From this highlight on the east shore of Cascade Lake, you can access a dedicated pedestrian and bicycle system of trails southwest along the South Fork of the Zumbro River, southeast along Bear Creek, west to Silver Lake and Quarry Hill Park, and north to the Douglas State Trail.
I think this is a former quarry, at least when I first pedaled here maybe 10 years ago, it was fenced off and there were diggers and stuff around the lake. It's definitely at least a run off pond now. But it is a great point to loop around before heading back to Pine Island when doing the Douglas State Trail.
Cascade Lake is part of the park of the same name and is located in the west of Rochester. There's a trail, called Cascade Creek Loop Trail, leading around lake and if that's not enough for you, you can extend the hike around the neighboring lakes called Interlachen Lake and Manorwoods Lake.