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B

Minerva Lake

Clearwater County, MinnesotaMesotrophic

Minerva Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake bottoms out at 16 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 230 acres and 2.8 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 the 40 graded lakes of Clearwater County, Minerva Lake sits at rank 31, near the bottom of the county list.

Minerva Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Minerva Lake, one of 11 fish species on record for the lake. A documented public access point at Minerva 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 2024-09-10. Grade methodology: LakeGrade methodology.

Reviewed by LakeQuality Editorial Team · Updated

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Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Moderate clarity, visible to about 7.3 ft. Phosphorus level: 26 µg/L. Trophic State Index: 50.

MetricValueGrade
Water Clarity (Secchi Depth)7.3 ftC
Phosphorus26 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)50Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Maximum Depth16 ft
Average Depth7.9 ft
Surface Area230.02 acres
Shoreline Length2.8 mi
Littoral Zone95%
Public AccessYes

Fish Species

black bullhead,black crappie,bluegill,brown bullhead,hybrid sunfish,largemouth bass,northern pike,pumpkinseed,walleye,white sucker,yellow perch

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

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

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

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

Water Quality Trend: Stable

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

MetricTrendChange/YearYears
Water Clarity Improving+0.104 m/yr5
Phosphorus Declining+1.6 µg/L/yr5
See year-by-year chart →

Location

Loading map…

County Ranking

Ranked #31 of 40 lakes in Clearwater County

Cleaner Lakes Within 30 Miles

Minerva Lake holds Grade B. 4 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Clearwater County

DNR Fisheries Survey Summary

7 surveys on file from MN DNR Fisheries. Most recent: 2016-06-27 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Yellow Perch29.230.27 lb
Black Bullhead23.150.6 lb
Brown Bullhead10.090.87 lb
Bluegill7.700.45 lb
Pumpkinseed6.430.24 lb
Largemouth Bass5.141.55 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.

Yellow Perch

338 fish · 510 in · 2016-06-27
1276405678910

Black Bullhead

18 fish · 812 in · 2016-06-27
53089101112

Brown Bullhead

87 fish · 814 in · 2016-06-27
31160891011121314

Bluegill

342 fish · 310 in · 2016-06-27
142710trophy 10345678910

From the 2016-06-27 survey

Lake Minerva is a 230-acre lake with a maximum depth of 16 feet located 12 miles south of Bagley in Clearwater County. There is a DNR public water access located on the southeast shore of the lake with an earthen ramp and parking for about 8 trucks/trailers. Lake Minerva is managed for Walleye, Black Crappie, and…

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 Minerva Lake. 4 reports on file.

Reservoir Info (USACE NID)

Minerva Lake is a man-made reservoir impounded by the Upper Rice Lake (completed 1968), built primarily for fish and wildlife pond on the Wild Rice River; gravity-type dam, 7 ft tall and 26 ft long.

Normal storage
11,160 ac-ft
Max storage
14,880 ac-ft
Drainage area
14.3 sq mi
Hazard class
Low
Owner
MNDNR-Wildlife

Source: USACE National Inventory of Dams, NID ID MN00231 · Operator website · Matched by proximity (0.82 km)

EPA Impairment Status

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

Causes of impairment

Mercury

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

Source: EPA ATTAINS assessment unit MN15-0079-00 · 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: 2024-09-10

Monitoring stations: 1