Hypereutrophic Lakes in Ohio

19 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. 19 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	Maumee R Upst Independence Dam Lake	Defiance	D	-	-	75
2	Amann Reservoir	Morrow	D	-	-	83
3	Buck Creek Lake	Clark	F	2.5 ft	-	63
4	Buck Creek Lake	Clark	F	2.3 ft	-	63
5	Buck Creek Lake	Clark	F	2.5 ft	-	63
6	Buck Creek Lake	Clark	F	2 ft	-	64
7	Tappan Lake	Harrison	F	1.8 ft	-	68
8	Auglaize R Lake	Paulding	F	-	-	74
9	Grand Lake St Marys	Mercer	F	-	-	83
10	Spring Valley Lake Lake	Columbiana	F	-	-	82
11	Somerset Reservoir	Perry	F	-	-	65
12	Grand Lake St Marys @ Intake	Mercer	F	-	-	84
13	St Joseph Lake	Perry	F	-	-	67
14	Alum Creek Lake	Delaware	F	-	-	69
15	Amicks Reservoir	Morrow	F	-	-	65
16	O'Shaughnessy Reservoir Lake	Delaware	F	-	-	73
17	Bresler Reservoir	Allen	F	-	-	67
18	Hoover Reservoir	Franklin	F	-	-	66
19	Hoover Reservoir	Delaware	F	-	-	75

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 →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Washington version →Wyoming version →Georgia version →Massachusetts version →Ontario version →Québec version →All Ohio lakes →

Source: EPA National Aquatic Resource Surveys, 2026.