New stretches of St. Croix River and its tributaries declared impaired

State agency says nutrient levels exceed new standards, though the water has been improving in recent decades.




4 minute read

State authorities today said today that another 25 miles of the St. Croix River are suffering from excess nutrients and algae that can degrade its waters for fish and other wildlife. The Minnesota Pollution Control Agency announced the designation for the stretch from Taylors Falls to Stillwater.

The new segment joins the lower 25 miles of the river, which was designated as impaired for nutrients in 2008. More than 30 other stream stretches and 15 lakes throughout the watershed are also being added to the list. A total of 580 other water bodies across Minnesota were added to the list this year.

While the St. Croix is protected as a National Park, the announcement shows how human land use far away can reach into the river. Individuals, organizations, and government agencies can do things locally that benefit the St. Croix.

“I think it’s a wake-up call that what is done across this whole watershed has an effect on the river.”

– Greg Seitz, St. Croix River, 580 other waterways added to state’s list of troubled waters, MPR News, Nov. 12, 2019

The St. Croix is being added now because of new water standards finalized in 2015. Water quality in this stretch of the river has actually improved since 1976, but it remains below standards for a healthy ecosystem.

After the new standard for large rivers was adopted in 2015, the MPCA conducted two years of water quality monitoring, assessment, and reviewing other data on the St. Croix River, and based its decision on how it found nutrients were affecting living things in the river.

A pocketbook mussel sits in the sand on the St. Croix River near Marine on St. Croix, MN. (Greg Seitz, St. Croix 360)

The river remains safe for recreation and fish consumption, although there are some other fish-related consumption advisories in effect.

River advocates say the designation is a rallying call for sustained stewardship.

“The river is vulnerable and will always be vulnerable,” said Deb Ryun of the St. Croix River Association. “This is a reminder that continual work and public action are necessary to preserve and protect our precious St. Croix River.”

In contrast to Lake St. Croix, which considered contaminated to the point that it degrades recreation, only aquatic life is affected on the new stretch of the river. The St. Croix’s healthy habitat and natural ecosystem are some of its most prized values.

“One of the best things about getting out there is witnessing a natural landscape and a place that feels pretty untouched by humans.”

– Greg Seitz, State finds 56% of Minnesota’s lakes and streams are ‘impaired’, Star Tribune, Nov. 12, 2019

Nutrient pollution like that affecting the St. Croix comes from numerous sources. While wastewater treatment facilities used to be a major source, required changes in recent decades have greatly reduced their effect. Runoff from agricultural and developed lands remain a persistent problem.

By designating the river as impaired, the sources of nutrients can be studied and quantified, so that work can be targeted to areas with the greatest impact.

The 2012 plan to improve Lake St. Croix’s water quality identified farmlands as the biggest source of nutrients to the water.

“Agriculture is the most significant phosphorus contributor of these sources in the basin and the primary pathways for phosphorus transport are via stormwater runoff from cropland, pastureland and feedlots. Atmospheric deposition of windblown soil from exposed croplands can occur as well,” the report reads.

The same is true across Minnesota, with pastures and croplands the largest source of phosphorus runoff statewide, according to the MPCA.

“Even if it’s not impairing my enjoyment of the river, it is impairing the food web and everything else.”

– Greg Seitz, More than half of Minnesota waters — including the St. Croix River — are ‘impaired.’ What does that mean? MinnPost, Nov. 13, 2019

Since 2012, the St. Croix region has been home to numerous projects to improve its heath. A variety of tactics to reduce runoff and hold back nutrients, have been implemented across the watershed.

Other streams in the watershed that are now listed as impaired include the Kettle River headwaters, Sand Creek, Hay Creek, and the Pine River. Numerous streams in the Snake River watershed are also listed, as is Pokegama Lake, the popular reservoir on the Snake in Pine City.

The full list will be submitted to the U.S. Environmental Protection Agency by law next spring. Plans will then be developed to help the impaired waters, and then restoration work can begin.

Public meetings and comments

The river near Scandia, MN. (Greg Seitz, St. Croix 360)

The MPCA is accepting public comment on the proposed listings until January 14, 2020. Submit written comments to or Miranda Nichols, Minnesota Pollution Control Agency, 520 Lafayette Rd N, St. Paul, MN 55155 (must provide a return address).

Four public meetings around the state will be held in December:

Central: December 11 (10 a.m.)

  • Brainerd MPCA, 7678 College Rd, Suite 105, Baxter, MN 56425

Webex: December 11 (10 a.m.)
Meeting number (access code): 964 052 022; Meeting password: JcdcZw4S
Join by phone: 415-655-0003

West: December 12 (9 a.m.)

  • Marshall MPCA, 504 Fairgrounds Rd Suite 200 Marshall, MN 56258
  • Detroit Lakes MPCA, 714 Lake Ave, Suite 220, Detroit Lakes, MN 56501
  • Mankato MPCA, 12 Civic Center Plaza, Suite 2165, Mankato, MN 56001

Webex: December 12 (9 a.m.)
Meeting number (access code): 961 734 616; Meeting password: WyT2Y7x2
Join by phone: 415-655-0003

North: December 17 (1 p.m.)

  • Falls International Airport, Conference Room, 3214 2nd Ave E, International Falls, MN 56649
  • Duluth MPCA, 525 Lake Ave, Suite 400, Duluth, MN 55802

Webex: December 17 (1 p.m.)
Meeting number (access code): 965 278 342; Meeting password: J7AhgfxP
Join by phone: 415-655-0003

Metro: December 19 (1 p.m.)

  • St. Paul MPCA, 520 Lafayette Rd N, St. Paul, MN 55155
  • Rochester MPCA, 18 Wood Lake Drive SE, Rochester, MN 55904

Webex: December 19 (1 p.m.)
Meeting number (access code): 968 910 929, Meeting password: zZMapXp8
Join by phone: 415-655-0003


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3 responses to “New stretches of St. Croix River and its tributaries declared impaired”

  1. Allison Avatar

    Greg, good article. But can you clarify the statement “only aquatic life is affected on the new stretch of the river”?? What’s meant by aquatic life and what’s meant by new stretch.? Sorry for my ignorance! Thanks.

    1. St. Croix 360 Avatar
      St. Croix 360

      Great question. So, there is too much phosphorus in the water. That itself might hurt some types of life, from microbes to fish to vegetation. And that extra phosphorus can feedsl more algae than natural, which can also affect the ecosystem. So “impaired for aquatic life” just means phosphorus is interfering with some part or parts of the river ecosystem. It’s on contrast to impaired for recreation, for example, which would mean the extra phosphorus is fueling cyanobacteria blooms, which are unsightly and produce toxins in the water.

    2. St. Croix 360 Avatar
      St. Croix 360

      That’s not the slightest bit “ignorant” to ask, obviously I should have explained it better.


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New stretches of St. Croix River and its tributaries declared impaired