Pierz Lake

Pierz Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. 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 near 47 places Pierz Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. The lake bottoms out at 34 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. At 189 acres, Pierz Lake fits the Minnesota median for monitored lakes, with 3.3 miles of shoreline. Pierz Lake ranks 15 of 16 in Morrison County — at the lower end of the locally monitored distribution.

Pierz Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. Walleye are documented at Pierz Lake, one of 16 fish species on record for the lake. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been logged at Pierz Lake more than two dozen times, putting the median around Apr 15 — a useful baseline for tracking climate trends. 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.