FAIRMONT — A recent study by the Minnesota Pollution Control Agency has found that the Minnesota River is unhealthy.

The river flows through western and central Minnesota and into the Mississippi River near St. Paul.

The study assessed all 338 miles of the river, using data gathered from about 139 sites by local partners and other state agencies, using data spanning 10 years. The river was monitored for levels of nutrients, sediment, bacteria, toxics, dissolved oxygen, chloride, pH and ammonia; fish and aquatic insects that inhabit the river; the flow of the river; and possible contaminants in the fish.

Major trends in the Minnesota River that need to be addressed are the increase of water flow, too much sediment from unstable stream banks and farm fields, too many nutrients such as phosphorous and nitrate, and too much bacteria, which can increase the risk of human illness.

Too much water flow, which has been identified as an issue, is the result of an increase of rain and artificial drainage, and a lack of perennial vegetation and wetlands. This can leave the river vulnerable to erosion, which threatens the infrastructure and reduces water quality. According to the study, land use practices and drainage within the Minnesota River basin have greatly affected the channel stability and flow rates of the river. This makes it difficult for organisms such as aquatic insects and mussels to survive.

The study found that the major pollutants in the Minnesota River are sediment, phosphorous, bacteria and nitrate. Each pollutant affects the river in a different way. Sediment clouds the river, phosphorous causes algae to form and nitrogen and bacteria can be harmful to humans. The pollutants can also be a harm to the river’s ecosystem, including fish, insects and mussels. According to the study, more than 25 percent of mussel species that were once found in the river are no longer present, rising to 50 percent in the lower reaches of the Minnesota River.

According to the study, the Blue Earth, Cottonwood and Le Sueur rivers bring in the most pollutants to the Minnesota River.

The Blue Earth River runs through Faribault and Blue Earth counties and enters the Minnesota River near Mankato. In Faribault County, the river passes through Blue Earth and Winnebago.

Cathy Rofshus, information officer for the MPCA Southeast Region, said the biggest problem that the Blue Earth River faces is the amount of sediment it is bringing into the Minnesota River, including soil, silt and sand. This is due to the changing landscape through farming, the building of cities and extensive drainage systems that has taken away wetlands and perennial coverage on the land.

However, said Rofshus, there is a lot that can be done at the local level to improve the overall health of the Minnesota River. This includes investing in water storage, such as increasing temporary water storage area, managing drainage with outlet controls, grass waterways and ditch and saturated buffers and installing more storm water basins. Building up soil health through expanding use of cover crops, increasing soil organic matter and reducing tillage can also improve the river’s health.

To view the results of the study, visit: https://www.pca.state.mn.us/mn-river-study