Horseshoe Lake

Horseshoe Lake earns a D — measurements through 2024 show persistent nutrient pressure that limits clarity through the summer. Algal biomass — measured through chlorophyll-a — is the worst of the three parameters here, signaling repeated bloom pressure.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. Horseshoe Lake is a shallow lake at 11 ft maximum depth, which means it warms quickly, mixes constantly, and amplifies nutrient inputs. The lake is compact at 75 acres, with 2.9 miles of shoreline and little volume to buffer nutrient inputs. Within Washington County's 83 graded lakes, Horseshoe Lake ranks 62 — below the local median, though not at the bottom.

Eurasian watermilfoil has been documented at Horseshoe Lake, requiring shoreline management to keep dense mats from crowding native vegetation. Bass fishing is part of the appeal: the species list runs to 8, anchored by largemouth and/or smallmouth bass. No formal public access is documented at Horseshoe Lake — most use is by shoreline residents and their guests. Multiple sampling years from Minnesota PCA volunteers and partner agencies back the grade, so the letter should hold steady absent a major watershed shift.