ICLR study: Involving Homeowners in Urban Flood Risk Reduction

Juny 9, 2011 – ICLR’s latest study, Involving Homeowners in Urban Flood Risk Reduction: A Case Study, investigates basement flood perceptions and mitigative behaviours of residents in the Sherwood Forest neighbourhood of London, Ontario. Though the Sherwood Forest area is relatively new and serviced by a separated sewer system, considerable sewer backup flood risk exists largely due to foundation drain connections to the sanitary sewer system. On May 28, 2009, a rainfall event consisting of 83 mm of precipitation over a five hour period flooded dozens of homes in the neighbourhood. The study investigates several aspects of homeowner knowledge and behaviour related to urban flood reduction and revealed many opportunities for both the City of London and insurers to increase homeowner knowledge and home-level action for urban flood reduction.

Similar to previous urban flooding surveys, respondents in this study had limited awareness of sewer backup insurance coverage. Almost half of the respondents could not indicate if they had sewer backup insurance coverage. One third of respondents also did not know whether or not their home had a backwater valve. Inability to indicate the existence of backwater valves has implications for insurers, specifically reliability of sewer backup questionnaire responses for new business. The City of London had taken various measures to inform residents in the Sherwood Forest area of flood risk and city programs for flood risk reduction, including information mailings, surveys, brochures and public meetings. However, many respondents reported that they had not read or received any City of London information on flooding and many respondents had not heard of the City’s basement flood reduction subsidy program. Further, a considerable proportion of respondents who experienced sewer backup flooding and the majority of respondents who experienced clean water flooding did not report their flood experiences to the City.

There are opportunities for the City of London to partner with the insurance industry to address several of the above-mentioned issues, specifically addressing resident uncertainty about sewer backup insurance coverage and in identifying which residents have experienced sewer backup in the past. Government sponsored inspections may also help address homeowner uncertainty about flood reduction measures in their home. To increase lot-level flood reduction, the City may choose to implement stronger means of incorporating mitigation measures into homes, including by-laws or policies requiring backwater valves in all new homes. Requiring mitigation in all new homes could also help address uncertainties created by climate change.

The study can be downloaded at www.iclr.org

About the Institute for Catastrophic Loss Reduction (ICLR)

Established in 1998 by Canada’s property and casualty insurers, ICLR is an independent, not-for-profit research institute based in Toronto and at the University of Western Ontario in London, Canada. ICLR is a centre of excellence for disaster loss prevention research and education. ICLR’s research staff is internationally recognized for pioneering work in a number of fields including wind and seismic engineering, atmospheric sciences, water resources engineering and economics. Multi-disciplined research is a foundation for ICLR’s work to build communities more resilient to disasters. www.iclr.org

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