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LakeQuality

Turtle Lake

NR
Not yet rated
10.5 ft clear · Mesotrophic · 218 acres
Limited DataMesotrophic

Turtle Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility. Maximum depth: 21 ft. Surface area: 218.04 acres.

Clarity
10.5 ft
Max depth
21 ft
Area
218 acres
Public access
Yes

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AMaple Lake14.1 ft clear · Douglas CountyView →
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Why Turtle Lake has no grade

We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Turtle Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).

Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.

Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.

Turtle Lake is a 218-acre lake in Douglas County, Minnesota with a maximum depth of 21 feet (7-foot average). The lake supports 12 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2020-08-04. Grade methodology: LakeGrade methodology.

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Swimming Safety

Not rated

Limited data

Not rated for swimming — there is not enough monitoring data to judge this lake

Compare the safest swimming lakes near Alexandria

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Water quality measurements for Turtle Lake

These readings exist but do not meet the evidence bar for an A–F grade — see why.

Good clarity, visible to about 10.5 ft. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)10.5 ftNot graded
PhosphorusNo recent samples
Chlorophyll-a (Algae)No recent samples
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Where to stay near Turtle Lake

Compare lakeside cabins, hotels, and vacation rentals near Turtle Lake in Douglas County, Minnesota — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water.

Top-rated places to stay near Turtle Lake

Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.

Planning a whole trip? See where to stay at Minnesota’s top lakes →

Lake Details

CharacteristicValue
Maximum Depth21 ft
Average Depth7 ft
Surface Area218 acres
Shoreline Length3.1 mi
Littoral Zone88%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
1 sq mi
Elevation
1,375 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Recreation & Access

2
Boat Landings
Yes
Public Access
  • Turtle LakePublic
  • Lake Reno (Northeast)Public

Fish Species

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

Fishing Turtle Lake

Invasive & Introduced Species

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

zebra mussel

DNR Fisheries Survey Summary

10 surveys on file from MN DNR Fisheries. Most recent: 2021-07-12 (Standard Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluntnose Minnow42.75
Bluegill20.800.2 lb
Green Sunfish18.100.08 lb
Largemouth Bass14.781.41 lb
Yellow Perch11.430.13 lb
Black Crappie9.040.32 lb

CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.

Length Distributions

Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.

Bluegill

437 fish · 38 in · 2021-07-12
163820345678

Green Sunfish

1 fish · 44 in · 2000-07-05
104

Largemouth Bass

162 fish · 319 in · 2021-07-12
36180trophy 204681012141618

Yellow Perch

68 fish · 58 in · 2021-07-12
512605678

From the 2021-07-12 survey

Turtle Lake is a shallow, productive basin located in southern Douglas County. Consisting of two large bays, average depth is only 7.0 feet and aquatic vegetation is common. Water clarity was approximately 13.0 feet at the time of the July survey. A concrete boat launch is located in the southwest corner of Turtle…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Turtle Lake. 4 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

EPA Impairment Status

Turtle Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN21-0079-00 · Official waterbody report · Matched by proximity (2.18 km)

Graded lakes near Turtle Lake

Turtle Lake has no grade, but these lakes within a short drive do.

Nearby Lakes in Douglas County

Frequently asked questions about Turtle Lake

What is the water quality grade for Turtle Lake?

Turtle Lake in Douglas County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 10.5 ft visibility. Maximum depth: 21 ft. Surface area: 218.04 acres.

Is Turtle Lake safe to swim in?

Not rated for swimming — there is not enough monitoring data to judge this lake. Turtle Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.

How deep is Turtle Lake?

Turtle Lake has a maximum depth of 21 feet and an average depth of 7 feet. The lake covers 218.04 acres.

What fish are in Turtle Lake?

Fish species found in Turtle Lake include black bullhead, black crappie, bluegill, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, walleye, yellow bullhead, yellow perch. Turtle Lake is located in Douglas County, Minnesota.

Are there boat ramps on Turtle Lake?

Turtle Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Turtle Lake, Lake Reno (Northeast). Public access is listed as yes.

Where this data comes from

7 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.

Collected and reported by

  • Minnesota Pollution Control Agency - Ambient Surface WaterMNPCA7 samples · 2020

Analytical methods

  • Field measurement/observation, generic method
Monitoring station identifiers (1)

Grade thresholds from the EPA National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See how grades are calculated and data sources.

Other records on this page

Impairment status from EPA ATTAINS 303(d) database

Lake size & watershed from HydroLAKES (HydroSHEDS)

Lake details from Minnesota DNR LakeFinder

Named boat-access points from the USGS National Boat Ramps inventory