The North Shore partnership conducted a coastal flood consequence assessment to estimate the potential impacts of sea level rise with coastal flooding scenarios in order to understand the consequences of not undertaking sea level rise adaptation measures, i.e. a “do nothing” approach. The assessment was completed to identify and quantify the consequences of coastal flooding under two future coastal stillwater scenarios if no adaptation measures are undertaken:
- 1 m sea level rise during a major storm, 10% annual probability stillwater level (10-year return period), and
- 2 m sea level rise during an extreme storm, 0.5% annual probability stillwater level (200-year return period).
A total of 24 variables representing major elements across the following six sectors were used to estimate and assess the potential flood impacts: 1) Number of residents that could experience flooding; 2) Cost of building damage; 3) Amount of building damage debris; 4) Number of businesses that could experience flooding or power outage; 5) Area of parkland that could flood; 6) Number of cultural and heritage places that could flood. Methods used to estimate and assess the potential flood consequences for the variables included: census-based modeling using the Canadian version of the HAZUS model for population displacement, building and contents damage, and building and contents debris generation; business disruption modelling and power outage assessments; and spatial identification of variables within the scenario flood extent using GIS.