Engineer explains changes to Bow and Elbow after 2013 flood
Posted Jun 16, 2016 8:31 am.
This article is more than 5 years old.
It’s a summer no one will forget — the three year anniversary of the Calgary flood is just days away.
A lot has happened since 2013 and the city and the province continue to work on flood mitigation plans. The Elbow and Bow Rivers underwent some massive transformations as well.
Rivers are always changing, making their own shape as they twist and turn, but those changes are usually subtle, and rivers tend to stay the same width.
However, Frank Frigo, leader of the River Engineer Team with the City of Calgary, explains a significant event like the flood can knock things out of whack and about 20 per cent of the bank lines on the Bow and the Elbow were altered to a degree that key infrastructure was put at risk.
“So in general the Bow River is about 100 metres wide, and the Elbow River is about 30 metres wide,” he explained. “Along the Bow River, we had places where up to 60 or 70 metres of additional width of river formed by erosion.”
The impact to the banks of the Elbow was much less. Most changes were no more than 10 meters, but that was downstream of the Glenmore Reservoir and upstream did see more significant changes.
Engineers didn’t try and redraw the banks. Instead, Frigo says they very selectively put fill where there was infrastructure like bridges, pipelines and electrical stations.
He adds flooding is a natural process so it’s important rivers stay environmentally sound and have the space and capacity they need to flow.
