State of the St. Croix River Report

The St. Croix River Association (SCRA) is often asked about the health of the river. For decades, scientists, resource managers, and volunteers have studied the St. Croix River and the extraordinary flora and fauna found here. This ongoing research is the basis for planning, protection, and restoration activities. 

What we’ve learned is that information often does not translate well to the general public, even if they have access to the information. People are left wondering: "Can I swim in the river?" "Is water quality improving or getting worse?" "Can I eat the fish I catch?" This is especially true with a new segment of the St. Croix added to the Minnesota impaired waters list in 2020.

The State of the St. Croix River Report was designed to answer these questions and more. We hope to increase awareness and understanding of the issues that cause problems in the St. Croix River ecosystem. We hope the success stories motivate actions that lead to not just the enjoyment of the river, but inspire people to act to preserve and improve its integrity for future generations.

We are blessed with a truly special wild and scenic river, a generally healthy and intact Riverine system seldom seen elsewhere. But the river is vulnerable and will always be vulnerable. Development pressure, land use changes, increased occurrence of invasive species, and contaminates such as microplastics pose threats to the condition of the river. Fundamentally, it will take people to protect the Riverway. Continual work and public action will be necessary to preserve and protect the St. Croix River.

We hope you enjoy learning more about your wild and scenic St. Croix, and learn more about what it will take to keep it that way. Thank you to everyone that contributed to this report, and to all Riverway Stewards, we need you.

Respectfully,

Deb Ryun, Executive Director

Report invasive plants and animals to the Wisconsin or Minnesota DNR.

• WI:  https://dnr.wi.gov/topic/Invasives/report.html 
• MN:  https://www.dnr.state.mn.us/invasives/report_invasives.html 

Follow the state aquatic invasive species laws every time you launch and pull your boat:

• INSPECT - Check your boat, trailer and equipment.
• CLEAN - Remove all zebra mussels, and place them in a trash receptacle.
• DRAIN - This means all water (including pools of water in the boat) to eliminate tiny larval zebra mussels, and leave your drain plugs out during transport. Throw out all unused bait in a trash receptacle.
• DRY - Leave your boat in the sun for at least 5 days before moving between bodies of water.

Although the tannin-tinted waters of the St. Croix are some of the cleanest in the Midwest, not all is well. Some of these problems are hard to see at a glance, while others are visible. Learn more about threats to the Riverway's water quality below.

1. Reduce runoff from your property with infiltration projects such as native plantings and rain gardens. Runoff carries nutrients, sediment, and salt to water bodies. 
2. Use phosphate-free soaps and detergents.
3. Reduce or eliminate use of lawn fertilizers and other chemicals.
4. Test your water to ensure a water softener is needed, and make sure your water softener works properly.
5. Use non-salt forms of deicer on sidewalks and driveways.

Due to its proximity to a major metropolitan area, the river is a corridor surrounded by lands and waters used for a variety of purposes. These uses can have huge impacts on the health of the waters of the St. Croix River - often in ways we might not expect. Here are a few of the most pressing threats to the health of our river.

As the St. Croix and Mississippi Rivers meet at the confluence at Prescott, Wisconsin, the water from the St. Croix helps to reduce the concentration of the pollutants in the Mississippi. But the St. Croix is not immune to threats, and continual efforts to protect and restore the river will be essential in years to come—just as they have been in years past. 

Scientists are gaining a better understanding of how this river and its lake function and the factors which drive algae growth. The slow, long-term decline of phosphorus is hopeful, but more work is needed to understand and reduce algae in Lake St. Croix. Finding new ways to conserve and reduce phosphorus is a key piece in the process to the long-term health of the St. Croix River.

Over a decade after Lake St. Croix’s impairment designation in 2008, the Minnesota Pollution Control Agency (MPCA) proposed adding a segment of the St. Croix River from Taylors Falls to Lake St. Croix to their impaired waterbody list in 2019. The proposal for this segment was due to excess nutrients, specifically phosphorus and increased levels of algae (expressed as the amount of chlorophyll a) in response to this excess phosphorus.

It’s important to note that excess phosphorus leading to an overabundance of algae can harm aquatic life; therefore, this impairment proposal is for an “aquatic life” impairment and not for human activity. People can still safely use the river for recreation. 

But this is a powerful example and reminder that the river is vulnerable, and will always be vulnerable. Continual work and public action will be necessary to preserve and protect the St. Croix River for generations to come.

The St. Croix River Association would like to thank the Mortenson Family Foundation, the Wisconsin Department of Natural Resources, the St. Croix River Basin Team, and the St. Croix National Scenic Riverway for their support and collaboration in the creation of this report.