Etang de la Hardouinais
Etang de la Hardouinais in Côtes-d'Armor, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.9 m visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 14.4 µg/L.
- Clarity
- 0.9 m
Why Etang de la Hardouinais has no A–F grade
Etang de la Hardouinais 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, phosphorus 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.
Etang de la Hardouinais is a lake in Côtes-d'Armor County, France.
Source: the French water agencies, via UNEP GEMS/Water — not the EPA Water Quality Portal, last sampled 2019-10-08. 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 de la Hardouinais
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 3 ft of visibility. Phosphorus level: 40 µg/L. Chlorophyll-a: 14.4 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.9 m | Not graded |
| Phosphorus | 40 µg/L | Not graded |
| Chlorophyll-a (Algae) | 14.4 µg/L | Not graded |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Etang de la Hardouinais
Compare lakeside cabins, hotels, and vacation rentals near Etang de la Hardouinais in Côtes-d'Armor, 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 Etang de la Hardouinais
Frequently asked questions about Etang de la Hardouinais
What is the water quality of Etang de la Hardouinais?
- Etang de la Hardouinais in Côtes-d'Armor, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.9 m visibility. Phosphorus: 40 µg/L. Chlorophyll-a (algae): 14.4 µg/L.
Is Etang de la Hardouinais safe to swim in?
- Etang de la Hardouinais 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
24 measurements from 1 monitoring station, 2016–2019. 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-fr24 samples · —
Analytical methods
- Hub'Eau / Naïades plans d'eau
Monitoring station identifiers (1)
J730510
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See how grades are calculated and data sources.