Lake Mcdonald is a cold, clear oligotrophic lake in Flathead County, Montana. Water quality is graded A based on 2 sampling years through 2018. Compared to the 79 other monitored lakes in Flathead County, Lake Mcdonald ranks #73 for water quality.
Source: EPA Water Quality Portal sampling records, Montana DNR, last sampled 2018-09-19. Grade methodology: LakeGrade methodology.
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Swimming Safety
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A, Excellent
No clarity data. Phosphorus level: 20.5 µg/L. Chlorophyll-a: 0.7 µg/L. Trophic State Index: 37.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 20.5 µg/L | B |
| Chlorophyll-a (Algae) | 0.7 µg/L | A |
| Trophic State Index (TSI) | 37 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lake Mcdonald
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Fishing Lake Mcdonald
Location
County Ranking
Ranked #73 of 80 lakes in Flathead County
Nearby Lakes in Flathead County
Explore Lake Mcdonald across LakeGrade
More Montana Lake Rankings
Other Grade A Lakes in Montana
Oligotrophic 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: 2018-09-19
Monitoring stations: 1