Retenue de Saint Michel
Retenue de Saint Michel in Finistère, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 1 m visibility. Chlorophyll-a (algae): 4.5 µg/L.
- Clarity
- 1 m
Why Retenue de Saint Michel has no A–F grade
Retenue de Saint Michel 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.
Retenue de Saint Michel is a lake in Finistère County, France.
Source: the French water agencies, via UNEP GEMS/Water — not the EPA Water Quality Portal, last sampled 2025-10-09. 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 Retenue de Saint Michel
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 3.4 ft. Chlorophyll-a: 4.5 µg/L. Trophic State Index: 52.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1.04 m | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | 4.5 µg/L | Not graded |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Retenue de Saint Michel
Compare lakeside cabins, hotels, and vacation rentals near Retenue de Saint Michel in Finistère, 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 Retenue de Saint Michel
Frequently asked questions about Retenue de Saint Michel
What is the water quality of Retenue de Saint Michel?
- Retenue de Saint Michel in Finistère, France has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 1 m visibility. Chlorophyll-a (algae): 4.5 µg/L.
Is Retenue de Saint Michel safe to swim in?
- Retenue de Saint Michel 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, 2017–2025. 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)
J362510T
Authority classifications are stored separately from LakeQuality A–F letters and are never blended. See how grades are calculated and data sources.