Mann Lake
Lanark, OntarioView mapDirections
Ontario MECP publishes the water-quality measurements for Mann Lake. Here is what has been measured.
- 32 ft max depth
- Limited data
Mann Lake in Lanark, Ontario has water-quality measurements published by Ontario MECP, shown here as reported. Phosphorus: 16.4 µg/L.
Mann Lake is a lake in Lanark County, Ontario with an estimated average depth of about 32 feet.
Source: Ontario open-data programmes (Lake Partner Program and Broad-scale Monitoring) — not the EPA Water Quality Portal, last sampled 2011-07-20. Methodology: how these readings are compared.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Mann Lake is safe to swim in today is a call for the Ontario Ministry of the Environment, Conservation and Parks and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Mann Lake
These are the measurements Ontario MECP publishes for Mann Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
No clarity data. Phosphorus 16.4 µg/L. TSI 44.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | No reading How deep a black-and-white disk stays visible from the surface. Higher is clearer. | |
| Total phosphorus | 16.4µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 44 | Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Moderate nutrients, good water quality
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Lake Details
Max depth
~9.8 m est.
Depth marked “est.” is a modeled maximum from GLOBathy (Khazaei et al. 2022, CC0), not a measured survey. Ontario has not published bathymetry for Mann Lake.
Lake Size & Watershed
Watershed (drainage) area
1 sq mi
HydroLAKES / HydroSHEDS
Surface area
42 acres
HydroLAKES / HydroSHEDS
Shoreline
2 mi
HydroLAKES / HydroSHEDS
Elevation
879 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.
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Frequently asked questions about Mann Lake
Where is Mann Lake?
- Mann Lake is a lake in Lanark, Ontario. Its water-quality measurements are published by Ontario MECP and shown on this page as reported.
What is the water quality of Mann Lake?
- Mann Lake in Lanark, Ontario has water-quality measurements published by Ontario MECP, shown here as reported. Phosphorus: 16.4 µg/L.
Is Mann Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
How deep is Mann Lake?
- No published bathymetric survey covers Mann Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 32 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
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Where this data comes from
Measurements for Mann Lake come from Ontario open-data programmes (Lake Partner Program and Broad-scale Monitoring), not the EPA Water Quality Portal. Per-sample source details are not recorded for this lake. Contains information licensed under the Open Government Licence – Ontario. See data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)