Little Rock Lake

Little Rock Lake earns an F: 157 µg/L of phosphorus and clarity at 2.0 ft signal heavy nutrient loading from the surrounding watershed. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

The hypereutrophic status — TSI 72 — reflects sustained heavy nutrient loading from the surrounding watershed and frequent algal pressure. Little Rock Lake reaches 17 ft at its deepest point — typical for Minnesota mid-sized lakes, with seasonal stratification but limited cold-water refuge. Little Rock Lake covers 1,311 acres alongside 10.6 miles of shoreline, large enough that conditions can vary meaningfully between bays. Within the 2 graded lakes of Benton County, Little Rock Lake sits at rank 2, near the bottom of the county list.

Little Rock Lake is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The fishery includes walleye alongside the lake's other 21 documented species — a notable draw for Minnesota anglers. A documented public access point at Little Rock Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a long ice-out record — 40 observations on file, with a median ice-out around Apr 10. 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.