Hypereutrophic Lakes in Iowa

47 hypereutrophic lakes in Iowa. 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. 47 hypereutrophic lakes are on the Iowa 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	White Oak Lake	Mahaska	F	1.4 ft	-	72
2	Hannen Lake	Benton	F	1.2 ft	-	76
3	Briggs Woods Lake	Hamilton	F	1.5 ft	-	71
4	Littlefield Lake	Audubon	F	0.9 ft	-	77
5	Union Grove Lake	Tama	F	1.6 ft	-	73
6	Casey Lake	Tama	F	1.2 ft	-	75
7	Meyers Lake	Black Hawk	F	1.1 ft	-	76
8	Swan Lake Max Depth	Carroll	F	1.4 ft	-	73
9	Upper Pine Lake	Hardin	F	1.3 ft	-	73
10	Sands Timber Lake	Taylor	F	1.8 ft	-	70
11	Badger Creek Max Depth Lake	Madison	F	1.6 ft	-	72
12	North Twin Lake	Calhoun	F	1.1 ft	-	70
13	Green Valley Lake	Union	F	1.5 ft	-	71
14	East Lake Osceola	Clarke	F	1.2 ft	-	74
15	Black Hawk Lake	Sac	F	0.9 ft	-	74
16	Silver Lake	Palo Alto	F	1.2 ft	-	72
17	Little Wall Lake	Hamilton	F	0.7 ft	-	78
18	Lake Orient	Adair	F	1.3 ft	-	75
19	Prairie Rose Lake	Shelby	F	1.6 ft	-	72
20	Lake Miami Max Depth	Monroe	F	1.3 ft	-	72
21	Summit Lake	Union	F	1.4 ft	-	70
22	South Prairie Lake	Black Hawk	F	1.6 ft	-	71
23	Lower Pine Lake	Hardin	F	1.3 ft	-	73
24	Mckinley Lake	Union	F	1 ft	-	75
25	Rock Creek Max Depth Lake	Jasper	F	1.1 ft	-	76
26	Lake Keomah	Mahaska	F	1.5 ft	-	71
27	Cedar Lake	Madison	F	1.6 ft	-	71
28	Cedar Lake	Linn	F	0.9 ft	-	79
29	Avenue of the Saints Lake	Bremer	F	1.2 ft	-	75
30	Spring Lake Max Depth	Greene	F	0.7 ft	-	74
31	Lake Darling Max Depth	Washington	F	1.6 ft	-	71
32	Desoto Bend Lake	Harrison	F	1 ft	-	76
33	Lake Manawa	Pottawattamie	F	1 ft	-	75
34	Ottumwa Lagoon Max Depth Lake	Wapello	F	0.9 ft	-	77
35	Arbor Lake Max Depth	Poweshiek	F	1.3 ft	-	71
36	Browns Lake	Woodbury	F	0.6 ft	-	78
37	Williamson Pond Max Depth	Lucas	F	1.6 ft	-	72
38	Indian Lake	Van Buren	F	1.2 ft	-	74
39	Ingham Lake	Emmet	F	1.4 ft	-	71
40	Lake Hendricks	Howard	F	1.5 ft	-	74
41	Blue Lake	Monona	F	0.9 ft	-	73
42	Terry Trueblood Lake	Johnson	F	1.1 ft	-	73
43	Pine Lake South Beach	Hardin	F	1.4 ft	-	73
44	Alice Wyth Lake	Black Hawk	F	1.6 ft	-	73
45	Lpinelk T Lake	Hardin	F	1.3 ft	-	73
46	Rock Creek Beach Lake	Jasper	F	1.1 ft	-	75
47	Okamanpeedan Lake	Emmet	F	1 ft	-	78

All hypereutrophic lakes →Minnesota version →Wisconsin version →Illinois version →Michigan version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →All Iowa lakes →

Source: EPA National Aquatic Resource Surveys, 2026.