Hypereutrophic Lakes in Iowa

96 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. 96 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	Big Creek Lake	Polk	F	2.6 ft	-	65
2	Arrowhead Lake	Pottawattamie	F	1.8 ft	-	71
3	White Oak Lake	Mahaska	F	1.4 ft	-	73
4	Crystal Lake Max Depth	Hancock	F	1.6 ft	-	70
5	Hannen Lake	Benton	F	1.2 ft	-	76
6	Briggs Woods Lake	Hamilton	F	1.5 ft	-	70
7	Nelson Lake	Crawford	F	3.8 ft	-	65
8	Grays Lake	Polk	F	1.6 ft	-	70
9	Union Grove Lake	Tama	F	1.6 ft	-	74
10	Casey Lake	Tama	F	1.2 ft	-	74
11	Littlefield Lake	Audubon	F	0.9 ft	-	79
12	Meyers Lake	Black Hawk	F	1.1 ft	-	77
13	Diamond Lake	Poweshiek	F	1.6 ft	-	69
14	Lake Belva Deer	Keokuk	F	2.1 ft	-	65
15	Swan Lake Max Depth	Carroll	F	1.4 ft	-	79
16	Black Pit Lake	Cerro Gordo	F	5.6 ft	-	60
17	Badger Lake	Webster	F	2.8 ft	-	66
18	Blue Heron Lake	Polk	F	2.2 ft	-	68
19	Greenfield Lake	Adair	F	2.1 ft	-	70
20	Upper Pine Lake	Hardin	F	1.3 ft	-	72
21	Silver Lake Max Depth	Dickinson	F	2.7 ft	-	70
22	Silver Lake Max Depth	Delaware	F	2.4 ft	-	69
23	Twelve Mile Lake	Union	F	2.4 ft	-	67
24	Sands Timber Lake	Taylor	F	1.8 ft	-	70
25	Crawford Creek Lake	Ida	F	1.6 ft	-	70
26	Badger Creek Max Depth Lake	Madison	F	1.6 ft	-	73
27	North Twin Lake	Calhoun	F	1.1 ft	-	70
28	Lake Ahquabi	Warren	F	1.8 ft	-	67
29	Green Valley Lake	Union	F	1.5 ft	-	71
30	Beeds Lake	Franklin	F	2.5 ft	-	69
31	Black Hawk Lake	Sac	F	0.9 ft	-	75
32	Meadow Lake	Adair	F	1.7 ft	-	70
33	East Lake Osceola	Clarke	F	1.2 ft	-	78
34	Lake Iowa	Iowa	F	1.9 ft	-	68
35	Don Williams Lake	Boone	F	1.8 ft	-	68
36	George Wyth Lake	Black Hawk	F	1.9 ft	-	67
37	Silver Lake	Palo Alto	F	1.2 ft	-	75
38	Little Wall Lake	Hamilton	F	0.7 ft	-	77
39	Ellis Lake	Lucas	F	2 ft	-	66
40	Morris Lake	Lucas	F	1.6 ft	-	70
41	Fort des Moines Park Pond	Polk	F	2.8 ft	-	64
42	Lake Orient	Adair	F	1.3 ft	-	82
43	Lake Anita	Cass	F	2.2 ft	-	65
44	Roberts Creek Lake	Marion	F	1.5 ft	-	71
45	Prairie Rose Lake	Shelby	F	1.6 ft	-	74
46	Lake Miami Max Depth	Monroe	F	1.3 ft	-	73
47	Summit Lake	Union	F	1.4 ft	-	71
48	Rodgers Lake	Benton	F	2.6 ft	-	67
49	South Prairie Lake	Black Hawk	F	1.6 ft	-	71
50	Center Lake	Dickinson	F	2.3 ft	-	65
51	Lower Pine Lake	Hardin	F	1.3 ft	-	75
52	Mckinley Lake	Union	F	1 ft	-	75
53	Brushy Creek Lake	Webster	F	2.8 ft	-	64
54	Lake Icaria	Adams	F	2.7 ft	-	63
55	Rock Creek Max Depth Lake	Jasper	F	1.1 ft	-	77
56	Red Haw Lake	Lucas	F	3.1 ft	-	61
57	Lake Keomah	Mahaska	F	1.5 ft	-	72
58	Cedar Lake	Madison	F	1.6 ft	-	70
59	Cedar Lake	Linn	F	0.9 ft	-	80
60	Beaver Lake	Dallas	F	1.9 ft	-	70
61	Fin And Feather Lake	Cerro Gordo	F	2.3 ft	-	68
62	Five Island Lake	Palo Alto	F	1.6 ft	-	69
63	Avenue of the Saints Lake	Bremer	F	1.2 ft	-	76
64	Spring Lake Max Depth	Greene	F	0.9 ft	-	71
65	Lake Darling Max Depth	Washington	F	1.6 ft	-	75
66	Desoto Bend Lake	Harrison	F	1 ft	-	78
67	Eldred Sherwood Lake	Hancock	F	3 ft	-	65
68	Lake Manawa	Pottawattamie	F	1 ft	-	74
69	Big Hollow Lake	Des Moines	F	1.8 ft	-	70
70	Wilson Lake	Taylor	F	1.6 ft	-	70
71	Ottumwa Lagoon Max Depth Lake	Wapello	F	0.9 ft	-	79
72	Fogle Lake	Ringgold	F	2.3 ft	-	64
73	Arbor Lake Max Depth	Poweshiek	F	1.3 ft	-	71
74	Lake of Three Fires Max Depth	Taylor	F	2 ft	-	69
75	Lake Geode	Des Moines	F	2.1 ft	-	64
76	Browns Lake	Woodbury	F	0.7 ft	-	79
77	Thayer Lake	Union	F	3.5 ft	-	63
78	Williamson Pond Max Depth	Lucas	F	1.6 ft	-	75
79	Indian Lake	Van Buren	F	1.2 ft	-	75
80	Ingham Lake	Emmet	F	1.4 ft	-	73
81	Smith Lake	Kossuth	F	2.4 ft	-	69
82	Lake Sugema	Van Buren	F	2.3 ft	-	64
83	Lake Hendricks	Howard	F	1.5 ft	-	73
84	Viking Lake	Montgomery	F	3.3 ft	-	61
85	Windmill Lake	Taylor	F	2.5 ft	-	66
86	Little River Lake	Decatur	F	2.3 ft	-	69
87	Blue Lake	Monona	F	0.9 ft	-	75
88	Pierce Creek Lake	Page	F	2.2 ft	-	70
89	Lake Pahoja	Lyon	F	1.7 ft	-	73
90	Volga Lake	Fayette	F	2.1 ft	-	67
91	Terry Trueblood Lake	Johnson	F	1.1 ft	-	74
92	Alice Wyth Lake	Black Hawk	F	1.6 ft	-	75
93	Lake Fisher	Davis	F	2 ft	-	67
94	Corydon Reservoir	Wayne	F	1.9 ft	-	77
95	Humeston Reservoir	Wayne	F	1.6 ft	-	72
96	Okamanpeedan Lake	Emmet	F	1 ft	-	75

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 →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 Iowa lakes →

Source: EPA National Aquatic Resource Surveys, 2026.