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LakeQuality
C

Deadfish Lake

Carlton County, MinnesotaEutrophic

Deadfish Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Carlton County's 33 graded lakes, Deadfish Lake ranks 22 — below the local median, though not at the bottom.

No invasive species are currently listed at Deadfish Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Deadfish Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-10-16. Grade methodology: LakeGrade methodology.

Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

Very murky, less than 1.9 ft of visibility. Phosphorus level: 48.5 µg/L. Chlorophyll-a: 4.5 µg/L. Trophic State Index: 58.

MetricValueGrade
Water Clarity (Secchi Depth)1.9 ftF
Phosphorus48.5 µg/LC
Chlorophyll-a (Algae)4.5 µg/LA
Trophic State Index (TSI)58Eutrophic

High nutrients, frequent algae, reduced clarity

Water Quality Trend: Improving

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

MetricTrendChange/YearYears
Water Clarity Improving+1.963 m/yr5
Phosphorus Declining+25 µg/L/yr2
Chlorophyll-a Improving-3.09 µg/L/yr6

Location

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County Ranking

Ranked #22 of 33 lakes in Carlton County

Nearby Lakes in Carlton County

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Deadfish Lake. 1 report on file.

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2024-10-16

Monitoring stations: 1