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F

Roberds Lake

Rice County, MinnesotaHypereutrophic

Roberds Lake grades an F: every scored parameter (clarity and phosphorus) rates poorly, placing it among the most stressed lakes monitored in Minnesota. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

A TSI above 70 puts Roberds Lake in hypereutrophic territory: visible blooms are common, and clarity rarely climbs even in early summer. A maximum depth of 43 ft puts Roberds Lake in the middle of Minnesota's depth distribution. The lake's 632 acres and 5.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Rice County's 12 graded lakes, Roberds Lake ranks 7 — below the local median, though not at the bottom.

Roberds Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Muskie are on the species list at Roberds Lake, among the lake's 18 documented fish. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Roberds Lake more than two dozen times, putting the median around Apr 3 — a useful baseline for tracking climate trends. 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 2024-10-10. 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 2 ft of visibility. Phosphorus level: 355 µg/L. Trophic State Index: 78.

MetricValueGrade
Water Clarity (Secchi Depth)2 ftF
Phosphorus355 µg/LF
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)78Hypereutrophic

Very high nutrients, dense algae, poor clarity

Lake Details

CharacteristicValue
Maximum Depth43 ft
Surface Area632.29 acres
Shoreline Length5.6 mi
Littoral Zone62%
Public AccessYes

Fish Species

bigmouth buffalo,black bullhead,black crappie,bluegill,bowfin (dogfish),brown bullhead,channel catfish,common carp,crappie,freshwater drum,largemouth bass,muskellunge,northern pike,walleye,white bass,white crappie,yellow bullhead,yellow perch

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

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

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

Roberds Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.171 m/yr5
See year-by-year chart →

Ice Season

Historical ice data from Minnesota DNR (65 observations).

Typical Ice-Out
Apr 3
Typical Ice-In
Dec 1

Estimated open water season: 242 days

EarliestLatest
Ice-Out2024-02-29 (2024)2018-04-30 (2018)
Ice-In1995-11-09 (1995)2001-12-21 (2001)

Most recent ice-out: 2026-03-26

Location

Loading map…

County Ranking

Ranked #7 of 12 lakes in Rice County

Cleaner Lakes Within 30 Miles

Roberds Lake holds Grade F. 4 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Rice County

Hypereutrophic Lakes in Minnesota

DNR Fisheries Survey Summary

14 surveys on file from MN DNR Fisheries. Most recent: 2023-10-23 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Largemouth Bass3856.081.21 lb
Black Bullhead32.070.78 lb
Black Crappie23.730.32 lb
Bluegill13.270.29 lb
Yellow Perch12.830.2 lb
Freshwater Drum6.961.97 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.

Largemouth Bass

54 fish · 618 in · 2023-06-26
14706789101112131415161718

Black Bullhead

60 fish · 914 in · 2023-06-26
2412091011121314

Black Crappie

92 fish · 314 in · 2023-06-26
31160trophy 1034567891011121314

Bluegill

108 fish · 310 in · 2023-06-26
43220trophy 10345678910

From the 2023-10-23 survey

A survey targeting age-0 Walleye was conducted at Roberds Lake on 23 October 2023 using 56 minutes of standard boat electrofishing. Zero age-0 Walleye were sampled for a catch rate of 0.0/hour on-time. Catch rates have averaged 3.1/hour on-time during 7 surveys since 2017. During that period non-stocked years (n = 4)…

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 Roberds Lake. 3 reports on file.

EPA Impairment Status

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

Causes of impairment

Nutrients (phosphorus, nitrogen)

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

Source: EPA ATTAINS assessment unit MN66-0018-00 · 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

Ice data from Minnesota DNR Climate

Most recent sample: 2024-10-10

Monitoring stations: 2