Study Maps Path to Cleaner Water in Lake Michigan Basin

MADISON, Wis. – A new study provides a strategic roadmap for improving water quality in the Lake Michigan Basin, demonstrating that widespread adoption of "regenerative agriculture" practices could lead to a significant reduction in nutrient and sediment pollution. However, the research also reveals that current conservation efforts and projected increases fall short of state and federal clean water goals, underscoring the need for critical collective investment.

The study, published in the latest issue of the Journal of Environmental Quality, used the U.S. Environmental Protection Agency's Pollutant Load Estimation Tool (PLET) to model how various conservation practices would impact water pollution from agricultural land in 23 watersheds across Wisconsin and Michigan. Researchers found that a comprehensive "regenerative agriculture" scenario—combining practices like cover crops, no-till farming, and nutrient management—could reduce phosphorus pollution by an average of 21% and sediment pollution by 10%.

"Our framework shows that when stakeholders collaborate with science-based tools, we can create a clear, actionable plan for making progress on water quality," said Dr. Heidi Peterson, Sand County Foundation’s Vice-President of Agricultural Research & Conservation. "We've translated complex federal and state policies into tangible goals, such as the number of farmers needed to adopt conservation practices and the financial investment required to get there."

The analysis estimates that to achieve these reductions, approximately 3,000 farmers would need to adopt at least one conservation practice, requiring a total investment of roughly $260 million across the basin.

The study identified nutrient management as the single most effective practice for reducing phosphorus pollution. In contrast, while cover crops and conservation tillage also showed positive impacts, the most substantial gains were seen when these practices were combined in the regenerative agriculture scenario. The southern watersheds of the basin, which have a higher proportion of agricultural land, showed the greatest potential for pollution reduction.

Despite these promising results, the researchers cautioned that even with this extensive investment and practice adoption, the goals set by federal Total Maximum Daily Loads (TMDLs) for clean water would not be fully met. This indicates that while the modeled scenario represents a significant step forward, it is only a starting point.

"Meaningful outcomes are within reach with the current trajectory of adoption, but reaching our full clean water goals will require a level of investment and collective action that goes beyond our current efforts," Peterson stated.

The framework developed in this study can serve as a valuable tool for local watershed groups, government agencies, and private investors to prioritize conservation funding and focus on practices that will have the greatest impact on water quality. It helps in identifying cost-effective solutions and directing resources to watersheds where they can yield the most significant results.

About the Research The study, "A Collective Action Framework to Advance Clean Water Goals in the Lake Michigan Basin," was published in the Journal of Environmental Quality. It utilized the U.S. Environmental Protection Agency’s Pollutant Load Estimation Tool (PLET) to model the effects of conservation practices on phosphorus and sediment loads from agricultural land. The research provides a practical, science-based framework for collaborative efforts to improve water quality.