Island Park Reservoir is a mesotrophic lake in Broadwater County, Montana. Water quality is graded B based on 2 sampling years through 2024. Compared to the 2 other monitored lakes in Broadwater County, Island Park Reservoir ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DNR, last sampled 2024-09-17. Grade methodology: LakeGrade methodology.
Watch Island Park Reservoir water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
No clarity data. Phosphorus level: 23.5 µg/L. Chlorophyll-a: 6.3 µg/L. Trophic State Index: 49.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 23.5 µg/L | B |
| Chlorophyll-a (Algae) | 6.3 µg/L | B |
| Trophic State Index (TSI) | 49 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Island Park Reservoir
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Top-rated places to stay near Island Park Reservoir
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Fishing Island Park Reservoir
Location
County Ranking
Ranked #1 of 3 lakes in Broadwater County
Nearby Lakes in Broadwater County
Explore Island Park Reservoir across LakeGrade
More Montana Lake Rankings
Other Grade B Lakes in Montana
Mesotrophic 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: 2024-09-17
Monitoring stations: 1