Knowing where, and how deep water will be during a flood are essential pieces of the flood management puzzle. Some of our previous blogposts have talked about our GIS database of floodplain maps in BC. Equally as important is knowing how many people people currently live on these floodplains and are at risk from flooding. As part of our ongoing thought project on floodmaps in BC, we set out to learn just that – how many people live on river floodplains across BC?
To do this, we gathered our previously compiled floodplain maps from across the province. One glaring hole in the coverage of these maps is in the most densely populated region in the province, the Fraser River floodplain. It may be a shock for some to learn that no comprehensive floodplain map of the Lower Fraser exists – rough flood extents yes, but flood depths, contours, and return periods, no. For our purposes, flood extent was suffficient, so we digitized an overview map of the approximate floodplain from the Fraser Basin Council. It should be noted that this is for illustrative purposes only.
Once we compiled our maps, we georeferenced 2011 Statistics Canada census data to see where populations overlapped with floodplains. The resulting map seen below shows where the greatest number of people live on floodplains across the province.
Not surprisingly, the greatest population on floodplains occurs in southwestern BC around the Fraser River. Richmond is particularly vulnerable, as are Delta, Coquitlam and Chilliwack. We calculated that 315,000 people live on the Lower Fraser River floodplain alone. Province wide, 424,000 people live on floodplains – that’s roughly 10% of the total population. Other areas of interest include the population centers of Duncan, Nanaimo, Kamloops, Squamish, Osoyoos, Prince George, and Terrace.
You can use this map to explore the province’s at risk regions and see if you live within one. Clicking on the floodplain will reveal the number of people who live on it.
The Ebbwater BC Flood Map Project
We’ve just started our gap analysis and thought project on flood maps in BC and have a whole host of other analyses that we want to complete. We’d love to hear from you if you have a good idea on how to use or present the data, we’d also love to hear from you if you know of or have a map that’s not in our database – we’ve started our project using the Province of BC dataset, but know there are other maps (newer and better ones!) out there and would like to include them. You can contact us by email: BCFloodMapProject@ebbwater.ca or feel free to call or drop by our office.