In simple terms, a watershed is the area of land that catches rain and snow that drains or seeps into a marsh, stream, river, lake or groundwater. In the Toronto region, all watersheds are river watersheds, with the exception of the waterfront which drains into Lake Ontario.
You’re in a watershed right now
Wherever you are in the Toronto region, you are sitting on a watershed. Check the map to discover on which one you are situated.