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LakeQuality
B

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.

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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.

MetricValueGrade
Water Clarity (Secchi Depth)10 ftB
Phosphorus25.7 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)47Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth48 ft
Surface Area187 acres
Public AccessYes

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.

Chinese Mystery SnailCurly-Leaf Pondweed

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable+0.036 m/yr4
Phosphorus Declining+2.66 µg/L/yr5
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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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

State Parks Near Big Moon Lake at

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)

Panfish(Common)Largemouth Bass(Common)Walleye(Common)Musky(Present)Northern Pike(Present)

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

Nutrients (phosphorus, nitrogen)

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

Compare lakeside cabins, hotels, and vacation rentals near Big Moon Lake at in Barron County, Wisconsin — live availability and prices for your trip.

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