Irving Lake

Irving Lake sits at a C on the grading scale — not impaired, not pristine, with summer measurements that vary year to year. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

At a TSI of 53, Irving Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 19 ft puts Irving Lake in the middle of Minnesota's depth distribution. Irving Lake covers 662 acres alongside 5.2 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within the 86 graded lakes of Beltrami County, Irving Lake sits at rank 77, near the bottom of the county list.

Zebra mussel presence at Irving Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. Muskie are on the species list at Irving Lake, alongside the lake's 20 other documented fish. Public access is available — the lake is on the Minnesota PCA public-access list. Ice-out has been recorded 21 times at Irving Lake, with a median around Apr 24. 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.