Blackwater Lake
Itasca County, Minnesota601 acresView mapDirections
Minnesota PCA publishes the water-quality measurements for Blackwater Lake. Here is what has been measured.
- Impaired · Mercury
- 72 ft max depth
- Public access
- Limited data
Blackwater Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.4 ft visibility. Maximum depth: 72 ft. Surface area: 600.53 acres.
Minnesota DNR's Standard Survey on July 7, 2003 caught 0.25 walleye per gill net at Blackwater Lake. DNR survey details →
Blackwater Lake is a 601-acre lake in Itasca County, Minnesota with a maximum depth of 72 feet. The lake supports 14 documented fish species including black crappie, bluegill, and bowfin (dogfish). Public access is available.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-08. Methodology: how these readings are compared.
What Blackwater Lake is good for
From access and monitoring records, not editorial picks.
- Fishing14 species recorded
- Deep water72 ft surveyed max depth
Swimming conditions
No readingLimited data
Nutrient and algae readings are not a swimming clearance. Blackwater Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
Whether Blackwater Lake is safe to swim in today is a call for the Minnesota Pollution Control Agency and the Minnesota DNR and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Blackwater Lake
These are the measurements Minnesota PCA publishes for Blackwater 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 4.4 ft. TSI 56.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 4.4ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | No reading The nutrient that most limits algae growth in freshwater. More phosphorus, more algae potential. | |
| 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. | 56 | Eutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
High nutrients, frequent algae, reduced clarity
Ask about Blackwater Lake
Answers come straight from the public measurements and survey records on this page.
Water Temperature
Blackwater Lake typically sits around 69°F at the surface in September. Summer average is about 71°F. Usually warmest in Aug (about 72°F) and coldest in May (about 62°F). These are typical values by month — not a live reading.
Column height runs from this lake’s coldest month (62°F) to its warmest (72°F).
Typical surface water temperature by month, from 12 field readings (2022–2022) via the EPA Water Quality Portal. See the full Blackwater Lake water temperature breakdown →
Minnesota DNR's Standard Survey on July 7, 2003 caught 0.25 walleye per gill net at Blackwater Lake.
A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Blackwater Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2019-06-05 (Targeted Survey).
5 surveys on file · most recent 2019-06-05 (Targeted Survey)
| Species | Catch rate (CPUE) | Size | Avg weight |
|---|---|---|---|
| Largemouth Bass | 15.26 | 6–19 in 2003-07-07 | 1.19 lb |
| Bluegill | 4.93 | 2–10 in 2019-06-05 | 0.28 lb |
| Yellow Perch | 3.27 | 5–12 in 2003-07-07 | 0.26 lb |
| Bowfin | 1.56 | 17–28 in 2003-07-07 | 5.32 lb |
| Rock Bass | 1.51 | 3–11 in 2003-07-07 | 0.62 lb |
| Pumpkinseed | 1.48 | 4–8 in 2019-06-05 | 0.27 lb |
CPUE = catch per unit effort, fish caught per net per set in a standardised survey. It measures abundance, not size, and is not a weekly bite report.
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.
Largemouth Bass
Bluegill
Yellow Perch
Bowfin
From the 2019-06-05 survey
Blackwater Lake is a 674 acre reservoir in the Mississippi River a few miles west of Grand Rapids, MN. The lake is mostly shallow with large beds of wild rice. Boswell Energy has a coal-fired electric plant on the north side that receives upstream water for cooling. This plant previously discharged heated water to an…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Blackwater Lake. 1 report on file.
These links open on the official state DNR websites (Wisconsin DNR survey PDFs · Minnesota DNR LakeFinder).
- —Fisheries Lake Survey — BlackwaterFisheries Lake Survey · MN DNR LakeFinder
Lake Details
Max depth
72 ft
Surface area
601 acres
Shoreline
10.1 mi
Public access
Yes
Listed by Minnesota PCA
Lake Size & Watershed
Watershed (drainage) area
3,210 sq mi
HydroLAKES / HydroSHEDS
Elevation
1,263 ft
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Stays via Stay22
Stays near Blackwater Lake
Compare lakeside cabins, hotels, and vacation rentals near Blackwater Lake in Itasca 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 Blackwater Lake
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Fish Species
Click a species to see every lake where it is documented.
Fishing Blackwater 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)
Blackwater Lake is a man-made reservoir impounded by the Clay-Boswell, built primarily for tailings on the Mississippi River-TR; earth-type dam, 50 ft tall and 20,000 ft long.
- Surface area
- 464 ac
- Normal storage
- 2,500 ac-ft
- Max storage
- 8,250 ac-ft
- Drainage area
- 0.13 sq mi
- Hazard class
- Significant
- Owner
- MN Power and Light
Source: USACE National Inventory of Dams, NID ID MN01498 · Operator website · Matched by proximity (0.86 km)
EPA Impairment Status
Blackwater Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 4A).
Causes of impairment
Designated uses not supporting: Fish consumption.
A Total Maximum Daily Load (TMDL) plan has been approved.
Source: EPA ATTAINS assessment unit MN31-0561-00 · Official waterbody report
Regulated Pollution Sources Nearby
1 EPA-permitted facility operate within about 5 miles of Blackwater 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.
- Minnesota Power - Boswell Energy CenterCohasset · 1 mi away · NPDES MN0001007MajorRecent 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.
Nearby Lakes in Itasca County
Frequently asked questions about Blackwater Lake
Where is Blackwater Lake?
- Blackwater Lake is a lake in Itasca County, Minnesota. Its water-quality measurements are published by Minnesota PCA and shown on this page as reported.
What is the water quality of Blackwater Lake?
- Blackwater Lake in Itasca County, Minnesota has water-quality measurements published by Minnesota PCA, shown here as reported. Water clarity: 4.4 ft visibility. Maximum depth: 72 ft. Surface area: 600.53 acres.
Is Blackwater Lake safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Blackwater Lake is listed impaired under Clean Water Act §303(d) (IR 4A) for mercury. Check local advisories before you swim.
What is the water temperature of Blackwater Lake?
- Blackwater Lake typically sits around 69°F at the surface in September, from 12 EPA Water Quality Portal field readings (2022–2022). That is a typical value for the month, not a live reading.
How deep is Blackwater Lake?
- Blackwater Lake has a maximum depth of 72 feet. The lake covers 600.53 acres.
What fish are in Blackwater Lake?
- Fish species found in Blackwater Lake include black crappie, bluegill, bowfin (dogfish), brown bullhead, hybrid sunfish, largemouth bass, northern pike, pumpkinseed, rock bass, shorthead redhorse, walleye, white sucker, yellow bullhead, yellow perch. Blackwater Lake is located in Itasca County, Minnesota.
What did the DNR fisheries survey find at Blackwater Lake?
- Minnesota DNR's Standard Survey on July 7, 2003 caught 0.25 walleye per gill net at Blackwater Lake. A DNR fisheries survey reports fish abundance and catch rates, not water quality. LakeQuality shows Blackwater Lake’s water-quality measurements separately. Catch rate is not a swim clearance and is not a weekly bite report.
Can I fish at Blackwater Lake?
- Public access to Blackwater Lake is listed as yes on the lake record. Seasons, size and bag limits, and whether you need a license are set by Minnesota's fish and wildlife agency, so check its current regulations before you go.
Explore Blackwater Lake across LakeQuality
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Where this data comes from
5 measurements from 1 monitoring station, 2022. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Minnesota Pollution Control Agency - Ambient Surface Water
MNPCA5 samples · 2022
Analytical methods
- Field measurement/observation, generic method
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
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