2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

Assessing Potential Climate Change Impacts to a Stormwater Management System for a Residential Subdivision in Southern Ontario

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Mr. Matthew Senior, Wood Environment & Infrastructure Solutions (Presenter)
Mr. Ron Scheckenberger, Amec Foster Wheeler
Mr. Peter Nimmrichter, Wood
Mr. Marvin Ingebrigsten, City of Welland

Numerous previous studies have concluded that climate change has the potential to increase rainfall, in terms of total depth, peak intensity, and frequency.  These changes have the potential to impact the performance of stormwater management (SWM) systems which were designed and constructed based on legacy data from long-term rainfall datasets from historic records, which inherently assume stationarity and do not account for expected changes due to climate change.  Changes to rainfall severity may as a result cause decreased SWM system performance, leading to increases in flooding and adverse impacts to downstream receivers.

The City of Welland, Ontario has been proactively considering and planning for the impacts of climate change through the completion of several vulnerability assessments, and from this has considered adopting revised drainage design standards.  In order to better understand the potential influences of climate change impacts on system performance, a focused assessment of climate change impacts was undertaken for the 25 hectare South Pelham Subdivision.  An integrated, dual-drainage hydrologic/hydraulic model was developed, including storm sewers, roadways, and the downstream SWM facility.  The modelling was applied to assess a range of climate-change altered rainfall scenarios, and to quantify the associated range of potential impacts to the performance of the storm sewer system, overland drainage (roadways), SWM facility, and downstream receivers.  In addition, the implications to the design of these features, if designed to climate-changed altered rainfall scenarios, were considered and assessed, including the associated cost implications associated building climate change resiliency into the system.  The results of these combined analyses provide a greater insight into the potential climate change impacts to SWM systems, both to designers and municipalities.