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LakeQuality
A

Unnamed Lake

Polk County, WisconsinMesotrophic

On the LakeGrade rubric, Unnamed Lake pulls an A: clarity at 16.4 ft and 22 µg/L of phosphorus put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI near 43 places Unnamed Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. 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. Unnamed Lake ranks 38 of 77 in Polk County — solidly in the upper half of the local distribution.

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.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 16.4 ft down. Phosphorus level: 22.4 µg/L. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)16.4 ftA
Phosphorus22.4 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Water Quality Trend: Declining

Based on 3 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-4.787 m/yr3
Phosphorus Declining+4.25 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #38 of 77 lakes in Polk County

Nearby Lakes in Polk County

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