Extreme weather events caused by changing climate are occurring with increasing intensity, duration and frequency. They are also revealing vulnerabilities in existing infrastructure. The Insurance Bureau of Canada required a ground-breaking risk assessment tool that would be able to predict potential issues in municipal infrastructure that would lead to basement flooding.
Dillon developed MRAT to answer the following:
- What are the current risks of sewer-backup claims based on existing infrastructure and climatic conditions?
- What are the future risks of sewer-backup claims based on existing infrastructure and future climatic conditions?
- Is current infrastructure performing at acceptable levels?
- Are there vulnerabilities in current infrastructure that require mitigation?
The tool provides a visual representation of storm and sanitary sewer backflow risk zones within a municipality, based on the existing sewer system parameters and present and future climatic factors. This tool benefits municipalities by:
- Making the calculation of costs and benefits of infrastructure investments more accurate.
- Offering access to updated rainfall return period statistics.
- Providing information about future climate patterns.
MRAT aides municipalities in developing infrastructure programs based on statistical results that enable them to focus spending and allow for higher returns on investment.
The MRAT concept was based on:
RISK = Hazard x Exposure x Vulnerability
In the MRAT scenario, hazards are the natural circumstances that contribute to undesired events. Exposure is the conditions that influence the severity of an event and vulnerability is the sensitivity to having sewers back-up.
Nine municipalities across Canada shared information as part of the prototype development. Three municipalities – Coquitlam, BC, Hamilton, ON and Fredericton, NB – acted as pilots that verified the potential operational utility of the MRAT process.