School Grove Lake

On the LakeGrade rubric School Grove Lake fails the cutoffs — a TSI of 67 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.

At a TSI of 67, School Grove Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. School Grove Lake is a shallow lake at 11 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake's 349 acres and 5.0 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within the 5 graded lakes of Lyon County, School Grove Lake sits at rank 4, near the bottom of the county list.

No invasive species are currently listed at School Grove Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 10 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.