The best way to make a building safe from a river or coastal flood is to locate it outside of a flood hazard area.
Be aware in doing your research that a property may be vulnerable to flooding from more than one source, such as a nearby creek, a river or the ocean. Contact the local municipality for information on flood hazards and maps.
In general, a flood that is more likely to occur in a given year (for example, a flood with a 10% Annual Exceedance Probability (AEP) or a 10% chance of happening in any given year) would flood a relatively small area. A rarer but more major flood, like a 0.2% AEP flood, would affect a much larger area with deeper floodwaters.
Some BC municipalities have land use policies or bylaws that restrict or guide development or redevelopment in a flood hazard area for a given flood event (e.g., a 0.5% AEP flood). Mapping of the area usually accompanies such regulations (e.g., zoning, development permit area, designated floodplain or flood hazard area). Contact your local municipal planning department to learn about the restrictions and requirements and to find out what maps are available and how to access them. See also Flood Maps for more information about reading and accessing flood maps.
If there are no municipal designations or restrictions, and you are considering building a new home or moving to a new property, it is up to you as a prospective owner or tenant to get the most up-to-date flood information. You want to identify flood-prone areas, find out which flood events they correspond to, and decide whether locating within that area is worth the risk and what things can be done to reduce that risk. In cases where there is no flood hazard information available, it would be wise to hire a qualified professional to conduct a flood assessment.
If your only choice is to locate your home or business in a flood hazard area, consider choosing a location:
- Away from the watercourse or shoreline because that is where flood depths and velocities would be most severe
- In an area of higher elevation
- In an area that will allow for safe access to and from the site in case of a flood
- Where new construction will not create new hazards or increase flooding on adjacent or other properties (for example by changing drainage patterns).
For buildings and structures in a flood hazard area, floodproofing measures can help reduce the amount of damage caused by a flood.