Hypereutrophic Lakes in Ohio
1 hypereutrophic lakes in Ohio. Very high nutrients, dense algae, poor clarity.
Hypereutrophic lakes (TSI above 70) are at the upper end of the productivity scale: visible algal blooms most weeks of summer, clarity often under 3 feet, and meaningful risk of harmful-algal-bloom toxin events. 1 hypereutrophic lakes are on the Ohio books. Almost none of them are deep — 0% break 50 feet. Shallow basin plus heavy nutrient input is the consistent recipe.
Hypereutrophic lakes overwhelmingly grade D or F — the trophic class and the grade are measuring closely-related dimensions of the same underlying nutrient regime.
| # | Lake | County | Grade | Clarity | Depth | TSI |
|---|---|---|---|---|---|---|
| 1 | Charles Mill Reservoir | Ashland | F | 0.9 ft | - | 79 |
All hypereutrophic lakes →Minnesota version →Wisconsin version →Illinois version →Michigan version →Iowa version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →All Ohio lakes →
Source: EPA National Aquatic Resource Surveys, 2026.