Last year I watched a PBS show about Wisconsin waterways and how the ecosystems are evolving. They used Lake Hallie as an example of a lake that used to have cool enough water to support trout. But as more of the area was developed there was increased runoff of warm surface water that raised the water temp to a level where it will no longer support trout.
They also talked about development on Long Lake (chippewa county) and are monitoring what effect that will have in the next few years. Very interesting show.