Diamond Lake

The LakeGrade rubric puts Diamond Lake at a C: clarity at 3.5 ft, 25 µg/L of phosphorus, and a TSI of 55 signal an intermediate trophic state. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

A TSI in the eutrophic range signals a lake doing what nutrient-loaded waters do — supporting an active algal community at the cost of clear water. The lake bottoms out at 17 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Diamond Lake covers 117 acres alongside partial shoreline records — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Oneida County's 134 graded lakes, Diamond Lake ranks 77 — below the local median, though not at the bottom.

Diamond Lake has no invasive species recorded in Wisconsin state databases as of 2020, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 5 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.