Eau Claire Lake
Eau Claire County, WisconsinEutrophic
Eau Claire Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Wisconsin average. clarity and phosphorus rate similarly, so there is no obvious single lever to pull on watershed management.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. Eau Claire Lake reaches 25 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 870 acres, Eau Claire Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within Eau Claire County's 3 graded lakes, Eau Claire Lake ranks 2 — below the local median, though not at the bottom.
An invasive species record — Chinese Mystery Snail — has been logged at Eau Claire Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye among the lake's 5 documented species — a notable draw for Wisconsin anglers. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2024-10-07. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Very murky, less than 2.8 ft of visibility. Phosphorus level: 88 µg/L. Trophic State Index: 66.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 2.8 ft | F |
| Phosphorus | 88 µg/L | D |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 66 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 25 ft |
| Surface Area | 870 acres |
Fish Species
Click a species to see all Wisconsin and Minnesota lakes where it is found.
→ Best fishing times for Eau Claire Lake (14-day solunar calendar)
→ Is it safe to eat fish from Eau Claire Lake? (mercury & PFAS guide)
→ Eau Claire Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: → Stable
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.25 m/yr | 3 |
| Phosphorus | ↑ Improving | -3.09 µg/L/yr | 4 |
Location
County Ranking
Ranked #2 of 3 lakes in Eau Claire County
Cleaner Lakes Within 30 Miles
Eau Claire Lake holds Grade D. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Eau Claire County
More Wisconsin Lake Rankings
State Parks Near Eau Claire Lake
Other Grade D Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Compare Eau Claire Lake With Nearby Lakes
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 12 stations on file (most recent sample 2024).
Fish Species (DNR-rated)
EPA Impairment Status
Eau Claire Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5R).
Causes of impairment
Source: EPA ATTAINS assessment unit WI10004681 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-10-07
Monitoring stations: 2