Black Brook Flowage Lake
Polk County, Wisconsin69 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Black Brook Flowage Lake. Here is what has been measured.
- Eutrophic
- 2 aquatic invasives
- 23 ft max depth
- Public access
- Limited data
Black Brook Flowage Lake in Polk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 10.5 ft visibility. Phosphorus: 46.6 µg/L. Maximum depth: 23 ft. Surface area: 69 acres.
Black Brook Flowage Lake is a 69-acre productive, nutrient-rich eutrophic lake in Polk County, Wisconsin with a maximum depth of 23 feet. 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. Methodology: how these readings are compared.
What Black Brook Flowage Lake is good for
From access and monitoring records, not editorial picks.
- Clear water10.5 ft of visibility
- Boat launch1 documented ramp
- Fishing4 species recorded
Swimming conditions
Readings onlyLimited data
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
Whether Black Brook Flowage Lake is safe to swim in today is a call for the Wisconsin Department of Natural Resources and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Black Brook Flowage Lake
These are the measurements Wisconsin DNR publishes for Black Brook Flowage Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Good clarity, visible to about 10.5 ft. Phosphorus 46.6 µg/L. TSI 51.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 10.5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 46.6µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | No reading The green pigment in algae — a direct measure of how much algae is in the water. | |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 51 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Black Brook Flowage Lake
Answers come straight from the public measurements and survey records on this page.
Lake Details
Max depth
23 ft
Surface area
69 acres
Public access
Yes
Listed by Wisconsin DNR
Recreation & Access
- Black Brook FlowagePublic
Named access points in the USGS National Boat Ramps inventory, within about 3 miles. More lakes with boat ramps
Stays via Stay22
Stays 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 readings cover 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
Prices for Oct 16–18, 4 adults. Change dates on the map below.
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a whole trip? See where to stay at Wisconsin’s top lakes →
Follow Black Brook Flowage Lake’s readings
Email me when new measurements post for this lake. Updates stay free.
Or email
Fish Species
Click a species to see every 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.
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. Its water-quality measurements are published by Wisconsin DNR and shown on this page as reported.
What is the water quality of Black Brook Flowage Lake?
- Black Brook Flowage Lake in Polk County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. 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?
- Nutrient and algae readings are not a swimming clearance. Check local advisories before you swim.
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.
Can I fish at Black Brook Flowage Lake?
- Black Brook Flowage Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Seasons, size and bag limits, and whether you need a license are set by Wisconsin's fish and wildlife agency, so check its current regulations before you go.
Explore Black Brook Flowage Lake across LakeQuality
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Polk County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the St. Croix Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
More lakes in Wisconsin
State Parks Near Black Brook Flowage Lake
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
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)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from 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