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F

Lady Slipper Lake

Lyon County, MinnesotaLimited DataHypereutrophic

Lady Slipper Lake grades an F: every scored parameter (clarity) rates poorly, placing it among the most stressed lakes monitored in Minnesota.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. Lady Slipper Lake is a shallow lake at 11 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. Lady Slipper Lake covers 286 acres alongside 4.2 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Lady Slipper Lake sits at rank 3 of 5 in Lyon County, in the lower half of the local distribution.

No invasive species are currently listed at Lady Slipper Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Lady Slipper Lake, one of 6 fish species on record for the lake. A documented public access point at Lady Slipper Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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, Minnesota DNR LakeFinder, last sampled 2024-09-01. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Avoid swimming, very poor water quality, potential algae toxins

Water Quality Grade: F, Very Poor

Very murky, less than 1.5 ft of visibility. Trophic State Index: 71.

MetricValueGrade
Water Clarity (Secchi Depth)1.5 ftF
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)71Hypereutrophic

Very high nutrients, dense algae, poor clarity

Lake Details

CharacteristicValue
Maximum Depth11 ft
Surface Area286.15 acres
Shoreline Length4.2 mi
Littoral Zone100%
Public AccessYes

Fish Species

black bullhead,common carp,hybrid sunfish,orangespotted sunfish,walleye,yellow perch

Click a species to see all Minnesota and Wisconsin lakes where it is found.

→ Best fishing times for Lady Slipper Lake (14-day solunar calendar)

→ Is it safe to eat fish from Lady Slipper Lake? (mercury & PFAS guide)

Lady Slipper Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+0.053 m/yr2

Location

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County Ranking

Ranked #3 of 5 lakes in Lyon County

Nearby Lakes in Lyon County

Hypereutrophic Lakes in Minnesota

DNR Fisheries Survey Summary

12 surveys on file from MN DNR Fisheries. Most recent: 2023-09-11 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Black Bullhead128.270.17 lb
Walleye85.391.15 lb
Common Carp21.803.11 lb
Yellow Perch21.420.22 lb
OSS7.280.04 lb
Bluegill2.960.4 lb

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.

Black Bullhead

395 fish · 39 in · 2022-06-15
21610803456789

Walleye

11 fish · 410 in · 2023-09-11
42045678910

Common Carp

373 fish · 1131 in · 2022-06-15
8241012141618202224262830

Yellow Perch

12 fish · 710 in · 2022-06-15
42078910

From the 2023-09-11 survey

A targeted fall night electrofishing survey was conducted on Lady Slipper during September 11, 2023 to evaluate young of year "YOY" (fingerling sized) Walleye numbers due to a fry stocking. Three electrofishing stations were sampled for a total of 30 minutes. Clarity was poor (1.5 feet). The water temperature was 71…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Lady Slipper Lake. 3 reports on file.

EPA Impairment Status

Lady Slipper Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

MercuryNutrients (phosphorus, nitrogen)

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN42-0020-00 · Official waterbody report

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

Lake details from Minnesota DNR LakeFinder

Most recent sample: 2024-09-01

Monitoring stations: 2