How Clean Is Mark Twain Lake?
Mark Twain Lake has poor water quality, with elevated phosphorus and algae. It received a water quality grade of D (Poor) based on EPA monitoring data. Water clarity (Secchi depth): 2.5 ft. Phosphorus: 60.8 µg/L. Chlorophyll-a (algae): 18.3 µg/L. Trophic State Index: 62.
Cleanliness Snapshot
| Metric | Mark Twain Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | D | C |
| Water Clarity (Secchi) | 2.5 ft | — |
| Phosphorus | 60.8 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 18.3 µg/L | <10 = clean |
| Trophic State Index | 62 | <50 = clean |
How does Mark Twain Lake compare?
Mark Twain Lake's grade of D falls below the Wisconsin state average of C. It ranks #3 of 4 lakes in Ralls County by water quality score.