How Clean Is Otter Lake?
Otter 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): 1.8 ft. Phosphorus: 81 µg/L. Chlorophyll-a (algae): 33.1 µg/L. Trophic State Index: 67.
Cleanliness Snapshot
| Metric | Otter Lake | Illinois avg |
|---|---|---|
| Overall Grade | F | D |
| Water Clarity (Secchi) | 1.8 ft | — |
| Phosphorus | 81 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 33.1 µg/L | <10 = clean |
| Trophic State Index | 67 | <50 = clean |
How does Otter Lake compare?
Otter Lake's grade of F falls below the Illinois state average of D. It ranks #2 of 3 lakes in Macoupin County by water quality score.
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