Unnamed Lake
Unnamed Lake in Big Stone County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.9 ft visibility. Phosphorus: 167.5 µg/L. Chlorophyll-a (algae): 11.6 µg/L.
- Clarity
- 6.9 ft
- Typical in August
- 76°F
- Mean depth
- ~8 ft est.
- Trend
- ↓ Declining
- Public access
- No
Next lake in Big Stone County
Why Unnamed Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Unnamed Lake, no nutrient or algae measurement meets the evidence bar (at least 3 samples within 10 years). Sampling here has recorded water clarity, phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
Unnamed Lake is a lake in Big Stone County, Minnesota with an estimated average depth of about 8 feet. Overall water quality is declining over recent sampling years. Limited fish-species data available. No public access — the lake is private or restricted.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-08-10. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Unnamed Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Moderate clarity, visible to about 6.9 ft. Phosphorus level: 167.5 µg/L. Chlorophyll-a: 11.6 µg/L. Trophic State Index: 61.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 6.9 ft | Not graded |
| Phosphorus | 167.5 µg/L | Not graded |
| Chlorophyll-a (Algae) | 11.6 µg/L | Not graded |
| Trophic State Index (TSI) | 61 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Unnamed Lake
Compare lakeside cabins, hotels, and vacation rentals near Unnamed Lake in Big Stone 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.
Top-rated places to stay near Unnamed Lake
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Water Temperature
Unnamed Lake typically sits around 76°F at the surface in August. Summer average is about 74°F. Usually warmest in Aug (about 76°F) and coldest in Sep (about 68°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 11 field readings (2017–2023) via the EPA Water Quality Portal. See the full Unnamed Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~8 ft est. |
| Public Access | No |
Depth marked “est.” is a modeled estimate from HydroLAKES, not a measured survey. Minnesota has not published bathymetry for Unnamed Lake.
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS). Mean depth here is modelled, not surveyed — HydroLAKES v1.0 estimates lake depth from surrounding terrain rather than from soundings. Treat it as an approximation, and prefer a state bathymetric survey where one exists.
Fishing Unnamed Lake
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.8 m/yr | 2 |
| Phosphorus | ↓ Declining | +231 µg/L/yr | 2 |
| Chlorophyll-a | ↓ Declining | +19.1 µg/L/yr | 2 |
Graded lakes near Unnamed Lake
Unnamed Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Big Stone County
Frequently asked questions about Unnamed Lake
What is the water quality grade for Unnamed Lake?
- Unnamed Lake in Big Stone County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 6.9 ft visibility. Phosphorus: 167.5 µg/L. Chlorophyll-a (algae): 11.6 µg/L.
Is Unnamed Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Unnamed Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Algae concentration (chlorophyll-a) is 11.6 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Unnamed Lake?
- Unnamed Lake typically sits around 76°F at the surface in August, from 11 EPA Water Quality Portal field readings (2017–2023). That is a typical value for the month, not a live reading.
How deep is Unnamed Lake?
- No published bathymetric survey covers Unnamed Lake, so its depth has not been measured. The HydroLAKES global model estimates an average depth of about 8 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Explore Unnamed Lake across LakeGrade
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Where this data comes from
8 measurements from 2 monitoring stations, 2022–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA8 samples · 2022–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (2)
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
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder