What are eutrophic lakes in Colorado?

12 eutrophic lakes in Colorado. High nutrients, frequent algae, reduced clarity.

What does eutrophic mean?

High nutrients, frequent algae, reduced clarity.

Eutrophic Lakes in Colorado

A eutrophic lake is a productive ecosystem with the trade-offs that come with productivity: more food at the base of the food web, more clarity reduction by mid-summer, more dissolved-oxygen variability near the bottom. 12 Colorado lakes register as eutrophic. Only 0% are deep — eutrophy correlates with shallowness, agricultural watersheds, and the kind of nutrient-input history that takes decades to shift.

Eutrophic lakes typically grade C or D on our A–F scale. The same nutrient richness that defines the trophic class drives the lower grade.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Chatfield Reservoir	Jefferson	B	6.2 ft	-	51
2	Windsor Lake	Weld	D	2 ft	-	68
3	Deweese Reservoir	Custer	D	5.2 ft	-	56
4	Jackson Reservoir	Morgan	D	2.1 ft	-	64
5	Union Reservoir	Weld	D	3.2 ft	-	54
6	Beaver Creek Reservoir	Rio Grande	D	6.2 ft	-	53
7	Eggleston Lake	Delta	D	4.9 ft	-	64
8	Big Meadows Reservoir	Mineral	D	7.2 ft	-	50
9	Vega Reservoir	Mesa	D	3.9 ft	-	60
10	Horse Creek Outlet Lake	Weld	D	-	-	78
11	Stagecoach Lake	Routt	D	-	-	61
12	Twin Lake West Lower	Lake	D	-	-	59

All eutrophic lakes →Minnesota version →Wisconsin 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 →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 Colorado lakes →

Source: EPA National Aquatic Resource Surveys, 2026.