Improving Flood Risk Evaluation through Cross-Sector Sharing of Richer Data
Canadian Water Network, Insurance Bureau of Canada, Natural Resources Canada (2018-2019)
Flooding has caused significant damage in Canadian communities over the past two decades. Property claims represent approximately 35% of insurance claims and flood claims have overtaken fire as the principal reason for payouts. Canada’s insurance sector is expected to insure private and public properties against future flood loss, but if flood risks are not assessed appropriately, then insurers expose themselves to financial risk. Poorly assessed flood risks also pose challenges to municipalities, particularly when model-derived flood hazard maps do not incorporate flood mitigation measures undertaken by municipalities. As a result, insurers may not cover areas which are deemed to be at high-risk for flooding even though municipal flood mitigation efforts may have improved the risk in those areas.
Although pluvial flooding has typically been excluded from home insurance coverage, recent large floods have resulted in increasing demand for coverage under home insurance policies. As a result, the availability of coverage is slowly changing, with more and more insurers offering coverage for pluvial flooding. With the increase in coverage, there is a need to ensure that flood risks are accurately assessed to overcome the current challenges faced by municipalities and insurers.
Many organizations are looking at how to address flood risk more accurately, but most of these efforts have not been coordinated among the various sectors, leaving gaps in foundational data. Currently, no mechanisms exist to adequately access and share relevant and current data across sectors. Canadian Water Network sees a significant opportunity to better coordinate the key players involved to improve flood risk mapping and modelling outcomes.
Current large-scale flood risk models in Canada rely largely on mixed quality low-resolution (e.g., 30 m) topographical data and give limited consideration to flood reduction controls such as storm sewers, dykes and dry-ponds. Model accuracy could be improved with better higher-quality data. There is a need to determine which data could improve model certainty and the resulting degree of improvement.
Canadian Water Network, in partnership with the Insurance Bureau of Canada and Natural Resources Canada, is evaluating how higher-resolution topographical and municipal flood-defense data impacts flood risk evaluation. An 8-month pilot project will collect data from several Canadian municipalities to test whether pluvial hazard maps derived from large-scale risk models will change, and the degree to which they will change, when richer datasets are used. The objectives of this pilot project are:
- To assess the potential reduction in uncertainty in large-scale flood risk model-derived flood hazard maps with the use of richer datasets such as higher-resolution maps and municipal flood mitigation work
- To propose mechanisms for sharing up-to-date and relevant data with stakeholders to support more accurate flood risk evaluation
A report will be released in 2019 with the pilot’s key findings, recommendations to improve data sharing and proposed next steps.