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Clearwater Lake

Oneida County, WisconsinOligotrophic

On the LakeGrade rubric, Clearwater Lake pulls an A: clarity at 16.8 ft and 10 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 value of 37 puts Clearwater Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake bottoms out at 48 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 360 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Oneida County's 134 graded waters, Clearwater Lake sits at rank 15, near the top of the local distribution.

Eurasian watermilfoil has been documented at Clearwater Lake, requiring shoreline management to keep dense mats from crowding native vegetation. Walleye are documented at Clearwater Lake, one of 6 fish species on record for the 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 2025-10-13. Grade methodology: LakeGrade methodology.

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Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

Crystal clear, you can see 16.8 ft down. Phosphorus level: 10 µg/L. Trophic State Index: 37.

MetricValueGrade
Water Clarity (Secchi Depth)16.8 ftA
Phosphorus10 µg/LA
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)37Oligotrophic

Low nutrients, clear water, excellent for swimming

Lake Details

CharacteristicValue
Maximum Depth48 ft
Surface Area360 acres

Fish Species

Click a species to see every graded lake where it is documented.

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

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

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

Invasive & Introduced Species

Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.

Chinese Mystery SnailEurasian Water-Milfoil

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+0.893 m/yr3
Phosphorus Improving-0.7 µg/L/yr4
See year-by-year chart →

Location

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County Ranking

Ranked #15 of 134 lakes in Oneida County

Nearby Lakes in Oneida County

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 2017. 2 stations on file (most recent sample 2025).

DNR Assessment
Excellent · Deep Lowland lake
Trophic State Index 35 (oligotrophic) · 5-year average

Fish Species (DNR-rated)

Smallmouth Bass(Common)Walleye(Common)Musky(Present)Panfish(Present)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: 2025-10-13

Monitoring stations: 1

Where to stay near Clearwater Lake

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