Green Lake East Basin

Green Lake East Basin comes in at a B on the grading rubric — a respectable showing for a Wisconsin lake of its size and depth. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Mesotrophic conditions dominate at Green Lake East Basin: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. Green Lake East Basin is unusually deep for Wisconsin at 236 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. With 7,920 acres of surface and partial shoreline records, Green Lake East Basin is a large water by Wisconsin standards — recreational pressure is spread across a long shoreline. Among the 13 graded lakes in Green Lake County, Green Lake East Basin sits at rank 5, above the county median.

Zebra mussels have been documented at Green Lake East Basin, 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 7 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.