Matawinie County, Québec · Water Quality Report Card
Lac Gervais
Lac Gervais in Matawinie, Québec received a water quality grade of C (Fair). Water clarity: 1.4 m visibility. Phosphorus: 21.9 µg/L. Chlorophyll-a (algae): 12.9 µg/L.
- Clarity
- 1.4 m
- Type
- Eutrophic
Lac Gervais is a productive, nutrient-rich eutrophic lake in Matawinie County, Québec. Water quality is graded C based on 3 sampling years through 2025. Compared to the 111 other monitored lakes in Matawinie County, Lac Gervais ranks #110 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
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 4.6 ft. Phosphorus level: 21.9 µg/L. Chlorophyll-a: 12.9 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.4 m | D |
| Phosphorus | 21.9 µg/L | B |
| Chlorophyll-a (Algae) | 12.9 µg/L | C |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
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Fishing Lac Gervais
Location
County Ranking
Ranked #110 of 112 lakes in Matawinie
Cleaner Lakes Within 30 Miles
Lac Gervais holds Grade C. 5 nearby lakes hold higher grades.
- ALac VertMatawinie · 1.3 mi · Two grade letters higher (C → A)
- ALac MondorMatawinie · 3.5 mi · Two grade letters higher (C → A)
- ALac MironMatawinie · 3.6 mi · Two grade letters higher (C → A)
- ALac ClairMatawinie · 3.5 mi · Two grade letters higher (C → A)
- BLac NoirMatawinie · 2.6 mi · Higher grade (C → B)
Nearby Lakes in Matawinie
Explore Lac Gervais across LakeGrade
More Québec Lake Rankings
Other Grade C Lakes in Québec
Eutrophic Lakes in Québec
More records, surveys & data sources
Where this data comes from
Measurements for Lac Gervais 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: