Ottawa Riverkeeper Meredith Brown, shown on the river’s shore near the Rideau Canal headlocks, said untreated water adds pathogens and viruses to the river that pose a public health risk. Brea Elford, Centretown NewsThe City of Ottawa is set to begin construction on a major project to help preserve the Ottawa River: an enhanced system of giant pipes and tanks designed to prevent raw sewage from reaching the waterway.
A series of combined sewage storage tunnels (CSST) is slated to be installed under the streets of the downtown core to replace the existing sewers, which were designed to overflow into the river in heavy rains to prevent flooding of streets and buildings.
But contaminated water during such storms has ended up in the Ottawa River, degrading water quality and posing a threat to all types of wildlife.
“When storms hit, significant quantities of untreated sewage rush into the Ottawa River, as the capacity of the city’s treatment plant is overwhelmed,” said Coun. David Chernushenko, environment committee chair. “For a decade or more, the city has been working towards a solution, and the CSST is a key component.”
The project, costing more than $230 million, consists of six kilometres of pipe spanning from LeBreton Flats to New Edinburgh Park, and the Ottawa River Pathway to Kent and Chamberlain.
The pipes, along with storage chambers, will hold enough water to fill nearly 18 Olympic-sized swimming pools. The water will then be transported to a treatment plant before being released into the river, which will help reduce the contamination levels.
“When untreated water is poured into our river it depletes the dissolved oxygen that is critical for fish and other aquatic species,” said Meredith Brown, head of the Ottawa Riverkeeper group. “It adds pathogens and viruses into our river, making it a public health risk for swimming, paddling and playing in the water.”
The province has set targets for acceptable levels of combined sewer overflow for waterways that determine whether the water is safe for swimmers. On average, the city has about 30 overflows per year, which the CSST project would reduce.
“I’d like to see the city reach zero water overflows,” said Graham Saul, executive director of Ecology Ottawa. “It’s an embarrassment that this is still an issue.”
The city has made cleaning up the river a top priority, explained Coun. Chernushenko, and thanks to the funding the city has received from all three levels of government, there is no longer a reason to delay.
The tunnels themselves are about three metres in diameter, and will be installed between 10 and 31 metres below the streets of downtown Ottawa. In a report presented to the city in 2013, it was predicted that “some localized disruptions, both temporary and permanent” should be expected during construction. The installation is due to be finished in 2019.
Brown pointed out there are things Ottawa residents can do in the mean time to help prevent further pollution.
“A good way to start is to remember that the drains in your house are ultimately connected to the river,” she said. “Be mindful of the products you use in your home — our water and wastewater treatment plants are not designed to remove these chemicals, so be mindful of all who live downstream.”
CSST construction has begun at Confederation Park, New Edinburgh Park, and around the intersection of Kent and Chamberlain streets. The locations slated for the next round of construction have not yet been announced.