Black Brook Flowage Lake
Black Brook Flowage Lake in Polk County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 10.5 ft visibility. Phosphorus: 46.6 µg/L. Maximum depth: 23 ft. Surface area: 69 acres.
- Clarity
- 10.5 ft
- Max depth
- 23 ft
- Area
- 69 acres
- Type
- Eutrophic
- Public access
- Yes
Grade D measures nutrients and algae, not whether this is a good place for a cabin trip. Cabins and rentals near Black Brook Flowage Lake →
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Black Brook Flowage Lake is a 69-acre productive, nutrient-rich eutrophic lake in Polk County, Wisconsin with a maximum depth of 23 feet. Water quality is graded D based on 1 sampling years through 2020. The lake supports 4 documented fish species including Musky, Panfish, and Largemouth Bass. Public access is available with 1 public boat landing. Compared to the 54 other monitored lakes in Polk County, Black Brook Flowage Lake ranks #47 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2020-09-09. Grade methodology: LakeQuality methodology.
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Swimming Safety
Grade onlyLimited data
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.
Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum
Water Quality Grade: D (Nutrient-rich)
Good clarity, visible to about 10.5 ft. Phosphorus level: 46.6 µg/L. Trophic State Index: 51.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft | Not graded |
| Phosphorus | 46.6 µg/L | Poor |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 51 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay near Black Brook Flowage Lake
Compare lakeside cabins, hotels, and vacation rentals near Black Brook Flowage Lake in Polk County, Wisconsin — 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 Black Brook Flowage Lake are listed below.
Top-rated places to stay near Black Brook Flowage Lake
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Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 23 ft |
| Surface Area | 69 acres |
| Public Access | Yes |
Recreation & Access
- Black Brook FlowagePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Fish Species
Click a species to see every graded lake where it is documented.
Fishing Black Brook Flowage 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.
Reservoir Info (USACE NID)
Black Brook Flowage Lake is a man-made reservoir impounded by the Black Brook (completed 1917), built primarily for hydroelectric on the Apple River; gravity-type dam, 32 ft tall and 270 ft long.
- Surface area
- 98 ac
- Normal storage
- 1,220 ac-ft
- Max storage
- 1,400 ac-ft
- Drainage area
- 162 sq mi
- Hazard class
- Low
- Owner
- Northwestern Wisconsin Electric Company
All listed purposes: Hydroelectric;Fish and Wildlife Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID WI00050 · Operator website
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Black Brook Flowage Lake under Clean Water Act (NPDES) discharge permits.
- Minglewood IncBlack Brook, Town Of · 3.5 mi away · NPDES WI0059358
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 #47 of 55 lakes in Polk County
Nearby Lakes With Higher Grades
Black Brook Flowage Lake holds Grade D. 2 nearby lakes hold higher nutrient-and-algae grades — useful for a swim day, not a reason to skip lodging here.
Nearby Lakes in Polk County
Frequently asked questions about Black Brook Flowage Lake
Where is Black Brook Flowage Lake?
- Black Brook Flowage Lake is a lake in Polk County, Wisconsin. LakeQuality grades it D for nutrients and algae. The letter is not a swimming clearance.
What is the water quality grade for Black Brook Flowage Lake?
- Black Brook Flowage Lake in Polk County, Wisconsin has a water quality grade of D (Nutrient-rich). Water clarity: 10.5 ft visibility. Phosphorus: 46.6 µg/L. Maximum depth: 23 ft. Surface area: 69 acres.
Is Black Brook Flowage Lake safe to swim in?
- Nutrients and algae run higher than average — check local advisories before swimming, and skip the water if you see scum. Black Brook Flowage Lake has a water quality grade of D (Nutrient-rich). Always check local health department advisories before swimming.
How deep is Black Brook Flowage Lake?
- Black Brook Flowage Lake has a maximum depth of 23 feet. The lake covers 69 acres.
What fish are in Black Brook Flowage Lake?
- Fish species found in Black Brook Flowage Lake include Musky, Panfish, Largemouth Bass, Northern Pike. Black Brook Flowage Lake is located in Polk County, Wisconsin.
Are there boat ramps on Black Brook Flowage Lake?
- Black Brook Flowage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Black Brook Flowage. Public access is listed as yes.
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Where this data comes from
7 measurements from 1 monitoring station, 2020. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX7 samples · 2020
Analytical methods
- Phosphorus by Colorimetry
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
Regulated discharger data from EPA ECHO (ICIS-NPDES)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory