Middle Eau Claire Lake
Middle Eau Claire Lake in Bayfield County, Wisconsin has a water quality grade of B (Good). Water clarity: 18.2 ft visibility. Phosphorus: 12.9 µg/L. Maximum depth: 66 ft. Surface area: 880 acres.
- Clarity
- 18.2 ft
- Typical in August
- 74°F
- Max depth
- 66 ft
- Area
- 880 acres
- Type
- Oligotrophic
- Trend
- → Stable
- Public access
- Yes
Next lake in Bayfield County
Middle Eau Claire Lake is a 880-acre cold, clear oligotrophic lake in Bayfield County, Wisconsin with a maximum depth of 66 feet. Water quality is graded B based on 1 sampling years through 2026. Water clarity is improving over recent sampling years. The lake supports 6 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 23 other monitored lakes in Bayfield County, Middle Eau Claire Lake ranks #15 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2026-04-22. 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)
Crystal clear, you can see 18.2 ft down. Phosphorus level: 12.9 µg/L. Trophic State Index: 38.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 18.2 ft | Not graded |
| Phosphorus | 12.9 µg/L | Good |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 38 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Middle Eau Claire Lake
Compare lakeside cabins, hotels, and vacation rentals near Middle 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
Middle Eau Claire Lake typically sits around 74°F at the surface in August. Summer average is about 75°F. Usually warmest in Jul (about 78°F) and coldest in Jun (about 73°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 13 field readings (2024–2025) via the EPA Water Quality Portal. See the full Middle Eau Claire Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 66 ft |
| Surface Area | 880 acres |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Middle Eau Claire LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Middle 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. Monitored by volunteers since 1987. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.668 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.49 µg/L/yr | 6 |
Reservoir Info (USACE NID)
Middle Eau Claire Lake is a man-made reservoir impounded by the Middle Eau Claire Lake (completed 1939), built primarily for recreation on the EAU CLAIRE; gravity-type dam, 16 ft tall and 100 ft long.
- Surface area
- 902 ac
- Normal storage
- 4,000 ac-ft
- Max storage
- 6,000 ac-ft
- Drainage area
- 57 sq mi
- Hazard class
- Significant
- Owner
- Bayfield County
Source: USACE National Inventory of Dams, NID ID WI00523 · Operator website
County Ranking
Ranked #15 of 24 lakes in Bayfield County
Nearby Lakes in Bayfield County
Frequently asked questions about Middle Eau Claire Lake
What is the water quality grade for Middle Eau Claire Lake?
- Middle Eau Claire Lake in Bayfield County, Wisconsin has a water quality grade of B (Good). Water clarity: 18.2 ft visibility. Phosphorus: 12.9 µg/L. Maximum depth: 66 ft. Surface area: 880 acres.
Is Middle Eau Claire Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Middle 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 Middle Eau Claire Lake?
- Middle Eau Claire Lake typically sits around 74°F at the surface in August, from 13 EPA Water Quality Portal field readings (2024–2025). That is a typical value for the month, not a live reading.
How deep is Middle Eau Claire Lake?
- Middle Eau Claire Lake has a maximum depth of 66 feet. The lake covers 880 acres.
What fish are in Middle Eau Claire Lake?
- Fish species found in Middle Eau Claire Lake include Musky, Panfish, Largemouth Bass, Smallmouth Bass, Northern Pike, Walleye. Middle Eau Claire Lake is located in Bayfield County, Wisconsin.
Are there boat ramps on Middle Eau Claire Lake?
- Middle Eau Claire Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Middle Eau Claire Lake. Public access is listed as yes.
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Where this data comes from
96 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_WQX96 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
Named boat-access points from the USGS National Boat Ramps inventory