Toronto, the largest city in Canada, is geographically the most vulnerable to extreme weather conditions due to its location near the watersheds of the Don River in the East and Humber River in the West, which drain into Lake Ontario. This city has experienced four major floods documented in 1954, 1976, 2005 and 2013. These severe floods had a significant impact on the city’s infrastructure. The flood of 1954 that followed Hurricane Hazel soaked the city of Toronto with about 200 mm of rain that fell for 12 hours. This massive flood left 81 people dead, approximately 7500 people without homes and $220 million damages.This figure shows three rivers that dominate Toronto city: the Humber, the Don and the Rouge.
Although Hurricane Hazel remains one of the most severe floods in recorded history of Canada, Toronto also experienced two other disastrous floods recently. The recent floods also negatively affected Toronto financially. In 2005, the city recorded around 150 mm of rain that lasted for 3 hours. This flood was caused by as strong storm near the Don valley river. The flood left 10,000 Toronto residents without power, the city received about 1200 calls of complains regarding flooded basements. It also caused around $500 million damages to critical infrastructure and bank erosions.
The most recent flood occurred in July of 2013, like the 2005 flood, also affected the city greatly. About 300,000 residents remained without power for few days, flights were canceled and many transportation services closed. According to the Insurance Bureau of Canada, property damages exceeded $940 million. The flood of 2013 caused the most expensive damages to the province of Ontario.
A study by Costas Armenakis and N. Nirupama in 2014 published in Elsevier, shows the locations that are the most vulnerable in Toronto during severe flooding. The figure below reflects upon the conclusion that higher risk of flooding is generally located in the Southern (where downtown of the city of Toronto is located), Northwestern and Northeastern regions of the Greater Toronto Area.
Floods will continue to impose a significant risk for the city of Toronto. It is vital to recognize the importance of adopting new polices and procedures regarding flood management and water conservation. The best practices to manage the risk of future floods are flood risk mapping for spatial modeling and flood mitigation strategies such as retrofitting solutions for those who currently are living in flood-prone areas. The construction of dams, reservoirs, channels, and other infrastructure are sufficient to control the possible damage in flood-prone areas and lessen the risk to human life. It is crucial to develop disaster impact reduction strategies that continue with the initiatives produced by the city of Toronto to reduce any tremendous damages of flooding events in the future as the city has already witnessed and experienced in the past.
Armenakis, C. and Nirupama, N. 2014. Flood risk mapping for the city of Toronto. Elsevier. 18: 320-326.
Nirupama, N. and Armenakis, C. 2014. Is flooding in Toronto a concern? Natural Hazards. 72(2): 1259-1264
Ogrodnik, Irene. (2013, July 9). By the numbers: 2013 Toronto flood. Global News. Retrieved from http://globalnews.ca/news/704015/by-the-numbers-2013-toronto-summer-storm/
Robinson, D. and Cruikshank, K. 2006. Hurricane Hazel: Disaster Relief, Politics, and Society in Canada, 1954-55. Journal of Canadian Studies. 18(1): 37-70
Insurance Bureau of Canada
Images from CP 24
City of Toronto Emergency Plan