Safeguarding the Ottawa River through Innovative Sewage Solutions

The city of Ottawa is making significant strides towards preserving one of its most precious resources– the Ottawa River. This river is an important landmark, having been a key route for the fur and timber trade in the 19th century and currently housing a diverse ecosystem of flora and fauna. The Combined Sewage Storage Tunnel Project reduces overflows into the river, as well as mitigates the risk of basement flooding in vulnerable areas.

The project involves the construction of two interconnected storage tunnels that play a crucial role in intercepting surface runoff and wastewater, referred to as combined sewage. The waste is temporarily stored, undergoes treatment at the Robert O. Pickard Environmental Centre, and is ultimately safely returned to the Ottawa River.

In addition to the tunnels, new diversion chambers and sewers have been constructed. These elements work in tandem to intercept and channel excess sewage towards the proposed tunnels. The implementation of three new odour control facilities, along with a flushing gate and flow by-pass chamber, further enhances the system's efficiency and environmental impact.

With an investment of over $230 million in infrastructure, the city is fortifying itself against the impacts of climate change while protecting Canada's vital waterways, ensuring a cleaner, safer future for its residents and the Ottawa River.

Quick facts

• Infrastructure Canada’s Investing in Canada Plan Green Stream has contributed to an increase in total wastewater treatment capacity of around 2.5 million cubic meters per day. 
• The volume of combined sewage overflow decreased by 39% from 2018 to 2020 (Source: Statistics Canada)