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LakeQuality
D

Bass Lake

St. Louis County, MinnesotaLimited DataEutrophic

Bass Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

At a TSI of 56, Bass Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. 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 the 187 graded lakes of St. Louis County, Bass Lake sits at rank 160, near the bottom of the county list.

An invasive species record — spiny waterflea — has been logged at Bass Lake; Minnesota PCA maintains the official infested-waters list. The state fisheries records do not list documented species for Bass Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. Public access is available — the lake is on the Minnesota PCA public-access list. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2024-08-31. Grade methodology: LakeGrade methodology.

Swimming Safety

Swimming not recommended, poor water quality with high algae risk

Water Quality Grade: D, Poor

Murky, only visible to about 4.2 ft. Trophic State Index: 56.

MetricValueGrade
Water Clarity (Secchi Depth)4.2 ftD
PhosphorusNo data
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)56Eutrophic

High nutrients, frequent algae, reduced clarity

Invasive Species

spiny waterflea

Water Quality Trend: Declining

Based on 5 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Declining-0.084 m/yr5

Location

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County Ranking

Ranked #160 of 187 lakes in St. Louis County

Nearby Lakes in St. Louis County

Eutrophic Lakes in Minnesota

DNR Reports & Resources

Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Bass 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: 2024-08-31

Monitoring stations: 1