One particular factoid tucked away in an old official Minnesota road map has stuck with Mike LaFave for many years: Water only comes out of Minnesota, but doesn’t come in.
LaFave spent 20 years on the road working for a union, often driving between Minnesota and Washington, D.C. The more time he spent behind the wheel, the more unusual it seemed that no rivers flowed in his home country.
“In all these other states, water is flowing everywhere,” said LaFave, who is now retired. “And it stuck with me, that we were sort of the center of the water universe for North America.”
He asked the Star Tribune to explore the weirdness as part of his Curious Minnesota project, a community series fueled by curious readers.
The card was telling the truth. Across the state, rivers carry water from Minnesota to distant destinations.
The Mississippi River flows south to Iowa and eventually the Gulf of Mexico. The Red River of the North and the Rainy River deliver water north to Hudson Bay and the Arctic Ocean. And the Saint-Louis River feeds Lake Superior, which empties into the Atlantic Ocean.
A rare crossroads
This is because the water is flowing down. While no one is claiming Minnesota has a particularly high elevation, it rises above everything around it, said Harvey Thorleifson, director of the Minnesota Geological Survey.
As the continent has formed over billions of years, there has occurred a meeting place where three river basins touch, Thorleifson said.
“We’re in the middle of the continent,” Thorleifson said. “And on this side of the Rocky Mountains, that is…where all the excess water from precipitation flows north, south, or east.”
Continental divisions are the high points of vast – and sometimes imperceptible – slopes that span entire states and regions, ultimately directing water towards an ocean. Two of these divisions meet in the Iron Range of Minnesota, in the Three Waters Hill near Hibbing.
The Laurentian Divide sends precipitation either north to the Arctic Ocean or south to the Gulf of Mexico, depending on which side of the ridge it falls. The St. Lawrence Divide carries some of the water that would otherwise flow north or south into Lake Superior.
There are a few exceptions, such as small rivers and streams that plunge into Minnesota before joining larger border rivers.
This continental divide intersection, pushing water into three watersheds, is rare but not unique to Minnesota. This happens in western New York, Alberta, and northern Montana as well.
Where does Minnesota get its water?
If no significant amount of water flows into the state, then where does it come from to fill Minnesota’s nearly 12,000 lakes, 70,000 miles of streams and 11 million acres of wetlands? ?
“Precipitation,” Thorleifson said. “It’s practically all precipitation – rain and snow.”
Wisconsin and Michigan also have very few, if any, rivers that come from out of state. This puts people in the Upper Midwest in the unusual position of having no one to blame for river pollution but themselves. Pollution problems worsen further downstream as nutrients from agriculture and municipal wastewater systems encounter other weathered waters and tributaries.
Minnesota’s nutrient pollution has contributed to the dead zone in the Gulf of Mexico and helped spur toxic algal blooms in Lake Superior, for example.
The problems are worse along the Red River and its tributaries. The Red River basin has become one of the most altered and artificially drained landscapes around the world, according to the US Geological Survey and the Minnesota Pollution Control Agency. Minnesota and North Dakota send 2,600 tonnes of phosphorus north each year to Lake Winnipeg – which is fed by the Red River – causing huge algae and water quality problems.
Continental divides that send water from an area in the same direction also help explain how tiny streams become great rivers.
The Mississippi, which begins as a small stream flowing out of Lake Itasca, is truly awe-inspiring thanks to the St. Croix, Minnesota, Ohio, Missouri, and all the other rivers and tributaries that flow into it. , said Thorleifson.
“We start the rivers from rain and snow that lands on Minnesota, but most of the water joins well downstream,” he said.
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Read more curious stories from Minnesota:
Is Little Lake Itasca in Minnesota the true source of the Mississippi River?
How do cities make Mississippi River water safe to drink?
Why don’t farms water their crops at night?
What happens to all the de-icing fluid sprayed on planes at MSP airport?
Is it safe to swim in the rivers of the Twin Cities, or are they too polluted?
When you flush the toilet in the Twin Cities, where does everything go?
This article has been updated to indicate that there are rare exceptions to the principle that water only comes out of Minnesota.