Is Upper Estuary Lake Safe for Swimming?
Upper Estuary Lake in St. Louis County, Minnesota has a water quality grade of C (Fair). Generally safe for swimming, moderate water quality. Water clarity: 1.9 ft visibility. Phosphorus: 49.5 µg/L. Chlorophyll-a (algae): 1.7 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | C (Fair) |
| Water Clarity (Secchi Depth) | 1.9 ft |
| Phosphorus | 49.5 μg/L |
| Chlorophyll-a (Algae) | 1.7 μg/L |
| Maximum Depth | 55 ft |
| Location | St. Louis County, Minnesota |
How does Upper Estuary Lake compare?
With an overall water quality grade of C, Upper Estuary Lake matches or beats the Minnesota state average of Grade C. It ranks #62 of 68 lakes in St. Louis County by water quality score.
Water clarity (Secchi depth) sits at 1.9 feet. That signals heavy algae or sediment, often tied to high phosphorus from runoff. Algae levels (chlorophyll-a) measure 1.7 µg/L — low and well within safe swimming guidelines.