Toronto waterway system

[3] The Humber collects from about 750 creeks and tributaries in a fan-shaped area north of Toronto that encompasses portions of Dufferin County, the Regional Municipality of Peel, Simcoe County, and the Regional Municipality of York.

They join north of Toronto and then flow in a generally southeasterly direction into Lake Ontario at what was once the far western portions of the city.

Its mouth was just east of the street grid of the town of York, Upper Canada, the municipality that evolved into Toronto, Ontario.

The Toronto and Region Conservation Authority (TRCA) is responsible for managing the river and its surrounding watershed.

Due to the urbanized nature of the watershed, the Don River experiences low base flows interspersed with high volume floods.

At its southern end, the Rouge River is the boundary between Toronto and southwestern Pickering in the Regional Municipality of Durham.

Map of Toronto and its rivers that make up "Toronto ravine system".
The Humber River from the Dundas Street Bridge.
The lower Don River near Riverdale Park , south of where the two main branches meet.
The Rouge River at Rouge National Urban Park .