Wolf Lake
Douglas County, MinnesotaEutrophic
Wolf Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.
A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. A maximum depth of 42 ft puts Wolf Lake in the middle of Minnesota's depth distribution. At 307 acres, Wolf Lake fits the Minnesota median for monitored lakes, with 5.2 miles of shoreline. Within the 51 graded lakes of Douglas County, Wolf Lake sits at rank 42, near the bottom of the county list.
Wolf Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. Walleye are documented at Wolf Lake, one of 12 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-07-12. Grade methodology: LakeGrade methodology.
Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 3.6 ft. Phosphorus level: 44 µg/L. Trophic State Index: 59.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.6 ft | D |
| Phosphorus | 44 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 59 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 42 ft |
| Average Depth | 10 ft |
| Surface Area | 307.37 acres |
| Shoreline Length | 5.2 mi |
| Littoral Zone | 66% |
| Public Access | Yes |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Wolf Lake (14-day solunar calendar)
→ Is it safe to eat fish from Wolf Lake? (mercury & PFAS guide)
→ Wolf Lake fishing regulations (limits, seasons, special rules)
Invasive Species
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 |
Location
County Ranking
Ranked #42 of 51 lakes in Douglas County
Nearby Lakes in Douglas County
More Minnesota Lake Rankings
State Parks Near Wolf Lake
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
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.
- —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
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Most recent sample: 2022-07-12
Monitoring stations: 1