Etang du Grand Coulon
Etang du Grand Coulon in Marne, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.5 m visibility. Chlorophyll-a (algae): 59 µg/L.
- Clarity
- 0.5 m
Why Etang du Grand Coulon has no A–F grade
Etang du Grand Coulon 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 water clarity and algae (chlorophyll-a), but not phosphorus.
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.
Etang du Grand Coulon is a lake in Marne County, France.
Source: the French water agencies, via UNEP GEMS/Water — not the EPA Water Quality Portal, last sampled 2021-09-22. 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 Etang du Grand Coulon
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 1.6 ft of visibility. Chlorophyll-a: 59 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.5 m | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 59 µg/L | Not graded |
| Trophic State Index (TSI) | 70 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Etang du Grand Coulon
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Fishing Etang du Grand Coulon
Frequently asked questions about Etang du Grand Coulon
What is the water quality of Etang du Grand Coulon?
- Etang du Grand Coulon in Marne, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.5 m visibility. Chlorophyll-a (algae): 59 µg/L.
Is Etang du Grand Coulon safe to swim in?
- Etang du Grand Coulon 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
8 measurements from 1 monitoring station, 2021. Retrieved from UNEP GEMS/Water GFQA (not the EPA Water Quality Portal) on 2026-08-20.
Collected and reported by
- Office français de la biodiversité (Hub'Eau)
hubeau-fr8 samples · —
Analytical methods
- Hub'Eau / Naïades plans d'eau
Monitoring station identifiers (1)
F1237203
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See how grades are calculated and data sources.