Blackwater Lake
Blackwater Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.4 ft visibility. Maximum depth: 72 ft. Surface area: 600.53 acres.
- Clarity
- 4.4 ft
- Typical in August
- 72°F
- Max depth
- 72 ft
- Area
- 601 acres
- Public access
- Yes
Next lake in Itasca County
Why Blackwater Lake has no grade
We grade a lake only when its monitoring record clears the evidence bar: at least three phosphorus or chlorophyll-a samples in the last ten years, scored against EPA National Lakes Assessment thresholds for this lake’s ecoregion. For Blackwater Lake, the only measurement available is water clarity, which is not a water-quality indicator on its own — EPA's National Lakes Assessment does not grade clarity. Sampling here has recorded water clarity, but not phosphorus and algae (chlorophyll-a).
Not Rated is not an F. It is EPA Integrated Reporting Category 3 — insufficient information. The water here may be excellent or poor; nobody has measured enough of it to say. Everything below that has been measured is still reported on this page.
Sampling is run by MPCA and volunteer programs, and published through the EPA Water Quality Portal. Read the full grading methodology.
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 with 1 public boat landing.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2022-09-08. Grade methodology: LakeGrade methodology.
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Swimming Safety
Not ratedLimited data
Not rated for swimming — there is not enough monitoring data to judge this lake
Water quality measurements for Blackwater Lake
These readings exist but do not meet the evidence bar for an A–F grade — see why.
Murky, only visible to about 4.4 ft. Trophic State Index: 56.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.4 ft | Not graded |
| Phosphorus | No recent samples | |
| Chlorophyll-a (Algae) | No recent samples | |
| Trophic State Index (TSI) | 56 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Where to stay 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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Water Temperature
Blackwater Lake typically sits around 72°F at the surface in August. 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.
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 →
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 72 ft |
| Surface Area | 601 acres |
| Shoreline Length | 10.1 mi |
| Littoral Zone | 105% |
| Public Access | Yes |
Lake Size & Watershed
Size, shoreline, and watershed area from HydroLAKES (HydroSHEDS).
Recreation & Access
- Snells LakePublic
Fish Species
Click a species to see every graded 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.
DNR Fisheries Survey Summary
5 surveys on file from MN DNR Fisheries. Most recent: 2019-06-05 (Targeted Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Largemouth Bass | 15.26 | 1.19 lb |
| Bluegill | 4.93 | 0.28 lb |
| Yellow Perch | 3.27 | 0.26 lb |
| Bowfin | 1.56 | 5.32 lb |
| Rock Bass | 1.51 | 0.62 lb |
| Pumpkinseed | 1.48 | 0.27 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.
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
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
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.
Graded lakes near Blackwater Lake
Blackwater Lake has no grade, but these lakes within a short drive do.
Nearby Lakes in Itasca County
Frequently asked questions about Blackwater Lake
What is the water quality grade for Blackwater Lake?
- Blackwater Lake in Itasca County, Minnesota is not rated for water quality — its monitoring record does not meet the evidence bar. Water clarity: 4.4 ft visibility. Maximum depth: 72 ft. Surface area: 600.53 acres.
Is Blackwater Lake safe to swim in?
- Not rated for swimming — there is not enough monitoring data to judge this lake. Blackwater Lake is not rated for water quality — its monitoring record does not meet the evidence bar. Always check local health department advisories before swimming.
What is the water temperature of Blackwater Lake?
- Blackwater Lake typically sits around 72°F at the surface in August, 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.
Are there boat ramps on Blackwater Lake?
- Blackwater Lake has 1 documented boat landing in the USGS National Boat Ramps inventory. Named access points include Snells Lake. Public access is listed as yes.
Explore Blackwater Lake across LakeGrade
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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)
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
Named boat-access points from the USGS National Boat Ramps inventory