As part of its mandate to protect people and property from flooding and other natural hazards, South Nation Conservation (SNC) is updating hazard mapping for its jurisdiction along the Ottawa River and the Bear Brook catchment area within the City of Ottawa.
Natural hazard maps are used by municipalities and SNC when updating official plans and zoning schedules, and in reviewing development applications to protect people and property from flooding, landslides, and erosion, and to guide safe and sustainable development.
Development projects within natural hazard areas like floodplains require permission from the Conservation Authority before proceeding. SNC updates natural hazard maps on behalf of its partner municipalities, when requested.
“Over the last few months, SNC staff and contractors have been surveying the depths and widths of the Ottawa River, and measuring bridge and culvert dimensions in the area,” explained SNC Engineering Lead Sandra Mancini. “Preparing mapping involves a combination of field work and computer modelling.”
“We gather background data such as land use, topography, and precipitation, and use this to build a computer model that calculates flows during storm events. The standard of protection is to the one-in-100-year flood event. This is the event that has a one-per-cent chance of occurring in any year.”
SNC has received federal funding from the National Disaster Mitigation Program for both the Ottawa River and Bear Brook studies, with additional support from the City of Ottawa and the United Counties of Prescott and Russell.
SNC is also working with its Ottawa Conservation Authority Partners (Mississippi Valley and Rideau Valley) to complete a flood risk assessment in each watershed. This information will help identify flood-prone areas and guide efforts to update hazard mapping.
“Once the studies are complete and new natural hazard maps are prepared, we will provide draft maps through public consultations in 2022 where residents will be invited to review and comment on the updated mapping, for both the Ottawa River and Bear Brook,” said Mancini.