Mesotrophic Lakes in Iowa
13 mesotrophic lakes in Iowa. Moderate nutrients, good water quality.
Most well-managed working lakes register as mesotrophic — the band that balances productivity with clarity. 13 lakes in Iowa 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 sit in the middle of the phosphorus and chlorophyll-a range: productive but still clear, with readings that rarely reach the EPA's poorest condition class.
| # | Lake | County | Clarity | Depth | TSI |
|---|---|---|---|---|---|
| 1 | West Okoboji Lake | Dickinson | 15.7 ft | - | 41 |
| 2 | Dale Maffitt Reservoir | Dallas | 9.8 ft | - | 43 |
| 3 | Blue Pit Lake | Cerro Gordo | 17.1 ft | - | 41 |
| 4 | Ada Hayden Heritage Park Lake | Story | 6.8 ft | - | 48 |
| 5 | Little Sioux Park Lake | Woodbury | 5.7 ft | - | 49 |
| 6 | Rudd Lake | Floyd | 8.1 ft | - | 45 |
| 7 | Slipbluff Lake | Decatur | 9 ft | - | 45 |
| 8 | Lacey Keosauqua Lake | Van Buren | 7.1 ft | - | 48 |
| 9 | Yenruogis Pond | Keokuk | 9.9 ft | - | 47 |
| 10 | Sand Lake | Marshall | 6.4 ft | - | 48 |
| 11 | Terra Park Lake | Polk | 11.5 ft | - | 45 |
| 12 | Green Castle Lake | Marshall | 4.6 ft | - | 56 |
| 13 | Lambach Lake | Scott | 7.9 ft | - | 53 |
All mesotrophic 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 →Nova Scotia version →British Columbia version →Newfoundland and Labrador version →All Iowa lakes →
Source: EPA National Aquatic Resource Surveys, 2026.