Great Lakes Watersheds
The map color codes every drainage basin (watershed). A watershed can be as small as a few acres draining into a
farm pond or as large as several thousand square miles for a major lake,
such as one of our Great Lakes. For example, on this map, all the
different watersheds for Lake Huron are a shade of green. All the water –
clean and polluted – which flows into all those green watersheds eventually flows into Lake Huron.