Wellner-Hageman Reservoir
Wellner-Hageman Reservoir in Brown County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3.7 ft visibility. Phosphorus: 45 µg/L. Chlorophyll-a (algae): 30.3 µg/L. Maximum depth: 24 ft. Surface area: 74.92 acres.
- Clarity
- 3.7 ft
- Typical in August
- 74°F
- Max depth
- 24 ft
- Area
- 75 acres
- Type
- Eutrophic
- Trend
- ↓ Declining
- Public access
- Yes
Grade F measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Wellner-Hageman Reservoir →
Next lake in Brown County
Wellner-Hageman Reservoir is a 75-acre productive, nutrient-rich eutrophic lake in Brown County, Minnesota with a maximum depth of 24 feet. Water quality is graded F based on 2 sampling years through 2023. Overall water quality is declining over recent sampling years. The lake supports 9 documented fish species including black bullhead, black crappie, and bluegill. Public access is available with 1 public boat landing. Compared to the 3 other monitored lakes in Brown County, Wellner-Hageman Reservoir ranks #3 for water quality.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2023-10-11. Grade methodology: LakeGrade methodology.
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Swimming Safety
Grade onlyAlgae risk
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.
Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom
Water Quality Grade: F (Algae-prone)
Murky, only visible to about 3.7 ft. Phosphorus level: 45 µg/L. Chlorophyll-a: 30.3 µg/L. Trophic State Index: 60.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 3.7 ft | Not graded |
| Phosphorus | 45 µg/L | Fair |
| Chlorophyll-a (Algae) | 30.3 µg/L | Poor |
| Trophic State Index (TSI) | 60 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Wellner-Hageman Reservoir
Compare lakeside cabins, hotels, and vacation rentals near Wellner-Hageman Reservoir in Brown 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. The water-quality grade measures nutrients and algae, not lodging — cabins and rentals around Wellner-Hageman Reservoir are listed below.
Top-rated places to stay near Wellner-Hageman Reservoir
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Planning a whole trip? See where to stay at Minnesota’s top lakes →
Water Temperature
Wellner-Hageman Reservoir typically sits around 74°F at the surface in August. Summer average is about 74°F. Usually warmest in Jul (about 75°F) and coldest in Oct (about 53°F). These are typical values by month — not a live reading.
Typical surface water temperature by month, from 236 field readings (2017–2023) via the EPA Water Quality Portal. See the full Wellner-Hageman Reservoir water temperature breakdown →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 24 ft |
| Surface Area | 75 acres |
| Shoreline Length | 3.5 mi |
| Public Access | Yes |
Recreation & Access
- Mound Creek ReservoirPublic
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Wellner-Hageman Reservoir
DNR Fisheries Survey Summary
6 surveys on file from MN DNR Fisheries. Most recent: 2022-07-25 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Yellow Perch | 52.57 | 0.14 lb |
| Black Bullhead | 47.37 | 0.37 lb |
| Black Crappie | 14.80 | 0.26 lb |
| Bluegill | 14.02 | 0.25 lb |
| White Sucker | 2.85 | 1.81 lb |
| Walleye | 1.22 | 3.21 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.
Yellow Perch
Black Bullhead
Black Crappie
Bluegill
From the 2022-07-25 survey
Wellner-Hageman Reservoir (aka Mound Creek Reservoir), near Sanborn, is a man-made 70-acre lake located in Brown County. The class 33 reservoir was created in the spring of 1993 for flood and erosion control for Mound Creek and lower portions of the Cottonwood River. Wellner-Hageman Reservoir is within a large…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Wellner-Hageman Reservoir. 3 reports on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — Wellner-Hageman ReservoirFisheries Lake Survey · MN DNR LakeFinder
- —Fish Stocking History — Wellner-Hageman ReservoirFish Stocking History · MN DNR LakeFinder
- —Public Water Access Sites — Wellner-Hageman ReservoirPublic Water Access Sites · MN DNR LakeFinder
Water Quality Trend: ↓ Declining
Based on 4 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.043 m/yr | 4 |
| Phosphorus | → Stable | -0.6 µg/L/yr | 4 |
| Chlorophyll-a | ↓ Declining | +3.12 µg/L/yr | 4 |
Reservoir Info (USACE NID)
Wellner-Hageman Reservoir is a man-made reservoir impounded by the Wellner-Hageman (completed 1993), built primarily for flood risk reduction on the Mound Creek, 52 ft tall and 2,200 ft long.
- Surface area
- 71 ac
- Normal storage
- 71 ac-ft
- Max storage
- 227 ac-ft
- Drainage area
- 13.1 sq mi
- Hazard class
- Low
- Owner
- County of Brown
Source: USACE National Inventory of Dams, NID ID MN01001 · Operator website
County Ranking
Ranked #3 of 4 lakes in Brown County
Nearby Lakes With Higher Grades
Wellner-Hageman Reservoir holds Grade F. 2 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 Brown County
Frequently asked questions about Wellner-Hageman Reservoir
What is the water quality grade for Wellner-Hageman Reservoir?
- Wellner-Hageman Reservoir in Brown County, Minnesota has a water quality grade of F (Algae-prone). Water clarity: 3.7 ft visibility. Phosphorus: 45 µg/L. Chlorophyll-a (algae): 30.3 µg/L. Maximum depth: 24 ft. Surface area: 74.92 acres.
Is Wellner-Hageman Reservoir safe to swim in?
- Algae and nutrients are often high — check current advisories before swimming. Skip the water if you see scum or a paint-like bloom. Wellner-Hageman Reservoir has a water quality grade of F (Algae-prone). Algae concentration (chlorophyll-a) is 30.3 µg/L. Always check local health department advisories before swimming.
What is the water temperature of Wellner-Hageman Reservoir?
- Wellner-Hageman Reservoir typically sits around 74°F at the surface in August, from 236 EPA Water Quality Portal field readings (2017–2023). That is a typical value for the month, not a live reading.
How deep is Wellner-Hageman Reservoir?
- Wellner-Hageman Reservoir has a maximum depth of 24 feet. The lake covers 74.92 acres.
What fish are in Wellner-Hageman Reservoir?
- Fish species found in Wellner-Hageman Reservoir include black bullhead, black crappie, bluegill, common carp, green sunfish, largemouth bass, walleye, white sucker, yellow perch. Wellner-Hageman Reservoir is located in Brown County, Minnesota.
Are there boat ramps on Wellner-Hageman Reservoir?
- Wellner-Hageman Reservoir has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Mound Creek Reservoir. Public access is listed as yes.
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Where this data comes from
357 measurements from 1 monitoring station, 2020–2023. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA357 samples · 2020–2023
Analytical methods
- Field measurement/observation, generic method
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
- Turbidity, Nephelometric Method
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
Lake details from Minnesota DNR LakeFinder
Named boat-access points from the USGS National Boat Ramps inventory