What are hypereutrophic lakes in Wisconsin?

28 hypereutrophic lakes in Wisconsin. Very high nutrients, dense algae, poor clarity.

What does hypereutrophic mean?

Very high nutrients, dense algae, poor clarity.

Hypereutrophic Lakes in Wisconsin

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. 28 hypereutrophic lakes are on the Wisconsin books. Almost none of them are deep — 11% break 50 feet. Shallow basin plus heavy nutrient input is the consistent recipe.

Hypereutrophic lakes carry the highest phosphorus and chlorophyll-a readings on record; the trophic class and the readings are measuring closely related dimensions of the same underlying nutrient regime.

#	Lake	County	Clarity	Depth	TSI
1	Beaver Dam Lake	Dodge	1 ft	-	80
2	Rice Lake	Dane	1.5 ft	8 ft	76
3	Indian Lake	Dane	0.7 ft	-	84
4	Big Eau Pleine Lake	Marathon	1.5 ft	-	73
5	Eagle Lake	Racine	1.5 ft	11 ft	72
6	Comus Lake	Walworth	1.5 ft	6 ft	76
7	Lake Koshkonong	Jefferson	1.7 ft	7 ft	77
8	Ludden Lake	Iowa	1.5 ft	14 ft	75
9	Beckers Lake	Calumet	1.5 ft	52.5 ft	73
10	Mason Lake	Adams	1.1 ft	9 ft	73
11	Upper Vermillion Lake	Barron	1.7 ft	9 ft	73
12	Odana Pond	Dane	1 ft	5 ft	82
13	Lazy Lake	Columbia	4 ft	8 ft	71
14	Yellowstone Lake	Lafayette	1.3 ft	14 ft	75
15	Chilton Millpond	Calumet	2.9 ft	7 ft	74
16	Little Lake Butte des Morts	Winnebago	2 ft	18 ft	71
17	Garner Lake	Richland	1.3 ft	8 ft	73
18	Dexter Lake	Wood	1.5 ft	17 ft	82
19	Investment Court Pond	Dane	-	-	92
20	Silent Street Pond	Dane	-	-	94
21	Outlet To Lake Geneva	Walworth	-	135 ft	98
22	Prairie Oaks Pond	Dane	-	-	89
23	Cathedral Point Pond	Dane	-	-	84
24	Decorah Lake	Juneau	-	15 ft	73
25	Lake Tomah	Monroe	-	19 ft	75
26	County K Marsh Lake	Green Lake	-	-	75
27	Silver Creek Estuary Lake	Green Lake	-	236 ft	74
28	Giltners Lake	Fond du Lac	-	13 ft	78

All hypereutrophic lakes →Minnesota version →Illinois version →Michigan version →Iowa 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 →Nova Scotia version →British Columbia version →Newfoundland and Labrador version →All Wisconsin lakes →

Source: EPA National Aquatic Resource Surveys, 2026.