Petit Lac Saint-Mathieu
Les Basques, QuébecView mapDirections
This is MELCCFP's own trophic classification for 2025, not a LakeQuality grade. See every year
Petit Lac Saint-Mathieu in Les Basques, Québec is classified classe eutrophe by Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec) for 2025. Water clarity: 1.6 m visibility. Phosphorus: 12.6 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
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Petit Lac Saint-Mathieu is a lake in Les Basques County, Québec.
Source: Québec RSVL (MELCCFP) — not the EPA Water Quality Portal, last sampled 2025-08-01. Grade methodology: LakeQuality methodology.
Swimming conditions
No readingNot rated
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Petit Lac Saint-Mathieu is safe to swim in today is a call for le Ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Petit Lac Saint-Mathieu
These are the measurements MELCCFP publishes for Petit Lac Saint-Mathieu, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5.2 ft. Phosphorus 12.6 µg/L. Chlorophyll-a 3.2 µg/L.
| Metric | Value | EPA condition class |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.6 m | Measured, not scored |
| Phosphorus | 12.6 µg/L | Measured, not scored |
| Chlorophyll-a (Algae) | 3.2 µg/L | Measured, not scored |
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Frequently asked questions about Petit Lac Saint-Mathieu
Ask about Petit Lac Saint-Mathieu
Answers come straight from the public measurements and survey records on this page.
Where is Petit Lac Saint-Mathieu?
- Petit Lac Saint-Mathieu is a lake in Les Basques, Québec. MELCCFP classifies it classe eutrophe for 2025. This is MELCCFP's own trophic classification for 2025, not a LakeQuality grade.
What is the water quality of Petit Lac Saint-Mathieu?
- Petit Lac Saint-Mathieu in Les Basques, Québec is classified classe eutrophe by Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec) for 2025. Water clarity: 1.6 m visibility. Phosphorus: 12.6 µg/L. Chlorophyll-a (algae): 3.2 µg/L.
Is Petit Lac Saint-Mathieu safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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The authority’s own classification
Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec) publishes its own classification for Petit Lac Saint-Mathieu. It is shown here as theirs, in their words, and is not folded into the LakeQuality letter.
This is MELCCFP's own trophic classification for 2025, not a LakeQuality grade.
A trophic class ranks how nutrient-rich a lake is, from oligotrophic at the low end to eutrophic at the high end. It describes nutrients and plant growth, not bacteria, and it is not a swimming clearance.
Earlier years (5 classified 2020–2025)
| Year | Published class |
|---|---|
| 2024 | zone de transition oligo-mésotrophe |
| 2023 | zone de transition oligo-mésotrophe |
| 2022 | zone de transition méso-eutrophe |
| 2020 | classe eutrophe |
Published by Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec). A classification is not a same-day swimming clearance. See data sources.
Where this data comes from
Measurements for Petit Lac Saint-Mathieu come from the Réseau de surveillance volontaire des lacs (RSVL), not the EPA Water Quality Portal. Per-sample source details are not recorded for this lake. MELCCFP RSVL (CC BY 4.0). See data sources.