Lower Eau Claire Lake
Lower Eau Claire Lake in Bayfield County, Wisconsin has a water quality grade of B (Good). Water clarity: 14.1 ft visibility. Phosphorus: 13 µg/L. Maximum depth: 41 ft. Surface area: 784 acres.
- Clarity
- 14.1 ft
- Typical in August
- 74°F
- Max depth
- 41 ft
- Area
- 784 acres
- Type
- Mesotrophic
- Trend
- ↓ Declining
Next lake in Bayfield County
Lower Eau Claire Lake is a 784-acre mesotrophic lake in Bayfield County, Wisconsin with a maximum depth of 41 feet. Water quality is graded B based on 1 sampling years through 2026. Overall water quality is declining over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Compared to the 23 other monitored lakes in Bayfield County, Lower Eau Claire Lake ranks #4 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-05-06. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Good clarity, visible to about 14.1 ft. Phosphorus level: 13 µg/L. Trophic State Index: 40.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 14.1 ft | Not graded |
| Phosphorus | 13 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 40 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Lower Eau Claire Lake
Compare lakeside cabins, hotels, and vacation rentals near Lower Eau Claire Lake in Bayfield 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.
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Water Temperature
Lower Eau Claire Lake typically sits around 74°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 78°F) and coldest in May (about 55°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 12 field readings (2024–2026) via the EPA Water Quality Portal. See the full Lower Eau Claire Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Lower Eau Claire Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (48,753 cells/mL) on April 11, 2026.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 41 ft |
| Surface Area | 784 acres |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Lower Eau Claire Lake
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. 2 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
DNR Reports & Resources
Wisconsin DNR Fisheries scientists publish multi-year survey reports for Lower Eau Claire Lake covering fish populations, stocking, water quality, and management. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- 2025Eau Claire, Middle spring shocking survey, 2025Spring Shocking Survey · WI DNR · 2025 (PDF)
- 2025Eau Claire, Upper spring shocking survey, 2025Spring Shocking Survey · WI DNR · 2025 (PDF)
- 2017Upper Eau Claire comprehensive fisheries survey, 2017Comprehensive Survey · WI DNR · 2017 (PDF)
- 2014Middle Eau Claire comprehensive fisheries survey, 2014Comprehensive Survey · WI DNR · 2014 (PDF)
Water Quality Trend: ↓ Declining
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.559 m/yr | 5 |
| Phosphorus | → Stable | -0.25 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Lower Eau Claire Lake is a man-made reservoir impounded by the Lower Eau Claire Lake (completed 1938), built primarily for recreation on the EAU CLAIRE; gravity-type dam, 12 ft tall and 60 ft long.
- Surface area
- 802 ac
- Normal storage
- 3,100 ac-ft
- Max storage
- 7,100 ac-ft
- Drainage area
- 109 sq mi
- Hazard class
- Low
- Owner
- Douglas County
Source: USACE National Inventory of Dams, NID ID WI01074 · Operator website
County Ranking
Ranked #4 of 24 lakes in Bayfield County
Nearby Lakes in Bayfield County
Frequently asked questions about Lower Eau Claire Lake
What is the water quality grade for Lower Eau Claire Lake?
- Lower Eau Claire Lake in Bayfield County, Wisconsin has a water quality grade of B (Good). Water clarity: 14.1 ft visibility. Phosphorus: 13 µg/L. Maximum depth: 41 ft. Surface area: 784 acres.
Is Lower Eau Claire Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Lower Eau Claire Lake has a water quality grade of B (Good). Always check local health department advisories before swimming.
What is the water temperature of Lower Eau Claire Lake?
- Lower Eau Claire Lake typically sits around 74°F at the surface in August, from 12 EPA Water Quality Portal field readings (2024–2026). That is a typical value for the month, not a live reading.
How deep is Lower Eau Claire Lake?
- Lower Eau Claire Lake has a maximum depth of 41 feet. The lake covers 784 acres.
What fish are in Lower Eau Claire Lake?
- Fish species found in Lower Eau Claire Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Lower Eau Claire Lake is located in Bayfield County, Wisconsin.
Does Lower Eau Claire Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Lower Eau Claire Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (48,753 cells/mL). Blue-green algae can appear and clear within days, so check Wisconsin's current advisory before swimming.
Explore Lower Eau Claire Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
105 measurements from 1 monitoring station, 2020–2026. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX105 samples · 2020–2026
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes