Planning for Extreme Precipitation: Assessing Alternatives for Stormwater Infrastructure Resiliency

March 22, 2017

Presented by:

• Peter Nimmrichter (Associate & Climate Change Specialist in Water Resources, Amec Foster Wheeler)
• Marvin Ingebrigtsen (Infrastructure Planning & Development Supervisor, City of Welland, Ontario)

The City of Welland, Ontario, with assistance from Amec Foster Wheeler, assessed the resiliency of the City’s stormwater/combined sewer systems and the wastewater treatment plant, in 2012, to potential climate change impacts using the Public Infrastructure Engineering Vulnerability Committee (PIEVC) vulnerability assessment protocol. The outcomes of that assessment have been supporting City staff to better manage infrastructure risks, by increasing the understanding of uncertainty related to infrastructure planning and design.

This presentation focuses on the next phase of the climate change impact assessment which is founded on dynamic modelling of the major/minor stormwater systems contributing to a stormwater management facility in the City which is presently experiencing performance issues. The objective of the modelling is to investigate how changing precipitation patterns in the future may exacerbate current problems, and specifically identify if more frequent surcharging events will manifest as more frequent at ground or on street flooding. This assessment examines various infrastructure adaptation considerations, notably to either “offset” the projected rainfall increases or to convey more runoff, in a framework of risk and uncertainty.