Okamanpeedan Lake
Emmet County, IowaHypereutrophic
Okamanpeedan Lake is a highly nutrient-loaded hypereutrophic lake in Emmet County, Iowa. Water quality is graded F based on 2 sampling years through 2025. Compared to the 1 other monitored lakes in Emmet County, Okamanpeedan Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Iowa DNR, last sampled 2025-09-16. Grade methodology: LakeGrade methodology.
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Swimming Safety
Avoid swimming, very poor water quality, potential algae toxins
Water Quality Grade: F, Very Poor
Very murky, less than 1 ft of visibility. Phosphorus level: 164 µg/L. Trophic State Index: 78.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | F |
| Phosphorus | 164 µg/L | F |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 78 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Location
County Ranking
Ranked #2 of 2 lakes in Emmet County
Nearby Lakes in Emmet County
More Iowa Lake Rankings
Other Grade F Lakes in Iowa
Hypereutrophic Lakes in Iowa
EPA Impairment Status
Okamanpeedan 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 04-EDM-975 · Official waterbody report · Matched by proximity (0.31 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: 2025-09-16
Monitoring stations: 1