Sargent Lake

On the LakeGrade scale Sargent Lake grades a B, with clarity at 8.9 ft and 16 µg/L of phosphorus placing it above the Minnesota median. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

Mesotrophic conditions dominate at Sargent Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Sargent Lake reaches 15 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. The lake's 138 acres and 3.6 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Among the 16 graded lakes in Mahnomen County, Sargent Lake sits at rank 6, above the county median.

Zebra mussel presence at Sargent Lake means the lake's clarity numbers carry an asterisk — filtered water is not the same as nutrient-poor water. The fishery includes walleye alongside the lake's other 12 documented species — a notable draw for Minnesota anglers. A documented public access point at Sargent Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.