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.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 12.3 ft | B |
| Phosphorus | 57 µg/L | C |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 52 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 286 acres |
| Public Access | Yes |
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
Water Quality Trend: ↑ Improving
Based on 7 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.143 m/yr | 7 |
| Phosphorus | ↑ Improving | -4.36 µg/L/yr | 6 |
Recreation & Access
Location
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.
- AEcho LakeBarron County · 4.4 mi · Higher grade (B → A)
- ALoon LakeBarron County · 5.9 mi · Higher grade (B → A)
- ABig Moon Lake atBarron County · 3.8 mi · Higher grade (B → A)
- AHorseshoe LakePolk County · 5.3 mi · Higher grade (B → A)
- BPoskin LakeBarron County · 6 mi · Higher overall water quality score
Nearby Lakes in Barron County
More Wisconsin Lake Rankings
State Parks Near Lower Turtle Lake
Other Grade B Lakes in Wisconsin
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).
Fish Species (DNR-rated)
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