Marlu Lake

Marlu Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. 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.

At a TSI of 59, Marlu Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Pope County's 25 graded lakes, Marlu Lake ranks 17 — below the local median, though not at the bottom.

Zebra mussel presence at Marlu Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The state fisheries records do not list documented species for Marlu Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Marlu Lake — most use is by shoreline residents and their guests. The lake has a partial ice record — 15 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.