Unnamed Lake
Polk County, WisconsinEutrophic
Unnamed Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.
At a TSI of 51, Unnamed Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Polk County's 74 graded lakes, Unnamed Lake ranks 45 — below the local median, though not at the bottom.
Unnamed Lake has no invasive species recorded in Wisconsin state databases as of 2022, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Unnamed Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-09-13. Grade methodology: LakeGrade methodology.
Watch Unnamed Lake water quality
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 5 ft. Phosphorus level: 22.4 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 5 ft | D |
| Phosphorus | 22.4 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Water Quality Trend: ↓ Declining
Based on 2 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -5.25 m/yr | 2 |
| Phosphorus | ↓ Declining | +4.25 µg/L/yr | 2 |
Location
County Ranking
Ranked #45 of 74 lakes in Polk County
Cleaner Lakes Within 30 Miles
Unnamed Lake holds Grade C. 3 nearby lakes hold higher grades.
- AClear LakePolk County · mi · Two grade letters higher (C → A)
- BKing LakePolk County · mi · Higher grade (C → B)
- BBlack Brook Flowage LakePolk County · mi · Higher grade (C → B)
Nearby Lakes in Polk County
More Wisconsin Lake Rankings
State Parks Near Unnamed Lake
Other Grade C Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Fish and recreation data from Wisconsin DNR Lakes
Most recent sample: 2022-09-13
Monitoring stations: 1
Where to stay near Unnamed Lake
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