Mesotrophic Lakes in Idaho
4 mesotrophic lakes in Idaho. Moderate nutrients, good water quality.
Mesotrophic lakes are the productive middle of the trophic scale — TSI between 40 and 50. Clear enough to be inviting, productive enough to support a strong fishery, with moderate phosphorus and a modest algal community that does not dominate the optical signal. 4 lakes in Idaho sit in the mesotrophic band. About 0% are deep (50+ ft); the rest are shallower basins where watershed management keeps nutrients from pushing the system into eutrophy.
Mesotrophic lakes tend to grade B or C on our A–F scale — the productive-but-clear band lines up with the middle of the letter grades.
| # | Lake | County | Grade | Clarity | Depth | TSI |
|---|---|---|---|---|---|---|
| 1 | Black Cnyn Reservoir Ns of | Gem | A | 7.5 ft | - | 48 |
| 2 | Lake Lowell Across From Upper Embankment | Canyon | A | 7.2 ft | - | 49 |
| 3 | Pasisades Reservoir | Bonneville | C | 10.5 ft | - | 42 |
| 4 | Palisades Lake | Bonneville | C | 13.1 ft | - | 42 |
All mesotrophic 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 →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona 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 Idaho lakes →
Source: EPA National Aquatic Resource Surveys, 2026.