By Richard Leitner, News Staff
Putting in a bigger sewer pipe by the Old Dundas Road sewage pumping station is being touted as the best immediate fix for occasional basement flooding of homes in the area during major rainstorms.
In the long term, though, the city will seek regulatory approvals to build an emergency overflow pipe to send stormwater into Ancaster Creek when the pumping station is overwhelmed.
City staff presented the solutions to periodic flooding in Ancaster Heights and the Old Mill neighbourhood at a public open house at the Ancaster Public Library.
Senior project manager Chris Gainham said the city will first proceed with replacing a 200-metre section of pipe by the pumping station, along with rehabilitating any leaky sanitary pipes and reducing flows into manholes.
The new pipe will be 1,650mm in diameter, or nearly four times the existing one, and store up to 400 cubic metres of excess flows, giving the pumping station the ability to handle a 100-year storm. It’s expected to be in place by 2016 and cost about $500,000.
Gainham said the city will also seek approval for the emergency overflow pipe into Ancaster Creek, but the initiative will take several years because it must undergo a more rigorous environmental assessment given the potential impact on aquatic life.
It will likely also require approval from the Ministry of the Environment, Hamilton Conservation Authority and Niagara Escarpment Commission.
“It is the fail-safe measure in the system if storage does fill up and if the rehab works are not as successful as we hope,” Gainham said. “You never say never when it comes to flooding, so we will still be pursuing that.”
Gainham said the city will also encourage homeowners in the area to disconnect any downspouts and driveway catch basins from the storm sewer, but smoke testing has determined they aren’t a major contributor to excess flows.
“It looks like it’s mostly groundwater coming into the sanitary system, which can actually get in quite fast,” he said.
A study of solutions rejected expanding the pumping station capacity because it was the most expensive option and flooding could occur because of inadequate sewer capacity.