How Clean Is Old Reservoir?
Old Reservoir 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): 3.6 ft. Phosphorus: 33 µg/L. Chlorophyll-a (algae): 14.2 µg/L. Trophic State Index: 57.
Cleanliness Snapshot
| Metric | Old Reservoir | Wisconsin avg |
|---|---|---|
| Overall Grade | C | C |
| Water Clarity (Secchi) | 3.6 ft | — |
| Phosphorus | 33 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 14.2 µg/L | <10 = clean |
| Trophic State Index | 57 | <50 = clean |
How does Old Reservoir compare?
Old Reservoir's grade of C matches or beats the Wisconsin state average of C. It ranks #1 of 7 lakes in Randolph County by water quality score.