How Clean Is Oldham Lake?
Oldham Lake has fair water quality — typical of lakes with moderate nutrient enrichment. It received a water quality grade of C (Fair) based on EPA monitoring data. Water clarity (Secchi depth): 5.1 ft. Chlorophyll-a (algae): 8.5 µg/L. Trophic State Index: 53.
Cleanliness Snapshot
| Metric | Oldham Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | C | D |
| Water Clarity (Secchi) | 5.1 ft | — |
| Chlorophyll-a (Algae) | 8.5 µg/L | <10 = clean |
| Trophic State Index | 53 | <50 = clean |
How does Oldham Lake compare?
Oldham Lake's grade of C matches or beats the Wisconsin state average of D. It ranks #1 of 2 lakes in Monona County by water quality score.