Mékinac County, Québec · Water Quality Report Card
Lac à la Roche
Lac à la Roche in Mékinac, Québec received a water quality grade of A (Excellent). Phosphorus: 9.8 µg/L. Chlorophyll-a (algae): 3.3 µg/L.
- Type
- Oligotrophic
Lac à la Roche is a cold, clear oligotrophic lake in Mékinac County, Québec. Water quality is graded A based on 2 sampling years through 2025. Compared to the 24 other monitored lakes in Mékinac County, Lac à la Roche ranks #8 for water quality.
Source: EPA Water Quality Portal sampling records, MELCCFP, last sampled 2025-08-01. 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: 9.8 µg/L. Chlorophyll-a: 3.3 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No data | |
| Phosphorus | 9.8 µg/L | A |
| Chlorophyll-a (Algae) | 3.3 µg/L | A |
| Trophic State Index (TSI) | 40 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Lac à la Roche
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Fishing Lac à la Roche
Location
County Ranking
Ranked #8 of 25 lakes in Mékinac
Nearby Lakes in Mékinac
Explore Lac à la Roche across LakeGrade
More Québec Lake Rankings
Other Grade A Lakes in Québec
Oligotrophic Lakes in Québec
More records, surveys & data sources
Where this data comes from
Measurements for Lac à la Roche come from the EPA Water Quality Portal. Per-sample source details are not recorded for this lake.
Data Sources
Water quality data from the EPA Water Quality Portal
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion
Most recent sample: 2025-08-01
Monitoring stations: