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LakeQuality
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Shadow Lake

Oconto County, WisconsinMesotrophic

Shadow Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. 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.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake is compact at 24 acres, with partial shoreline records and little volume to buffer nutrient inputs. Among the 66 graded lakes in Oconto County, Shadow Lake sits at rank 17, above the county median.

No invasive species are currently listed at Shadow Lake — the lake remains off the Wisconsin infested-waters roster. Bass fishing is part of the appeal: the species list runs to 3, anchored by largemouth and/or smallmouth bass. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2023-08-23. 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 19.7 ft down. Phosphorus level: 18 µg/L. Trophic State Index: 40.

MetricValueGrade
Water Clarity (Secchi Depth)19.7 ftA
Phosphorus18 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)40Mesotrophic

Moderate nutrients, good water quality

Lake Details

CharacteristicValue
Surface Area24 acres
Public AccessYes

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Shadow Lake (14-day solunar calendar)

→ Is it safe to eat fish from Shadow Lake? (mercury & PFAS guide)

Shadow Lake fishing regulations (limits, seasons, special rules)

Water Quality Trend: Declining

Based on 4 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-2.5 m/yr4
Phosphorus Declining+1.9 µg/L/yr2
See year-by-year chart →

Recreation & Access

1
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #17 of 66 lakes in Oconto County

Nearby Lakes in Oconto County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 1 station on file (most recent sample 2023).

Fish Species (DNR-rated)

Panfish(Common)Largemouth Bass(Present)Northern Pike(Present)

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: 2023-08-23

Monitoring stations: 1