Some homeowners in the Sunningdale area have dealt with frequent sewer backups since 2014, a problem city administration thinks could be due to issues with ground elevation.
Coun. Chris Warren asked city administration during the Aug. 10 regular council meeting about reports of sewer backups and overland flooding of residential properties, particularly on Calypso Drive and Wood Lily Drive, after rainstorms in early August. He requested an update on what city administration was doing to resolve the issues.
Report on the problem
During the Aug. 24 regular meeting, city administration provided a written report saying 2.5 inches of rain fell in less than an hour during the rainstorm. The department of public works and utilities inspected the Calypso Drive and Flax Road sanitary sewer systems via CCTV and found no significant defects within the sewer mains. It also checked raised manholes in the north end to ensure they were still adequately sealed from surface water penetration.
“They were all found to be in adequate, functioning condition,” the report said.
Backflow preventers are required to prevent sanitary line backups, as per Bylaw No. 5152, continued the report. The department noted it was unknown how many instances there were of overland drainage flooding or sanitary sewer backups.
The department also reviewed a report from 2014 to determine if there was any additional information that could clarify this problem.
That document indicated overland drainage issues were seen on the 400-block of Wood Lily Drive, the council report said. Ground elevation of a neighbouring property — built before 2016 — might have been an aggravating factor. Meanwhile, city hall recommended elevations on developed lots only before 2016, at which point elevations became mandatory under the building bylaw.
“A review of this area is a priority, and time will be set aside in the early fall to continue assessing the area and develop a program to return the overland drainage courses to their original designed flows,” the report added.
Council discussion
Warren thought it was good news that city hall was investigating this issue and that there wasn’t a problem with the sanitary sewer system. He thought city administration should provide information to help these residents understand the situation, even if nothing is wrong with the sewer system.
“There has to be something going on in the system to allow these backups to happen,” he added.
City administration reviewed the reports from 2014 and is looking at what happened during this rainstorm, while it is also looking at possible remediation efforts, explained city manager Jim Puffalt. While administrators will bring forward more information soon, they can’t say anything now since some of those homeowners are suing the city over this problem.
The overland flooding problem on Wood Lily Drive is a separate issue from what happened in 2014, said Coun. Brian Swanson. Meanwhile, he wondered if the elevation grading of subdivisions could be altered now if they were constructed before 2016, since it seems city hall’s position is that it’s not their responsibility for something constructed before that year.
Before 2016, the elevation of buildings was included in the construction permits and there was no recommendation at that time, which means they are not as enforceable, explained Michelle Sanson, director of planning and development. However, the requirement to not flood out the neighbours was always there.
There is a drainage ditch near one of the affected properties that runs from Wood Lily Drive to Iris Drive and it appears to have been altered, said Swanson. He thought the last 20 to 30 feet of that ditch had been changed and had affected the elevation.
“There are some neighbours who are afraid to leave their homes any time there’s a rainfall,” he added. “It shouldn’t happen.”
The public works department has investigated that area and found some overland drainage issues could be addressed quickly, said Bevan Harlton, director of engineering. However, he was unsure if the ditch was on city property or private property, which could make a difference.
The next regular council meeting is Monday, Sept. 14.
