Where is Iso Arajärvi?

Iso Arajärvi is a lake in Vesilahti, Finland. This page reports official water-quality measurements, shown as reported.

Is Iso Arajärvi safe to swim in?

Iso Arajärvi 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 Iso Arajärvi?

Iso Arajärvi has a maximum depth of 77.4 feet.

Iso Arajärvi

Vesilahti, FinlandView map Directions

Syke publishes the water-quality measurements for Iso Arajärvi. Here is what has been measured.

Clarity

3 m

Clearer than most

Secchi · sampled 2025

Phosphorus

8.6 µg/L

Less phosphorus than most

Measured by Syke

Chlorophyll-a

4 µg/L

Less algae than most

Measured by Syke

Max depth

23.6 m

Bathymetric survey

77 ft max depth
Limited data

See the measurements Directions Where to stay

Iso Arajärvi in Vesilahti, Finland has official water-quality measurements, shown as reported. Water clarity: 3 m visibility. Phosphorus: 8.6 µg/L. Chlorophyll-a (algae): 4 µg/L. Maximum depth: 77.4 ft.

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How Iso Arajärvi is classified

Iso Arajärvi in Finland 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, phosphorus and algae (chlorophyll-a).

LakeQuality publishes no grade of its own beside it. Everything below thathas been measured is reported on this page.

Monitoring: the Finnish Environment Institute (Syke) and the ELY Centres.

Iso Arajärvi is a lake in Vesilahti County, Finland with a maximum depth of 77 feet.

Source: the Finnish Environment Institute (Syke) and the ELY Centres — not the EPA Water Quality Portal, last sampled 2025-10-29. Methodology: how these readings are compared.

What Iso Arajärvi is good for

From access and monitoring records, not editorial picks.

Clear water9.8 ft of visibility
Deep water77.4 ft surveyed max depth

Swimming conditions

No reading

Limited data

Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.

Whether Iso Arajärvi is safe to swim in today is a call for the Finnish Environment Institute (Syke) and the ELY Centres and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.

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Water quality measurements for Iso Arajärvi

These are the measurements Syke publishes for Iso Arajärvi. More on the source.

Moderate clarity, visible to about 9.8 ft. Phosphorus 8.6 µg/L. Chlorophyll-a 4 µg/L. TSI 41.

Water quality readings
Measure	Reading	Where it sits
Water clarity (Secchi depth)	3m	Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer.
Total phosphorus	8.6µg/L	Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential.
Chlorophyll-a (algae)	4µg/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.	41	Mesotrophic OligotrophicMesotrophicEutrophicHypereutrophic

Moderate nutrients, good water quality

Ask about Iso Arajärvi

Answers come straight from the public measurements and survey records on this page.

Lake Details

Max depth

23.6 m

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Fishing Iso Arajärvi

→ Iso Arajärvi fishing regulations (limits, seasons, special rules)

Frequently asked questions about Iso Arajärvi

Where is Iso Arajärvi?: Iso Arajärvi is a lake in Vesilahti, Finland. This page reports official water-quality measurements, shown as reported.
What is the water quality of Iso Arajärvi?: Iso Arajärvi in Vesilahti, Finland has official water-quality measurements, shown as reported. Water clarity: 3 m visibility. Phosphorus: 8.6 µg/L. Chlorophyll-a (algae): 4 µg/L. Maximum depth: 77.4 ft.
Is Iso Arajärvi safe to swim in?: Iso Arajärvi 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 Iso Arajärvi?: Iso Arajärvi has a maximum depth of 77.4 feet.

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Where this data comes from

39 measurements from 2 monitoring stations, 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 Centressyke-vesla39 samples · 2016–2025

Analytical methods

SYKE VESLA

Monitoring station identifiers (2)

8000
8002

Authority classifications are shown as the authority published them. See where the data comes from and data sources.