Minerva Lake
Minerva Lake in Clearwater County, Minnesota has a water quality grade of C (Fair). Water clarity: 7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.5 µg/L. Maximum depth: 16 ft. Surface area: 230.02 acres.
- Clarity
- 7 ft
- Typical in August
- 71°F
- Max depth
- 16 ft
- Area
- 230 acres
- Type
- Eutrophic
- Trend
- ↑ Improving
- Public access
- Yes
Next lake in Clearwater County
Minerva Lake is a 230-acre productive, nutrient-rich eutrophic lake in Clearwater County, Minnesota with a maximum depth of 16 feet (8-foot average). Water quality is graded C based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 11 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 36 other monitored lakes in Clearwater County, Minerva Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-09. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyModerate
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Generally safe for swimming, moderate water quality
Water Quality Grade: C (Fair)
Moderate clarity, visible to about 7 ft. Phosphorus level: 26 µg/L. Chlorophyll-a: 7.5 µg/L. Trophic State Index: 50.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 7 ft | Not graded |
| Phosphorus | 26 µg/L | Fair |
| Chlorophyll-a (Algae) | 7.5 µg/L | Fair |
| Trophic State Index (TSI) | 50 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Minerva Lake
Compare lakeside cabins, hotels, and vacation rentals near Minerva Lake in Clearwater County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.
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Water Temperature
Minerva Lake typically sits around 71°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 75°F) and coldest in Sep (about 64°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 131 field readings (2018–2025) via the EPA Water Quality Portal. See the full Minerva Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 16 ft |
| Average Depth | 7.9 ft |
| Surface Area | 230 acres |
| Shoreline Length | 2.8 mi |
| Littoral Zone | 95% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Minerva LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Minerva Lake
DNR Fisheries Survey Summary
7 surveys on file from MN DNR Fisheries. Most recent: 2016-06-27 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 29.23 | 0.27 lb |
| Black Bullhead | 23.15 | 0.6 lb |
| Brown Bullhead | 10.09 | 0.87 lb |
| Bluegill | 7.70 | 0.45 lb |
| Pumpkinseed | 6.43 | 0.24 lb |
| Largemouth Bass | 5.14 | 1.55 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
Black Bullhead
Brown Bullhead
Bluegill
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…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Minerva Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — MinervaFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Minerva (1698)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — MinervaFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — MinervaPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.05 m/yr | 6 |
| Phosphorus | → Stable | -0.07 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.22 µg/L/yr | 6 |
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
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN15-0079-00 · Official waterbody report
County Ranking
Ranked #30 of 37 lakes in Clearwater County
Nearby Lakes With Higher Grades
Minerva Lake holds Grade C. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Clearwater County
Frequently asked questions about Minerva Lake
What is the water quality grade for Minerva Lake?
- Minerva Lake in Clearwater County, Minnesota has a water quality grade of C (Fair). Water clarity: 7 ft visibility. Phosphorus: 26 µg/L. Chlorophyll-a (algae): 7.5 µg/L. Maximum depth: 16 ft. Surface area: 230.02 acres.
Is Minerva Lake safe to swim in?
- Generally safe for swimming, moderate water quality. Minerva Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 7.5 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Minerva Lake?
- Minerva Lake typically sits around 71°F at the surface in August, from 131 EPA Water Quality Portal field readings (2018–2025). That is a typical value for the month, not a live reading.
How deep is Minerva Lake?
- Minerva Lake has a maximum depth of 16 feet and an average depth of 7.9 feet. The lake covers 230.02 acres.
What fish are in Minerva Lake?
- Fish species found in Minerva Lake include black bullhead, black crappie, bluegill, brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, white sucker, yellow perch. Minerva Lake is located in Clearwater County, Minnesota.
Are there boat ramps on Minerva Lake?
- Minerva Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Minerva Lake. Public access is listed as yes.
Explore Minerva Lake across LakeGrade
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Where this data comes from
87 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA87 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory