Rush Lake

On the LakeGrade rubric Rush Lake fails the cutoffs — a TSI of 70 and persistent algal pressure put it in the bottom tier. 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 only 11 ft deep, Rush Lake is shallow — wind keeps the water column mixed and sediment resuspension drives phosphorus levels harder to manage. At 161 acres, Rush Lake fits the Minnesota median for monitored lakes, with 2.7 miles of shoreline. Within the 24 graded lakes of Sherburne County, Rush Lake sits at rank 23, near the bottom of the county list.

Rush Lake carries an invasive watermilfoil record — boat-launch decontamination and shoreline care matter more here than at uninfested lakes. Walleye are documented at Rush Lake, one of 18 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. The lake has a partial ice record — 17 observed ice-outs, centered near Apr 1. 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.