Brophy Lake
Brophy Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.4 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 44 ft. Surface area: 296.53 acres.
- Clarity
- 15.4 ft
- Typical in August
- 74°F
- Max depth
- 44 ft
- Area
- 297 acres
- Type
- Mesotrophic
- Trend
- → Stable
- Public access
- Yes
- Ice-out
- Apr 11
- Open water
- 231 days
Next lake in Douglas County
Brophy Lake is a 297-acre mesotrophic lake in Douglas County, Minnesota with a maximum depth of 44 feet. Water quality is graded A based on 2 sampling years through 2025. Phosphorus level is declining over recent sampling years. The lake supports 16 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 2 public boat landings. Compared to the 36 other monitored lakes in Douglas County, Brophy Lake ranks #19 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.
Excellent for swimming, crystal clear water with minimal algae
Water Quality Grade: A (Excellent)
Crystal clear, you can see 15.4 ft down. Phosphorus level: 21 µg/L. Chlorophyll-a: 2.7 µg/L. Trophic State Index: 42.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 15.4 ft | Not graded |
| Phosphorus | 21 µg/L | Good |
| Chlorophyll-a (Algae) | 2.7 µg/L | Good |
| Trophic State Index (TSI) | 42 | Mesotrophic |
Moderate nutrients, good water quality
Where to stay near Brophy Lake
Compare lakeside cabins, hotels, and vacation rentals near Brophy 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.
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Water Temperature
Brophy Lake typically sits around 74°F at the surface in August. Summer average is about 72°F. Usually warmest in Jul (about 76°F) and coldest in Jun (about 65°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 61 field readings (2010–2024) via the EPA Water Quality Portal. See the full Brophy Lake water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 44 ft |
| Surface Area | 297 acres |
| Shoreline Length | 3.5 mi |
| Littoral Zone | 55% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Lake BrophyPublic
- Mina LakePublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Brophy 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
12 surveys on file from MN DNR Fisheries. Most recent: 2023-07-10 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Bluegill | 19.21 | 0.18 lb |
| Largemouth Bass | 14.89 | 0.9 lb |
| Yellow Bass | 14.52 | 0.66 lb |
| TPM | 6.93 | — |
| BKS | 6.56 | — |
| Northern Pike | 5.72 | 1.78 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
Northern Pike
From the 2023-07-10 survey
A targeted survey of nearshore fish species in Brophy Lake was conducted on July 10, 2023, by Index of Biological Integrity (IBI) Program 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…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Brophy Lake. 4 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BrophyFisheries Lake Survey · MN DNR LakeFinder
- —Aquatic Plant Report — Brophy (1067)Aquatic Plant Report · MN DNR LakeFinder
- —Fish Stocking History — BrophyFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — BrophyPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: → Stable
Based on 6 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | → Stable | +0.064 m/yr | 6 |
| Phosphorus | ↓ Declining | +0.81 µg/L/yr | 6 |
| Chlorophyll-a | ↑ Improving | -0.06 µg/L/yr | 6 |
Ice Season
Historical ice data from Minnesota DNR (13 observations).
Estimated open water season: 231 days
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2004-04-07 (2004) | 2008-04-30 (2008) |
| Ice-In | 2014-11-25 (2014) | 2004-12-13 (2004) |
Most recent ice-out: 2015-04-11
EPA Impairment Status
Brophy 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 MN21-0108-00 · Official waterbody report · Matched by proximity (2.83 km)
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Brophy Lake under Clean Water Act (NPDES) discharge permits.
- Garfield WwtpGarfield · 3.7 mi away · NPDES MN0023515
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 #19 of 37 lakes in Douglas County
Nearby Lakes in Douglas County
Frequently asked questions about Brophy Lake
What is the water quality grade for Brophy Lake?
- Brophy Lake in Douglas County, Minnesota has a water quality grade of A (Excellent). Water clarity: 15.4 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 2.7 µg/L. Maximum depth: 44 ft. Surface area: 296.53 acres.
Is Brophy Lake safe to swim in?
- Excellent for swimming, crystal clear water with minimal algae. Brophy Lake has a water quality grade of A (Excellent). Algae concentration (chlorophyll-a) is 2.7 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Brophy Lake?
- Brophy Lake typically sits around 74°F at the surface in August, from 61 EPA Water Quality Portal field readings (2010–2024). That is a typical value for the month, not a live reading.
How deep is Brophy Lake?
- Brophy Lake has a maximum depth of 44 feet. The lake covers 296.53 acres.
What fish are in Brophy Lake?
- Fish species found in Brophy Lake include black bullhead, black crappie, bluegill, bowfin (dogfish), brown bullhead, common carp, green sunfish, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, walleye, white sucker, yellow bullhead, yellow perch. Brophy Lake is located in Douglas County, Minnesota.
When does Brophy Lake thaw?
- Brophy Lake typically has ice-out around Apr 11. Ice typically forms around Nov 28. The open water season is approximately 231 days.
Are there boat ramps on Brophy Lake?
- Brophy Lake has 2 documented boat landings in the USGS National Boat Ramps inventory. Named access points include Lake Brophy, Mina Lake. Public access is listed as yes.
Explore Brophy Lake across LakeGrade
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Moderate nutrients, good water quality
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Where this data comes from
53 measurements from 4 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
MNPCA52 samples · 2020–2025 - Minnesota Department of Agriculture - Pesticide Monitoring
MNDA_PESTICIDE1 sample · 2022
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Two Reagent Colorimetry
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- 2120 B ~ Color in Water by Visual Comparison
- 10200 H 2 ~ Chlorophyll a-b-c Determination by spectrophotometer
Monitoring station identifiers (4)
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