American Falls Reservoir is a productive, nutrient-rich eutrophic lake in Power County, Idaho. Water quality is graded C based on 2 sampling years through 2024. Compared to the 5 other monitored lakes in Power County, American Falls Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Idaho DNR, last sampled 2024-07-23. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
No clarity data. Phosphorus level: 32 µg/L. Chlorophyll-a: 13.4 µg/L. Trophic State Index: 55.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 32 µg/L | C |
| Chlorophyll-a (Algae) | 13.4 µg/L | C |
| Trophic State Index (TSI) | 55 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near American Falls Reservoir
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Fishing American Falls Reservoir
Location
County Ranking
Ranked #2 of 6 lakes in Power County
Cleaner Lakes Within 30 Miles
American Falls Reservoir holds Grade C. 2 nearby lakes hold higher grades.
- BNla LakeBingham County · 20.9 mi · Higher grade (C → B)
- BAmerican Falls R LakeBannock County · 14.3 mi · Higher grade (C → B)
Nearby Lakes in Power County
Explore American Falls Reservoir across LakeGrade
More Idaho Lake Rankings
Other Grade C Lakes in Idaho
Eutrophic 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: 2024-07-23
Monitoring stations: 2