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LakeQuality

Lac Trois Milles

Mékinac, QuébecView mapDirections

zone de transition oligo-mésotrophe

This is MELCCFP's own trophic classification for 2025, not a LakeQuality grade. See every year

Clarity
2.6 m
Secchi · sampled 2025
Phosphorus
8.4 µg/L
Measured by MELCCFP
Chlorophyll-a
3.3 µg/L
Measured by MELCCFP
Max depth
~12.2 m est.
GLOBathy model
  • 40 ft max depth

Lac Trois Milles in Mékinac, Québec is classified zone de transition oligo-mésotrophe by Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec) for 2025. Water clarity: 2.6 m visibility. Phosphorus: 8.4 µg/L. Chlorophyll-a (algae): 3.3 µg/L.

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Lac Trois Milles is a lake in Mékinac County, Québec with an estimated average depth of about 40 feet.

Source: Québec RSVL (MELCCFP) — not the EPA Water Quality Portal, last sampled 2025-08-01. Grade methodology: LakeQuality methodology.

Swimming conditions

No reading

Not rated

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Lac Trois Milles 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.

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Water quality measurements for Lac Trois Milles

These are the measurements MELCCFP publishes for Lac Trois Milles, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.

Moderate clarity, visible to about 8.5 ft. Phosphorus 8.4 µg/L. Chlorophyll-a 3.3 µg/L.

MetricValueEPA condition class
Water Clarity (Secchi Depth)2.6 mMeasured, not scored
Phosphorus8.4 µg/LMeasured, not scored
Chlorophyll-a (Algae)3.3 µg/LMeasured, not scored

Lake Details

CharacteristicValue
Maximum Depth~12.2 m est.
Average Depth~6.7 m est.

Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Québec has not published bathymetry for Lac Trois Milles.

Lake Size & Watershed

Watershed (drainage) area
6 sq mi
Surface area
104 acres
Shoreline
5.3 mi
Elevation
692 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.

Fishing Lac Trois Milles

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Frequently asked questions about Lac Trois Milles

Ask about Lac Trois Milles

Answers come straight from the public measurements and survey records on this page.

Where is Lac Trois Milles?

Lac Trois Milles is a lake in Mékinac, Québec. MELCCFP classifies it zone de transition oligo-mésotrophe for 2025. This is MELCCFP's own trophic classification for 2025, not a LakeQuality grade.

What is the water quality of Lac Trois Milles?

Lac Trois Milles in Mékinac, Québec is classified zone de transition oligo-mésotrophe by Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs (Québec) for 2025. Water clarity: 2.6 m visibility. Phosphorus: 8.4 µg/L. Chlorophyll-a (algae): 3.3 µg/L.

Is Lac Trois Milles safe to swim in?

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

How deep is Lac Trois Milles?

No published bathymetric survey covers Lac Trois Milles, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 40 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.

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 Lac Trois Milles. It is shown here as theirs, in their words, and is not folded into the LakeQuality letter.

Most recent, 2025
zone de transition oligo-mésotrophe

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 (3 classified 2023–2025)
YearPublished class
2024classe mésotrophe
2023zone de transition oligo-mésotrophe

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 Lac Trois Milles 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.

Other records on this page

Lake size & watershed from HydroLAKES (HydroSHEDS)