Orwell Lake
Otter Tail County, Minnesota608 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Orwell Lake. Here is what has been measured.
- Impaired · Mercury
- zebra mussel
- 25 ft max depth
- Public access
- Limited data
Orwell Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.1 ft visibility. Phosphorus: 54 µg/L. Chlorophyll-a (algae): 9.7 µg/L. Maximum depth: 25 ft. Surface area: 607.58 acres.
Minnesota DNR's Targeted Survey on May 13, 2024 caught 273.87 black crappie per hour of electrofishing at Orwell Lake. Length samples in the latest survey that recorded them ran 2–14 inches. DNR survey details →
Orwell Lake is a 608-acre lake in Otter Tail County, Minnesota with a maximum depth of 25 feet. Overall water quality is declining over recent sampling years. The lake supports 17 documented fish species including bigmouth buffalo, black bullhead, and black crappie. Public access is available with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-06-28. Methodology: how these readings are compared.
What Orwell Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing17 species recorded
Orwell Lake Water Quality Summary (2026)
A printable one-page summary for Orwell Lake: clarity, phosphorus, algae, multi-year trend, depth, and fish — with sources.
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Orwell Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, salinity / chlorides. Check local advisories before you swim.
Whether Orwell Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Orwell Lake
These are the measurements Minnesota PCA publishes for Orwell Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 4.1 ft. Phosphorus 54 µg/L. Chlorophyll-a 9.7 µg/L. TSI 57.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.1ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 54µg/L | Measured, not scored The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. |
| Chlorophyll-a (algae) | 9.7µg/L | Measured, not scored The green pigment in algae — a direct measure of how much algae is in the water. |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 57 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Orwell Lake
Answers come straight from the public measurements and survey records on this page.
Current Conditions
USGS snapshot Jul 6, 2026, 5:00 AM from gauge 05045950 (Orwell Lake at Orwell Dam Near Fergus Falls, MN). Station page ↗ — a live reading replaces this snapshot when the gauge responds. Missing live data is not an all-clear.
→ Orwell Lake water level: the live USGS gauge reading
Water Temperature
Orwell Lake typically sits around 67°F at the surface in September. Summer average is about 76°F. Usually warmest in Aug (about 77°F) and coldest in May (about 56°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (56°F) to its warmest (77°F).
Typical surface water temperature by month, from 63 field readings (2016–2022) via the EPA Water Quality Portal. See the full Orwell Lake water temperature breakdown →
Minnesota DNR's Targeted Survey on May 13, 2024 caught 273.87 black crappie per hour of electrofishing at Orwell Lake. Length samples in the latest survey that recorded them ran 2–14 inches.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Orwell Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
7 surveys on file from MN DNR Fisheries. Most recent: 2024-05-13 (Targeted Survey).
7 surveys on file · most recent 2024-05-13 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Black Crappie | 26.47 | 2–14 in 2024-05-13 | 0.39 lb |
| Black Bullhead | 6.15 | 6–9 in 2023-07-10 | 0.39 lb |
| Common Carp | 5.18 | 14–22 in 2023-07-10 | 2.39 lb |
| Channel Catfish | 4.21 | 5–30 in 2023-07-10 | 1.87 lb |
| Walleye | 3.49 | 4–25 in 2023-07-10 | 1.29 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Black Crappie
Black Bullhead
Common Carp
Channel Catfish
From the 2024-05-13 survey
Orwell Reservoir is a United States Army Corps of Engineers flood control impoundment. It is located approximately 8 miles southwest of Fergus Falls, MN in Otter Tail County. Construction of the dam on the Otter Tail River was completed in 1952, and the reservoir encompasses 782-acres at normal pool. Because the main…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Orwell Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — OrwellFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Orwell (1033)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — OrwellFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — OrwellPublic Water Access Sites · MN DNR LakeFinder
Lake Details
Max depth
25 ft
Surface area
608 acres
Shoreline
11.7 mi
Littoral zone
100%
Share shallower than 15 ft
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
1,754 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,063 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Orwell ReservoirPublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
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Stays near Orwell Lake
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Follow Orwell Lake’s readings
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Fish Species
Click a species to see every lake where it is documented.
Fishing Orwell 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.
Water quality readings over time
2 seasons of samples on record (2021–2022). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Worsening2 years
Reservoir Info (USACE NID)
Orwell Lake is a man-made reservoir impounded by the Orwell Dam (completed 1953), built primarily for flood risk reduction on the OTTER TAIL RIVER; earth-type dam, 60 ft tall and 1,355 ft long.
- Surface area
- 805 ac
- Normal storage
- 8,050 ac-ft
- Max storage
- 20,600 ac-ft
- Drainage area
- 1,820 sq mi
- Hazard class
- High
- Owner
- USACE - St. Paul District
All listed purposes: Flood Risk Reduction;Other;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID MN00574 · Operator website
EPA Impairment Status
Orwell Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Cultural, Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN56-0945-00 · Official waterbody report
Nearby Lakes in Otter Tail County
Frequently asked questions about Orwell Lake
Where is Orwell Lake?
- Orwell Lake is a lake in Otter Tail County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Orwell Lake?
- Orwell Lake in Otter Tail County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.1 ft visibility. Phosphorus: 54 µg/L. Chlorophyll-a (algae): 9.7 µg/L. Maximum depth: 25 ft. Surface area: 607.58 acres.
Is Orwell Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Orwell Lake is listed impaired under Clean Water Act §303(d) (IR 5) for mercury, salinity / chlorides. Check local advisories before you swim.
What is the water temperature of Orwell Lake?
- Orwell Lake typically sits around 67°F at the surface in September, from 63 EPA Water Quality Portal field readings (2016–2022). That is a typical value for the month, not a live reading.
How deep is Orwell Lake?
- Orwell Lake has a maximum depth of 25 feet. The lake covers 607.58 acres.
What fish are in Orwell Lake?
- Fish species found in Orwell Lake include bigmouth buffalo, black bullhead, black crappie, bluegill, bowfin (dogfish), channel catfish, common carp, golden redhorse, greater redhorse, northern pike, rock bass, shorthead redhorse, smallmouth bass, walleye, white sucker, yellow bullhead, yellow perch. Orwell Lake is located in Otter Tail County, Minnesota.
What did the DNR fisheries survey find at Orwell Lake?
- Minnesota DNR's Targeted Survey on May 13, 2024 caught 273.87 black crappie per hour of electrofishing at Orwell Lake. Length samples in the latest survey that recorded them ran 2–14 inches. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Orwell Lake’s water-quality measurements separately, and the water-quality trend over 2 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
What is the water level at Orwell Lake?
- The USGS snapshot on this page for Orwell Lake is 64.07 ft of gage height, recorded Jul 6, 2026, 5:00 AM at gauge 05045950. Current Conditions hydrates a live NWIS reading from that same station when the gauge responds. A missed live fetch is not an all-clear.
Are there boat ramps on Orwell Lake?
- Orwell Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Orwell Reservoir. Public access is listed as yes.
Can I fish at Orwell Lake?
- Orwell Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
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Where this data comes from
10 measurements from 1 monitoring station, 2021–2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA10 samples · 2021–2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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