Riley Lake

Riley Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

Mesotrophic conditions dominate at Riley Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 49 ft puts Riley Lake in the middle of Minnesota's depth distribution. Riley Lake covers 296 acres alongside 3.3 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Within Hennepin County's 95 graded waters, Riley Lake sits at rank 3, near the top of the local distribution.

Zebra mussels have been documented at Riley Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery includes walleye alongside the lake's other 11 documented species — a notable draw for Minnesota anglers. A documented public access point at Riley 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.