Big Eau Pleine Lake
Marathon County, WisconsinView mapDirections
Wisconsin DNR publishes the water-quality measurements for Big Eau Pleine Lake. Here is what has been measured.
- Hypereutrophic
- Public access
Big Eau Pleine Lake in Marathon County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 131 µg/L.
Big Eau Pleine Lake is a highly nutrient-loaded hypereutrophic lake in Marathon County, Wisconsin. Overall water quality is improving over recent sampling years. Limited fish-species data available. Public access is available. Compared to the 3 other monitored lakes in Marathon County, Big Eau Pleine Lake ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-07-12. Methodology: how these readings are compared.
Swimming conditions
Readings onlyElevated nutrients
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Big Eau Pleine Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Big Eau Pleine Lake
These are the measurements Wisconsin DNR publishes for Big Eau Pleine Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.5 ft of visibility. Phosphorus 131 µg/L. TSI 73.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 131µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading 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. | 73 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Big Eau Pleine Lake
Answers come straight from the public measurements and survey records on this page.
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Big Eau Pleine Lake covering fish populations, stocking, water quality, and management. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2024Big Eau Pleine Reservoir comprehensive survey, 2024Comprehensive Survey · WI DNR · 2024 (PDF)
Stays via Stay22
Stays near Big Eau Pleine Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Eau Pleine Lake in Marathon County, Wisconsin — 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. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Big Eau Pleine Lake are listed below.
Top-rated places to stay near Big Eau Pleine Lake
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Fishing Big Eau Pleine Lake
Water quality readings over time
3 seasons of samples on record (2020–2022). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving3 years
Phosphorus
Improving-19.25 µg/L/yr3 years
Nearby Lakes in Marathon County
Frequently asked questions about Big Eau Pleine Lake
Where is Big Eau Pleine Lake?
- Big Eau Pleine Lake is a lake in Marathon County, Wisconsin. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Big Eau Pleine Lake?
- Big Eau Pleine Lake in Marathon County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 1.5 ft visibility. Phosphorus: 131 µg/L.
Is Big Eau Pleine Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Can I fish at Big Eau Pleine Lake?
- Public access to Big Eau Pleine Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Big Eau Pleine Lake across LakeQuality
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Where this data comes from
234 measurements from 7 monitoring stations, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX234 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (7)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.