Big Newton Lake

On the LakeGrade rubric, Big Newton Lake pulls an A: clarity at 17.0 ft and 10 µg/L of phosphorus put it in the top bracket for Wisconsin. With clarity and phosphorus scored, the sub-grades cluster within a letter of each other, pointing to stable conditions rather than one specific stressor.

A TSI value of 37 puts Big Newton Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 40 ft puts Big Newton Lake in the middle of Wisconsin's depth distribution. The lake is compact at 69 acres, with partial shoreline records and little volume to buffer nutrient inputs. Big Newton Lake ranks 5 of 21 in Marinette County, putting it in the upper tier of locally monitored lakes.

An invasive species record — Banded Mystery Snail — has been logged at Big Newton Lake; Wisconsin DNR maintains the official infested-waters list. The fishery includes walleye among the lake's 5 documented species — a notable draw for Wisconsin anglers. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.