Hypereutrophic Lakes in Colorado
3 hypereutrophic lakes in Colorado. 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. 3 hypereutrophic lakes are on the Colorado 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 | Prospect Lake | El Paso | F | 1.6 ft | - | 75 |
| 2 | Prospect Lake | Weld | F | - | - | 77 |
| 3 | North Sterling Reservoir | Logan | F | 1.1 ft | - | 78 |
All hypereutrophic 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.