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LakeQuality

Blackhawk Lake

C
Grade C — Fair
Fair · #11 of 45 lakes in the county · 7.9 ft clear · Mesotrophic · 40 acres · from B
Mesotrophic

Blackhawk Lake in Dakota County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.9 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 5.3 µg/L. Maximum depth: 12 ft. Surface area: 39.85 acres.

Clarity
7.9 ft
Typical in August
77°F
Max depth
12 ft
Area
40 acres
Type
Mesotrophic
Trend
Stable
Public access
Yes

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CFish Lake7.2 ft clear · Dakota CountyView →
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Blackhawk Lake is a 40-acre mesotrophic lake in Dakota County, Minnesota with a maximum depth of 12 feet. Water quality is graded C based on 2 sampling years through 2025. Water clarity is improving over recent sampling years. The lake supports 7 documented fish species including black bullhead, black crappie, and bluegill. Public access is available. Compared to the 44 other monitored lakes in Dakota County, Blackhawk Lake ranks #11 for water quality.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2025-09-23. Grade methodology: LakeGrade methodology.

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Swimming Safety

Grade only

Moderate

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.

Generally safe for swimming, moderate water quality

Compare the safest swimming lakes near St. Paul

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Water Quality Grade: C (Fair)

Moderate clarity, visible to about 7.9 ft. Phosphorus level: 28 µg/L. Chlorophyll-a: 5.3 µg/L. Trophic State Index: 49.

MetricValueGrade
Water Clarity (Secchi Depth)7.9 ftNot graded
Phosphorus28 µg/LFair
Chlorophyll-a (Algae)5.3 µg/LGood
Trophic State Index (TSI)49Mesotrophic

Moderate nutrients, good water quality

Where to stay near Blackhawk Lake

Compare lakeside cabins, hotels, and vacation rentals near Blackhawk Lake in Dakota 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.

Top-rated places to stay near Blackhawk Lake

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Planning a whole trip? See where to stay at Minnesota’s top lakes →

Water Temperature

Blackhawk Lake typically sits around 77°F at the surface in August. Summer average is about 76°F. Usually warmest in Jul (about 77°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.

Jan
Feb
Mar
Apr
May
62°
Jun
74°
Jul
77°
Aug
77°
Sep
69°
Oct
Nov
Dec

Typical surface water temperature by month, from 83 field readings (20102025) via the EPA Water Quality Portal. See the full Blackhawk Lake water temperature breakdown →

Lake Details

CharacteristicValue
Maximum Depth12 ft
Surface Area40 acres
Shoreline Length1.8 mi
Littoral Zone118%
Public AccessYes

Lake Size & Watershed

Watershed (drainage) area
21 sq mi
Elevation
797 ft

Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).

Fish Species

Click a species to see every graded lake where it is documented.

Fishing Blackhawk 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.

Eurasian watermilfoil

DNR Fisheries Survey Summary

4 surveys on file from MN DNR Fisheries. Most recent: 2025-05-21 (Targeted Survey).

Top Species by Catch Rate

SpeciesAvg CPUEAvg Weight
Bluegill31.520.09 lb
Largemouth Bass20.760.47 lb
Hybrid Sunfish7.570.16 lb
Black Bullhead6.560.56 lb
GOS3.570.12 lb
Pumpkinseed3.110.15 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

172 fish · 37 in · 2025-05-21
7538034567

Largemouth Bass

2 fish · 914 in · 2025-05-21
1091011121314

Hybrid Sunfish

50 fish · 38 in · 2025-05-21
19100345678

Black Bullhead

5 fish · 510 in · 2025-05-21
3205678910

From the 2025-05-21 survey

Blackhawk Lake is a 54-acre, class 42 lake located in the City of Eagan. The south shoreline is located within Blackhawk Lake Park, which is managed by the City of Eagan Parks and Recreation Department, and the north shoreline is developed with single-family homes. The City of Eagan maintains a carry-in boat access,…

Source: MN DNR LakeFinder Fisheries Lake Survey

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Blackhawk Lake. 3 reports on file.

These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Improving+0.087 m/yr6
Phosphorus Declining+1.44 µg/L/yr6
Chlorophyll-a Stable-0.01 µg/L/yr6
See year-by-year chart →

EPA Impairment Status

Blackhawk Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).

Causes of impairment

Mercury

A Total Maximum Daily Load (TMDL) plan has been approved.

Source: EPA ATTAINS assessment unit MN19-0059-00 · Official waterbody report

Regulated Pollution Sources Nearby

1 EPA-permitted facility operate within about 5 miles of Blackhawk Lake under Clean Water Act (NPDES) discharge permits, including 1 classified by the EPA as major discharger. 1 facility has a reported Clean Water Act violation in the past three years.

  • Met Council - Seneca Wwtp
    Eagan · 1.2 mi away · NPDES MN0030007
    MajorRecent violation

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 #11 of 45 lakes in Dakota County

Nearby Lakes in Dakota County

Frequently asked questions about Blackhawk Lake

What is the water quality grade for Blackhawk Lake?

Blackhawk Lake in Dakota County, Minnesota has a water quality grade of C (Fair). Water clarity: 7.9 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 5.3 µg/L. Maximum depth: 12 ft. Surface area: 39.85 acres.

Is Blackhawk Lake safe to swim in?

Generally safe for swimming, moderate water quality. Blackhawk Lake has a water quality grade of C (Fair). Algae concentration (chlorophyll-a) is 5.3 µg/L. Always check local health department advisories before swimming.

What is the water temperature of Blackhawk Lake?

Blackhawk Lake typically sits around 77°F at the surface in August, from 83 EPA Water Quality Portal field readings (2010–2025). That is a typical value for the month, not a live reading.

How deep is Blackhawk Lake?

Blackhawk Lake has a maximum depth of 12 feet. The lake covers 39.85 acres.

What fish are in Blackhawk Lake?

Fish species found in Blackhawk Lake include black bullhead, black crappie, bluegill, green sunfish, hybrid sunfish, largemouth bass, pumpkinseed. Blackhawk Lake is located in Dakota County, Minnesota.

Mesotrophic Lakes in Minnesota

Where this data comes from

182 measurements from 2 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 WaterMNPCA182 samples · 2020–2025

Analytical methods

  • Field measurement/observation, generic method
  • Phosphorus by Two Reagent Colorimetry
  • 10200 H ~ Chlorophyll a-b-c Determination
  • Turbidity, Nephelometric Method
Monitoring station identifiers (2)

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