How Clean Is Twelve Mile Lake?
Twelve Mile Lake is algae-prone, with a higher bloom risk in warm months. It received a water quality grade of F (Algae-prone) based on EPA monitoring data. Water clarity (Secchi depth): 2.4 ft. Phosphorus: 79 µg/L. Chlorophyll-a (algae): 45 µg/L. Trophic State Index: 67.
Cleanliness Snapshot
| Metric | Twelve Mile Lake | Iowa avg |
|---|---|---|
| Overall Grade | F | D |
| Water Clarity (Secchi) | 2.4 ft | — |
| Phosphorus | 79 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 45 µg/L | <10 = clean |
| Trophic State Index | 67 | <50 = clean |
How does Twelve Mile Lake compare?
Twelve Mile Lake's grade of F falls below the Iowa state average of D. It ranks #2 of 6 lakes in Union County by water quality score. Multi-year monitoring data shows water quality is stable based on 5 years of records.
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