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LakeQuality
B

Lower Turtle Lake

Barron County, WisconsinEutrophic

Lower Turtle Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. 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.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake bottoms out at 24 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Lower Turtle Lake covers 286 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Barron County's 38 graded lakes, Lower Turtle Lake ranks 27 — below the local median, though not at the bottom.

Lower Turtle Lake has at least one documented invasive species (Chinese Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. The fishery includes walleye alongside the lake's other 4 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. 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 2025-08-31. Grade methodology: LakeGrade methodology.

Swimming Safety

Good for swimming, clear water with low algae levels

Water Quality Grade: B, Good

Good clarity, visible to about 12.3 ft. Phosphorus level: 57 µg/L. Trophic State Index: 52.

MetricValueGrade
Water Clarity (Secchi Depth)12.3 ftB
Phosphorus57 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)52Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth24 ft
Surface Area286 acres
Public AccessYes

Fish Species

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

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

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

Lower Turtle Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Chinese Mystery SnailCurly-Leaf Pondweed

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+0.143 m/yr7
Phosphorus Improving-4.36 µg/L/yr6
See year-by-year chart →

Recreation & Access

2
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #27 of 38 lakes in Barron County

Cleaner Lakes Within 30 Miles

Lower Turtle Lake holds Grade B. 5 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Barron County

State Parks Near Lower Turtle Lake

Eutrophic Lakes in Wisconsin

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1987. 5 stations on file (most recent sample 2025).

DNR Assessment
Fair · Shallow Lowland lake
Trophic State Index 69 (eutrophic) · 5-year average

Fish Species (DNR-rated)

Largemouth Bass(Common)Northern Pike(Common)Walleye(Common)Panfish(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: 2025-08-31

Monitoring stations: 2