How Clean Is Decatur Lake?
Decatur Lake is nutrient-rich, with elevated phosphorus and algae. It received a water quality grade of D (Nutrient-rich) based on EPA monitoring data. Water clarity (Secchi depth): 1.3 ft. Phosphorus: 103 µg/L. Chlorophyll-a (algae): 25 µg/L. Trophic State Index: 69.
Cleanliness Snapshot
| Metric | Decatur Lake | Illinois avg |
|---|---|---|
| Overall Grade | D | D |
| Water Clarity (Secchi) | 1.3 ft | — |
| Phosphorus | 103 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 25 µg/L | <10 = clean |
| Trophic State Index | 69 | <50 = clean |
How does Decatur Lake compare?
Decatur Lake's grade of D matches or beats the Illinois state average of D. It ranks #1 of 1 lakes in Macon County by water quality score.
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