Is Little Rock Lake Safe for Swimming?
Little Rock Lake in Benton County, Minnesota has a water quality grade of F (Very Poor). Avoid swimming, very poor water quality, potential algae toxins. Water clarity: 1.8 ft visibility. Phosphorus: 156.5 µg/L. Chlorophyll-a (algae): 115 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | F (Very Poor) |
| Water Clarity (Secchi Depth) | 1.8 ft |
| Phosphorus | 156.5 μg/L |
| Chlorophyll-a (Algae) | 115 μg/L |
| Maximum Depth | 17 ft |
| Location | Benton County, Minnesota |
How does Little Rock Lake compare?
With an overall water quality grade of F, Little Rock Lake falls below the Minnesota state average of Grade C. It ranks #1 of 1 lakes in Benton County by water quality score.
Water clarity (Secchi depth) sits at 1.8 feet. That signals heavy algae or sediment, often tied to high phosphorus from runoff. Algae levels (chlorophyll-a) measure 115 µg/L — elevated; risk of harmful algal bloom advisories increases at this concentration.