Blackwater Lake

Blackwater Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. At 72 ft of maximum depth, Blackwater Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Blackwater Lake covers 601 acres alongside 10.1 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within the 141 graded lakes of Itasca County, Blackwater Lake sits at rank 132, near the bottom of the county list.

An invasive species record — faucet snail — has been logged at Blackwater Lake; Minnesota PCA maintains the official infested-waters list. Walleye are documented at Blackwater Lake, one of 14 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.