Blue Lake
Monona County, WisconsinHypereutrophic
Blue Lake is a highly nutrient-loaded hypereutrophic lake in Monona County, IA. Water quality is graded F based on 2 sampling years through 2024. Compared to the 1 other monitored lakes in Monona County, Blue Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, local state DNR records, last sampled 2024-09-19. Grade methodology: LakeGrade methodology.
Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 0.9 ft of visibility. Chlorophyll-a: 37 µg/L. Trophic State Index: 73.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 ft | F |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | 37 µg/L | F |
| Trophic State Index (TSI) | 73 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Location
County Ranking
Ranked #2 of 2 lakes in Monona County
Cleaner Lakes Within 30 Miles
Blue Lake holds Grade F. 3 nearby lakes hold higher grades.
- COldham LakeMonona County · 19.1 mi · Two grade letters higher (F → C)
- CWillow LakeHarrison County · 26.9 mi · Two grade letters higher (F → C)
- DSnyder Bend LakeWoodbury County · 18.7 mi · Higher grade (F → D)
Nearby Lakes in Monona County
More Wisconsin Lake Rankings
Other Grade F Lakes in Wisconsin
Hypereutrophic Lakes in Wisconsin
EPA Impairment Status
Blue Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit IA 06-WEM-1728 · Official waterbody report · Matched by proximity (1.31 km)
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-19
Monitoring stations: 1