Sullivan Lake

On the scoring rubric Sullivan Lake grades a D: clarity at 6.0 ft and phosphorus readings still being added keep it in the lower bracket for Wright County. 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.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake's 58 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. At 71 acres, Sullivan Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Within Wright County's 64 graded lakes, Sullivan Lake ranks 39 — below the local median, though not at the bottom.

Sullivan Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. 11 fish species are on record, with panfish making up the recreational core. Public access is available — the lake is on the Minnesota PCA public-access list. 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.