Minnesota's large rivers — the Mississippi, Minnesota, Rainy, Red, and St. Croix — are prized for recreation, and serve as water supplies and engines of commerce. They also connect us to other states and countries – flowing south in the Mississippi to the Gulf of Mexico and north in the Rainy and Red rivers to Lake of the Woods and Hudson Bay.
Because they receive pollutants from their tributaries and the surrounding watersheds, their health is a reflection of how well we are protecting overall water quality. The MPCA began monitoring the large rivers in 2013, starting with the Mississippi River from its headwaters to St. Anthony Falls in Minneapolis. The work provides insight into both the challenges to the rivers' health and reasons to protect them.
Upper Mississippi River
The Upper Mississippi River is largely healthy in its northern reaches. The river's health supported by forest and wetland landscapes it flows through. It then acquires significant problems south of St. Cloud, where tributaries from agricultural and more developed landscapes begin to flow into the Mississippi.
The Rainy River is in excellent condition. In the past, it's health was degraded by industrial and municipal pollution, this river has made a remarkable recovery over the last 50 years due to regulation and hard work by local business, industry and individuals.
St. Croix River
The St. Croix River offers good water quality, excellent fisheries, and a thriving mussel population. There are some concerns, including phosphorus levels and resulting algae in two sections of the river, with more threats to water quality on the horizon. As one of the first rivers in the United States to be designated as wild and scenic, with special protections, the St. Croix River now needs protective measures more than ever.
Overall, the Minnesota River is unhealthy. Sediment clouds the water, phosphorus causes algae, nitrogen poses risks to humans and fish, and bacteria make the water unsafe for swimming. Too much water flowing into the river plays a big part in all these problems.
Red River of the North
There are a number of concerns about the health of the Red River of the North. In general, fish and aquatic insect communities are doing reasonably well, but decline as you go downstream. In various sections of the Red River of the North there is too much sediment which makes it harder for many fish to find food, detect predators and reproduce. Some sections are also impaired for swimming due to high bacteria levels. Phosphorous levels within the river impact downstream waters and nitrogen levels are increasing.
Part of the solution includes reducing peak flows during spring runoff and heavy rains, and increase base flows during dry periods. Although some progress has bee made, more is needed to keep our farmlands highly productive while at the same time improving and protecting water quality.