Grindstone Creek begins in a swampy area above the Niagara Escarpment. The creek passes through rural lands in Hamilton and west Halton before winding through the urban neighbourhoods of Waterdown, Aldershot, and Bayview and discharging into Hamilton Harbour. Grindstone Creek drains about 100 square kilometres and provides 14 percent of the water that flows into Hamilton Harbour. A portion of the watershed is within the Carolinian forest, which is a unique ecosystem that supports incredible biodiversity, including species found nowhere else in the world.

Bronte Creek watershed is about 300 square kilometres of mostly rural land that includes parts of Wellington, Hamilton, Milton, Burlington, and Oakville where the creek empties into Lake Ontario. The main branch of Bronte Creek is 48 kilometres long and there are 12 tributaries that feed into the creek. Many people who live and work in the Bronte Creek watershed are dependent on groundwater sources for drinking water and agricultural purposes.

Sixteen Mile Creek watershed is about 360 square kilometres that includes both rural and urban land uses. The creek drains parts of Halton Hills, Milton, Mississauga, and Oakville where it flows into Lake Ontario. There are three water control reservoirs used to manage floods and low flows within the Sixteen Mile Creek watershed.

In addition to the three main watersheds (Grindstone Creek, Bronte Creek, and Sixteen Mile Creek), there are 18 smaller watersheds within Hamilton, Burlington, Oakville and parts of Mississauga. These watersheds tend to be long, narrow areas of land, more rural at the northern reaches, and more urban in the southern areas, where they drain into Lake Ontario. These watersheds offer unique natural features such as the Niagara Escarpment, Carolinian forests and remnants of prairie and oak savannah despite the amount of development within them.

There are about 31 kilometres of Lake Ontario shoreline included in the watersheds that drain into Lake Ontario. The nearshore is where sediments and runoff from the watersheds are mixed, sorted and transported along the shoreline. This zone supports a wide variety of aquatic species and is where biological activity in the lake is the greatest. It also supplies drinking water for and receives treated wastewater from many urban residents living in the watersheds.

Hamilton Harbour was identified as an Area of Concern under the Great Lakes Water Quality Agreement in 1987 because of extensive environmental degradation. The Hamilton Harbour Remedial Action Plan was prepared and is implemented by a coalition of agencies and community groups to address environmental damage. The goal is to remediate the harbour and remove it as an Area of Concern. Conservation Halton is a member of the coalition and performs secretariat duties for the group. We are proud to be part of this collaboration.

Click here to visit the Hamilton Harbour Remedial Action Plan website.