Is High Island Lake Safe for Swimming?
High Island Lake in Sibley County, Minnesota has a water quality grade of D (Nutrient-rich). Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Water clarity: 2.1 ft visibility. Phosphorus: 180 µg/L. Chlorophyll-a (algae): 14.6 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | D (Nutrient-rich) |
| Water Clarity (Secchi Depth) | 2.1 ft |
| Phosphorus | 180 μg/L |
| Chlorophyll-a (Algae) | 14.6 μg/L |
| Maximum Depth | 6.5 ft |
| Location | Sibley County, Minnesota |
How does High Island Lake compare?
With an overall water quality grade of D, High Island Lake falls below the Minnesota state average of Grade C. It ranks #1 of 2 lakes in Sibley County by water quality score.
Water clarity (Secchi depth) sits at 2.1 feet. That signals heavy algae or sediment, often tied to high phosphorus from runoff. Algae levels (chlorophyll-a) measure 14.6 µg/L — moderate; acceptable for swimming on most days, but worth checking advisories.