South Twin Lake

South Twin Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth.

Trophically, South Twin Lake reads as oligotrophic — nutrient-poor, clear, and ecologically more sensitive to disturbance than richer lakes. The lake bottoms out at 40 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 141 acres and 2.9 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. South Twin Lake sits at rank 83 of 141 in Itasca County, in the lower half of the local distribution.

Eurasian watermilfoil has been documented at South Twin Lake, requiring shoreline management to keep dense mats from crowding native vegetation. Walleye are documented at South Twin Lake, one of 13 fish species on record for the lake. The lake lacks a documented public access point, so visitor use is limited. 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.