Spring and summer 2017 have been among the wettest on record in eastern North America. And the world is watching Houston this week, where the remains of Hurricane Harvey have caused devastating flooding.
Rainfall amounts in the spring broke records in places like Toronto, where 44.6 millimetres of rain fell in 24 hours. The downpours earlier this spring caused the stormwater infrastructure in Canada’s biggest city to overflow, leading to flooding of busy downtown streets.
Urbanization in many North American cities has led to a rapid loss of permeable surfaces where water can freely drain. Coupled with the growing downtown core population in cities Toronto, this means that the stormwater and sewer systems in place must manage more water than in previous decades.
Furthermore, global temperature increases have been linked to the rise in extreme weather events worldwide, a trend that could worsen if global warming is not brought under control.
Many cities are ill-equipped to deal with these unprecedented amounts of precipitation due to their insufficient and outdated stormwater infrastructure.