Big Spunk Lake
Big Spunk Lake in Stearns County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Maximum depth: 38 ft. Surface area: 415.27 acres.
- Clarity
- 10 ft
- Typical in August
- 74°F
- Max depth
- 38 ft
- Area
- 415 acres
- Type
- Mesotrophic
- Trend
- ↑ Improving
- Public access
- Yes
- Ice-out
- Apr 8
- Open water
- 235 days
Next lake in Stearns County
Big Spunk Lake is a 415-acre mesotrophic lake in Stearns County, Minnesota with a maximum depth of 38 feet (16-foot average). Water quality is graded A based on 2 sampling years through 2025. Overall water quality is improving over recent sampling years. The lake supports 19 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 31 other monitored lakes in Stearns County, Big Spunk Lake ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-29. 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)
Good clarity, visible to about 10 ft. Phosphorus level: 14 µg/L. Chlorophyll-a: 3.7 µg/L. Trophic State Index: 43.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10 ft | Not graded |
| Phosphorus | 14 µg/L | Good |
| Chlorophyll-a (Algae) | 3.7 µg/L | Good |
| Trophic State Index (TSI) | 43 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Big Spunk Lake
Compare lakeside cabins, hotels, and vacation rentals near Big Spunk Lake in Stearns 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
Big Spunk Lake typically sits around 74°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 76°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 227 field readings (2016–2025) via the EPA Water Quality Portal. See the full Big Spunk Lake water temperature breakdown →
Blue-Green Algae (Cyanobacteria)
There’s no recent EPA CyAN cyanobacteria estimate for Big Spunk Lake — clouds, ice, or an off-season gap in coverage. The most recent reading was moderate (77,983 cells/mL) on November 15, 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 | 38 ft |
| Average Depth | 15.9 ft |
| Surface Area | 415 acres |
| Shoreline Length | 4.9 mi |
| Littoral Zone | 36% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Big Spunk LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Big Spunk Lake
DNR Fisheries Survey Summary
10 surveys on file from MN DNR Fisheries. Most recent: 2023-09-05 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 45.72 | 0.14 lb |
| BCS | 41.27 | — |
| PGS | 32.01 | — |
| Bluntnose Minnow | 25.58 | — |
| CNM | 15.66 | — |
| Largemouth Bass | 14.91 | 0.69 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
Bluntnose Minnow
Largemouth Bass
From the 2023-09-05 survey
A targeted survey of nearshore fish species in Big Spunk Lake was conducted on September 5-7, 2023, by Index of Biological Integrity (IBI) Program staff. Ten 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.…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Big Spunk Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Big SpunkFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Big Spunk (1987)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — Big SpunkFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Big SpunkPublic 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 | → Stable | +0.005 m/yr | 6 |
| Phosphorus | ↑ Improving | -3.5 µg/L/yr | 2 |
| Chlorophyll-a | ↑ Improving | -1.9 µg/L/yr | 2 |
Ice Season
Historical ice data from Minnesota DNR (22 observations).
Estimated open water season: 235 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-03-13 (2012) | 2018-05-03 (2018) |
| Ice-In | 2021-11-11 (2021) | 2004-12-14 (2004) |
Most recent ice-out: 2022-04-23
EPA Impairment Status
Big Spunk Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN73-0117-00 · Official waterbody report
County Ranking
Ranked #2 of 32 lakes in Stearns County
Nearby Lakes in Stearns County
Frequently asked questions about Big Spunk Lake
What is the water quality grade for Big Spunk Lake?
- Big Spunk Lake in Stearns County, Minnesota has a water quality grade of A (Excellent). Water clarity: 10 ft visibility. Phosphorus: 14 µg/L. Chlorophyll-a (algae): 3.7 µg/L. Maximum depth: 38 ft. Surface area: 415.27 acres.
Is Big Spunk Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Big Spunk Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 3.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Big Spunk Lake?
- Big Spunk Lake typically sits around 74°F at the surface in August, from 227 EPA Water Quality Portal field readings (2016–2025). That is a typical value for the month, not a live reading.
How deep is Big Spunk Lake?
- Big Spunk Lake has a maximum depth of 38 feet and an average depth of 15.9 feet. The lake covers 415.27 acres.
What fish are in Big Spunk Lake?
- Fish species found in Big Spunk Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, channel catfish, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow bullhead, yellow perch. Big Spunk Lake is located in Stearns County, Minnesota.
When does Big Spunk Lake thaw?
- Big Spunk Lake typically has ice-out around Apr 8. Ice typically forms around Nov 29. The open water season is approximately 235 days.
Does Big Spunk Lake have blue-green algae?
- There is no recent EPA CyAN cyanobacteria estimate for Big Spunk 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 Big Spunk Lake?
- Big Spunk Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Big Spunk Lake. Public access is listed as yes.
Explore Big Spunk Lake across LakeGrade
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Where this data comes from
347 measurements from 3 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
MNPCA347 samples · 2020–2025
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- Phosphorus by Two Reagent Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (3)
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
Ice data from Minnesota DNR Climate