According to a Minnesota Pollution Control study, the Upper Mississippi River, which starts at Lake Itasca in northern Minnesota, is in great shape until pollutants flow in from farmland and cities.

By the time it reaches Minneapolis, the agency says it no longer meets water quality standards for river life and recreation. Results from a new MPCA study highlight areas along the river where farmers should employ best management practices to curb pollution.

According to the report, the river is nearly pristine as it flows through forests, wetlands and lakes until the land changes to cropland and cities. South of St. Cloud, sediment, nutrients and bacteria start to pour in with runoff, drainage and tributaries.

“What we do on the land is reflected in the water,” says John Linc Stine, MPCA commissioner. “This study underscores that point.”

After the Crow River flows into the Mississippi, phosphorus and nitrate pollution double in levels. The Crow drains a heavily farmed area and makes up about 15% of the total land area draining to the Upper Mississippi in Minnesota.

“The dominant land use tends to be the dominant source of pollutants, whether urban or agriculture,” says Dana Vanderbosch, manager of lake and stream monitoring for the MPCA. “We can have both good economic development and good water quality. It’s a matter of working together to achieve that balance.”

MPCA provided this graphic to explain the health of the Upper Mississippi River.

Many farmers have been using advanced technology and best management practices to achieve those objectives. To better manage nitrogen fertilizer, farmers routinely use soil testing, variable-rate application and variable seeding. Minimum and conservation tillage reduce sediment runoff. With a renewed emphasis on building soil health, many are experimenting with cover crops, which offer both production and water quality benefits.

More than 300 farms have been "certified" as meeting water quality protection standards through the Minnesota Ag Water Quality Certification program. To date, these farms have generated 531 new best management practices that are keeping 14.7 million pounds of soil on Minnesota fields, and keeping 9.7 million pounds of sediment and 6,086 pounds of phosphorus from entering the state's lakes, rivers and streams annually.

The MPCA study also highlights the need to protect the Upper Mississippi as a source of drinking water. Nitrate can make water unsafe for drinking. While levels are currently well below the threat level, water monitoring shows a trend of increasing nitrate levels, a concern for the 1.2 million Minnesotans who depend on the Upper Mississippi for drinking water, as well as millions farther downstream.

It’s also important to continue efforts to decrease mercury levels in Minnesota waters, MPCA staff point out. Mercury levels in fish and in the water in the entire Upper Mississippi violate the consumption standard. This means guidelines will remain in place on how much and what size fish to eat.

Many projects are underway at the state and local levels to ensure that the Upper Mississippi meets the standards for river life, recreation and fish consumption.

“The future health of the Mississippi River will depend on the ability of these projects to protect healthy conditions and reduce pollutant loads so that future generations can enjoy this invaluable resource,” Vanderbosch says.

About the study
As part of assessing the health of major watersheds across Minnesota, the MPCA studied the 510 miles of the Upper Mississippi from Lake Itasca to St. Anthony Falls in Minneapolis. Scientists measured levels of pollutants such as sediment, nutrients, bacteria and mercury. They also studied populations of fish and other aquatic life such as insects. Using data from nearly 200 monitoring stations along the Upper Mississippi from many partners and spanning 10 years, the agency determined whether several sections of the river met water quality standards.

The agency and local partners conduct more detailed monitoring of the Upper Mississippi, and the 20,105 square miles draining to it, at a smaller scale, known as major watersheds. These watersheds are areas of drainage to tributaries or the Mississippi.

For more information, visit the study webpage, www.pca.state.mn.us/upper-miss.

Source: MPCA