Mann Creek Reservoir is a highly nutrient-loaded hypereutrophic lake in Washington County, Idaho. Water quality is graded D based on 2 sampling years through 2021. Compared to the 2 other monitored lakes in Washington County, Mann Creek Reservoir ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Idaho DNR, last sampled 2021-07-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
No clarity data. Phosphorus level: 53.5 µg/L. Chlorophyll-a: 179 µg/L. Trophic State Index: 72.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 53.5 µg/L | C |
| Chlorophyll-a (Algae) | 179 µg/L | F |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Mann Creek Reservoir
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Fishing Mann Creek Reservoir
Location
County Ranking
Ranked #3 of 3 lakes in Washington County
Nearby Lakes in Washington County
Explore Mann Creek Reservoir across LakeGrade
More Idaho Lake Rankings
Other Grade D Lakes in Idaho
More records, surveys & data sources
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2021-07-21
Monitoring stations: 1