Hazard- Pluvial Flooding
Pluvial Flood risk at Toronto Pearson International Airport
Stormwater management at Toronto Pearson
Keywords
Toronto Pearson International Airport is in a region with harsh winters and significant precipitation year-round. The airport is bounded on one side with by a significant creek and a tributary with the flood plains extending into the airport boundary. On July 8th, 2013, a rainstorm with 126 mm of rainfall submerged most of Pearson Airport including the airfield.
This along with the unpredictability of the weather is a key consideration in the development of the storm water network. The airport conducts cyclical reviews to ensure that stormwater events and possible environmental impacts are mitigated, and creek flooding is considered. Typically certain elements of the system are oversized. In a recent review the system was found to be sufficient if the system was not compromised in any way – for example clogging of pipes. The airport has four storm water management facilities with a total capacity of 164,000m3, 11 major stormwater ponds and some minor ponds and ditches. The largest facility is the Moore Creek facility with a capacity of 42 million litres or 17 Olympic sized swimming pools.
In the planning stages, the airport considers flood risk as an integral factor. The plan for another runway would require an extension of an existing triple box culvert approaching 50 years in age, with additional hydraulic capacity to convey the tributary by means of a new large-diameter pipe. The staff conducting the hydraulic study took the unpredictability of the weather as a key factor for calculations.
