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LakeQuality
A

Cable Lake

Bayfield County, WisconsinOligotrophic

Cable Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

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. Cable Lake ranks 27 of 55 in Bayfield County — solidly in the upper half of the local distribution.

Cable Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Cable 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 2025-11-15. 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 50.9 ft down. Phosphorus level: 14.1 µg/L. Trophic State Index: 31.

MetricValueGrade
Water Clarity (Secchi Depth)50.9 ftA
Phosphorus14.1 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)31Oligotrophic

Low nutrients, clear water, excellent for swimming

Water Quality Trend: Declining

Based on 7 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.594 m/yr7
Phosphorus Declining+0.3 µg/L/yr3
See year-by-year chart →

Location

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County Ranking

Ranked #27 of 55 lakes in Bayfield County

Nearby Lakes in Bayfield County

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2025-11-15

Monitoring stations: 4