South Center Lake

The LakeGrade rubric puts South Center Lake at a C: clarity at 4.9 ft, 29 µg/L of phosphorus, and a TSI of 55 signal an intermediate trophic state. The lake's weakest score is on Secchi depth — the water looks more turbid than its phosphorus number alone would predict.

At a TSI of 55, South Center Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake's 109 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. At 910 acres, South Center Lake fits the Minnesota median for monitored lakes, with 12.1 miles of shoreline. Within Chisago County's 31 graded lakes, South Center Lake ranks 17 — below the local median, though not at the bottom.

Eurasian watermilfoil has been documented at South Center Lake, requiring shoreline management to keep dense mats from crowding native vegetation. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. A documented public access point at South Center Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been recorded 13 times at South Center Lake, with a median around Apr 2. The grade is supported by multiple sampling years from Minnesota PCA volunteers and partner agencies, giving the letter a reasonably stable foundation.