The City of Ottawa is set to upgrade a sewer chamber in its wastewater system located at a key Centretown juncture.
The new technology aims to prevent the kind of storm-related sewer spills in the Ottawa River that caused one of the city’s biggest controversies in the past few years.
“We are being proactive about sewage spills,” says Coun. Bob Monette. “Many of our regulators are dated and need to be replaced, so they are continually being phased out.”
The planned infrastructure at Booth and Old Wellington streets, near LeBreton Flats, will remove the hydraulic-based regulators from the 1960s, and install a real-time control system that uses electrical gates and allows the city to control the sewage flow, says Alain Gonthier, the city’s infrastructure manager.
“In the past, we could have an overflow event and the pipes would not be full,” says project engineer Randy Dempsey. “That was a waste of space.”
Real-time control means the city will be able to respond instantaneously, says Ronald Droste, a civil engineering professor at the University of Ottawa. It works like one’s ability to control the flow of water from the kitchen tap, he explains. In this case, the city is not motivated out of thirst or dirty dishes, but by the need to react to changing sewage levels.
The city will be able to monitor the flow and maximize the capacity in the pipes.
As of March 19, more than 37,000 cubic metres of combined sewage has spilled into the Ottawa River since the beginning of the month, says Dixon Weir, the city’s director of water and wastewater services.
“It’s not something we can control. The ministry has mandated that we have to control between April and November,” says Dempsey. “But that doesn’t mean we’re not optimizing outside of those times. Even after we’re operational, the system still runs 365 days a year.”
With an average amount of rain, the City of Ottawa discharges about 400,000 cubic metres each year between April 15 and Nov. 15 (the Ministry of Environment’s mandated control period). The new system will reduce this output by 65 per cent, says Weir.
The Booth-Wellington chamber sees 22 to 25 overflow events in the average control period. The upgrade is predicted to reduce it to eight, says Dempsey.
Spills will happen, Weir explains, because once the pipes are full, the system will discharge to the river to prevent floods in neighbourhoods.
The city is currently making upgrades to other sites in downtown Ottawa, New Edinburgh, and Lowertown. Together, these sites are responsible for 95 per cent of the city's sewage overflow.
There are also other areas that pose threats, says Weir.
“If the focus is protecting the environment, and Ottawa River quality, then it may be more environmentally sound to focus the next set of funds toward addressing storm sewer outlets,” says Weir.
A report will be presented in June to Ottawa’s planning and environment committee that will help the city determine a long- term strategy.
Construction is set to begin mid-May and could last until the end of this year. For safety reasons, a concrete barrier will separate the excavation site from traffic, but drivers on Booth Street will see the same number of lanes. Buses will not be able to park on Old Wellington Street, but the city is working on alternatives east of the Transitway.
It will take several months to install the electronics so the system may not be operational until next spring, says Dempsey.
The public has until April 14 to send in written concerns.