Scalp Lake
Scalp Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 90 ft. Surface area: 254.38 acres.
- Clarity
- 20 ft
- Typical in August
- 75°F
- Max depth
- 90 ft
- Area
- 254 acres
- Type
- Oligotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 20
- Open water
- 228 days
Next lake in Otter Tail County
Scalp Lake is a 254-acre cold, clear oligotrophic lake in Otter Tail County, Minnesota with a maximum depth of 90 feet. Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 13 documented fish species including black crappie, bluegill, and green sunfish. Public access is available with 3 public boat landings. Compared to the 65 other monitored lakes in Otter Tail County, Scalp Lake ranks #30 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-17. 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 20 ft down. Phosphorus level: 9 µg/L. Chlorophyll-a: 1.8 µg/L. Trophic State Index: 35.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 20 ft | Not graded |
| Phosphorus | 9 µg/L | Good |
| Chlorophyll-a (Algae) | 1.8 µg/L | Good |
| Trophic State Index (TSI) | 35 | Oligotrophic |
Low nutrients, clear water, excellent for swimming
Where to stay near Scalp Lake
Compare lakeside cabins, hotels, and vacation rentals near Scalp 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
Scalp Lake typically sits around 75°F at the surface in August. Summer average is about 70°F. Usually warmest in Jul (about 78°F) and coldest in May (about 51°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 28 field readings (2011–2025) via the EPA Water Quality Portal. See the full Scalp Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 90 ft |
| Surface Area | 254 acres |
| Shoreline Length | 2.6 mi |
| Littoral Zone | 26% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Rose LakePublic
- Six LakePublic
- Scalp LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Scalp 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
8 surveys on file from MN DNR Fisheries. Most recent: 2025-07-31 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 42.16 | 0.13 lb |
| MMS | 33.10 | — |
| Spottail Shiner | 22.07 | — |
| Bluntnose Minnow | 19.94 | — |
| JND | 14.79 | — |
| BNS | 14.35 | — |
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
From the 2025-07-31 survey
A targeted survey of nearshore fish species in Scalp Lake was conducted on July 31, 2025, by Area Fisheries staff. Sampling sites were evenly spaced around the lake, and each was sampled by backpack electrofishing and seining with a 50-foot or 15-foot seine, where possible. Backpack electrofishing was completed at 10…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Scalp Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — ScalpFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Scalp (1193)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — ScalpFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — ScalpPublic 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 | +0.518 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.83 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.13 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (35 observations).
Estimated open water season: 228 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2024-03-24 (2024) | 2022-05-07 (2022) |
| Ice-In | 2018-11-20 (2018) | 2015-12-19 (2015) |
Most recent ice-out: 2024-03-24
EPA Impairment Status
Scalp 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 MN56-0360-00 · Official waterbody report · Matched by proximity (2.76 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Scalp Lake under Clean Water Act (NPDES) discharge permits.
- Vergas WwtpVergas · 1.7 mi away · NPDES MN0025097
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 #30 of 66 lakes in Otter Tail County
Nearby Lakes in Otter Tail County
Frequently asked questions about Scalp Lake
What is the water quality grade for Scalp Lake?
- Scalp Lake in Otter Tail County, Minnesota has a water quality grade of A (Excellent). Water clarity: 20 ft visibility. Phosphorus: 9 µg/L. Chlorophyll-a (algae): 1.8 µg/L. Maximum depth: 90 ft. Surface area: 254.38 acres.
Is Scalp Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Scalp Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 1.8 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Scalp Lake?
- Scalp Lake typically sits around 75°F at the surface in August, from 28 EPA Water Quality Portal field readings (2011–2025). That is a typical value for the month, not a live reading.
How deep is Scalp Lake?
- Scalp Lake has a maximum depth of 90 feet. The lake covers 254.38 acres.
What fish are in Scalp Lake?
- Fish species found in Scalp Lake include black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Scalp Lake is located in Otter Tail County, Minnesota.
When does Scalp Lake thaw?
- Scalp Lake typically has ice-out around Apr 20. Ice typically forms around Dec 4. The open water season is approximately 228 days.
Are there boat ramps on Scalp Lake?
- Scalp Lake has 3 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Rose Lake, Six Lake, Scalp Lake. Public access is listed as yes.
Explore Scalp Lake across LakeGrade
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Where this data comes from
114 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA114 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 (2)
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