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LakeQuality
A

Paulsen Lake

Polk County, WisconsinOligotrophic

Paulsen Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Polk County. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI value of 32 puts Paulsen Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. 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. Paulsen Lake ranks 24 of 77 in Polk County — solidly in the upper half of the local distribution.

No invasive species are currently listed at Paulsen Lake — the lake remains off the Wisconsin infested-waters roster. The state fisheries records do not list documented species for Paulsen Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-09-08. 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 39.4 ft down. Phosphorus level: 12.7 µg/L. Trophic State Index: 32.

MetricValueGrade
Water Clarity (Secchi Depth)39.4 ftA
Phosphorus12.7 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)32Oligotrophic

Low nutrients, clear water, excellent for swimming

Water Quality Trend: Improving

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable+0.086 m/yr6
Phosphorus Improving-1.1 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #24 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

Most recent sample: 2025-09-08

Monitoring stations: 2