Boneau Reservoir is a productive, nutrient-rich eutrophic lake in Chouteau County, Montana. Water quality is graded D based on 2 sampling years through 2022. Compared to the 2 other monitored lakes in Chouteau County, Boneau Reservoir ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DNR, last sampled 2022-09-20. 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: 50 µg/L. Chlorophyll-a: 39 µg/L. Trophic State Index: 64.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 50 µg/L | C |
| Chlorophyll-a (Algae) | 39 µg/L | F |
| Trophic State Index (TSI) | 64 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Boneau Reservoir
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Fishing Boneau Reservoir
Location
County Ranking
Ranked #2 of 3 lakes in Chouteau County
Cleaner Lakes Within 30 Miles
Boneau Reservoir holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Chouteau County
Explore Boneau Reservoir across LakeGrade
More Montana Lake Rankings
Other Grade D Lakes in Montana
Eutrophic Lakes in Montana
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: 2022-09-20
Monitoring stations: 3