Wolf Lake
Wolf Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.6 ft visibility. Phosphorus: 44 µg/L. Chlorophyll-a (algae): 17 µg/L. Maximum depth: 42 ft. Surface area: 307.37 acres.
- Clarity
- 3.6 ft
- Max depth
- 42 ft
- Area
- 307 acres
- Trend
- ↓ Declining
- Public access
- Yes
Next lake in Douglas County
Why Wolf Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Wolf Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Wolf Lake is a 307-acre lake in Douglas County, Minnesota with a maximum depth of 42 feet (10-foot average). Overall water quality is declining over recent sampling years. The lake supports 12 documented fish species including black crappie, bluegill, and brown bullhead. Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-07-12. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Wolf Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 3.6 ft. Phosphorus level: 44 µg/L. Chlorophyll-a: 17 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.6 ft | Not graded |
| Phosphorus | 44 µg/L | Not graded |
| Chlorophyll-a (Algae) | 17 µg/L | Not graded |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Wolf Lake
Compare lakeside cabins, hotels, and vacation rentals near Wolf Lake in Douglas County, Minnesota — 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.
Top-rated places to stay near Wolf Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 42 ft |
| Average Depth | 10 ft |
| Surface Area | 307 acres |
| Shoreline Length | 5.2 mi |
| Littoral Zone | 66% |
| Public Access | Yes |
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 Wolf 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.
DNR Fisheries Survey Summary
12 surveys on file from MN DNR Fisheries. Most recent: 2022-07-11 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 33.54 | 0.92 lb |
| Bluegill | 20.30 | 0.16 lb |
| Bluntnose Minnow | 11.82 | — |
| Green Sunfish | 10.03 | 0.24 lb |
| Black Crappie | 7.76 | 0.29 lb |
| BNS | 6.50 | — |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Largemouth Bass
Bluegill
Green Sunfish
Black Crappie
From the 2022-07-11 survey
A trap net survey was conducted on Blackwell Lake on July 11-12, 2022 by Index of Biological Integrity (IBI) Program Staff. Nine trap nets were set along the shoreline in locations that encompassed multiple habitat types. Bluegill comprised a majority of the trap net catch by number. The number of Bluegill sampled per…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Wolf Lake. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BlackwellFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Blackwell (1079)Aquatic Plant Report · MN DNR LakeFinder
- —Public Water Access Sites — BlackwellPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.155 m/yr | 3 |
EPA Impairment Status
Wolf Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN21-0180-00 · Official waterbody report · Matched by proximity (1.49 km)
Graded lakes near Wolf Lake
Wolf Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Douglas County
Frequently asked questions about Wolf Lake
What is the water quality grade for Wolf Lake?
- Wolf Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 3.6 ft visibility. Phosphorus: 44 µg/L. Chlorophyll-a (algae): 17 µg/L. Maximum depth: 42 ft. Surface area: 307.37 acres.
Is Wolf Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Wolf Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 17 µg/L. Always check local health department advisories before swimming.
How deep is Wolf Lake?
- Wolf Lake has a maximum depth of 42 feet and an average depth of 10 feet. The lake covers 307.37 acres.
What fish are in Wolf Lake?
- Fish species found in Wolf Lake include black crappie, bluegill, brown bullhead, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow bullhead, yellow perch. Wolf Lake is located in Douglas County, Minnesota.
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Where this data comes from
4 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder