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About the Bay

Learn all about our Bay

The Hamilton Harbour watershed includes all the land area that drains into the Harbour; the watershed itself spans 500 kilometres squared. Multiple communities lie within the Hamilton Harbour watershed, including Dundas, Ancaster, Aldershot, and the Hamilton Mountain and the city’s downtown urban core.

What is the Hamilton Harbour Watershed? Why is it Special?

Map displaying all of the different watersheds in the Hamilton HarbourHamilton Harbour sits at the very western end of Lake Ontario. As part of the Great Lakes, the Harbour is vital to the well-being of nature and community in the Hamilton region. The triangular-shaped body of water forms a naturally sheltered harbour with deep waters. 

A watershed is an area of land where all surface water drains into a single location. The Hamilton Harbour watershed is the area of land where the surface water from rain or snowmelt drains into the Hamilton Harbour. The Hamilton Harbour watershed can be broken down into three sub-watersheds; Grindstone Creek watershed, Spencer Creek watershed, and Redhill Creek watershed. Multiple communities lie within the Hamilton Harbour watershed, including Dundas, Ancaster, Aldershot, and the Hamilton Mountain and the city’s downtown urban core.

Watersheds are important systems that clean, filter and store water. This process not only prevents flooding within rural and urban areas, but also improves the overall quality of water.

One of Hamilton’s defining features is the Niagara Escarpment, a large cliff that extends through Hamilton, Stoney Creek and Dundas Valley. Because water flows over the escarpment down to Hamilton Harbour, Hamilton has earned the title of the waterfall capital of the world. 

Hamilton is the third largest growing economy in Ontario. The City also contains the largest port in Ontario. Not only is the deep harbour a good location for ships to dock, but the Harbour also supplies water for industry purposes, making its west-end a prime industrial site. 

What Lives in Hamilton Harbour?

Hamilton Harbour is rich in biodiversity, making it home to many species. It is a migratory bird spot as well as a fish breeding ground. 

BARC’s education and volunteer programs work to increase the public’s knowledge of specific species including:


Cattails are native plants that provide food and shelter for animals in wetlands. The plants also reduce soil erosion and filter the water in wetland environments. At BARC, we plant cattails and other native wetland plants in Cootes Paradise Marsh each year as part of restoration efforts. Check out our Marsh Volunteer Plantings. 


Turtles are keystone species, which means they have a large impact on the healthy functioning of an ecosystem. All eight native freshwater turtles in Ontario are threatened, largely due to busy roads and habitat loss. In the Harbour, there are four native freshwater turtles that can be found: the Common Snapping Turtle, the Blanding’s Turtle, the Northern Map Turtle and the Midland Painted Turtle. BARC provides a free educational program called Turtle Crossing to all schools within the Hamilton Harbour watershed.


Frogs are important species that contribute to the functioning of healthy ecosystems. Situated in the middle of the food chain, frogs provide food to predators while also controlling insect populations. Frogs are also indicator species, meaning that we can understand the health of our ecosystems by studying them. Their permeable skin absorbs substances into their bodies from their environment, which indicates how healthy environments are based on the health of their skin. To educate the public on our frog populations, BARC provides a free educational program titled Ribbit! to all schools within the Hamilton Harbour watershed.

Benthic Macroinvertebrates

Benthic macroinvertebrates are aquatic animals without a backbone that can be seen without a microscope. Examples include snails, worms, and the larvae of dragonflies, craneflies, and mayflies. These animals live at the bottom of our waterways and are indicators of water quality in our freshwater ecosystems. BARC provides a free educational program called Stream Scientists to all schools within the Hamilton Harbour watershed where students can learn all about benthic macroinvertebrates.

Key Issues

Want to learn about the threats to Hamilton Harbour’s ecosystems?

Watershed Experience

Explore how people interact with the Hamilton Harbour watershed.

Randle Reef

Discover the Randle Reef Sedimentation Project, a significant step in remediating Hamilton Harbour.