Big Moon Lake at
Barron County, WisconsinMesotrophic
On the LakeGrade scale Big Moon Lake at grades a B, with clarity at 10.0 ft and 26 µg/L of phosphorus placing it above the Wisconsin median. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.
Mesotrophic conditions dominate at Big Moon Lake at: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 48 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 187 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Big Moon Lake at ranks 12 of 37 in Barron County — solidly in the upper half of the local distribution.
An invasive species record — Chinese Mystery Snail — has been logged at Big Moon Lake at; Wisconsin DNR maintains the official infested-waters list. Walleye are documented at Big Moon Lake at, one of 5 fish species on record for the lake. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2025-09-14. Grade methodology: LakeGrade methodology.
Watch Big Moon Lake at water quality
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Swimming Safety
Good for swimming, clear water with low algae levels
Water Quality Grade: B, Good
Good clarity, visible to about 10 ft. Phosphorus level: 25.7 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | B |
| Phosphorus | 25.7 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 48 ft |
| Surface Area | 187 acres |
| Public Access | Yes |
Fish Species
Click a species to see every graded lake where it is documented.
→ Best fishing times for Big Moon Lake at (14-day solunar calendar)
→ Is it safe to eat fish from Big Moon Lake at? (mercury & PFAS guide)
→ Big Moon Lake at 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: ↓ Declining
Based on 5 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.036 m/yr | 4 |
| Phosphorus | ↓ Declining | +2.66 µg/L/yr | 5 |
Recreation & Access
Location
County Ranking
Ranked #12 of 37 lakes in Barron County
Cleaner Lakes Within 30 Miles
Big Moon Lake at holds Grade B. One nearby lake has a higher grade.
See full comparison →Nearby Lakes in Barron County
More Wisconsin Lake Rankings
State Parks Near Big Moon Lake at
Other Grade B Lakes in Wisconsin
Mesotrophic Lakes in Wisconsin
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1999. 1 station on file (most recent sample 2025).
Fish Species (DNR-rated)
Reservoir Info (USACE NID)
Big Moon Lake at is a man-made reservoir impounded by the Big Moon Lake (completed 1968), built primarily for recreation on the Moon Creek; earth-type dam, 9 ft tall and 500 ft long.
- Surface area
- 187 ac
- Normal storage
- 900 ac-ft
- Max storage
- 2,000 ac-ft
- Drainage area
- 7 sq mi
- Hazard class
- Low
- Owner
- Barron County
Source: USACE National Inventory of Dams, NID ID WI00486 · Operator website · Matched by proximity (0.38 km)
EPA Impairment Status
Big Moon Lake at 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 WI10004359 · Official waterbody report · Matched by proximity (0.46 km)
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
Fish and recreation data from Wisconsin DNR Lakes
Public boat-access points from the USGS National Boat Ramps inventory
Most recent sample: 2025-09-14
Monitoring stations: 1
Where to stay near Big Moon Lake at
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