Etang de la Grosse Pierre
Yvelines, FranceView mapDirections
Eau France publishes the water-quality measurements for Etang de la Grosse Pierre. Here is what has been measured.
- Limited data
Etang de la Grosse Pierre in Yvelines, France has official water-quality measurements, shown as reported. Water clarity: 0.9 m visibility. Chlorophyll-a (algae): 42 µg/L.
How Etang de la Grosse Pierre is classified
Etang de la Grosse Pierre in France is published with the authority's own measurements and class. The measurements here are published by the agency that samples the lake, as reported. Sampling here has recorded water clarity and algae (chlorophyll-a), but not phosphorus.
LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.
Monitoring: the French water agencies, via UNEP GEMS/Water.
Etang de la Grosse Pierre is a lake in Yvelines County, France.
Source: the French water agencies, via UNEP GEMS/Water — not the EPA Water Quality Portal, last sampled 2022-09-20. 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 Etang de la Grosse Pierre is safe to swim in today is a call for the French water agencies, via UNEP GEMS/Water and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Etang de la Grosse Pierre
These are the measurements Eau France publishes for Etang de la Grosse Pierre. More on the source.
Very murky, less than 3 ft of visibility. Chlorophyll-a 42 µg/L. TSI 64.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 0.9m | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| Chlorophyll-a (algae) | 42µg/L | Measured, not scored 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. | 64 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
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Frequently asked questions about Etang de la Grosse Pierre
Where is Etang de la Grosse Pierre?
- Etang de la Grosse Pierre is a lake in Yvelines, France. This page reports official water-quality measurements, shown as reported.
What is the water quality of Etang de la Grosse Pierre?
- Etang de la Grosse Pierre in Yvelines, France has official water-quality measurements, shown as reported. Water clarity: 0.9 m visibility. Chlorophyll-a (algae): 42 µg/L.
Is Etang de la Grosse Pierre safe to swim in?
- Etang de la Grosse Pierre 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, 2022. 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)
H3009523
Authority classifications are shown as the authority published them. See where the data comes from and data sources.