St. James Lake

On the scoring rubric St. James Lake grades a D: clarity at 3.0 ft and 51 µg/L of phosphorus keep it in the lower bracket for Watonwan County. Secchi readings are the weakest of the three parameters, suggesting suspended sediment or algal biomass dominates the optical signal.

Eutrophic conditions are the baseline here: clarity drops noticeably in late summer, and dissolved oxygen near the bottom can become a concern. The lake bottoms out at 15 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. The lake's 203 acres and 3.7 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. St. James Lake ranks 1 of 5 in Watonwan County, putting it in the upper tier of locally monitored lakes.

No invasive species are currently listed at St. James Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 12 documented species — a notable draw for Minnesota anglers. A documented public access point at St. James Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been recorded 13 times at St. James Lake, with a median around Apr 7. 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.