City outlines challenges battling flash flooding
Posted Aug 10, 2016 9:04 am.
This article is more than 5 years old.
Calgary has already seen more rain in the first week of August than it normally gets in the whole month, and it’s the speed with which the rain has been falling during recent storms which has led to flash floods.
The city knows it’s a problem, but it’s a long, slow process to try and fix.
Part of the issue is design standards, which used to be different.
Francois Bouchart, manager of infrastructure planning and water resources, says new neighbourhoods take overland flow into consideration, explaining streets are supposed to carry water away.
“The older communities do have a lack of overland drainage escape routes, and therefore that’s where you see more prominent surface flooding that occurs,” he said. “In other words, once the pipes are full and you start getting local ponding in the community, there isn’t a strategic design that’s embedded within the community to convey that water away.”
Bouchart explains the solution isn’t to just dump water into the rivers faster, because there are provincially regulated water quality and flow targets that need to be met.
“We can’t just discharge massive amounts of water that will either degrade the water quality of those receiving water or will create excessive erosion,” he said.
He says dry and wet ponds throughout the city help mitigate the environmental impact.
The city has been trying to identify problem areas since 1994 and figure out what upgrades they need to meet modern standards.
Bouchart says there are $240-million worth of planned upgrades or upgrades that are currently underway, with $40-million going into Braeside, Woodlands and Woodbine in the next five or six years.
“Recently we did some upgrades in the community of Rosemont, and a few years ago we did a lot of work around Lakeview,” he said.
