Stormwater pond in Toronto’s Don River watershed one of the largest in Canada

Earl Bales Stormwater Management Pond
The Earl Bales Stormwater Management Pond blending into the natural environment at Earl Bales Park.

Did you know that the Don River watershed is home to one of the largest stormwater ponds in the country? The Earl Bales Stormwater Management Pond covers an area of 3.2 hectares–approximately four and a half times the size of BMO Field!

The Earl Bales Stormwater Management Pond plays an important role in the Don River watershed by managing stormwater runoff and preventing flooding and downstream erosion. Intense urbanization in the Don watershed means that paved surfaced cause much of the stormwater to run off the surface.

Earl Bales Stormwater Management Pond

Before the stormwater pond, this water flowed into the Don River, resulting in streambank erosion and increased flooding during storm events. Now, stormwater is channeled and captured into the pond before it enters the river. The water is then retained, allowing suspended materials to settle to the bottom of the three-metre deep pond.

This impressive stormwater management pond is able to collect and treat runoff from a 550-hectare drainage area that includes the Wilson Heights area and a portion of Downsview Airport.

Pre-existing outfall from former De Havilland Creek
Pre-existing outfall from former De Havilland Creek, which now gets diverted to the stormwater pond.

What makes this project unique is how the pond water will be used. During the winter months, water will be pumped over to the Earl Bales Park ski hill and be used to make snow. In the summer months, water from the pond will be used to irrigate the fairways and greens of the Don Valley Golf Course.

Before the stormwater management pond, this water was taken from the Don River, which adversely impacted fish habitat and aquatic vegetation. By eliminating the need for direct water withdrawals, the stormwater pond will protect fish habitat and also help to reduce demand on the city’s water supply system.

Earl Bales Stormwater Management Pond

Read more about stormwater management and how the TRCA is working to minimize the impact of polluted runoff into our waterways.