Ottawa’s Overflow Woes
Ottawa beaches were closed again in last summer’s best swimming weather, as they were the year before, because E.coli levels in the water were too high to allow residents to safely go swimming. By late summer 2009, hundreds of millions of litres – about 320 Olympic-sized swimming pools worth – of untreated sewage and stormwater had overflowed into the Ottawa River as a result of both heavy rainfall and periodic system malfunctions. Although raw sewage was only a small proportion of Ottawa’s outflow to the river, combined with an undetermined overflow quantity from Gatineau, it led to the beach closures, as well as other problems for residents and aquatic ecosystems.
While the image of raw sewage flowing into the river is shocking, Ottawa’s situation is surprisingly common among Ontario municipalities – and indeed, cities around Canada and the world. In older cities in Ontario, sewer systems were designed before sewage was collected and treated. Also, sewer systems in many of Ontario’s cities are combined, with stormwater and sewage flowing into the same pipes. During times of heavy rainfall, when volume exceeds the maximum capacity at sewage treatment plants and holding tanks, sewers overflow into neighboring water bodies, in this case the Ottawa River.
As population increases and urban areas intensify around the province, additional pressures are put on sewer systems. Climate change adaptation is also of growing concern in municipal infrastructure upgrades. Stormwater systems are designed to handle heavy rainfall, but in recent years, rainfall events in Ottawa have increased in frequency and quantity – surpassing the amount water the system was built to withstand. It is anticipated that with climate change, such extreme events in Ontario’s rainfall will continue and could intensify.
While sewer systems are a crucial part of a functioning city, sewer infrastructure upgrades are often expensive and disruptive, and improvements are unseen, making them unsavory to city councils and residents alike. In Ottawa’s case, however, frustrations over the beach closures, flooding, sewage backup, and untreated sewage flowing by the Prime Minister’s residence caught media and public attention, and put pressure on local politicians to take action. The ECO was invited by the Member of Provincial Parliament for Ottawa West -- Nepean to review Ottawa’s sewage problems in summer 2009. Even by this time, many improvements had been made to reduce overflows to the river. It is hoped that Ottawa’s new plan for dealing with its sewer and stormwater problems, approved in February 2010, will eliminate the untreated sewage flowing to the Ottawa River under ‘normal’ rainfall years. City beaches should be swimmable again.
Ottawa will be an Ontario leader in controlling overflows into its water, but new infrastructure comes at a cost. Ottawa’s plan will require hundreds of millions of dollars, which may lead to increases in water costs for residents. Many other municipalities in Ontario will need to make similar tough decisions on upgrading their wastewater infrastructure - and how they will pay for it.
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| This is an article from the 2009/10 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article:
Environmental Commissioner of Ontario. 2010. "Ottawa's Overflow Woes." Redefining Conservation, ECO Annual Report, 2009/10. Toronto, ON : Environmental Commissioner of Ontario. 81-87.
