Nelson Lake

Nelson Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Mesotrophic conditions dominate at Nelson Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Nelson Lake is unusually deep for Minnesota at 52 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. At 86 acres, Nelson Lake sits below the Minnesota median: a small water where shoreline activity has an outsized effect on water quality. Within Douglas County's 51 graded lakes, Nelson Lake ranks 33 — below the local median, though not at the bottom.

No invasive species are currently listed at Nelson Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Nelson Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.