Ottawa Faces Sewage Overflow into Ottawa River Due to Heavy Rainfall

Last week, Ottawa experienced heavy rainfall, resulting in the overflow of a $232 million sewage tunnel and the discharge of approximately 316 million litres of untreated sewage into the Ottawa River. This incident, although not unusual, has raised concerns about the city’s ability to handle future extreme weather events. Dianne Saxe, a former environmental commissioner, emphasizes the need for better management of this issue, especially considering the predicted increase in severe storms.

However, an environmental engineer suggests that addressing these challenges by rebuilding infrastructure would require significant funding amounting to billions of dollars and several decades. Despite this, the City of Ottawa has made efforts to upgrade its infrastructure through the Combined Sewer Storage Tunnel, which was launched in 2020. This initiative aimed to reduce the amount of sewage flowing into the river and has substantially mitigated the problem. Nevertheless, the recent overflow was the largest since the tunnel’s establishment.

The combined sewage storage tunnel has provided the city with greater wastewater capacity, addressing the historical issues faced by older Ottawa neighborhoods with outdated combined sewer systems. The problem has been exacerbated by population growth and the impact of climate change, which is expected to result in more frequent intense rainfall events.

Dianne Saxe, currently a city councillor in Toronto, describes the consequences of the sewage overflow as “disgusting,” highlighting the contamination of the river, beaches, fish, and sediment. Moreover, she emphasizes the potential spread of diseases due to exposure to this harmful sewage.

Experts acknowledge the complexity of the problem and the challenges associated with building infrastructure that is resilient to overwhelming stormwater. However, they propose alternative solutions such as implementing green roofs, which absorb rainwater, and using waterproof membranes to prevent leaky pipes from adding unnecessary water to the sanitation system. Saxe suggests the implementation of a stormwater area charge, wherein landowners would pay a fee based on the amount of impermeable surfaces on their properties, such as parking lots.

Although it may require significant investment and effort, Saxe argues that there are ways to address the issue, blaming the existing challenges on past decisions motivated by financial constraints.