Fool Lake
Crow Wing County, MinnesotaLimited DataEutrophic
Fool Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota 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. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Fool Lake ranks 120 of 120 in Crow Wing County — at the lower end of the locally monitored distribution.
No invasive species are currently listed at Fool Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Fool Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. 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 2022-09-11. Grade methodology: LakeGrade methodology.
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Swimming Safety
Swimming not recommended, poor water quality with high algae risk
Water Quality Grade: D, Poor
Murky, only visible to about 6 ft. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6 ft | D |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -1.07 m/yr | 2 |
Ice Season
Historical ice data from Minnesota DNR (6 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2015-04-05 (2015) | 2022-04-29 (2022) |
| Ice-In | 2014-11-14 (2014) | 2021-11-22 (2021) |
Most recent ice-out: 2022-04-29
Location
County Ranking
Ranked #120 of 120 lakes in Crow Wing County
Cleaner Lakes Within 30 Miles
Fool Lake holds Grade D. 5 nearby lakes hold higher grades.
- ARabbit LakeCrow Wing County · mi · Two grade letters higher (D → A)
- AHorseshoe LakeCrow Wing County · mi · Two grade letters higher (D → A)
- ABass LakeCrow Wing County · mi · Two grade letters higher (D → A)
- BUpper Mission LakeCrow Wing County · mi · Two grade letters higher (D → B)
- CLower Mission LakeCrow Wing County · mi · Higher grade (D → C)
Nearby Lakes in Crow Wing County
More Minnesota Lake Rankings
State Parks Near Fool Lake
Other Grade D Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Fool Lake. 1 report on file.
- —Aquatic Plant Report — Fool (0393)Aquatic Plant Report · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Ice data from Minnesota DNR Climate
Most recent sample: 2022-09-11
Monitoring stations: 2