Overview of Vulnerabilities of Coastally-Influenced Conveyance and Treatment Infrastructure in Greater Vancouver to Climate Change: Identification of Adaptive Responses

Abstract

The Greater Vancouver Regional District (GVRD) and its member municipalities own and operate a variety of infrastructure including: combined, sanitary and storm sewers; creek and ditch drainage systems; and wastewater treatment plants (WWTPs). A significant portion of this infrastructure discharges either directly or indirectly to tidally-influenced receiving waters. Thus, both this infrastructure and its functionality can be impacted by coastal conditions, especially sea levels. The GVRD has developed a variety of long-range plans that provide a foundation to manage core infrastructure so as to satisfy various criteria, including protection of the receiving water ecosystem. The Liquid Waste Management Plan (LWMP) outlines a strategy to protect regional sustainability by managing liquid waste and addressing issues such as combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), wastewater treatment upgrading and stormwater management. Climate change, along with sea level rise (SLR), has the potential to impact the functionality of this infrastructure over the time frame of long-range planning (LRP). The specific vulnerabilities of coastally-influenced conveyance and treatment infrastructure to the impacts of climate change and SLR have not been widely evaluated in available research. This paper is intended to provide an overview understanding by reviewing some relevant research, identifying and classifying some of the potential vulnerabilities of this infrastructure to climate change and SLR and then discussing possible adaptive str ategies for this infrastructure. The field of research into adaptive strategies for infrastructure is expanding, along with a better understanding of these issues. A basic and preliminary methodology to evaluate regional vulnerabilities as part of LRP has been developed for consideration for ultimate refinement and implementation. The magnitude and timing of SLR and climate change is uncertain, but has a large impact on the vulnerability of infrastructure and the scope of appropriate adaptive strategies. Thus, maintenance of maximum system flexibility as reasonable may be an appropriate response for infrastructure planning to respond to a changing climate. Periodic study of developing climate change trends will assist in improving the understanding of both infrastructure vulnerabilities and appropriate adaptive strategies.