Diamond Lake

On the scoring rubric Diamond Lake grades a D: clarity at 5.0 ft and 68 µg/L of phosphorus keep it in the lower bracket for Kandiyohi County. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

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. A maximum depth of 27 ft puts Diamond Lake in the middle of Minnesota's depth distribution. At 1,610 acres, Diamond Lake is one of the larger lakes in Kandiyohi County, with 9.5 miles of shoreline supporting multiple distinct use patterns. Within Kandiyohi County's 35 graded lakes, Diamond Lake ranks 18 — below the local median, though not at the bottom.

Zebra mussel presence at Diamond Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The fishery includes walleye among the lake's 15 documented species — a notable draw for Minnesota anglers. A documented public access point at Diamond Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a long ice-out record — 77 observations on file, with a median ice-out around Apr 15. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.