Calgary storm sewers not designed for non-stop torrential rain

It's shaping up to be a soggy July in Calgary, andthat's putting pressure on the city's storm sewers.

• Calgary area hit by torrential rain, flooding
• Calgary flooding cleanup continues in some communities

Chris Huston with the City of Calgary's water services says these torrential downpours are becoming "more and more common."

Problem is, Calgary's storm sewer system wasn't built to handle "one in one hundred year" weather events.

"What that means is each year, we have a one per cent chance of getting them. Butin several communities we've already had those one in one hundred year events," said Huston.

"So when we get that much rain, our system just can't take it off the street fast enough."

City crews 'limited' by design

There are always going to be some streets that get flooded during severe weather events, said Huston.

Especially in newer communities, where roads are actually designed with low points for the water to pond.

"It's a little bit of storage spread out throughout community that allows that storm system to handle the storms," he said.

Huston said when it pours, city crews are out in full force clearing hail, leaves and branches from catch basins.

"Our crews can clear debris, but the volume of water is really limited by the storm system design."

If there's an emergency flooding situation, the city can bring out a truck to pump away water, said Huston, but said they don't have the resources to respond to "hundreds" of those kinds of situations at once.

Wet July

Asof July 18Calgary had recorded 118.9mm of rain. The average is 65 mm.

"Closing in on double the normal rainfall for the month, with almost half ofthe month still remaining," said Dan Kulak, a meteorologist with Environment Canada in Edmonton.

With files from the Calgary Eyeopener