Conservation Halton Watersheds

The overall watershed that Conservation Halton is responsible for covers an area of 1,059 square kilometre: 963 square kilometres is on land, and 96 square kilometres is water-based. This area is made up of the smaller watersheds of all the streams that enter Lake Ontario, from Grindstone Creek in the west to Joshua’s Creek in the east. Conservation Halton’s watershed management efforts cover the entire area, and are focused within three main watersheds (Grindstone Creek, Bronte Creek, Sixteen Mile Creek), and another that consists of the remaining 18 smaller watersheds (Urban Creeks), including Joshua Creek. Click here for a pdf map of Conservation Halton’s Watershed.

Click here to see Conservation Halton’s interactive Watershed Basemap

Grindstone Creek 

  • Runs through the urban districts of Waterdown, Aldershot, and Bayview, as well as the largely rural western area of Halton Region; 
  • Comprises 99 square kilometres of land and supplies 14 percent of the natural water into Hamilton Harbour/Burlington Bay; 
  • A portion lies within Carolinian forest zone. Halton Region signifies the northern limit of the Carolinian forests in Southern Ontario. This forest region is home to a large diversity of plant and animal species, including some that are found nowhere else in Canada.

 Bronte Creek

  • Covers portions of Wellington County, Hamilton, Burlington, Oakville, and Milton; 
  • Encompasses 304 square kilometres;
  • Contains mainly rural landscape; 
  • Residents rely on groundwater sources for drinking water, irrigation, and watering livestock. 
  • The main branch is 48 kilometres long;
  • There are 12 tributaries that feed into the creek, each with its own unique streamflow and morphology.

 Sixteen Mile Creek 

  • Incorporates portions of Milton, Halton Hills, Oakville, and Mississauga;
  • The Niagara Escarpment crosses the northwest region of the watershed;
  • Covers 357 square kilometres of land;
  • Drains into Lake Ontario at the Town of Oakville; 
  • Three reservoirs are located within this watershed; these are used for flood control, low flow augmentation, and recreation.

Urban Creeks

  • Consists of 18 smaller watersheds along the north shore of Lake Ontario and crosses through Hamilton, Burlington, Oakville, and portions of Mississauga (a typical small watershed that drains into Lake Ontario is long and narrow); 
  • The landscape tends to be rural in the northern reaches and becomes more heavily developed toward the lake; 
  • Despite heavy development, the North Shore watershed contains some interesting natural features such as the Niagara Escarpment, Carolinian forest, old-growth forest, and remnants of both prairie and oak savannah.