Understanding and Assessing Impacts
Saint John, with just under 71,000 inhabitants, lies on the Bay of Fundy in the Kennebecasis Valley at the mouth of the Saint John River in New Brunswick. Due to its geographic location and topography, Saint John is particularly susceptible to the impacts of climate change, such as sea level rise and riverine flooding. The combination of high tides and storm surges, which are expected to increase, result in significant climate-related hazards.
Saint John experienced historic spring freshet flooding in 2018 and 2019 resulting in evacuations, damage to nearly 150 homes and approximately $1M in flood claims submitted over both events. City infrastructure, including wastewater pumping stations, storm sewer systems and roads were significantly impacted by the two floods. Moreover, significant storm surges, often the result of hurricanes traveling up the east coast, have caused extensive coastal erosion within the municipality, an issue that has been ongoing since the 1990s. Overland flooding in winter months is also on the increase as snow events are increasingly replaced with freezing rain and ice storms, as winter air temperatures rise.
Once climate change impacts and hazards were identified, ACAP held public information sessions to solicit citizen input on areas at risk and provide feedback on hazards, via an online mapping tool, Maptionnaire. Moreover, a steering committee comprised of municipal departments, community organizations and citizens was established to provide ongoing feedback, as part of the development of the City’s Climate Change Adaptation Plan.
The recommended adaptation actions were derived from ACAP’s vulnerability and risk assessments for different municipal sectors and climate events. The vulnerability assessment was conducted by combining sensitivity and adaptive capacity ratings in a matrix. Risk ratings were calculated as a product of the climate event probability and the event consequence. High to medium risk ratings were determined for land and habitat loss due to sea level rise, for higher spring freshet flooding and for community isolation due to increased precipitation.
For the concurrent risk assessment for municipal infrastructure, the PIEVC engineering protocol was applied to different asset groups to determine risk mitigation and adaptation strategies. The protocol reviews historical climate information and predicts future climate changes and events. A similar methodology will be developed in-house to assess individual assets.
Use of Climate Information
To develop its Climate Change Adaptation Plan, St. John examined provincial climate and sea level rise data and climate and meteorological expertise was provided by external scientists. This information was fed into a Geographic Information System (GIS) system in addition to data from the Atlantic Climate Adaptation Solutions Association (ACASA), the Climate Atlas of Canada and the National Oceanic and Atmospheric Administration (NOAA). The provincial government has been developing flood hazard maps for coastal areas and has started this process for inland regions as well. ACAP Saint John also helped to identify areas at risk from flooding, using wet areas mapping (LiDAR-DEM based Surface Water Scenario Evaluations).