Diamond Lake

Diamond Lake earns an F: 172 µg/L of phosphorus and clarity at 1.4 ft signal heavy nutrient loading from the surrounding watershed. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Hypereutrophic conditions mean the lake is operating at the upper end of the productivity scale, with all the bloom risk that implies. Diamond Lake is a shallow lake at 8 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. Diamond Lake covers 405 acres alongside 4.6 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Diamond Lake sits at rank 71 of 95 in Hennepin County, in the lower half of the local distribution.

Diamond Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Diamond Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at Diamond Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.