For years Minnesotans have been working together through business, citizen and government organizations to reduce water pollution resulting from excess nutrients — primarily phosphorus and nitrogen. Pollution from these nutrients is a substantial threat to Minnesota’s lakes and rivers, and aquatic life, as well as downstream waters.
Minnesota is one of 12 states along the Mississippi River developing a cleanup plan for the excess nutrients (phosphorus and nitrogen) impairing waters within the states and causing a hypoxic “dead zone” in the Gulf of Mexico where aquatic life can’t live. Ultimately, the goal set by the U.S Environmental Protection Agency and other states is a 45 percent reduction in loading to the Gulf of Mexico.
To address the nutrient issue, 10 Minnesota agencies propose a strategy that looks at the main causes, solutions and how best to track our progress. This plan is simply a conversation starter. To reach the short-term and long-term goals, stakeholder input and local partnerships are critical.
Why is it important?
Minnesota is the headwater state of the Mississippi River and takes that role seriously. The rain and snow that falls on Minnesota is the starting point for major continental rivers, including the Red and Mississippi rivers and Great Lakes, however by the time it leaves the state, it is contaminated with nitrogen and phosphorus. Just from Minnesota, more than 200 million pounds of nitrogen flows out of the state via the Mississippi River each year.
Highlights of the strategy
Minnesota conducted both nitrogen and phosphorus assessments to identify nutrient source contributions. The foundation of the strategy builds on historical and recent data, setting realistic and achievable short- and long-term goals, tracking progress, and providing for adaptive management from future research and monitoring. The key is setting short-term goals, or milestones, to track progress to the long-term goals.
Southern Minnesota is the highest priority for both phosphorus and nitrogen reduction. But prevention of new additions of nutrients to waters is important across the state. Targeting implementation activities to priority sources in high-priority watersheds is a potential cost-effective approach to achieve initial nutrient reductions. It is important to recognize that while prioritization is an effective management tool for directing limited resources, significant reductions to meet the strategy goals cannot be achieved through implementation in a limited number of high-priority watersheds.
Progress has been made in some areas. Since 2000, there has been a 27 percent reduction in phosphorus — 8 percent from agriculture and 19 percent from wastewater. To continue towards progress, Minnesota needs to step up existing strategies such as continuing wastewater reduction strategies, preparing for future standards and increasing the adoption of agricultural best management practices.
Sources of excess nutrients
- Phosphorus: agricultural cropland runoff, wastewater and streambank erosion.
- Nitrogen: agricultural tile drainage and water leaving cropland via groundwater.
- Phosphorus: non-agricultural runoff, wastewater and streambank erosion.
- Nitrogen: Wastewater.
Red River/Lake Winnipeg
- Phosphorus: cropland runoff and non-agricultural rural runoff.
- Nitrogen: cropland to groundwater.
The milestones are meant to be meaningful and achievable, will balance meaningful environmental outcomes with action strategies and take into account the changing landscape, regulatory environment and changes in best management practices.
- Mississippi River: 35 percent reduction by 2025
- Red River: 10 percent reduction by 2025
- Lake Superior: 3 percent reduction by 2025
- Mississippi River: 20 percent reduction by 2025
- Red River: 13 percent reduction by 2025
To show progress, strategy summary cards were developed to clearly communicate what reductions have been achieved, remaining reductions needed to achieve our progress goals, and how much reduction is needed by each sector.
Nitrate and eutrophication water quality standards are important components of the strategy. Both the existing lake and proposed river eutrophication standards include phosphorus, but they do not include nitrogen. Nitrate toxicity standards to protect aquatic life in surface water are being considered for future rule making.
- A study of nitrogen in surface waters, along with the sources, pathways, trends and potential ways to reduce nitrogen in waters
- The Condition of Minnesota’s Groundwater, 2007-2011