About the Project

The St. Louis River Estuary, located at the headwaters of Lake Superior, has undergone extensive remediation and restoration following more than a century of pollution and habitat degradation. As the estuary approaches its anticipated delisting as a Great Lakes Area of Concern by 2030, new environmental stressors are raising concerns about its long-term health. In particular, cyanobacteria blooms, or harmful algal blooms (HABs), have emerged as a growing threat. This project was developed to better understand these challenges and to create a collaborative, science-based monitoring strategy for the estuary. The project findings revealed that environmental conditions, especially nitrogen concentrations affected by hydrologic conditions, strongly influence bloom dynamics, including bloom timing and composition.

About this Resource

Recommendation report: this report presents research results and monitoring recommendations from collaborative effort among water quality monitoring experts, scientists, and estuary caretakers. The report stems from the pressing need to chart a path forward to develop a long-term monitoring plan. This report is a first step toward building a more coordinated, efficient, and future-focused water quality monitoring program—one that supports the unique St. Louis River Estuary that serves as the foundation for the health, livelihoods, economies, and sense of place of the Twin Ports community and the broader Lake Superior watershed.

Interactive data exploration: explore the data that accompanies this report with these interactive graphing tools

• Water Quality at St Louis River Estuary Hot Spots (2023-2024): Explore the project’s environmental data with a tool that visualizes trends across time and differences among sites. This tool allows you to see interannual, seasonal, and spatial differences in conditions like nutrients, water clarity, and water chemistry.
• St. Louis River Annual Discharge Patterns (1908 - 2025): Explore St. Louis River discharge patterns from 1908 - 2025. This tool was developed based on the project findings that extended periods of low river discharge play an important role in cyanobacterial bloom formation. Visualize how any chosen year compares to the longer term mean discharge in the St. Louis River with this interactive version of Figure 6 in the recommendation report.
• Phytoplankton Biovolume Explorer 
  Explore the project’s phytoplankton data across study sites and across time. This tool allows you to see interannual, seasonal, and spatial differences in phytoplankton taxonomic groups as an interactive version of Figure 8 in the recommendation report.