Over the past year or so, there has been the discussion around flood management in the GTA communities. Most of these discussions were a result of the heavy rainfalls and flooding that took place last July (2013).
One of the downfalls of early city planning was the lack of including the environment and natural design. If you examine some communities it is noticeable that there is a lot of imprevious surfaces (asphalt and concrete) and a lack of greenspace. Urban Flooding has a lot to do with imprevious surface. I would recommend reading either Paving Paradise: The Peril of Imprevious Surfaces or The Need to Redice Imprevious Cover to Prevent Flooding and Protect Water Quality. Both articles discuss the issues surrounding urban flooding and ways in which they can be mitigated.
If you were to go back almost 10 years ago to the Finch Avenue Flood that washed away some of the roadway. It was partially due to both altering the natural flow of water for development and the massive amount of asphalt and cement in the area. The large amount of imprevious surfaces resulted in the water not having any place to go and building up.
Some communities are now focusing on and removing their imprevious surfaces and replacing them with either pemerable paving or creating gardens. An example of pemerable surfaces/paving that is currently being used for both commercial and residential uses is a company called CoreGravel. CoreGravel uses a series of raised hollow hexagons which can be filled with either gravel, soil, or grass. What I like about this product is that even though it is pemerable surface and can be filled with various product, it is still strong enough to stand up to the weight of automobiles and accessible devices.
A lot of communities are now focusing on rain gardens. These are gardens that are usually incorporated beside the sidewalk, where water run-off can be catched and reduce flooding. Take a look at these examples in various North American communities.
I would suggest that GTA communities begin focusing on adding and increasing their pemerable surfaces to help reduce urban flooding. There should also be a focus on ‘wild design’ and incorporating nature into current and future designs. It would also benefit communities to add in more greenspace such as Greenroofs and rain basins to reduce runoff. Implementing this now, would be able to reduce the cost of flooding and water damage in future years to come.