Irene Lake

On the LakeGrade scale Irene Lake grades a B, with clarity at 10.7 ft and 23 µg/L of phosphorus placing it above the Minnesota median. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Mesotrophic conditions dominate at Irene Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake bottoms out at 44 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Irene Lake covers 639 acres alongside 4.2 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Irene Lake sits at rank 29 of 51 in Douglas County, in the lower half of the local distribution.

Zebra mussels have been documented at Irene Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. Walleye are documented at Irene 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. The lake has a partial ice record — 6 observed ice-outs, centered near Apr 10. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.