Floods are one of the most devastating and damaging natural hazards, with adverse effects on human life and well-being, property, and the environment. In Canada, floods are the most common natural hazards and occur five times as often as wildfires, which are the second most common natural hazards. One of the most common types of flooding in Canada is residential/urban basement flooding. The factors which are responsible for this rise include extreme rainfall events accompanied by increased urbanisation, aging infrastructure, loss of natural stormwater management features and inadequate flood protection measures being implemented at the household level (CSA). Climate change has further aggravated the problem by changing the frequency and intensity of the extreme weather events. Although, residential subdivisions are designed to convey rainwater away from homes through overland flood routes and swales, alteration to the frequency and intensity of rainfall events due to changing climatic conditions has made it difficult to project the magnitude, intensity and duration of storms in order to design the effective solutions to mitigate adverse impacts from flooding. Thus, these storm events often end up overwhelming the stormwater management systems and cause urban flood events.
Residential homes can be flooded due to overland flooding (when water enters the basement from windows, doors and other openings), infiltration flooding (which results from water infiltrating through the foundation wall, footing and the joint between floor slab and footing) and sewer backup (when the sanitary sewer system overwhelms and back-up as a result of water entering the pipes through cracks and loose joints). In Canada, homeowners are usually covered for any loss due to sewer backup, but most insurance companies do not provide coverage for the damage caused by overland or infiltration flooding. Moreover, the coverage for sewage backup flooding can also be limited or even discontinued if there are repeated claims from the same household. Urban flooding events pose a significant risk to the homeowners, municipalities and insurers and there is a growing need for the homeowners to implement flood protection measures to protect their homes against basement flooding.
Increased knowledge of the flood protection measures will be beneficial for the government and the insurance companies, who spend millions of dollars to repair the damage caused by flooding. It will also be valuable for the homeowners who live in flood-prone areas and might help to prevent property damage through the implementation of lot-level flood mitigation measures.