Unnamed Lake
Unnamed Lake in Watonwan County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Phosphorus: 275 µg/L. Chlorophyll-a (algae): 142 µg/L.
- Clarity
- 1 ft
- Mean depth
- ~7 ft est.
- Public access
- Yes
Next lake in Watonwan 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 Watonwan County, Minnesota with an estimated average depth of about 7 feet. Limited fish-species data available. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-06-22. 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.
Very murky, less than 1 ft of visibility. Phosphorus level: 275 µg/L. Chlorophyll-a: 142 µg/L. Trophic State Index: 81.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 1 ft | Not graded |
| Phosphorus | 275 µg/L | Not graded |
| Chlorophyll-a (Algae) | 142 µg/L | Not graded |
| Trophic State Index (TSI) | 81 | Hypereutrophic |
Very high nutrients, dense algae, poor clarity
Where to stay near Unnamed Lake
Compare lakeside cabins, hotels, and vacation rentals near Unnamed Lake in Watonwan 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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Lake Details
| Characteristic | Value |
|---|---|
| Average Depth | ~7 ft est. |
| Public Access | Yes |
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.
Recreation & Access
- Butterfield Lake (South)Public
Fishing Unnamed Lake
Regulated Pollution Sources Nearby
2 EPA-permitted facilities operate within about 5 miles of Unnamed Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Butterfield WwtpButterfield · 4 mi away · NPDES MN0022977Recent violation
- Menken FarmsButterfield · 1.8 mi away · NPDES MN0071251
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
Graded lakes near Unnamed Lake
Unnamed Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Watonwan County
Frequently asked questions about Unnamed Lake
What is the water quality grade for Unnamed Lake?
- Unnamed Lake in Watonwan County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 1 ft visibility. Phosphorus: 275 µg/L. Chlorophyll-a (algae): 142 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 142 µg/L. Always check local health department advisories before swimming.
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 7 feet, but that is a modelled estimate derived from surrounding terrain rather than a measurement on the water, so treat it as approximate.
Are there boat ramps on Unnamed Lake?
- Unnamed Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Butterfield Lake (South). Public access is listed as yes.
Explore Unnamed Lake across LakeGrade
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Where this data comes from
4 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA4 samples · 2022
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 (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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory