Black Hawk Lake
Iowa County, Wisconsin212 acresView mapDirections
Wisconsin DNR publishes the water-quality measurements for Black Hawk Lake. Here is what has been measured.
- Eutrophic
- Impaired · Cause unknown
- 2 aquatic invasives
- 42 ft max depth
- Public access
Black Hawk Lake in Iowa County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 19.9 µg/L. Maximum depth: 42 ft. Surface area: 212 acres.
Wisconsin DNR lists Panfish as common on Black Hawk Lake. DNR survey details →
Black Hawk Lake is a 212-acre productive, nutrient-rich eutrophic lake in Iowa County, Wisconsin with a maximum depth of 42 feet. Overall water quality is declining over recent sampling years. The lake supports 4 documented fish species including Panfish, Largemouth Bass, and Smallmouth Bass. Public access is available with 1 public boat landing. Compared to the 5 other monitored lakes in Iowa County, Black Hawk Lake ranks #1 for water quality.
Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2025-08-20. Methodology: how these readings are compared.
Black Hawk Lake covers about 210 acres in Iowa County. It has one public boat landing. Vrbo is where to look for cabins and lake homes around Black Hawk Lake, and Booking.com and Expedia search hotels near the lake for your dates.
What Black Hawk Lake is good for
From access and monitoring records, not editorial picks.
- Boat launch1 documented ramp
- Fishing4 species recorded
- Deep water42 ft surveyed max depth
Swimming conditions
Readings onlyRecreation use not supported
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. Black Hawk Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown. Check local advisories before you swim.
Whether Black Hawk 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 Hawk Lake
These are the measurements Wisconsin DNR publishes for Black Hawk Lake, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Murky, only visible to about 5 ft. Phosphorus 19.9 µg/L. TSI 51.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 5ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 19.9µg/L | Good 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 Hawk Lake
Answers come straight from the public measurements and survey records on this page.
Wisconsin DNR lists Panfish as common on Black Hawk Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Black Hawk Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
WI DNR Lake Profile
Authoritative data from the Wisconsin DNR LakePages. Monitored by volunteers since 1997. 3 stations on file (most recent sample 2025).
Fish Species (DNR-rated)
Lake Details
Max depth
42 ft
Surface area
212 acres
Public access
Yes
Listed by Wisconsin DNR
Lake Size & Watershed
Watershed (drainage) area
18 sq mi
HydroLAKES / HydroSHEDS
Shoreline
3.5 mi
HydroLAKES / HydroSHEDS
Elevation
876 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Blackhawk Lake Recreation AreaPublic
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 Hawk Lake
Compare lakeside cabins, hotels, and vacation rentals near Black Hawk Lake in Iowa 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.
Top-rated places to stay near Black Hawk Lake
Prices for Oct 9–11, 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.
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Fish Species
Click a species to see every lake where it is documented.
Fishing Black Hawk 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.
Water Quality Trend: Worsening
Based on 6 years of monitoring (2020–2025).
Water clarity
Worsening4 years
Phosphorus
Worsening+3.06 µg/L/yr6 years
Reservoir Info (USACE NID)
Black Hawk Lake is a man-made reservoir impounded by the Blackhawk Lake (completed 1969), built primarily for recreation on the OTTER CREEK & CAVE HOLLOW BR; earth-type dam, 50 ft tall and 1,130 ft long.
- Surface area
- 220 ac
- Normal storage
- 3,810 ac-ft
- Max storage
- 7,900 ac-ft
- Drainage area
- 16.1 sq mi
- Hazard class
- Low
- Owner
- Iowa County
Source: USACE National Inventory of Dams, NID ID WI00014 · Operator website
EPA Impairment Status
Black Hawk Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Recreation.
Source: EPA ATTAINS assessment unit WI10002617 · Official waterbody report
Nearby Lakes in Iowa County
Frequently asked questions about Black Hawk Lake
Where is Black Hawk Lake?
- Black Hawk Lake is a lake in Iowa 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 Hawk Lake?
- Black Hawk Lake in Iowa County, Wisconsin has water-quality measurements published by Wisconsin DNR, shown here as reported. Water clarity: 5 ft visibility. Phosphorus: 19.9 µg/L. Maximum depth: 42 ft. Surface area: 212 acres.
Is Black Hawk Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Black Hawk Lake is listed impaired under Clean Water Act §303(d) (IR 5) for cause unknown. Check local advisories before you swim.
How deep is Black Hawk Lake?
- Black Hawk Lake has a maximum depth of 42 feet. The lake covers 212 acres.
What fish are in Black Hawk Lake?
- Fish species found in Black Hawk Lake include Panfish, Largemouth Bass, Smallmouth Bass, Walleye. Black Hawk Lake is located in Iowa County, Wisconsin.
What did the DNR fisheries survey find at Black Hawk Lake?
- Wisconsin DNR lists Panfish as common on Black Hawk Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Black Hawk Lake’s water-quality measurements separately, and the water-quality trend over 6 years of monitoring is declining. Catch rate is not a swim clearance and is not a weekly bite report.
Are there boat ramps on Black Hawk Lake?
- Black Hawk Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Blackhawk Lake Recreation Area. Public access is listed as yes.
Can I fish at Black Hawk Lake?
- Black Hawk 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 Hawk Lake across LakeQuality
Depth, room, public access, and the state wake-sport rules
Fish species and the cleanest lakes across Wisconsin
Fish species and best lakes in Iowa County
Species activity outlook by water temperature and season
Where to stay at Wisconsin's top lakes, each with its readings
Lakes in the Wisconsin River Watershed, ranked by water quality
Wisconsin's cleanest lakes, ranked on agency measurements
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State Parks Near Black Hawk Lake
Other Lakes in Wisconsin
Eutrophic Lakes in Wisconsin
Where this data comes from
49 measurements from 2 monitoring stations, 2020–2025. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Wisconsin Department of Natural Resources
WIDNR_WQX49 samples · 2020–2025
Analytical methods
- Phosphorus by Colorimetry
Monitoring station identifiers (2)
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
Impairment status from EPA ATTAINS 303(d) database
Lake size & watershed from HydroLAKES (HydroSHEDS)
Fish and recreation data from Wisconsin DNR Lakes
Named boat-access points from the USGS National Boat Ramps inventory