Is Twelve Mile Lake Safe for Swimming?
Twelve Mile Lake in Union County, Iowa has a water quality grade of F (Algae-prone). Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Water clarity: 2.4 ft visibility. Phosphorus: 79 µg/L. Chlorophyll-a (algae): 45 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | F (Algae-prone) |
| Water Clarity (Secchi Depth) | 2.4 ft |
| Phosphorus | 79 μg/L |
| Chlorophyll-a (Algae) | 45 μg/L |
| Location | Union County, Iowa |
How does Twelve Mile Lake compare?
With an overall water quality grade of F, Twelve Mile Lake falls below the Iowa state average of Grade D. It ranks #2 of 6 lakes in Union County by water quality score.
Water clarity (Secchi depth) sits at 2.4 feet. That signals heavy algae or sediment, often tied to high phosphorus from runoff. Algae levels (chlorophyll-a) measure 45 µg/L — elevated; risk of harmful algal bloom advisories increases at this concentration.
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