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LakeQuality
A

Ember Lake

Polk County, WisconsinOligotrophic

Ember Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Polk County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. 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. Ember Lake sits at rank 41 of 77 in Polk County, in the lower half of the local distribution.

Ember Lake has no invasive species recorded in Wisconsin state databases as of 2024, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Ember 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 2024-09-09. 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 27.1 ft down. Phosphorus level: 20.2 µg/L. Trophic State Index: 39.

MetricValueGrade
Water Clarity (Secchi Depth)27.1 ftA
Phosphorus20.2 µg/LB
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)39Oligotrophic

Low nutrients, clear water, excellent for swimming

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.5 m/yr2
Phosphorus Stable-0.4 µg/L/yr2
See year-by-year chart →

Location

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County Ranking

Ranked #41 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: 2024-09-09

Monitoring stations: 2