Köyliönjärvi
Köyliönjärvi in Säkylä, Finland has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.6 m visibility. Phosphorus: 92 µg/L. Chlorophyll-a (algae): 75.5 µg/L. Maximum depth: 27.9 ft.
- Clarity
- 0.6 m
- Max depth
- 8.5 m
Why Köyliönjärvi has no A–F grade
Köyliönjärvi in Finland 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 Finnish Environment Institute (Syke) and the ELY Centres.
Köyliönjärvi is a lake in Säkylä County, Finland with a maximum depth of 28 feet.
Source: EPA Water Quality Portal sampling records, your state environmental agency, last sampled 2025-08-18. 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 Köyliönjärvi
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Very murky, less than 2 ft of visibility. Phosphorus level: 92 µg/L. Chlorophyll-a: 75.5 µg/L. Trophic State Index: 70.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 0.6 m | Not graded |
| Phosphorus | 92 µg/L | Not graded |
| Chlorophyll-a (Algae) | 75.5 µg/L | Not graded |
| Trophic State Index (TSI) | 70 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 8.5 m |
Where to stay near Köyliönjärvi
Compare lakeside cabins, hotels, and vacation rentals near Köyliönjärvi in Säkylä, Finland — 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 Köyliönjärvi
Frequently asked questions about Köyliönjärvi
What is the water quality of Köyliönjärvi?
- Köyliönjärvi in Säkylä, Finland has official water-quality measurements, not a LakeQuality A–F grade. Water clarity: 0.6 m visibility. Phosphorus: 92 µg/L. Chlorophyll-a (algae): 75.5 µg/L. Maximum depth: 27.9 ft.
Is Köyliönjärvi safe to swim in?
- Köyliönjärvi 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.
How deep is Köyliönjärvi?
- Köyliönjärvi has a maximum depth of 27.9 feet.
Explore Köyliönjärvi across LakeGrade
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Where this data comes from
123 measurements from 1 monitoring station, 2016–2025. Retrieved from Syke VESLA (not the EPA Water Quality Portal) on 2026-08-16.
Collected and reported by
- Finnish Environment Institute (Syke) and ELY Centres
syke-vesla123 samples · 2016–2025
Analytical methods
- SYKE VESLA
Monitoring station identifiers (1)
6417
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: 2025-08-18
Monitoring stations: 1