La Grande Mare
La Grande Mare in Unknown, France has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 110 µg/L.
Why La Grande Mare has no A–F grade
La Grande Mare in France is published with the authority's own measurements, not a LakeQuality letter. official authority class; not a LakeQuality A–F letter Sampling here has recorded phosphorus, but not water clarity and algae (chlorophyll-a).
A letter on the LakeQuality scale would be an invention, not an official class. Everything below that has been measured is still reported on this page.
Monitoring: the French water agencies, via UNEP GEMS/Water.
La Grande Mare is a lake in Unknown County, France.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2023-09-27. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for La Grande Mare
These readings exist but do not meet the evidence bar for an A–F grade — see why.
No clarity data. Phosphorus level: 110 µg/L. Trophic State Index: 72.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | No recent samples | |
| Phosphorus | 110 µg/L | Not graded |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 72 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near La Grande Mare
Compare lakeside cabins, hotels, and vacation rentals near La Grande Mare in Unknown, France — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Fishing La Grande Mare
Frequently asked questions about La Grande Mare
What is the water quality of La Grande Mare?
- La Grande Mare in Unknown, France has official water-quality measurements, not a LakeQuality A–F grade. Phosphorus: 110 µg/L.
Is La Grande Mare safe to swim in?
- La Grande Mare has official nutrient and clarity measurements, not a bacteria swim class and not a safety clearance. Algal blooms, currents, and depth are not covered. Always check local notices before swimming.
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Where this data comes from
4 measurements from 1 monitoring station, 2023. Retrieved from UNEP GEMS/Water GFQA (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- European Environment Agency
europeanenvironmentagenc4 samples · —
Analytical methods
- GEMStat OPEN / CC BY 4.0
Monitoring station identifiers (1)
FRA01811
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See methodology and data sources.
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: 2023-09-27
Monitoring stations: 1