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LakeQuality
D

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. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. 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. Within the 120 graded lakes of Crow Wing County, Fool Lake sits at rank 120, near the bottom of the county list.

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.

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.

MetricValueGrade
Water Clarity (Secchi Depth)6 ftD
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)51Eutrophic

High nutrients, frequent algae, reduced clarity

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-1.07 m/yr2

Ice Season

Historical ice data from Minnesota DNR (6 observations).

Typical Ice-Out
Apr 21
EarliestLatest
Ice-Out2015-04-05 (2015)2022-04-29 (2022)
Ice-In2014-11-14 (2014)2021-11-22 (2021)

Most recent ice-out: 2022-04-29

Location

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County Ranking

Ranked #120 of 120 lakes in Crow Wing County

Nearby Lakes in Crow Wing County

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Fool Lake. 1 report on file.

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