The City of Airdrie’s storm system has been specially engineered to handle most severe weather events according to Lorne Stevens, director of Community Infrastructure, after a thunderstorm dumped heavy rain in the area on Aug. 14 and caused heavy flooding in the Reunion neighbourhood.
“We use what are called ‘trap lows’ on the streets,” explained Stevens. “You’ll see those in many intersection areas where there are catch basins. You’ll see the water pool and that’s so it can be released gradually into the storm system.”
Stevens said what the City is trying to avoid is the release of a “massive surge” of storm water into downstream water bodies, like Nose Creek.
The trap lows are designed to hold water until it can be safely released, thereby minimizing property damage.
Most residents would not even notice a trap low on their street, according to Stevens, since they are built simply by creating a lower section of road.
“By virtue of gravity, water would migrate to these particular points on city streets and get released into catch basins in those same areas,” explained Stevens.
For areas under construction, the city’s Public Works Department also installs orange baffles - long sandbags - to help keep silt out of the storm system.
Stevens said neighbourhoods built in the last 25 years in Airdrie are designed to have a number of trap lows, typically in intersections.
In a severe flooding situation such as the one southern Alberta experienced in June 2013, the trap lows would be overwhelmed and overland flooding could occur.
Leaves and debris being clogged in the drains can cause the storm system to back up. During the massive hail storm that hit Airdrie on Aug. 7 where golf-ball-size hail, numerous shrubs and trees were shredded and blocked sewer grates.
Airdrie Parks Department Team Leader Archie Lang said his team worked into the early hours of Aug. 8 to clear the catch basins of debris and get the storm system working properly again.
“That night I was out with crews, unplugging catch basins until about 3 a.m. to make sure the water was running,” he said.
“All it was, was debris on top of the catch basins so as soon as you pulled the debris off, it started draining properly again.”
According to Lang, a total of 20 public works staff were out on Aug. 7 to clear the catch basins.
Lang said city parks came through the Aug. 7 hailstorm in “pretty good shape.”
“They’ve done really well. Sure, there’s a few dents and bruises on them but (Nose Creek Park) was in great shape after the hailstorm on Aug. 7 for the (Airdrie Show and Shine) on Aug. 9.,” he said.
“The park fared very well.”
“You clean up where the high water was, because it will have left some debris behind,” he added. “You try to tidy up there as best you can.
According to Stevens, there are 2,210 catch basins in Airdrie, according to Stevens, along with 198 kilometres of storm line, 34 storm water ponds, and 2,891 manholes. The largest storm water ponds are located in Nose Creek Park and East Lake Park.
Stevens said there are things homeowners can do to ensure they have the best chance of keeping their property from flooding.
“If the concern is ‘how to I protect against property damage’, I would emphasise that homeowners have a responsibility to maintain their downspouts (and ensure) they have good grading away from their foundations,” said Stevens.
A resident who is concerned by on street flooding after a heavy rainfall or hailstorm, can call Public Works and Stevens said crews will come investigate. For more information, visit the City of Airdrie’s website at airdrie.ca The City of Airdrie’s storm system has been specially engineered to handle most severe weather events according to Lorne Stevens, director of Community Infrastructure.
“We use what are called ‘trap lows’ on the streets,” explained Stevens. “You’ll see those in many intersection areas where there are catch basins. You’ll see the water pool and that’s so it can be released gradually into the storm system.”
Stevens said what the city is trying to avoid is the release of a massive surge of storm water into downstream water bodies, like Nose Creek. The trap lows are designed to hold water until it can be safely released, thereby minimizing property damage.
Most residents would not even notice a trap low on their street, according to Stevens, since they are built simply by creating a lower section of road.
“By virtue of gravity, water would migrate to these particular points on city streets and get released into catch basins in those same areas,” explained Stevens. “
In areas under construction, the Ccity Ppublic Wworks Ddepartment also installs orange baffles that look a bit like long sandbags to help keep silt out of the storm system.
Stevens said neighbourhoods in Airdrie are designed to have a number of trap lows, typically in intersections. Trap lows have been a standard feature of development in Airdrie for more than 25 years, according to Stevens.
They do have a limit, however, said Stevens. In a severe flooding situation such as the one southern Alberta experienced in June 2013, the trap lows would be overwhelmed and overland flooding could occur.
Leaves and debris can cause the storm system to back up. During the massive hail storm that hit Airdrie on Aug.7 with golf- ball- size hail, many shrubs and trees were shredded, the rain carried them away and they blocked sewer grates.
Airdrie Parks Department Team Leader Archie Lang said his team sprung into action, working into the early hours of Aug. 8 to clear the catch basins of debris and get the storm system working properly again.
“That night I was out with crews as well, unplugging catch basins until about 3 a.m. to make sure the water was running,” he said. “All it was was debris on top of the catch basins so as soon as you pulled the debris off, it started draining properly again.”
According to Lang, a total of 20 people were out on Aug. 7 to clear the catch basins.
Lang said city parks came through the Aug. 7 hailstorm in pretty good shape.
“They’ve done really well. Sure, there’s a few dents and bruises on them but (Nose Creek Park) was in great shape after the hailstorm on Aug. 7 for the (Airdrie Show and Shine) on Aug. 9.,” he said. “The park fared very well.”
“You clean up where the high water was, because it will have left some debris behind,” he added. “You try to tidy up there as best you can.
Designing a storm system that could handle a once in 100 years storm event like the one that hit southern Alberta in June of 2013 would be extremely expensive, said Stevens.
“It would be prohibitively expensive to create underground storm lines that could handle a major weather event (like one inch of rain in three minutes),” he said. “On- street- ponding is part of the overall design of (Airdrie’s) storm water system. Those trap low areas are meant to complement the pipe system and the storm water ponds in the city.”
There are 2,210 catch basins in Airdrie, according to Stevens, along with 198 kilometres of storm line, 34 storm water ponds, and 2,891 manholes. The largest storm water ponds are located in Nose Creek Park and East Lake Park.
Stevens says there are things homeowners can do to ensure they have the best chance of keeping their property from flooding.
“If the concerns is ‘how to I protect against property damage’, I would want to emphasise that homeowners have a responsibility to maintain their downspouts (and ensure) they have good grading away from their foundations,” said Stevens.
A resident who is concerned by on street flooding after a heavy rainfall or hailstorm, can call public works and Stevens said crews will come investigate.
For more information, visit the City of Airdrie’s website at airdrie.ca
