even if outdoor recreation is not limited. “Even if it’s not impairing my enjoyment of the river, it is impairing the food web and everything else,” Seitz said.

So what’s the source of the St. Croix’s problems? Because the St. Croix is a “very heavily protected river corridor,” Nichols said the pollution is likely not coming from the river’s banks, but from tributaries in dirtier parts of the larger watershed.

But the exact culprit is still unknown. Researching that comes next. “It’s going to be a high priority for us to get that water body back to meeting standards,” Nichols said.

Part of the challenge for reducing pollution in the St. Croix is that the river’s watershed extends into Wisconsin. Nichols said Minnesota can’t tell Wisconsin what to do, but she said interest in action to improve the water could be high since the St. Croix is protected by the National Park Service.

Still, Nichols said Wisconsin’s regulations are weaker than Minnesota’s, and the state doesn’t list the St. Croix on its impaired waters list. 

Seitz said the St. Croix news is a “reminder” that how people use land around the river has a “really big impact.”

“We don’t know exactly why this section is now impaired, but we do know what we do on the land that affects the water and I would hope that everybody that loves the river pays attention to what we’re doing on the landscape,” Seitz said. 

The last leg of a 10-year effort is complete

The latest impaired waters list completes a 10-year research effort to collect data on Minnesota’s 80 watersheds. In the end, the state found about 30 percent of the state’s lakes and half of streams are impaired — at least when not counting mercury pollution. 

Nichols said mercury is a “complex and global pollutant” that comes from the air. While Minnesota has worked to regulate its mercury emissions, the toxin can blow in from around the world. With mercury in the picture, 56 percent of the state’s waters are impaired, said MPCA spokesman Darin Broton.

The latest round of testing also found 69 streams with high levels of bacteria, which is not safe to swim in, plus one Lake Superior beach.

Overall, Nichols said northeast Minnesota had “very little impairment,” but that water quality decreases in western Minnesota and the Twin Cities and is worst in southern Minnesota’s farm country.

Now that the first 10-year stretch is over, the MPCA will do a second assessment of Minnesota’s watersheds, which will reveal “developing trends” in water quality, Nichols said.

Battling against time

After an assessment by the MPCA, state government and local partners develop restoration and protection strategies and researches why waters are impaired.

Those watersheds then get grant money from the state to work on improvements, said Paul Gardner, administrator of the Clean Water Council, which advises the Legislature on how to spend Legacy money.

Gardner said a network of agencies also work with private landowners on clean-water projects, using a mix of money from state and federal programs. For instance, they may persuade a farmer to use cover crops, which are planted alongside corn and soybeans and limit runoff from fertilizer.

Much of this water quality work is paid for by the Legacy Amendment, which ends in 2034. Gardner said not all the watershed cleanup work can be completed by then. 

With the first 10-year cycle of watershed research complete, the MPCA is already looking ahead to what Broton called a “Legacy 2.0.” While he said the state will make “meaningful progress over the coming years” and start to take waters off the impairment list, it won’t be able to do the work fast enough.

“There’s probably going to be a need to start having conversations sooner than later about how do we keep the amendment going because the work is never going to end,” Broton said. “As you can see from our impairment list, it is large.”

The current Legacy Amendment has been controversial, at least in the state Legislature. For instance, some have hammered state government for not improving water quality enough, despite having spent roughly $1 billion of the sales tax money from the Clean Water Fund so far. 

The MPCA announcement is sure to reignite debate over whether the state has done enough to protect water by regulating farms and other polluting industries.