Lake Thirty

On the LakeGrade scale Lake Thirty grades a B, with clarity at 4.8 ft and 19 µg/L of phosphorus placing it above the Wisconsin median. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Wisconsin norms.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Lake Thirty reaches 27 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 75 acres, Lake Thirty sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Among the 37 graded lakes in Barron County, Lake Thirty sits at rank 15, above the county median.

An invasive species record — Chinese Mystery Snail — has been logged at Lake Thirty; Wisconsin DNR maintains the official infested-waters list. The fishery is bass-led, with 3 documented species across the lake's records. 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.