Though I am a relative newcomer to Alberta, I’m no stranger to floods. Having grown up in the Portland area, there have been significant flood events I’ve lived through. Recalling the 1996 flood of the Willamette and Columbia Rivers, I remember visiting the sandbagged banks lining along the riverfront and watching everyone pitch in to help keep the downtown core from flooding, as it has in the city’s history. Now that I’m living in Edmonton, I haven’t too much to worry about when it comes to flooding of the North Saskatchewan. However, Edmonton is not the only river city in the province. Nestled near the foot of the Rocky Mountains, residents of High River in Southern Alberta have seen their fair share of floods, much more catastrophic than what I’ve experienced.
High River gets its name from the Highwood River (and not named after an event as I originally thought). Unusually heavy rains during June of 2013 caused the, Bow, Little Bow, Elbow, Highwood, Red Deer, Sheep, and South Saskatchewan Rivers to inundate the cities and communities along their banks. Remaining snowpack from the Rockies further saturated the rivers and tributaries affected. Situated in the floodplain at the confluence of the Highwood River and the Little Bow River, the entire town of 13,000 residents was evacuated and left uninhabited for nearly one week. One neighbourhood – Beechwood Estates – was completely washed away, and following the aftermath any remaining homes were purchased by the province and demolished to restore the natural state of the floodplain.
In total, the estimated damage caused by such severe flooding amounted to over $5 billion. Over thirty states of emergency were declared in the areas of Calgary, Lethbridge, and Medicine Hat. Once flood waters receded and residents returned to their homes, residents of High River were advised not to return until another week later due to the presence of E. Coli in the standing water. Though Southern Alberta recovered from the 2013 floods, survivors of the year’s floods in High River has left an indelible mark on both the town and its residents.
Here on the floodplain map, I first generated a river channel network based on elevation point data provided by the Government of Alberta. The point files were interpolated into a complete raster with 10m resolution. The channel network was then used to calculate the difference between the channel network base and the vertical elevation of each point. The new raster generated by this process now shows the vertical difference between the elevation and the base height of the channel network, which I then clipped out 1m, 2m, and 3m heights. You can see that even 1 meter above the channel base can spread out over a good swath of High River’s area. At 3m difference, over half of the town has the potential to be inundated by flood waters.
While flood events have the potential to be catastrophic, the ways in which people adapt and live in flood-prone areas show how communities can band together and help one another. The use of social media throughout the flood event showed how much support came from both volunteers and officials, both local and provincial, to help out those displaced by the floods.