Prairie Lake
Prairie Lake in Otter Tail County, Minnesota has a water quality grade of B (Good). Water clarity: 8.9 ft visibility. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 7.3 µg/L. Maximum depth: 22 ft. Surface area: 1004.41 acres.
- Clarity
- 8.9 ft
- Typical in August
- 75°F
- Max depth
- 22 ft
- Area
- 1,004 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 7
Next lake in Otter Tail County
Free interactive depth-contour map of Prairie Lake, reaching a maximum surveyed depth of 20 ft. Toggle Depth contours to overlay the bathymetric survey lines. Contour data from Minnesota DNR.
Prairie Lake is a 1,004-acre mesotrophic lake in Otter Tail County, Minnesota with a maximum depth of 22 feet (10-foot average). Water quality is graded B based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 15 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available with 1 public boat landing. Compared to the 65 other monitored lakes in Otter Tail County, Prairie Lake ranks #50 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyLow algae
Based on clarity and algae grades from past sampling — we do not hold live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Good for swimming, clear water with low algae levels
Water Quality Grade: B (Good)
Moderate clarity, visible to about 8.9 ft. Phosphorus level: 18 µg/L. Chlorophyll-a: 7.3 µg/L. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.9 ft | Not graded |
| Phosphorus | 18 µg/L | Good |
| Chlorophyll-a (Algae) | 7.3 µg/L | Good |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Prairie Lake
Compare lakeside cabins, hotels, and vacation rentals near Prairie Lake in Otter Tail 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.
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Water Temperature
Prairie Lake typically sits around 75°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 80°F) and coldest in May (about 58°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 27 field readings (2010–2021) via the EPA Water Quality Portal. See the full Prairie Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Prairie Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (77,983 cells/mL) on November 22, 2025.
Blue-green algae can appear and clear within days, so check your state’s current advisory before swimming. EPA CyAN ↗
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 22 ft |
| Average Depth | 10 ft |
| Surface Area | 1,004 acres |
| Shoreline Length | 7.3 mi |
| Littoral Zone | 80% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Prairie LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Prairie 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.
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2024-06-04 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 27.00 | 0.17 lb |
| Largemouth Bass | 8.80 | 1.28 lb |
| Yellow Bass | 7.64 | 0.54 lb |
| Pumpkinseed | 6.05 | 0.24 lb |
| Northern Pike | 5.22 | 1.37 lb |
| Hybrid Sunfish | 3.78 | 0.28 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
Largemouth Bass
Yellow Bass
Pumpkinseed
From the 2024-06-04 survey
Prairie Lake is a 1,016-acre eutrophic (fertile) lake located in northwestern Otter Tail County. The city of Pelican Rapids, MN abuts the south shoreline of the lake. Prairie Lake is part of the Otter Tail River Watershed. The Pelican River inlet is located along the northeast shoreline while the outlet is located…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Prairie Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — PrairieFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Prairie (1040)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — PrairieFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — PrairiePublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↑ Improving
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↑ Improving | +0.103 m/yr | 6 |
| Phosphorus | ↑ Improving | -1.06 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.46 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (4 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2021-03-30 (2021) | 2022-05-05 (2022) |
Most recent ice-out: 2025-04-10
Reservoir Info (USACE NID)
Prairie Lake is a man-made reservoir impounded by the Prairie Lake (completed 1936), built primarily for recreation on the Pelican River; gravity-type dam, 12 ft tall and 49 ft long.
- Surface area
- 1,025 ac
- Normal storage
- 10,250 ac-ft
- Max storage
- 16,400 ac-ft
- Drainage area
- 340 sq mi
- Hazard class
- Low
- Owner
- MNDNR
Source: USACE National Inventory of Dams, NID ID MN00192 · Operator website
EPA Impairment Status
Prairie Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0915-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Prairie Lake under Clean Water Act (NPDES) discharge permits. 1 facility has a reported Clean Water Act violation in the past three years.
- Pelican Rapids WwtpPelican Rapids · 2.2 mi away · NPDES MN0022225Recent violation
Facilities permitted to discharge under the Clean Water Act within ~5 miles; proximity does not by itself mean a facility affects this lake. Source: EPA ECHO (ICIS-NPDES), as of 2026-07.
County Ranking
Ranked #50 of 66 lakes in Otter Tail County
Nearby Lakes With Higher Grades
Prairie Lake holds Grade B. 3 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
See full comparison →Nearby Lakes in Otter Tail County
Frequently asked questions about Prairie Lake
What is the water quality grade for Prairie Lake?
- Prairie Lake in Otter Tail County, Minnesota has a water quality grade of B (Good). Water clarity: 8.9 ft visibility. Phosphorus: 18 µg/L. Chlorophyll-a (algae): 7.3 µg/L. Maximum depth: 22 ft. Surface area: 1004.41 acres.
Is Prairie Lake safe to swim in?
- Good for swimming, clear water with low algae levels. Prairie Lake has a water quality grade of B (Good). Algae concentration (chlorophyll-a) is 7.3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Prairie Lake?
- Prairie Lake typically sits around 75°F at the surface in August, from 27 EPA Water Quality Portal field readings (2010–2021). That is a typical value for the month, not a live reading.
How deep is Prairie Lake?
- Prairie Lake has a maximum depth of 22 feet and an average depth of 10 feet. The lake covers 1004.41 acres.
What fish are in Prairie Lake?
- Fish species found in Prairie Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Prairie Lake is located in Otter Tail County, Minnesota.
When does Prairie Lake thaw?
- Prairie Lake typically has ice-out around Apr 7.
Does Prairie Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Prairie Lake (clouds, ice, or an off-season gap). The most recent reading was moderate (77,983 cells/mL). Blue-green algae can appear and clear within days, so check Minnesota's current advisory before swimming.
Are there boat ramps on Prairie Lake?
- Prairie Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Prairie Lake. Public access is listed as yes.
Explore Prairie Lake across LakeGrade
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Where this data comes from
88 measurements from 1 monitoring station, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA88 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Lake size & watershed from HydroLAKES (HydroSHEDS)
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory
Ice data from Minnesota DNR Climate